Antifungal Activity of New Eugenol-Benzoxazole Hybrids ...

Research ArticleAntifungal Activity of New Eugenol-BenzoxazoleHybrids against Candida spp

Larissa Incerti Santos de Carvalho1 Dalila Junqueira Alvarenga1

Letiacutecia Cruz Ferreira do Carmo1 Lucas Gomes de Oliveira1 Naiara Chaves Silva2

Amanda Lateacutercia Tranches Dias2 Luiz Felipe Leomil Coelho2

Thiago Belarmino de Souza3 Danielle Ferreira Dias3 and Diogo Teixeira Carvalho1

1Department of Foods and Drugs Faculty of Pharmaceutical Sciences Federal University of Alfenas37130-001 Alfenas MG Brazil2Department of Microbiology and Immunology Institute of Biomedical Sciences Federal University of Alfenas37130-001 Alfenas MG Brazil3Institute of Chemistry Federal University of Alfenas 37130-001 Alfenas MG Brazil

Correspondence should be addressed to Diogo Teixeira Carvalho diogotcarvgmailcom

Received 8 March 2017 Accepted 8 June 2017 Published 24 July 2017

Academic Editor PonnurengamMalliappan Sivakumar

Copyright copy 2017 Larissa Incerti Santos de Carvalho et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Eugenol is a natural allylphenol responsible for a wide range of biological activities especially antimicrobial Benzoxazoles areheterocycles with recognized antimicrobial activities This paper describes the design synthesis and the biological results forbenzoxazole type derivatives of eugenol as antifungal agents The products were obtained in good yields by a four-step syntheticsequence involving aromatic nitration nitroreduction amide formation and cycle condensation They were evaluated againstspecies of Candida spp in microdilution assays and four products (5a 5b1015840 5c and 5d1015840) were about five times more active thaneugenol against C albicans and C glabrata Two of them (5b1015840 and 5d1015840) showed good activity against C krusei a species which isnaturally resistant to fluconazole Furthermore the active products were more selective than eugenol against human blood cellsshowing that they are interesting substances for further optimization

1 Introduction

Infectious diseases are among the leading causes of deathsannually mainly in low income countries [1] In this contextopportunistic fungal infections for example candidiasisrepresent a serious medical problem since they may affectimmunocompromised patients Candida spp infections areusually controlled by azoles or amphotericin B-based ther-apies but the increasing fungal resistance findings limit thetherapeutic success and new drugs have been constantlysought [2]

Heterocyclic compounds are widely known for theirdistinct biological activities and many of them constitutepharmacophores in important drug molecules as macrolidesaminoglycosides and 120573-lactam antibiotics azole antifungals

HIV protease and integrase inhibitors and natural anticanceragents [3] Nitrogen-based heterocycles are among the mostfrequently used ring systems in drug discovery [4] Benzoxa-zoles are nitrogen-oxygen containing heterocycles that occurin a number of natural products and are easily obtained bytotal synthesisMany substances containing this cyclicmoietywere described in view of their wide range of biologicalactivities Ertan et al (2004) have synthesized a set ofvery active benzoxazoles against Bacillus subtilis which alsoshowed relevant antimicrobial activities against Escherichiacoli and Candida albicans [5] Potent benzoxazoles showingHIV reverse transcriptase inhibition were reported by Mede-bielle and colleagues and these products presented antifungalactivities against Aspergillus niger and A flavus [6] In 2008Jauhari and colleagues described the cytotoxic activity of

HindawiJournal of ChemistryVolume 2017 Article ID 5207439 8 pageshttpsdoiorg10115520175207439

2 Journal of Chemistry

synthetic benzoxazoles against cervical colon and breastadenocarcinoma cell lines [7] while Arisoy and contributorsdescribed the relevant activities of 25-disubstituted ben-zoxazoles against Candida krusei and gentamicin-resistantisolates of Pseudomonas aeruginosa [8] Kim et al (2010) haveprepared benzoxazole amides which presented good activityagainst Malassezia furfur a pathogenic fungus involved infatal sepsis cases [9] Recently Kuroyanagi and colleaguesshowed the outstanding potential of some 13-benzoxazol-4-carbonitriles against Candida strains [10]

At the same time eugenol (1) a natural allylphenolfound mainly in cloves [Eugenia caryophyllata L Merr ampPerry (Myrtaceae)] shows relevant pharmacological activi-ties especially the antibacterial and antifungal actions [11]Some authors have described the synthesis of eugenol deriva-tives in order to optimize its activities The antimicrobialactions of eugenol seem to be related to cellular membranesinterferences [12ndash14]

Following our interest in obtaining bioactive eugenolderivatives and in face of the potential of benzoxazole deriva-tives as antimicrobial agents we present herein the synthesisand anti-Candida activity of eugenol-benzoxazole basedhybrids Besides eugenol we also employed dihydroeugenolas a starting material in order to evaluate the influence of theallylic chain on antifungal activity

2 Materials and Methods

21 Chemistry Thin-layer chromatography (TLC) on sil-ica gel-G plates (Macherey-Nagel DC-Fertigfolien ALU-GRAM Xtra Sil GUV

254) was used to monitor reac-

tions courses Determination of the Rf values for the finalproducts was done with the same TLC plates employinghexaneethyl acetate (80 20 vv) for all compounds Forcolumn chromatography column grade silica gel (Sorbiline0040ndash0063mmmesh size) was employed Melting points ofthe compounds were obtained on Microquımica MOAs 301melting-point apparatus and are uncorrected IR spectrawere recorded on a Shimadzu FTIR-Affinity-1 spectrometerNMR spectra were recorded on a Bruker AC-300 spectrom-eter (Rheinstetten Germany) (300MHz for 1H-NMR and75MHz for 13C-NMR spectra) in deuterated chloroformChemical shifts (120575) were reported in parts per million (ppm)with reference to tetramethylsilane (TMS) as internal stan-dard and coupling constants (119869) were reported in Hertz (Hz)High-resolution mass (HRMS) spectra were obtained for thefinal products on a quadrupole time-of-flight instrument(micrOTOF-QII Bruker Daltonics Billerica MA USA)equipped with an ESI positive and negative ion source

Synthesis of Nitroderivatives 2 and 21015840 To a solution of eugenol(1 3253mmol) or dihydroeugenol (11015840 3126mmol) indichloromethane (50mL) were added equimolar amounts ofsodium bisulfate and potassium nitrate followed by additionof wet silica gel (1 1 ww 65 g for eugenol reaction and 63 gfor dihydroeugenol reaction) The reaction was kept undervigorous magnetic stirring at room temperature for 48 hoursand monitored by TLC (chloroformmethanol 95 05 vv)

After completion of the reaction the mixture was filteredoff the filtrate was dried over anhydrous sodium sulfate andconcentrated under reduced pressure The nitrocompounds2 and 21015840 were purified by column chromatography (hex-aneethyl acetate 9 1 vv) or by multiple extractions withhexane

4-Allyl-2-methoxy-6-nitrophenol (2) Yellow oil 37 yield IR(120592max in cmminus1) 3520 (O-H) 1600 1550 (C=C) 1515 1440(NO2) 1270 (C-O-C) 1HNMR (120575 CDCl

3 300MHz) 106 (s

1HO-H) 74 (d 1HH5 119869= 18Hz) 69 (d 1HH3 119869= 18Hz)59ndash58 (m 1H CH

2=CH-CH

2) 51ndash50 (m 2H CH

2=CH-

CH2) 39 (s 3H OCH

3) 33 (d 2H CH

2=CH-CH

2 119869 =

66Hz) 13CNMR (120575 CDCl3 75MHz) 1497 (C6) 1447 (C1)

1358 (CH2=CH-CH

2) 1335 (C2) 1311 (C4) 1185 (C5) 1170

(CH2=CH-CH

2) 1149 (C3) 566 (OCH

3) 393 (CH

2=CH-

CH2)

2-Methoxy-6-nitro-4-propylphenol (21015840) Yellow oil 62 yieldIR (120592max in cm

minus1) 3250 (O-H) 1591 (C=C) 1541 1448 (NO2)

1260 (C-O-C) 1HNMR (120575 CDCl3 300MHz) 106 (s 1H O-

H) 74 (d 1H H5 119869 = 18Hz) 69 (d 1H H3 119869 = 18Hz) 39(s 3H OCH

3) 25 (t 2H CH

3-CH2-CH2 119869 = 72Hz) 17ndash15

(m 2H CH3-CH2-CH2) 09 (t 3H CH

3-CH2-CH2 119869 =


1337 (C4) 1335 (C2) 1186 (C5) 1147 (C3) 566 (OCH3)

373 (CH3-CH2-CH2) 241 (CH

3-CH2-CH2) 135 (CH

3-CH2-

CH2)

Synthesis of Amino Derivatives 3 and 31015840The nitrocompounds2 (1187mmol) or 21015840 (1943mmol) were solubilized in ethanol(100mL) and to these solutions was added dihydrate stan-nous chloride (5 eq) The mixture was kept under magneticstirring at 70∘C for 3 hours and the consumption of start-ing material was followed by TLC (chloroformmethanol95 05 vv) The mixture was poured into ice water andaqueous NaHCO3 adjusted the pH to 7Themixture was thenextracted with ethyl acetate (10 times 20mL) the organic layerwas dried with anhydrous sodium sulfate and filtered andthe filtrate was concentrated under reduced pressure whichprovided the pure products

4-Allyl-2-amino-6-methoxyphenol (3) Yellow crystals 61yield mp 95ndash98∘C IR (120592max in cmminus1) 3371 3311 (NH

2)

3074 (O-H) 1606 1456 (C=C) 1512 (N-H) 1230 (C-O-C)1H NMR (120575 CDCl

3 300MHz) 62 (d 1H H5 119869 = 18Hz)

61 (d 1H H3 119869 = 18Hz) 60ndash58 (m 1H CH2=CH-CH

2)

51ndash50 (m 2HCH2=CH-CH

2) 38 (s 3HOCH

3) 32 (d 2H

CH2=CH-CH

2 119869 = 69Hz) 13C NMR (120575 CDCl

3 75MHz)

1466 (C6) 1378 (CH2=CH-CH

2) 1338 (C2) 1316 (C4)

