• Title/Summary/Keyword: Thiazoles

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Synthesis of New 2,4-Diimino-1,3-thiazoles and the Structure Determination (새로운 2,4-Diimino-1,3-thiazoles 유도체의 합성과 구조 결정)

  • Hoh-Gyu Hahn;Chul-soo Lim;Heduck Mah
    • Journal of the Korean Chemical Society
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    • v.47 no.1
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    • pp.38-42
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    • 2003
  • For the purpose of developing new agrochemical fungicides, compound 2 possessing 1,3-thiazole scaffold as well as urea moiety in the structure was designed through molecular modification of lead compound, 2-imino-1,3-thiazoline based on isosterism. The reaction of N-methylthiouea 5 and bromoacetonitrile in ethanol gave 2,4-diimino-1,3-thiazole 4 regioselectively, which was treated with phenyl isocyanates to give the corresponding 7 which is tautomer of 2. The structural assignment of 7 was confirmed by various spectra($^1H$ NMR, $^{13}C$ NMR, FT-IR, HRMS), and X-ray crystallographic data. Compound 8 which is a structural isomer of 7 was formed through thermodynamically unstable intermediate 2,4-diimino-1,3-thiazole 6.

Studies on the Volatile Flavor Compounds of Sesame Oils with Roasting Temperature (볶음온도에 따른 참기름의 휘발성향기성분 변화)

  • Kim, Hyeon-Wee;Park, Ki-Moon;Choi, Chun-Un
    • Korean Journal of Food Science and Technology
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    • v.32 no.2
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    • pp.238-245
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    • 2000
  • This study was investigated to compare the changes of flavors in sesame oil with roasting temperature $(110^{\circ}C{\sim}230^{\circ}C)$. In the results of analyzing the volatile flavor compounds of sesame oil with GC and GC/MS, 26 pyrazines, 11 pyridines, 9 thiazoles, 6 furans, 8 pyrroles, 5 phenols, 8 aldehydes, 8 hydrocarbons, 7 alcohols, 2 indoles, 3 ketones, 10 acids, 4 nitriles, 7 esters, and 5 others were isolated, identified, and quantified. The total amount of flavor compounds was increased with roasting temperature. Detected flavors could be devided into top(peak No. $1{\sim}91$), middle$(92{\sim}197)$ and last note$(198{\sim}224)$ by rentention time. The top notes(initial content 19.87 ppm) which contain pyrazines and provide representative roasted flavors were increased significantly with roasting temperature. Initial content of middle note(17.72 ppm) was increased to 36.71 ppm at $170^{\circ}C$, to 95.61 ppm at $220^{\circ}C$, and to 138.62 ppm at $230^{\circ}C$. Last note was almost unchanged up to $170^{\circ}C$ and increased at $190^{\circ}C$, whereas it indicated a tendency to decrease at $230^{\circ}C$. Pyrazines such as methylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, trimethylpyrazine, 2-ethyl-3,5-dimethylpyrazine which indicate the major components among volatile flavors were increased slightly up to $150^{\circ}C$ and revealed the higher increase than any other components above $170^{\circ}C$. This tendency was also similar to pyridines, thiazoles, and furans. Most of these compounds are assumed to be developed by thermochemical reactions of sesame components by roasting above $170^{\circ}C$. It seemed that a lot of increase in phenols above $210^{\circ}C$ resulted from the production of guaiacol. Acids were almost unchanged up to $190^{\circ}C$, increased at $210^{\circ}C$, and then decreased above $220^{\circ}C$. It seemed to be resulted from pyrolysis of free fatty acids formed from thermal oxidation of oil.

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Synthesis, Anticancer and Antioxidant Activity of Novel 2,4-Disubstituted Thiazoles

  • Tran, Nguyen Minh An;Kumar, Mungara Anil;Chang, Seung Hyun;Kim, Mi Yeong;Kim, Jung-Ae;Lee, Kap Duk
    • Bulletin of the Korean Chemical Society
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    • v.35 no.6
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    • pp.1619-1624
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    • 2014
  • A new series of carbazole based 2,4-disubstituted thiazole derivatives were synthesized. All the synthesized compounds were tested for their cytotoxicity against three different cancer cell lines A549, MCF-7, and HT29. Some of these compounds showed good cytotoxicity. These compounds were also evaluated for antioxidant activity. Compounds 3a, 3b, 3d-f and 3i showed higher antioxidant activity than standard BHT.