1312 (C1) 1153 (CH2=CH-CH

2) 1094 (C5) 1019 (C3) 559

(OCH3) 400 (CH

2=CH-CH

2)

2-Amino-6-methoxy-4-propylphenol (31015840) Yellow crystals 46yield mp 63ndash66∘C IR (120592max in cmminus1) 3370 3307 (NH

2)

3012 (O-H) 1513 (N-H) 1212 (C-O-C) 1H NMR (120575 CDCl3

300MHz) 62 (d 1H H5 119869 = 18Hz) 61 (d 1H H3 119869 =18Hz) 38 (s 3H OCH

3) 24 (t 2H CH

3-CH2-CH2 119869 =

Journal of Chemistry 3

72Hz) 16ndash15 (m 2H CH3-CH2-CH2) 09 (t 3H CH

3-

CH2-CH2 119869 = 75Hz) 13C NMR (120575 CDCl

3 75MHz) 1464

(C6) 1343 (C2) 1337 (C4) 1308 (C1) 1093 (C5) 1017(C3) 5592 (OCH

3) 3799 (CH

3-CH2-CH2) 2474 (CH

3-

CH2-CH2) 1382 (CH

3-CH2-CH2)

Synthesis of Amides 4andash4d and 4a1015840ndash4d1015840 To a solution of3 or 31015840 (1 eq) in diethyl ether (5mL) was added 5mL ofaqueous NaHCO

3(1 eq) and this mixture was stirred at 0∘C

for 5minThen a solution of the corresponding acyl chloride(1 eq) in 5mL of ethyl ether was added dropwise over30 minutes to the reaction mixture Then the mixture wasstirred at room temperature for 2 hours and the progress ofthe reaction was monitored by TLC (hexaneethyl acetate7 3 vv) The compound 4a was isolated by filtration andthe others were isolated by extraction with dichloromethaneafter evaporation of the diethyl ether When O-acylationbyproducts were detected the crude product was treatedwith NaHCO

3(1 eq) in aqueous methanol for 24 hours

at room temperature After deacylation (checked by TLChexaneethyl acetate 7 3 vv) water was removed withanhydrous sodium sulfate the mixture was filtered and thesolvent was removed under reduced pressure

N-(5-Allyl-2-hydroxy-3-methoxyphenyl)benzamide (4a)Light brown semi-solid 40 yield 1H NMR (120575 CDCl

3

300MHz) 83 (s 1H N-H) 79ndash78 (m 2H H21015840) 77 (d 1HH6 119869 = 18Hz) 75ndash74 (m 3H H31015840 e H41015840) 65 (d 1H H4119869 = 18Hz) 60ndash58 (m 1H CH

2=CH-CH

2-) 51ndash50 (m 2H

CH2=CH-CH

2) 38 (s 3H OCH

3) 33 (d 2H CH

2=CH-

CH2 119869=66Hz) 13CNMR(120575 CDCl

3 75MHz) 1656 (C=O)

1468 (C3) 1375 (CH2=CH-CH

2) 1346 (C11015840) 1336 (C2) 1319

(C5) 1318 (C41015840) 1287 (C31015840) 1271 (C21015840) 1258 (C1) 1157(CH2=CH-CH

2) 1133 (C6) 1072 (C4) 561 (OCH

3) 402

(CH2=CH-CH

2)

N-(5-Allyl-2-hydroxy-3-methoxyphenyl)-4-chlorobenzamide(4b) Pink crystals 64 yield 1H NMR (120575 CDCl

3

300MHz) 83 (s 1H N-H) 78 (d 2H H21015840 119869 = 81Hz)77 (s 1H H6) 74 (d 2H H31015840 119869 = 81Hz) 65 (s 1H H4)60ndash58 (m 1H CH

2=CH-CH

2-) 51ndash50 (m 2H CH

2=CH-

CH2) 38 (s 3H OCH

3) 33 (d 2H CH

2=CH-CH

2 119869 =

66Hz) 13C NMR (120575 CDCl3 75MHz) 1644 (C=O) 1466

(C3) 1381 (C41015840) 1374 (CH2=CH-CH

2) 1335 (C2) 1331

(C11015840) 1320 (C5) 1289 (C21015840) 1285 (C31015840) 1255 (C1) 1158(CH2=CH-CH

2) 1132 (C6) 1073 (C4) 561 (OCH

3) 402

(CH2=CH-CH

2)

N-(5-Allyl-2-hydroxy-3-methoxyphenyl)-4-methoxybenzam-ide (4c) Orange crystals 67 yield 1H NMR (120575 CDCl

3

300MHz) 79ndash78 (m 2H H21015840) 76 (d 1H H6 119869 = 18Hz)70ndash69 (m 2H H31015840) 65 (d 1H H4 119869 = 18Hz) 60ndash58(m 1H CH

2=CH-CH


2=CH-CH

2)

38 (s 3H C3-OCH3) 38 (s 3H C41015840-OCH

3) 33 (d 2H

CH2=CH-CH

2 119869 = 66Hz) 13C NMR (120575 CDCl

3 75MHz)

1651 (C=O) 1625 (C41015840) 1469 (C3) 1375 (CH2=CH-CH

2)

1337 (C2) 1319 (C5) 1290 (C21015840) 1268 (C1) 1259 (C11015840)

1157 (CH2=CH-CH

2) 1139 (C31015840) 1133 (C6) 1071 (C4) 561

(C3-OCH3) 554 (C41015840-OCH

3) 402 (CH

2=CH-CH

2)

N-(5-Allyl-2-hydroxy-3-methoxyphenyl)-4-nitrobenzamide(4d) Yellow crystals 86 yield 1H NMR (120575 CDCl

3

300MHz) 83 (s 1H N-H) 83ndash82 (m 2H H31015840) 81ndash80(m 2H H21015840) 77 (s 1H O-H) 65 (d 1H H6 119869 = 18Hz)60 (d 1H H4 119869 = 18Hz) 60ndash58 (m 1H CH

2=CH-CH

2-)

51ndash50 (m 2H CH2=CH-CH

2) 38 (s 3H OCH

3) 33

(d 2H CH2=CH-CH

2 119869 = 69Hz) 13C NMR (120575 CDCl

3

75MHz) 1632 (C=O) 1496 (C41015840) 1464 (C3) 1403 (C11015840)1373 (CH

2=CH-CH

2) 1334 (C2) 1322 (C5) 1282 (C21015840)

1251 (C1) 1239 (C31015840) 1159 (CH2=CH-CH

2) 1132 (C6)

1076 (C4) 561 (OCH3) 401 (CH

2=CH-CH

2)

N-(2-Hydroxy-3-methoxy-5-propylphenyl)benzamide (4a1015840)Orange oil 39 yield 1HNMR (120575 CDCl

3 300MHz) 83 (s

1H N-H) 79ndash78 (m 2H H21015840) 77 (d 1H H6 119869 = 15Hz)75ndash74 (m 2H H31015840 e H41015840) 65 (d 1H H4 119869 = 18Hz) 61 (s1H O-H) 38 (s 3H OCH

3) 25 (t 2H CH

3-CH2-CH2- 119869

= 75Hz) 17ndash15 (m 2H CH3-CH2-CH2-) 09 (t 3H CH

3-

CH2-CH2- 119869 = 72Hz) 13C NMR (120575 CDCl

3 75MHz) 1655

(C=O) 1465 (C3) 1347 (C2) 1336 (C11015840) 1332 (C5) 1318(C41015840) 1287 (C31015840) 1271 (C21015840) 1256 (C1) 1130 (C6) 1072 (C4)561 (OCH

3) 381 (CH

3-CH2-CH2-) 248 (CH

3-CH2-CH2-)

138 (CH3-CH2-CH2-)

N-(2-Hydroxy-3-methoxy-5-propylphenyl)-4-chlorobenzamide(4b1015840) White crystals 37 yield 1H NMR (120575 CDCl

3

300MHz) 82 (s 1H N-H) 79ndash78 (m 2H H21015840) 77 (d 1HH6 119869 = 18Hz) 75ndash74 (m 2H H31015840) 65 (d 1H H4 119869 =18Hz) 59 (s 1H O-H) 38 (s 3H OCH

3) 25 (t 2H CH

3-

CH2-CH2- 119869 = 75Hz) 17ndash15 (m 2H CH

3-CH2-CH2-) 09

(t 3H CH3-CH2-CH2- 119869 = 72Hz) 13C NMR (120575 CDCl

3

75MHz) 1643 (C=O) 1463 (C3) 1381 (C41015840) 1348 (C2)1332 (C1) 1330 (C5) 1290 (C21015840) 1285 (C31015840) 1254 (C1)1130 (C6) 1072 (C4) 561 (OCH

3) 381 (CH

3-CH2-CH2-)

248 (CH3-CH2-CH2-) 137 (CH

3-CH2-CH2-)

N-(2-Hydroxy-3-methoxy-5-propylphenyl)-4-methoxybenzam-ide (4c1015840) Brown crystals 95 yield 1H NMR (120575 CDCl

3

300MHz) 82 (s 1H N-H) 79ndash78 (m 2H H21015840) 76 (d 1HH6 119869 = 15Hz) 70ndash69 (m 2H H31015840) 65 (d 1H H4 119869 =18Hz) 39 (s 3H C3-OCH

3) 38 (s 3H C41015840-OCH

3) 25

(t 2H CH3-CH2-CH2- 119869 = 75Hz) 16ndash15 (m 2H CH

3-

CH2-CH2-) 09 (t 3H CH

3-CH2-CH2- 119869 = 72Hz) 13C

NMR (120575 CDCl3 75MHz) 1651 (C=O) 1625 (C41015840) 1468

(C3) 1346 (C2) 1334 (C5) 1290 (C21015840) 1269 (C1) 1258(C11015840) 1139 (C31015840) 1131 (C6) 1071 (C4) 561 (C3-OCH

3) 554

(C41015840-OCH3) 381 (CH

3-CH2-CH2-) 247 (CH

3-CH2-CH2-)

137 (CH3-CH2-CH2-)

N-(2-Hydroxy-3-methoxy-5-propylphenyl)-4-nitrobenzamide(4d1015840) Orange crystals 41 yield 1H NMR (120575 CDCl

3

300MHz) 84ndash83 (m 2H H31015840) 81ndash80 (m 2H H21015840) 78 (s1H H6) 65 (d 1H H4 119869 = 18Hz) 58 (s 1H O-H) 39 (s3H OCH

3) 25 (t 2H CH

3-CH2-CH2- 119869 = 72Hz) 17ndash15


(m 2H CH3-CH2-CH2-) 09 (t 3H CH

3-CH2-CH2- 119869 =


(C41015840) 1461 (C3) 1405 (C11015840) 1349 (C2) 1329 (C5) 1282(C21015840) 1249 (C1) 1240 (C31015840) 1129 (C6) 1074 (C4) 561(OCH

3) 381 (CH

3-CH2-CH2-) 248 (CH

3-CH2-CH2-) 137

(CH3-CH2-CH2-)

Synthesis of Benzoxazoles 5andash5d and 5a1015840ndash5d1015840 To a solution ofthe corresponding amides (4andash4d 4a1015840ndash4d1015840 1 eq) in toluene(25mL)was added p-toluenesulfonic acid (3 eq) and themix-ture was stirred under reflux The evolution of the reactionwas monitored by TLC (hexaneethyl acetate 7 3 vv) Afterthe end of reaction toluene was removed under reducedpressure and the crude product obtained was purified by fil-tration over silica gel with dichloromethane (compounds 4a4d 4a1015840 4b1015840 and 4d1015840) or by column chromatography (com-pounds 4b 4c 4c1015840 hexaneethyl acetate 9 1 vv)

5-Allyl-7-methoxy-2-phenylbenzo[d]oxazol (5a) Yellow semi-solid 36 yield Rf 08 IR (120592max in cmminus1) 1626 (C=N) 16031585 1449 (C=C) 1321 1202 (C-N) 1132 (C-O-C) 1H NMR(120575 CDCl

3 300MHz) 82-82 (m 2H H21015840) 75-75 (m 2H

H31015840) 75 (m 1H H41015840) 73ndash715 (m 1H H4) 67 (d 1H H6119869 = 15Hz) 60ndash59 (m 1H CH

2=CH-CH

2) 51ndash50 (m 2H

CH2=CH-CH

2) 40 (s 3H OCH

3) 32 (d 2H CH

2=CH-

CH2 119869 = 66Hz) 13C NMR (120575 CDCl

3 75MHz) 1443 (C2)

1439 (C7) 1375 (C3a) 1373 (CH2=CH-CH

2) 1314 (C41015840)

1288 (C31015840) 1276 (C21015840) 1271 (C5) 1257 (C7a) 1256 (C11015840)1160 (CH

2=CH-CH

2) 1120 (C6) 1088 (C4) 563 (OCH

3)

405 (CH2=CH-CH

2) HRMS-ESImz calcd for C

17H15O2N

(M+H)+ 2661176 found 2661184

5-Allyl-2-(4-chlorophenyl)-7-methoxy-benzo[d]oxazol (5b)Beige crystals 23 yield mp 1038ndash1055∘C Rf 083 IR(120592max in cm

minus1) 1624 (C=N) 1596 1578 1495 (C=C) 1317 1199(C-N) 1131 (C-O-C) 1HNMR (120575 CDCl

3 300MHz) 82ndash81

(m 2H H21015840) 74-74 (m 2H H31015840) 72ndash609 (m 1H H4) 67(d 1H H6 119869 = 12Hz) 60ndash59 (m 1H CH

2=CH-CH

2)


2) 40 (s 3H OCH

3) 34

(d 2H CH2=CH-CH

2 119869 = 66Hz) 13C NMR (120575 CDCl

3

75MHz) 1620 (C2) 1443 (C7) 1438 (C3a) 1385 (C5) 1377(C41015840) 1376 (C7a) 1372 (CH

2=CH-CH

2) 1291 (C31015840) 1288

(C21015840) 1256 (C11015840) 1161 (CH2=CH-CH

2) 1120 (C6) 1089

(C4) 563 (OCH3) 405 (CH

2=CH-CH

2) HRMS-ESI mz

calcd for C17H14O2NCl (M+H)+ 3000785 found 3000794

5-Allyl-7-methoxy-2-(4-methoxyphenyl)benzo[d]oxazol (5c)Yellow crystals 20 yieldmp 813ndash841∘CRf 066 IR (120592maxin cmminus1) 1622 (C=N) 1603 1582 1492 (C=C) 1322 1248 (C-N) 1131 (C-O-C) 1H NMR (120575 CDCl

3 300MHz) 82ndash81

(m 2H H21015840) 72ndash70 (m 1H H4) 70ndash69 (m 2H H31015840)66 (d 1H H6 119869 = 12Hz) 60ndash59 (m 1H CH

2=CH-CH

2)


2) 40 (s 3H C7-OCH

3) 38

(s 3H C4-OCH3) 34 (d 2H CH

2=CH-CH

2 119869 = 66Hz)

13C NMR (120575 CDCl3 75MHz) 1632 (C2) 1622 (C41015840)

1442 (C7) 1440 (C3a) 1374 (CH2=CH-CH

2) 1373 (C5)

1293 (C21015840) 1196 (C11015840) 1159 (CH2=CH-CH

2) 1142 (C31015840)

1117 (C6) 1084 (C4) 563 (C7-OCH3) 554 (C41015840-OCH

3)

405 (CH2=CH-CH


18H17O3N

(M+H)+ 2961281 found 2961291

5-Allyl-7-methoxy-2-(4-nitrophenyl)benzo[d]oxazol (5d) Yel-low crystals 81 yield mp 1612ndash164∘C Rf 076 IR (120592max incmminus1) 1618 (C=N) 1604 1459 (C=C) 1518 1342 (NO

2) 1319

1202 (C-N) 1126 (C-O-C) 1H NMR (120575 CDCl3 300MHz)

84ndash83 (m 4H H21015840 e H31015840) 72 (s 1H H4) 67 (s 1H H6)60ndash59 (m 1H CH

2=CH-CH

2) 51-51 (m 2H CH

2=CH-

CH2) 40 (s 3H OCH

3) 35 (d 2H CH

2=CH-CH

2 119869 =

66Hz) 13C NMR (120575 CDCl3 75MHz) 1606 (C2) 1492

(C41015840) 1445 (C7) 1436 (C3a) 1389 (C5) 1383 (C11015840) 1370(CH2=CH-CH

2) 1326 (C7a) 1283 (C31015840) 1240 (C21015840) 1163

(CH2=CH-CH

2) 1123 (C4) 1095 (C6) 563 (OCH

3) 404

(CH2=CH-CH

2) HRMS-ESI mz calcd for C

17H14O4N2

(M+H)+ 3111026 found 3111024

7-Methoxy-2-phenyl-5-propylbenzo[d]oxazol (5a1015840) Yellowsemi-solid 27 yield Rf 079 IR (120592max in cm

minus1) 1623 (C=N)1601 1496 1465 (C=C) 1309 1199 (C-N) 1129 (C-O-C) 1HNMR (120575 CDCl

3 300MHz) 82-82 (m 2H H21015840) 75ndash74

(m 3H H31015840 e H41015840) 721ndash702 (m 1H H4) 67 (d 1H H6119869 = 12Hz) 40 (s 3H OCH

3) 26 (t 2H CH

3-CH2-CH2

119869 = 72Hz) 17ndash16 (m 2H CH3-CH2-CH2) 09 (t 3H

CH3-CH2-CH2 119869 = 72Hz) 13C NMR (120575 CDCl

3 75MHz)

1629 (C2) 1441 (C7) 1438 (C3a) 1402 (C5) 1313 (C41015840)1287 (C31015840) 1284 (C7a) 1275 (C21015840) 1271 (C11015840) 1116 (C6)1088 (C4) 563 (OCH

3) 384 (CH

3-CH2-CH2) 249 (CH

3-

CH2-CH2) 137 (CH

3-CH2-CH2) HRMS-ESI mz calcd for

C17H17O2N (M+H)+ 2681332 found 2681338

2-(4-Chlorophenyl)-7-methoxy-5-propylbenzo[d]oxazol (5b1015840)Light brown crystals 26 yield mp 815ndash845∘C Rf 081IR (120592max in cmminus1) 1626 (C=N) 1596 1577 1493 1456(C=C) 1319 1201 (C-N) 1132 (C-O-C) 1H NMR (120575 CDCl

3

300MHz) 82ndash81 (m 2H H21015840) 75ndash74 (m 2H H31015840) 72ndash70(m 1H H4) 67 (d 1H H6 119869 = 12Hz) 40 (s 3H OCH

3)

26 (t 2H CH3-CH2-CH2 119869 = 72Hz) 17ndash16 (m 2H CH

3-

CH2-CH2) 09 (t 3H CH

3-CH2-CH2 119869 = 72Hz) 13C NMR

(120575 CDCl3 75MHz) 1619 (C2) 1442 (C7) 1436 (C3a) 1404

(C5) 1375 (C7a) 1291 (C31015840) 1288 (C21015840) 1256 (C41015840) 1217(C11015840) 1117 (C6) 1089 (C4) 563 (OCH

3) 384 (CH

3-CH2-

CH2) 249 (CH

3-CH2-CH2) 137 (CH

3-CH2-CH2) HRMS-

ESI mz calcd for C17H16O2NCl (M+H)+ 3020942 found

3020944

7-Methoxy-2-(4-methoxyphenyl)-5-propylbenzo[d]oxazol(5c1015840) Brown crystals 30 yield mp 894ndash925∘C Rf 059IR (120592max in cmminus1) 1622 (C=N) 1605 1583 1496 (C=C) 13241255 (C-N) 1132 (C-O-C) 1H NMR (120575 CDCl

3 300MHz)

82ndash81 (m 2H H21015840) 722ndash71 (m 1H H4) 70ndash69 (m 2HH31015840) 66 (d 1H H6 119869 = 12Hz) 40 (s 3H C7-OCH

3) 38

(s 3H C41015840-OCH3) 26 (t 2H CH

3-CH2-CH2 119869 = 75Hz)

17ndash16 (m 2H CH3-CH2-CH2) 09 (t 3H CH

3-CH2-CH2

119869 = 75Hz) 13C NMR (120575 CDCl3 75MHz) 1630 (C2) 1621


(C41015840) 1440 (C7) 1439 (C3a) 1400 (C5) 1380 (C7a) 1293(C21015840) 1197 (C11015840) 1142 (C31015840) 1114 (C6) 1084 (C4) 563(C7-OCH

3) 554 (C41015840-OCH

3) 384 (CH

3-CH2-CH2) 249

(CH3-CH2-CH2) 137 (CH

3-CH2-CH2) HRMS-ESI mz

calcd for C18H19O3N (M+H)+ 2981438 found 2981450

7-Methoxy-2-(4-nitrophenyl)-5-propylbenzo[d]oxazol (5d1015840)Yellow crystals 33 yield mp 1365ndash140∘C Rf 072 IR(120592max in cmminus1) 1625 (C=N) 1602 (C=C) 1518 1339 (NO

2)

1309 1200 (C-N) 1132 (C-O-C) 1H NMR (120575 CDCl3

300MHz) 84ndash83 (m 4H H21015840 e H31015840) 72 (s 1H H4) 67(s 1H H6) 40 (s 3H OCH

3) 27 (t 2H CH

3-CH2-CH2



3 75MHz)

1605 (C2) 1492 (C41015840) 1443 (C7) 1435 (C3a) 1410 (C11015840)1387 (C5) 1327 (C7a) 1283 (C21015840) 1241 (C31015840) 1123 (C6)1096 (C4) 563 (OCH

3) 384 (CH

3-CH2-CH2) 248 (CH

3-

CH2-CH2) 137 (CH


C17H16O4N2(M+H)+ 3131183 found 3131182

22 Antifungal Activity Evaluation The antifungal activityevaluation was performed through a Mueller-Hinton brothmicrodilution method and with the methodology and inter-pretative criteria proposed by document M27A3 [15] Thestock solutions of all the compounds were prepared inDMSO 1 at final concentration and tested at concentra-tions (120583gmL) 100 60 30 15 75 375 1875 0468 023006 The standard drug fluconazole was applied as controlof fungistatic action Results were visualized and analyzedat 530 nm in an Anthos Zenyth 200rt Microplate ReaderThe inhibitory concentrations of microbial growth weredetermined at 50 (IC

50) and 90 (IC

90) in 120583molmL and

compared among themicroorganismsThe tests were all donein duplicate

23 Cytotoxicity Assay The cytotoxicity of the compounds(200ndash15 120583gmL) to peripheral blood mononuclear cells(PBMCs) was determined using the 3-(45-dimethylthiazol-2-yl)-25-diphenyl tetrazolium bromide (MTT) method ThePBMCs were obtained from healthy volunteers by Ficoll-Hypaque density gradient centrifugation These cells weregrown inRMPImedium (Cultilab Brazil) supplementedwith10 (vv) heat-inactivated fetal bovine serum (FBS) (CultilabBrazil) 100mgmL penicillin and 100mgmL streptomycinin 5CO2 atmosphere at 37∘CThe cell suspension of PBMCsat a concentration of 24 times 106 cellsmL was distributed in a96-well plate 90 120583L in eachwell with 10 120583L of test compoundsat different concentrations and incubated at 37∘C in anincubator at 5 CO2 for 48 h After that 10120583L of MTT dyewas added (5mgmL) and the cells were incubated again foran additional 4 h period Then the medium was carefullyremoved and 100 120583L of DMSO was added for solubilizationof formazan crystals The plates were shaken for 5minand absorbance for each sample was measured in a spec-trophotometric microplate reader at 560 nm The percentageof cytotoxicity was calculated as [(119860 minus 119861)119860 times 100] whereA and B are the absorbance of control and treated cellsrespectively Data were analyzed using linear regression to

obtain values for CC50

and CC90

(cytotoxic concentrationfor 50 and 90 of cells resp) Selectivity indexes wereexpressed as the ratio CC

50IC50 The tests were all done in

duplicate

3 Results and Discussion

31 Chemistry The synthetic route used to obtain the molec-ular hybrids is depicted in Scheme 1

The synthesis of hybrid compounds was accomplishedinitially by orto-nitration of eugenol (1) and dihydroeugenol(11015840) using sodium nitrate potassium bisulfate and wet silicagel in dichloromethane as reported by Zolfigol and cowork-ers [16] These nitroderivatives (2 and 21015840) were obtained ingood yields as dark orange oils after successive extractions ofthe crude material with hexane and solvent evaporation Thenext step consisted in reducing these nitrated derivatives tothe known aminophenols derivatives 3 and 31015840 This objectivewas achieved by employing the classical and mild methodof reduction of nitrocompounds with stannous chloride inethanol [17] and the amphoteric intermediates were obtainedas pale yellow solids after careful acid-base extractions Thedata from spectrometric analysis of intermediates 2 21015840 3and 31015840 showed perfect agreement with those found in theliterature [18] Following these aminophenols were con-verted to N-(o-hydroxyphenyl)benzamides by acylation inmild conditions with appropriate carboxylic acid chlorides inan ice-cooledmixture of ether-water and sodium bicarbonate[19] The benzamides 4andash4d and 4a1015840ndash4d1015840 were obtained inexcellent yields after filtration or solvent extraction NMRspectra of these intermediates clearly showed the identity ofthe products and the maintenance of free phenolic hydroxylnecessary to the next reaction step Finally benzoxazoles5andash5d and 5a1015840ndash5d1015840 were synthesized by adaptation of themethods described by Nakamura et al [20] and Yang etal [21] in which the amides previously obtained wereheated under reflux in toluene with p-toluenesulfonic acidas a catalyst and dehydrating agent The products wereobtained in high yields as single products after filteringthe reaction mixture through a short pad of silica gel withdichloromethane and removing the solvent in rotavaporThe eight benzoxazoles are new compounds and were fullycharacterized by IR NMR and HRMS analysis

32 Biological Evaluations The final eight compounds werescreened for their potential antifungal activity against fivefungi species Candida albicans (C albicans) C tropicalis Ckrusei C parapsilosis and C glabrata (Table 1) The resultswere calculated using the inhibitory concentration of 50microbial growth and the interpretative criteria were thoseproposed by the document M27A3 from the Clinical andLaboratory Standards Institute [15] Fluconazole was used asthe positive control The assays were performed in triplicateand the results from these replicates were identical

Our expectation was that the fusion of two pharma-cophores that is eugenol and benzoxazole ring wouldenhance eugenol antimicrobial profiles against those fungi Infact four products showed fungistatic properties in the range321ndash380 120583M Moreover it is interesting to note that these


Table 1 In vitro antifungal activity (IC50 120583M) cytotoxic activity (CC

50 120583M) and selectivity index for eugenol (1) and related benzoxazole

derivatives (5andash5d1015840)

CompoundIC50[120583M]lowast

CC50[120583M]lowast SIC albicans

ATCC 10231C tropicalisATCC 750

C kruseiATCC 6258

C parapsilosisATCC 22019

C glabrataATCC 90030

1 1524 mdasha 1524 mdasha 1524 360 025a 380 mdasha mdasha mdasha mdasha 1111 295a1015840 mdasha mdasha mdasha mdasha mdasha 489 mdashb

5b mdasha mdasha mdasha mdasha mdasha 558 mdashb

5b1015840 mdasha mdasha 332 mdasha 332 629 195c 331 mdasha mdasha mdasha 338 888 265c1015840 mdasha mdasha mdasha mdasha mdasha 1216 mdashb

5d mdasha mdasha mdasha mdasha mdasha 1208 mdashb

5d1015840 321 mdasha 321 mdasha mdasha 613 19FLC 16 33 1043 33 522 mdashb mdashb

lowastThe experiments were done in triplicate and the results were identical ano significant activity bnot determined SI selectivity indexes expressed as the ratioCC50IC50 FLC fluconazole

a5a R = allyl ２= （

aa R = propyl ２= （

b5b R = allyl ２= Ｆ

bb R = propyl ２= Ｆ

c5c R = allyl ２= （3

cc R = propyl ２= （3

d5d R = allyl ２= 2

dd R = propyl ２= 2

R

OH

R

OH(i)

R

OH

(ii)

R N

O

R

(iii)OH

(iv)

N

H

O

（3（3 （3

（3（3

（2

2

R = allyl

R = propyl

andash d andash d5 5 55

andash d andash d

２

２

Scheme 1 Synthetic route to derivatives 5andash5d and 5a1015840ndash5d1015840 (i) NaNO3 KHSO

4 silicawater (1 1 ww) dichloromethane rt (ii)

SnCl2sdot2H2O ethanol 70∘C (iii) benzoyl chlorides NaHCO

3 ethyl etherwater (9 1 vv) 0∘C (iv) PTSA toluene reflux

derivatives were about five times more potent than eugenolwhich in turn could only inhibit three strains growing upto the highest concentration used Benzoxazoles 5a 5c and5d1015840 showed good fungistatic activities against C albicans(IC50values of 380 331 and 321 120583M resp) while compounds

5b1015840 and 5c could also inhibit C glabrata growing at 332and 338 120583M respectively Derivatives 5b1015840 and 5d1015840 inhibitedalso C krusei growing at IC

50332 and 321 120583M sequentially

Notably this shows that the potential of this new kind ofderivative against this strain since C krusei is naturallyresistant to many azole drugs for example fluconazole [22]Our study corroborates the findings of Carrasco et al [23]which showed that the phenolic hydroxyl was not necessaryin antifungal action against Candida sp An influence ofthe substituent group on the para-position of phenyl ringwas observed for products 5c and 5d since the presence


of the electron-donating group in 5c led to an activatedbenzoxazole while the nitrosubstituted product 5d is amongthe inactive compoundsHowever it is not possible to use thisobservation as a rule since in propyl derivatives 5c1015840 and 5d1015840one can see the opposite

The selective toxicity of these benzoxazoles expressed asthe selectivity index (SI) was then assessed on peripheralhuman blood mononuclear cells This parameter reflects thequantity of compound that is active against the pathogen butis not toxic towards the host cell Therefore compounds witha higher SI are very promising because the concentrationof the compound to induce an antimicrobial activity islower than the dose that induces cytotoxicity in host cellsThe analysis of SI values is very important to establish ifthe chemical modifications in each of the compounds canincrease the antifungal activity and decrease the cytotoxicityto host cells

The results from cytotoxicity assays showed that allhybrids had higher CC

50values than eugenol (Table 1)

Compounds 5a 5b1015840 5c and 5d1015840 presented selectivity index(SI) values 9 to 15 times higher than eugenol The blockadeof the phenolic hydroxyl may be related to the decreasedtoxicity of eugenol in mammalian cells while the nature ofpara-substituents in phenyl ring showed no clear relationshipwith the observed cytotoxicity profile as noted in the resultsof antifungal evaluation Meantime it could be noted thatderivatives 5a and 5dwere less toxic than their propyl analogs5a1015840 and 5d1015840 In vivo the allyl group can lead to toxicmetabolicproducts [24] but it is not always a toxicophore since this willdepend on other structural factors associated with the wholemolecule

In short these are new antifungal prototypes which maybe used for future chemical modifications to improve activityand reduce cytotoxicity

4 Conclusion

The present study described the synthesis and antifungalevaluation of benzoxazoles devised by molecular hybridiza-tion with eugenol or dihydroeugenol Four of them (5a5b1015840 5c and 5c1015840) showed activity against pathogenic andopportunistic species of Candida spp against which eugenolhad only modest activity Furthermore they were 9ndash15 timesmore selective than eugenol in cytotoxicity test The ongoinginvestigation of the mechanism by which these substancesplay antifungal effects can lead to a new class of antimicrobialcandidates and these benzoxazoles can be submitted tostructural variation for optimization of antifungal activity

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors acknowledge FAPEMIG for financial support(APQ-01268-16 and APQ-01209-13) and CNPq for the schol-arship (Process 1302412014-8)

References

[1] P N Fonkwo ldquoPricing infectious disease The economic andhealth implications of infectious diseasesrdquo EMBO Reports vol9 supplement 1 pp S13ndashS17 2008

[2] N Chami F Chami S Bennis J Trouillas and A RemmalldquoAntifungal treatment with carvacrol and eugenol of oralcandidiasis in immunosuppressed ratsrdquo Brazilian Journal ofInfectious Diseases vol 8 pp 217ndash226 2004

[3] P Martins J Jesus S Santos et al ldquoHeterocyclic anticancercompounds Recent advances and the paradigm shift towardsthe use of nanomedicinersquos tool Boxrdquo Molecules vol 20 no 9pp 16852ndash16891 2015

[4] A Majumder R Gupta and A Jain ldquoMicrowave-assisted syn-thesis of nitrogen-containing heterocyclesrdquo Green ChemistryLetters and Reviews vol 6 no 2 pp 151ndash182 2013

[5] T Ertan I Yildiz B Tekiner-Gulbas et al ldquoSynthesis biologicalevaluation and 2D-QSAR analysis of benzoxazoles as antimi-crobial agentsrdquo European Journal of Medicinal Chemistry vol44 no 2 pp 501ndash510 2009

[6] MMedebielle S Ait-Mohand C BurkhloderW R Jr DolbierG Laumond and A M Aubertin ldquoSynthesis of new difluo-romethylene benzoxazole and 124-oxadiazole derivatives aspotent non-nucleoside HIV-1 reverse transcriptase inhibitorsrdquoJournal of Fluorine Chemistry vol 126 pp 535ndash542 2005

[7] P K Jauhari A Bhavani S Varalwar K Singhal and PRaj ldquoSynthesis of some novel 2-substituted benzoxazoles asanticancer antifungal and antimicrobial agentsrdquo MedicinalChemistry Research vol 17 no 2-7 pp 412ndash424 2008

[8] M Arisoy O Temiz-Arpaci I Yildiz et al ldquoSynthesis antimi-crobial activity and QSAR studies of 25-disubstituted benzox-azolesrdquo SAR and QSAR in Environmental Research vol 19 no5-6 pp 589ndash612 2008

[9] B J Kim J Kim Y K Kim S Y Choi and H Y P ChooldquoSynthesis of benzoxazole amides as novel antifungal agentsagainst Malassezia furfurrdquo Bulletin of the Korean ChemicalSociety vol 31 pp 1270ndash1274 2010

[10] J-I Kuroyanagi K Kanai Y Sugimoto et al ldquo13-Benzoxazole-4-carbonitrile as a novel antifungal scaffold of 120573-16-glucansynthesis inhibitorsrdquo Bioorganic and Medicinal Chemistry vol18 no 21 pp 7593ndash7606 2010

[11] T S Kaufman ldquoThe multiple faces of Eugenol A versatilestartingmaterial and building block for organic and bio-organicsynthesis and a convenient precursor toward bio-based finechemicalsrdquo Journal of the Brazilian Chemical Society vol 26 no6 pp 1055ndash1085 2015

[12] R di Pasqua N Hoskins G Betts and G Mauriello ldquoChangesinmembrane fatty acids composition of microbial cells inducedby addiction of thymol carvacrol limonene cinnamaldehydeand eugenol in the growing mediardquo Journal of Agricultural andFood Chemistry vol 54 no 7 pp 2745ndash2749 2006

[13] G B Zore A D Thakre S Jadhav and S M KaruppayilldquoTerpenoids inhibitCandida albicans growth by affectingmem-brane integrity and arrest of cell cyclerdquo Phytomedicine vol 18no 13 pp 1181ndash1190 2011

[14] A O Gill and R A Holley ldquoMechanisms of bactericidalaction of cinnamaldehyde against Listeria monocytogenes andof eugenol against L monocytogenes and Lactobacillus sakeirdquoApplied and Environmental Microbiology vol 70 no 10 pp5750ndash5755 2004

[15] Clinical and Laboratory Standards Institute (CLSI) ReferenceMethod for Broth Dilution Antifungal Susceptibility Testing of


Yeasts Approved Standard- M27-A3 CLSI Wayne PA USA3rd edition 2008

[16] M A Zolfigol E Ghaemi and E Madrakian ldquoNitration ofphenols under mild and heterogeneous conditionsrdquoMoleculesvol 6 no 7 pp 614ndash620 2001

[17] F D Bellamy and K Ou ldquoSelective reduction of aromatic nitrocompounds with stannous chloride in non acidic and nonaqueous mediumrdquo Tetrahedron Letters vol 25 no 8 pp 839ndash842 1984

[18] D E Levin and A Lowy ldquoDerivatives of dihydroeugenol andcertain pharmacological properties of some of the compoundsrdquoJournal of theAmericanChemical Society vol 55 no 5 pp 1995ndash2000 1933

[19] E A Sener K K Bingol I Oren O T Arpaci I Yalcin andN Altanlar ldquoSynthesis and microbiological activity of someN-(o-hydroxyphenyl)benzamides and phenylacetamides as thepossible metabolites of antimicrobial active benzoxazoles PartIIrdquo Farmaco vol 55 no 6-7 pp 469ndash476 2000

[20] H Nakamura Y Yasui and H S Ban ldquoSynthesis and biologicalevaluation of ortho-carborane containing benzoxazole as aninhibitor of hypoxia inducible factor (HIF)-1 transcriptionalactivityrdquo Journal of Organometallic Chemistry vol 747 pp 189ndash194 2013

[21] X Yang G Shan and Y Rao ldquoSynthesis of 2-aminophenols andheterocycles by Ru-catalyzed C-Hmono- and dihydroxylationrdquoOrganic Letters vol 15 no 10 pp 2334ndash2337 2013

[22] J Loeffler and D A Stevens ldquoAntifungal drug resistancerdquoClinical Infectious Diseases vol 36 no 1 pp S31ndashS41 2003

[23] H Carrasco M Raimondi L Svetaz et al ldquoAntifungal activityof eugenol analogues Influence of different substituents andstudies on mechanism of actionrdquo Molecules vol 17 no 1 pp1002ndash1024 2012

[24] L M Lima ldquoSafrole and the versatility of a natural biophorerdquoRevista Virtual de Quimica vol 7 no 2 pp 495ndash538 2015

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

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Chemistry


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Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


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Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


synthetic benzoxazoles against cervical colon and breastadenocarcinoma cell lines [7] while Arisoy and contributorsdescribed the relevant activities of 25-disubstituted ben-zoxazoles against Candida krusei and gentamicin-resistantisolates of Pseudomonas aeruginosa [8] Kim et al (2010) haveprepared benzoxazole amides which presented good activityagainst Malassezia furfur a pathogenic fungus involved infatal sepsis cases [9] Recently Kuroyanagi and colleaguesshowed the outstanding potential of some 13-benzoxazol-4-carbonitriles against Candida strains [10]

At the same time eugenol (1) a natural allylphenolfound mainly in cloves [Eugenia caryophyllata L Merr ampPerry (Myrtaceae)] shows relevant pharmacological activi-ties especially the antibacterial and antifungal actions [11]Some authors have described the synthesis of eugenol deriva-tives in order to optimize its activities The antimicrobialactions of eugenol seem to be related to cellular membranesinterferences [12ndash14]

Following our interest in obtaining bioactive eugenolderivatives and in face of the potential of benzoxazole deriva-tives as antimicrobial agents we present herein the synthesisand anti-Candida activity of eugenol-benzoxazole basedhybrids Besides eugenol we also employed dihydroeugenolas a starting material in order to evaluate the influence of theallylic chain on antifungal activity

2 Materials and Methods

21 Chemistry Thin-layer chromatography (TLC) on sil-ica gel-G plates (Macherey-Nagel DC-Fertigfolien ALU-GRAM Xtra Sil GUV

254) was used to monitor reac-

tions courses Determination of the Rf values for the finalproducts was done with the same TLC plates employinghexaneethyl acetate (80 20 vv) for all compounds Forcolumn chromatography column grade silica gel (Sorbiline0040ndash0063mmmesh size) was employed Melting points ofthe compounds were obtained on Microquımica MOAs 301melting-point apparatus and are uncorrected IR spectrawere recorded on a Shimadzu FTIR-Affinity-1 spectrometerNMR spectra were recorded on a Bruker AC-300 spectrom-eter (Rheinstetten Germany) (300MHz for 1H-NMR and75MHz for 13C-NMR spectra) in deuterated chloroformChemical shifts (120575) were reported in parts per million (ppm)with reference to tetramethylsilane (TMS) as internal stan-dard and coupling constants (119869) were reported in Hertz (Hz)High-resolution mass (HRMS) spectra were obtained for thefinal products on a quadrupole time-of-flight instrument(micrOTOF-QII Bruker Daltonics Billerica MA USA)equipped with an ESI positive and negative ion source

Synthesis of Nitroderivatives 2 and 21015840 To a solution of eugenol(1 3253mmol) or dihydroeugenol (11015840 3126mmol) indichloromethane (50mL) were added equimolar amounts ofsodium bisulfate and potassium nitrate followed by additionof wet silica gel (1 1 ww 65 g for eugenol reaction and 63 gfor dihydroeugenol reaction) The reaction was kept undervigorous magnetic stirring at room temperature for 48 hoursand monitored by TLC (chloroformmethanol 95 05 vv)

After completion of the reaction the mixture was filteredoff the filtrate was dried over anhydrous sodium sulfate andconcentrated under reduced pressure The nitrocompounds2 and 21015840 were purified by column chromatography (hex-aneethyl acetate 9 1 vv) or by multiple extractions withhexane

4-Allyl-2-methoxy-6-nitrophenol (2) Yellow oil 37 yield IR(120592max in cmminus1) 3520 (O-H) 1600 1550 (C=C) 1515 1440(NO2) 1270 (C-O-C) 1HNMR (120575 CDCl

3 300MHz) 106 (s

1HO-H) 74 (d 1HH5 119869= 18Hz) 69 (d 1HH3 119869= 18Hz)59ndash58 (m 1H CH

2=CH-CH

2) 51ndash50 (m 2H CH

2=CH-

CH2) 39 (s 3H OCH

3) 33 (d 2H CH

2=CH-CH

2 119869 =


1358 (CH2=CH-CH

2) 1335 (C2) 1311 (C4) 1185 (C5) 1170

(CH2=CH-CH

2) 1149 (C3) 566 (OCH

3) 393 (CH

2=CH-

CH2)

2-Methoxy-6-nitro-4-propylphenol (21015840) Yellow oil 62 yieldIR (120592max in cm

minus1) 3250 (O-H) 1591 (C=C) 1541 1448 (NO2)

1260 (C-O-C) 1HNMR (120575 CDCl3 300MHz) 106 (s 1H O-

H) 74 (d 1H H5 119869 = 18Hz) 69 (d 1H H3 119869 = 18Hz) 39(s 3H OCH

3) 25 (t 2H CH

3-CH2-CH2 119869 = 72Hz) 17ndash15

(m 2H CH3-CH2-CH2) 09 (t 3H CH

3-CH2-CH2 119869 =


1337 (C4) 1335 (C2) 1186 (C5) 1147 (C3) 566 (OCH3)

373 (CH3-CH2-CH2) 241 (CH

3-CH2-CH2) 135 (CH

3-CH2-

CH2)

Synthesis of Amino Derivatives 3 and 31015840The nitrocompounds2 (1187mmol) or 21015840 (1943mmol) were solubilized in ethanol(100mL) and to these solutions was added dihydrate stan-nous chloride (5 eq) The mixture was kept under magneticstirring at 70∘C for 3 hours and the consumption of start-ing material was followed by TLC (chloroformmethanol95 05 vv) The mixture was poured into ice water andaqueous NaHCO3 adjusted the pH to 7Themixture was thenextracted with ethyl acetate (10 times 20mL) the organic layerwas dried with anhydrous sodium sulfate and filtered andthe filtrate was concentrated under reduced pressure whichprovided the pure products

4-Allyl-2-amino-6-methoxyphenol (3) Yellow crystals 61yield mp 95ndash98∘C IR (120592max in cmminus1) 3371 3311 (NH

2)

3074 (O-H) 1606 1456 (C=C) 1512 (N-H) 1230 (C-O-C)1H NMR (120575 CDCl

3 300MHz) 62 (d 1H H5 119869 = 18Hz)

61 (d 1H H3 119869 = 18Hz) 60ndash58 (m 1H CH2=CH-CH

2)

51ndash50 (m 2HCH2=CH-CH

2) 38 (s 3HOCH

3) 32 (d 2H

CH2=CH-CH

2 119869 = 69Hz) 13C NMR (120575 CDCl

3 75MHz)

1466 (C6) 1378 (CH2=CH-CH

2) 1338 (C2) 1316 (C4)

1312 (C1) 1153 (CH2=CH-CH

2) 1094 (C5) 1019 (C3) 559

(OCH3) 400 (CH

2=CH-CH

2)

2-Amino-6-methoxy-4-propylphenol (31015840) Yellow crystals 46yield mp 63ndash66∘C IR (120592max in cmminus1) 3370 3307 (NH

2)

3012 (O-H) 1513 (N-H) 1212 (C-O-C) 1H NMR (120575 CDCl3

300MHz) 62 (d 1H H5 119869 = 18Hz) 61 (d 1H H3 119869 =18Hz) 38 (s 3H OCH

3) 24 (t 2H CH

3-CH2-CH2 119869 =



3-

CH2-CH2 119869 = 75Hz) 13C NMR (120575 CDCl

3 75MHz) 1464

(C6) 1343 (C2) 1337 (C4) 1308 (C1) 1093 (C5) 1017(C3) 5592 (OCH

3) 3799 (CH

3-CH2-CH2) 2474 (CH

3-

CH2-CH2) 1382 (CH

3-CH2-CH2)







3


2=CH-CH

2-) 51ndash50 (m 2H

CH2=CH-CH

2) 38 (s 3H OCH

3) 33 (d 2H CH

2=CH-

CH2 119869=66Hz) 13CNMR(120575 CDCl

3 75MHz) 1656 (C=O)

1468 (C3) 1375 (CH2=CH-CH

2) 1346 (C11015840) 1336 (C2) 1319

(C5) 1318 (C41015840) 1287 (C31015840) 1271 (C21015840) 1258 (C1) 1157(CH2=CH-CH

2) 1133 (C6) 1072 (C4) 561 (OCH

3) 402

(CH2=CH-CH

2)


3


2=CH-CH


2=CH-

CH2) 38 (s 3H OCH

3) 33 (d 2H CH

2=CH-CH

2 119869 =


(C3) 1381 (C41015840) 1374 (CH2=CH-CH

2) 1335 (C2) 1331

(C11015840) 1320 (C5) 1289 (C21015840) 1285 (C31015840) 1255 (C1) 1158(CH2=CH-CH

2) 1132 (C6) 1073 (C4) 561 (OCH

3) 402

(CH2=CH-CH

2)


3


2=CH-CH


2=CH-CH

2)

38 (s 3H C3-OCH3) 38 (s 3H C41015840-OCH

3) 33 (d 2H

CH2=CH-CH

2 119869 = 66Hz) 13C NMR (120575 CDCl

3 75MHz)

1651 (C=O) 1625 (C41015840) 1469 (C3) 1375 (CH2=CH-CH

2)

1337 (C2) 1319 (C5) 1290 (C21015840) 1268 (C1) 1259 (C11015840)

1157 (CH2=CH-CH

2) 1139 (C31015840) 1133 (C6) 1071 (C4) 561

(C3-OCH3) 554 (C41015840-OCH

3) 402 (CH

2=CH-CH

2)


3


2=CH-CH

2-)


2) 38 (s 3H OCH

3) 33

(d 2H CH2=CH-CH

2 119869 = 69Hz) 13C NMR (120575 CDCl

3

75MHz) 1632 (C=O) 1496 (C41015840) 1464 (C3) 1403 (C11015840)1373 (CH

2=CH-CH

2) 1334 (C2) 1322 (C5) 1282 (C21015840)

1251 (C1) 1239 (C31015840) 1159 (CH2=CH-CH

2) 1132 (C6)

1076 (C4) 561 (OCH3) 401 (CH

2=CH-CH

2)


3 300MHz) 83 (s


3) 25 (t 2H CH

3-CH2-CH2- 119869


3-

CH2-CH2- 119869 = 72Hz) 13C NMR (120575 CDCl

3 75MHz) 1655


3) 381 (CH

3-CH2-CH2-) 248 (CH

3-CH2-CH2-)

138 (CH3-CH2-CH2-)


3


3) 25 (t 2H CH

3-


3-CH2-CH2-) 09


3


3) 381 (CH

3-CH2-CH2-)

248 (CH3-CH2-CH2-) 137 (CH

3-CH2-CH2-)


3


3) 38 (s 3H C41015840-OCH

3) 25


3-

CH2-CH2-) 09 (t 3H CH

3-CH2-CH2- 119869 = 72Hz) 13C

NMR (120575 CDCl3 75MHz) 1651 (C=O) 1625 (C41015840) 1468

(C3) 1346 (C2) 1334 (C5) 1290 (C21015840) 1269 (C1) 1258(C11015840) 1139 (C31015840) 1131 (C6) 1071 (C4) 561 (C3-OCH

3) 554

(C41015840-OCH3) 381 (CH

3-CH2-CH2-) 247 (CH

3-CH2-CH2-)

137 (CH3-CH2-CH2-)


3


3) 25 (t 2H CH

3-CH2-CH2- 119869 = 72Hz) 17ndash15


(m 2H CH3-CH2-CH2-) 09 (t 3H CH

3-CH2-CH2- 119869 =


(C41015840) 1461 (C3) 1405 (C11015840) 1349 (C2) 1329 (C5) 1282(C21015840) 1249 (C1) 1240 (C31015840) 1129 (C6) 1074 (C4) 561(OCH

3) 381 (CH

3-CH2-CH2-) 248 (CH

3-CH2-CH2-) 137

(CH3-CH2-CH2-)



3 300MHz) 82-82 (m 2H H21015840) 75-75 (m 2H


2=CH-CH

2) 51ndash50 (m 2H

CH2=CH-CH

2) 40 (s 3H OCH

3) 32 (d 2H CH

2=CH-

CH2 119869 = 66Hz) 13C NMR (120575 CDCl

3 75MHz) 1443 (C2)

1439 (C7) 1375 (C3a) 1373 (CH2=CH-CH

2) 1314 (C41015840)

1288 (C31015840) 1276 (C21015840) 1271 (C5) 1257 (C7a) 1256 (C11015840)1160 (CH

2=CH-CH

2) 1120 (C6) 1088 (C4) 563 (OCH

3)

405 (CH2=CH-CH


17H15O2N

(M+H)+ 2661176 found 2661184



3 300MHz) 82ndash81


2=CH-CH

2)


2) 40 (s 3H OCH

3) 34

(d 2H CH2=CH-CH

2 119869 = 66Hz) 13C NMR (120575 CDCl

3

75MHz) 1620 (C2) 1443 (C7) 1438 (C3a) 1385 (C5) 1377(C41015840) 1376 (C7a) 1372 (CH

2=CH-CH

2) 1291 (C31015840) 1288

(C21015840) 1256 (C11015840) 1161 (CH2=CH-CH

2) 1120 (C6) 1089

(C4) 563 (OCH3) 405 (CH

2=CH-CH

2) HRMS-ESI mz



3 300MHz) 82ndash81


2=CH-CH

2)


2) 40 (s 3H C7-OCH

3) 38

(s 3H C4-OCH3) 34 (d 2H CH

2=CH-CH

2 119869 = 66Hz)

13C NMR (120575 CDCl3 75MHz) 1632 (C2) 1622 (C41015840)

1442 (C7) 1440 (C3a) 1374 (CH2=CH-CH

2) 1373 (C5)

1293 (C21015840) 1196 (C11015840) 1159 (CH2=CH-CH

2) 1142 (C31015840)

1117 (C6) 1084 (C4) 563 (C7-OCH3) 554 (C41015840-OCH

3)

405 (CH2=CH-CH


18H17O3N

(M+H)+ 2961281 found 2961291


2) 1319



2=CH-CH

2) 51-51 (m 2H CH

2=CH-

CH2) 40 (s 3H OCH

3) 35 (d 2H CH

2=CH-CH

2 119869 =

66Hz) 13C NMR (120575 CDCl3 75MHz) 1606 (C2) 1492

(C41015840) 1445 (C7) 1436 (C3a) 1389 (C5) 1383 (C11015840) 1370(CH2=CH-CH

2) 1326 (C7a) 1283 (C31015840) 1240 (C21015840) 1163

(CH2=CH-CH

2) 1123 (C4) 1095 (C6) 563 (OCH

3) 404

(CH2=CH-CH


17H14O4N2

(M+H)+ 3111026 found 3111024



3 300MHz) 82-82 (m 2H H21015840) 75ndash74


3) 26 (t 2H CH

3-CH2-CH2



3 75MHz)


3) 384 (CH

3-CH2-CH2) 249 (CH

3-

CH2-CH2) 137 (CH


C17H17O2N (M+H)+ 2681332 found 2681338


3


3)


3-


3-CH2-CH2 119869 = 72Hz) 13C NMR

(120575 CDCl3 75MHz) 1619 (C2) 1442 (C7) 1436 (C3a) 1404

(C5) 1375 (C7a) 1291 (C31015840) 1288 (C21015840) 1256 (C41015840) 1217(C11015840) 1117 (C6) 1089 (C4) 563 (OCH

3) 384 (CH

3-CH2-

CH2) 249 (CH

3-CH2-CH2) 137 (CH

3-CH2-CH2) HRMS-


3020944


3 300MHz)


3) 38

(s 3H C41015840-OCH3) 26 (t 2H CH

3-CH2-CH2 119869 = 75Hz)


3-CH2-CH2

119869 = 75Hz) 13C NMR (120575 CDCl3 75MHz) 1630 (C2) 1621



3) 554 (C41015840-OCH

3) 384 (CH

3-CH2-CH2) 249

(CH3-CH2-CH2) 137 (CH




2)

1309 1200 (C-N) 1132 (C-O-C) 1H NMR (120575 CDCl3


3) 27 (t 2H CH

3-CH2-CH2



3 75MHz)


3) 384 (CH

3-CH2-CH2) 248 (CH

3-

CH2-CH2) 137 (CH


C17H16O4N2(M+H)+ 3131183 found 3131182


50) and 90 (IC





and CC90



duplicate













C kruseiATCC 6258

















R

OH

R

OH(i)

R

OH

(ii)

R N

O

R

(iii)OH

(iv)

N

H

O

（3（3 （3

（3（3

（2

2

R = allyl

R = propyl


andash d andash d

２

２
















4 Conclusion




Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



3-

CH2-CH2 119869 = 75Hz) 13C NMR (120575 CDCl

3 75MHz) 1464

(C6) 1343 (C2) 1337 (C4) 1308 (C1) 1093 (C5) 1017(C3) 5592 (OCH

3) 3799 (CH

3-CH2-CH2) 2474 (CH

3-

CH2-CH2) 1382 (CH

3-CH2-CH2)







3


2=CH-CH

2-) 51ndash50 (m 2H

CH2=CH-CH

2) 38 (s 3H OCH

3) 33 (d 2H CH

2=CH-

CH2 119869=66Hz) 13CNMR(120575 CDCl

3 75MHz) 1656 (C=O)

1468 (C3) 1375 (CH2=CH-CH

2) 1346 (C11015840) 1336 (C2) 1319

(C5) 1318 (C41015840) 1287 (C31015840) 1271 (C21015840) 1258 (C1) 1157(CH2=CH-CH

2) 1133 (C6) 1072 (C4) 561 (OCH

3) 402

(CH2=CH-CH

2)


3


2=CH-CH


2=CH-

CH2) 38 (s 3H OCH

3) 33 (d 2H CH

2=CH-CH

2 119869 =


(C3) 1381 (C41015840) 1374 (CH2=CH-CH

2) 1335 (C2) 1331

(C11015840) 1320 (C5) 1289 (C21015840) 1285 (C31015840) 1255 (C1) 1158(CH2=CH-CH

2) 1132 (C6) 1073 (C4) 561 (OCH

3) 402

(CH2=CH-CH

2)


3


2=CH-CH


2=CH-CH

2)

38 (s 3H C3-OCH3) 38 (s 3H C41015840-OCH

3) 33 (d 2H

CH2=CH-CH

2 119869 = 66Hz) 13C NMR (120575 CDCl

3 75MHz)

1651 (C=O) 1625 (C41015840) 1469 (C3) 1375 (CH2=CH-CH

2)

1337 (C2) 1319 (C5) 1290 (C21015840) 1268 (C1) 1259 (C11015840)

1157 (CH2=CH-CH

2) 1139 (C31015840) 1133 (C6) 1071 (C4) 561

(C3-OCH3) 554 (C41015840-OCH

3) 402 (CH

2=CH-CH

2)


3


2=CH-CH

2-)


2) 38 (s 3H OCH

3) 33

(d 2H CH2=CH-CH

2 119869 = 69Hz) 13C NMR (120575 CDCl

3

75MHz) 1632 (C=O) 1496 (C41015840) 1464 (C3) 1403 (C11015840)1373 (CH

2=CH-CH

2) 1334 (C2) 1322 (C5) 1282 (C21015840)

1251 (C1) 1239 (C31015840) 1159 (CH2=CH-CH

2) 1132 (C6)

1076 (C4) 561 (OCH3) 401 (CH

2=CH-CH

2)


3 300MHz) 83 (s


3) 25 (t 2H CH

3-CH2-CH2- 119869


3-

CH2-CH2- 119869 = 72Hz) 13C NMR (120575 CDCl

3 75MHz) 1655


3) 381 (CH

3-CH2-CH2-) 248 (CH

3-CH2-CH2-)

138 (CH3-CH2-CH2-)


3


3) 25 (t 2H CH

3-


3-CH2-CH2-) 09


3


3) 381 (CH

3-CH2-CH2-)

248 (CH3-CH2-CH2-) 137 (CH

3-CH2-CH2-)


3


3) 38 (s 3H C41015840-OCH

3) 25


3-

CH2-CH2-) 09 (t 3H CH

3-CH2-CH2- 119869 = 72Hz) 13C

NMR (120575 CDCl3 75MHz) 1651 (C=O) 1625 (C41015840) 1468

(C3) 1346 (C2) 1334 (C5) 1290 (C21015840) 1269 (C1) 1258(C11015840) 1139 (C31015840) 1131 (C6) 1071 (C4) 561 (C3-OCH

3) 554

(C41015840-OCH3) 381 (CH

3-CH2-CH2-) 247 (CH

3-CH2-CH2-)

137 (CH3-CH2-CH2-)


3


3) 25 (t 2H CH

3-CH2-CH2- 119869 = 72Hz) 17ndash15


(m 2H CH3-CH2-CH2-) 09 (t 3H CH

3-CH2-CH2- 119869 =


(C41015840) 1461 (C3) 1405 (C11015840) 1349 (C2) 1329 (C5) 1282(C21015840) 1249 (C1) 1240 (C31015840) 1129 (C6) 1074 (C4) 561(OCH

3) 381 (CH

3-CH2-CH2-) 248 (CH

3-CH2-CH2-) 137

(CH3-CH2-CH2-)



3 300MHz) 82-82 (m 2H H21015840) 75-75 (m 2H


2=CH-CH

2) 51ndash50 (m 2H

CH2=CH-CH

2) 40 (s 3H OCH

3) 32 (d 2H CH

2=CH-

CH2 119869 = 66Hz) 13C NMR (120575 CDCl

3 75MHz) 1443 (C2)

1439 (C7) 1375 (C3a) 1373 (CH2=CH-CH

2) 1314 (C41015840)

1288 (C31015840) 1276 (C21015840) 1271 (C5) 1257 (C7a) 1256 (C11015840)1160 (CH

2=CH-CH

2) 1120 (C6) 1088 (C4) 563 (OCH

3)

405 (CH2=CH-CH


17H15O2N

(M+H)+ 2661176 found 2661184



3 300MHz) 82ndash81


2=CH-CH

2)


2) 40 (s 3H OCH

3) 34

(d 2H CH2=CH-CH

2 119869 = 66Hz) 13C NMR (120575 CDCl

3

75MHz) 1620 (C2) 1443 (C7) 1438 (C3a) 1385 (C5) 1377(C41015840) 1376 (C7a) 1372 (CH

2=CH-CH

2) 1291 (C31015840) 1288

(C21015840) 1256 (C11015840) 1161 (CH2=CH-CH

2) 1120 (C6) 1089

(C4) 563 (OCH3) 405 (CH

2=CH-CH

2) HRMS-ESI mz



3 300MHz) 82ndash81


2=CH-CH

2)


2) 40 (s 3H C7-OCH

3) 38

(s 3H C4-OCH3) 34 (d 2H CH

2=CH-CH

2 119869 = 66Hz)

13C NMR (120575 CDCl3 75MHz) 1632 (C2) 1622 (C41015840)

1442 (C7) 1440 (C3a) 1374 (CH2=CH-CH

2) 1373 (C5)

1293 (C21015840) 1196 (C11015840) 1159 (CH2=CH-CH

2) 1142 (C31015840)

1117 (C6) 1084 (C4) 563 (C7-OCH3) 554 (C41015840-OCH

3)

405 (CH2=CH-CH


18H17O3N

(M+H)+ 2961281 found 2961291


2) 1319



2=CH-CH

2) 51-51 (m 2H CH

2=CH-

CH2) 40 (s 3H OCH

3) 35 (d 2H CH

2=CH-CH

2 119869 =

66Hz) 13C NMR (120575 CDCl3 75MHz) 1606 (C2) 1492

(C41015840) 1445 (C7) 1436 (C3a) 1389 (C5) 1383 (C11015840) 1370(CH2=CH-CH

2) 1326 (C7a) 1283 (C31015840) 1240 (C21015840) 1163

(CH2=CH-CH

2) 1123 (C4) 1095 (C6) 563 (OCH

3) 404

(CH2=CH-CH


17H14O4N2

(M+H)+ 3111026 found 3111024



3 300MHz) 82-82 (m 2H H21015840) 75ndash74


3) 26 (t 2H CH

3-CH2-CH2



3 75MHz)


3) 384 (CH

3-CH2-CH2) 249 (CH

3-

CH2-CH2) 137 (CH


C17H17O2N (M+H)+ 2681332 found 2681338


3


3)


3-


3-CH2-CH2 119869 = 72Hz) 13C NMR

(120575 CDCl3 75MHz) 1619 (C2) 1442 (C7) 1436 (C3a) 1404

(C5) 1375 (C7a) 1291 (C31015840) 1288 (C21015840) 1256 (C41015840) 1217(C11015840) 1117 (C6) 1089 (C4) 563 (OCH

3) 384 (CH

3-CH2-

CH2) 249 (CH

3-CH2-CH2) 137 (CH

3-CH2-CH2) HRMS-


3020944


3 300MHz)


3) 38

(s 3H C41015840-OCH3) 26 (t 2H CH

3-CH2-CH2 119869 = 75Hz)


3-CH2-CH2

119869 = 75Hz) 13C NMR (120575 CDCl3 75MHz) 1630 (C2) 1621



3) 554 (C41015840-OCH

3) 384 (CH

3-CH2-CH2) 249

(CH3-CH2-CH2) 137 (CH




2)

1309 1200 (C-N) 1132 (C-O-C) 1H NMR (120575 CDCl3


3) 27 (t 2H CH

3-CH2-CH2



3 75MHz)


3) 384 (CH

3-CH2-CH2) 248 (CH

3-

CH2-CH2) 137 (CH


C17H16O4N2(M+H)+ 3131183 found 3131182


50) and 90 (IC





and CC90



duplicate













C kruseiATCC 6258

















R

OH

R

OH(i)

R

OH

(ii)

R N

O

R

(iii)OH

(iv)

N

H

O

（3（3 （3

（3（3

（2

2

R = allyl

R = propyl


andash d andash d

２

２
















4 Conclusion




Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(m 2H CH3-CH2-CH2-) 09 (t 3H CH

3-CH2-CH2- 119869 =


(C41015840) 1461 (C3) 1405 (C11015840) 1349 (C2) 1329 (C5) 1282(C21015840) 1249 (C1) 1240 (C31015840) 1129 (C6) 1074 (C4) 561(OCH

3) 381 (CH

3-CH2-CH2-) 248 (CH

3-CH2-CH2-) 137

(CH3-CH2-CH2-)



3 300MHz) 82-82 (m 2H H21015840) 75-75 (m 2H


2=CH-CH

2) 51ndash50 (m 2H

CH2=CH-CH

2) 40 (s 3H OCH

3) 32 (d 2H CH

2=CH-

CH2 119869 = 66Hz) 13C NMR (120575 CDCl

3 75MHz) 1443 (C2)

1439 (C7) 1375 (C3a) 1373 (CH2=CH-CH

2) 1314 (C41015840)

1288 (C31015840) 1276 (C21015840) 1271 (C5) 1257 (C7a) 1256 (C11015840)1160 (CH

2=CH-CH

2) 1120 (C6) 1088 (C4) 563 (OCH

3)

405 (CH2=CH-CH


17H15O2N

(M+H)+ 2661176 found 2661184



3 300MHz) 82ndash81


2=CH-CH

2)


2) 40 (s 3H OCH

3) 34

(d 2H CH2=CH-CH

2 119869 = 66Hz) 13C NMR (120575 CDCl

3

75MHz) 1620 (C2) 1443 (C7) 1438 (C3a) 1385 (C5) 1377(C41015840) 1376 (C7a) 1372 (CH

2=CH-CH

2) 1291 (C31015840) 1288

(C21015840) 1256 (C11015840) 1161 (CH2=CH-CH

2) 1120 (C6) 1089

(C4) 563 (OCH3) 405 (CH

2=CH-CH

2) HRMS-ESI mz



3 300MHz) 82ndash81


2=CH-CH

2)


2) 40 (s 3H C7-OCH

3) 38

(s 3H C4-OCH3) 34 (d 2H CH

2=CH-CH

2 119869 = 66Hz)

13C NMR (120575 CDCl3 75MHz) 1632 (C2) 1622 (C41015840)

1442 (C7) 1440 (C3a) 1374 (CH2=CH-CH

2) 1373 (C5)

1293 (C21015840) 1196 (C11015840) 1159 (CH2=CH-CH

2) 1142 (C31015840)

1117 (C6) 1084 (C4) 563 (C7-OCH3) 554 (C41015840-OCH

3)

405 (CH2=CH-CH


18H17O3N

(M+H)+ 2961281 found 2961291


2) 1319



2=CH-CH

2) 51-51 (m 2H CH

2=CH-

CH2) 40 (s 3H OCH

3) 35 (d 2H CH

2=CH-CH

2 119869 =

66Hz) 13C NMR (120575 CDCl3 75MHz) 1606 (C2) 1492

(C41015840) 1445 (C7) 1436 (C3a) 1389 (C5) 1383 (C11015840) 1370(CH2=CH-CH

2) 1326 (C7a) 1283 (C31015840) 1240 (C21015840) 1163

(CH2=CH-CH

2) 1123 (C4) 1095 (C6) 563 (OCH

3) 404

(CH2=CH-CH


17H14O4N2

(M+H)+ 3111026 found 3111024



3 300MHz) 82-82 (m 2H H21015840) 75ndash74


3) 26 (t 2H CH

3-CH2-CH2



3 75MHz)


3) 384 (CH

3-CH2-CH2) 249 (CH

3-

CH2-CH2) 137 (CH


C17H17O2N (M+H)+ 2681332 found 2681338


3


3)


3-


3-CH2-CH2 119869 = 72Hz) 13C NMR

(120575 CDCl3 75MHz) 1619 (C2) 1442 (C7) 1436 (C3a) 1404

(C5) 1375 (C7a) 1291 (C31015840) 1288 (C21015840) 1256 (C41015840) 1217(C11015840) 1117 (C6) 1089 (C4) 563 (OCH

3) 384 (CH

3-CH2-

CH2) 249 (CH

3-CH2-CH2) 137 (CH

3-CH2-CH2) HRMS-


3020944


3 300MHz)


3) 38

(s 3H C41015840-OCH3) 26 (t 2H CH

3-CH2-CH2 119869 = 75Hz)


3-CH2-CH2

119869 = 75Hz) 13C NMR (120575 CDCl3 75MHz) 1630 (C2) 1621



3) 554 (C41015840-OCH

3) 384 (CH

3-CH2-CH2) 249

(CH3-CH2-CH2) 137 (CH




2)

1309 1200 (C-N) 1132 (C-O-C) 1H NMR (120575 CDCl3


3) 27 (t 2H CH

3-CH2-CH2



3 75MHz)


3) 384 (CH

3-CH2-CH2) 248 (CH

3-

CH2-CH2) 137 (CH


C17H16O4N2(M+H)+ 3131183 found 3131182


50) and 90 (IC





and CC90



duplicate













C kruseiATCC 6258

















R

OH

R

OH(i)

R

OH

(ii)

R N

O

R

(iii)OH

(iv)

N

H

O

（3（3 （3

（3（3

（2

2

R = allyl

R = propyl


andash d andash d

２

２
















4 Conclusion




Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



3) 554 (C41015840-OCH

3) 384 (CH

3-CH2-CH2) 249

(CH3-CH2-CH2) 137 (CH




2)

1309 1200 (C-N) 1132 (C-O-C) 1H NMR (120575 CDCl3


3) 27 (t 2H CH

3-CH2-CH2



3 75MHz)


3) 384 (CH

3-CH2-CH2) 248 (CH

3-

CH2-CH2) 137 (CH


C17H16O4N2(M+H)+ 3131183 found 3131182


50) and 90 (IC





and CC90



duplicate













C kruseiATCC 6258

















R

OH

R

OH(i)

R

OH

(ii)

R N

O

R

(iii)OH

(iv)

N

H

O

（3（3 （3

（3（3

（2

2

R = allyl

R = propyl


andash d andash d

２

２
















4 Conclusion




Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of








C kruseiATCC 6258

















R

OH

R

OH(i)

R

OH

(ii)

R N

O

R

(iii)OH

(iv)

N

H

O

（3（3 （3

（3（3

（2

2

R = allyl

R = propyl


andash d andash d

２

２
















4 Conclusion




Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of








4 Conclusion




Acknowledgments


References




































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Antifungal Activity of New Eugenol-Benzoxazole Hybrids ...

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