New Synthesis of 2-Substituted Imidazo[2, 1-b]thiazoles and their Antimicrobial Activities

  • Mahfouz, A.Abdel Aziz;Elhabashy, F.M.
    • Archives of Pharmacal Research
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    • v.13 no.1
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    • pp.9-13
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    • 1990
  • 4, 5-Diphenyl-2-mercaptiomidazole (I) was reacted with hydraziodyl halides IIa-d togive the S-alkyl derivatives III-a-d. Cyclization of IIIa-d afforded imidazo[2, 1-b]-thiazole derivatives Vla, b and VII. Treatment of 1 with a-chloroethylacetoaccetate (IV) gave ethyl 2(4, 5-diphenyl-2-imidazolinylthio)-3-keto-butyrate (V). Compound V coupled with benzendiazonium chloride to give the corresponding phenylhydrazo compound IIId. On heating V with polyphosphoric acid, cyclization took place and 2-acetyl-5, 6-diphenyl-imidazo [2, 1-b] thiazol-3-one (VIII) was obtained. The compound VIII was condensed with aromatic aldehydes to yield the cinnamoyl derivatives 1Xa, b. The antimicrobial activities of compounds IIIa-d, V, VIa, VII were examined.

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Synthesis of Histamine $H_2$-receptor antagonists - Synthesis of 5,6-dihydro[2,1-b]thiazole derivatives - (Histamine $H_2$-수용체길항제의 합성 - 5,6-Dihydroimidazo[2,1-b]thiazole 유도체의 합성 -)

  • 박상우;이강노
    • YAKHAK HOEJI
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    • v.35 no.5
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    • pp.368-371
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    • 1991
  • For the development of new antiulcer agents 5, 6-dihydroimidazo[2, 1-b]- thiazoles substituted at the 3-position are sythesized. Thus, the reaction of 3-chloromethyl-5, 6-dihydroimidazo[2, 1-b]thiazole(2) with thiourea and subsequently with 3-chloro-propionitrile gives 3-[3-[5, 6-dihydroimidazo[2, 1-b]thiazolyl]methylthio]propionitrile(4), which by partial alcoholysis with methanol is converted into methyl-3-[3-[5, 6-dihydro-imidazo[2, 1-b]thiazoyl]methylthio]propionimidate(5) . This compound(5) is treated finally with sulfamide or sulfonamides. 3-[3-[5, 6-dihydroimidazo[2, 1-b]thiazoyl]methylthiol-N$^{2}$-sulfamoyl-propionamidine(6) inhibited gastric acid secretion (45%) when administered intraduodenally (100 mg/kg) to pylorus-ligated rats.

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Physicochemical and Sensory Characteristics of Sesame Oils Manufactured in Korea, Japan and China (한국(韓國), 일본(日本), 중국(中國) 삼개국(三個國) 참기름의 이화학적(理化學的) 특성(特性) 및 궁능적(宮能的) 특성(特性))

  • Kim, Hyeon-Wee;Lee, Min-Jung;Kim, Ki-Hong
    • Proceedings of the EASDL Conference
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    • 2004.10a
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    • pp.107-129
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    • 2004
  • Sesame oil has been popular for hundreds of years in Korea because of its pleasant flavor and health benefits and has been studied for its antioxidant properties and flavor preferences attributed to its manufacturing methods. The objective of this study was to investigate the qualitative properties of six commercial sesame oils (3 Korean, 2 Japanese, 1 Chinese), The fatty acids in the oil are composed of two main acids oleic acid and linoleic acid with a P/S ratio of 4.99${\sim}$5.73. Of the tocopherol isomers, ${\gamma}$-toc ranged from 23.14 to 34.85mg/100g. Lignan such as sesamin(322.91${\sim}$689.39ppm) and sesamolin (62.19${\sim}$289.82 ppm) is found predominantly in sesame oil. Sesamol (8.52${\sim}$51.21 ppm) was significantly different depending on manufacturer, observed as greatest in the Korean and least in the Japanese products. The induction period was longest in order of the Korean, Chinese, and then Japanese product. The red and yellow values in Lovibond color were highest in the Korean and lowest in the Japanese product. The major volatile compounds (in order of content) were pyrazines, phenols, aldehydes, and then furans and contained a small amount of pyrroles, thiazoles and indoles. The levels of total volatiles were greatest in the Korean and least in the Japanese product. The most abundant volatiles in the Korean product were pyrazines, whereas phenols were higher in the Chinese product compared to the others. From these results, the relationships among pyrazines, sesamol, yellowness and induction period showed positive, respectively. In sensory evaluation, Korean panelists preferred, in order, the Korean, Japanese, and then the Chinese product in strength of and preference for the sesame flavor, also ranking it best in overall acceptance. Japanese panelists found similarities in the Korean and Japanese products and gave an equal level of preference for the sesame flavor and overall acceptance. On the other hand, Chinese panelists preferred the Japanese product in strength and sesame flavor rating it best on overall acceptance.

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Synthesis of New Heterocycles Derived from 3-(3-Methyl-1H-indol-2-yl)-3-oxopropanenitrile as Potent Antifungal Agents

  • Gomha, Sobhi M.;Abdel-Aziz, Hatem A.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.9
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    • pp.2985-2990
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    • 2012
  • New thiazoline derivatives 7a-c, and thiophenes 9a-c linked to indole moiety were easily prepared via the reaction of the acrylamide derivative 3 with phenacyl bromides 4a-c, depending on the reaction conditions. In addition, the reaction of compound 3 with hydrazonoyl chlorides 11a-f afforded a series of 1,3,4-thiadiazole derivatives 13a-f. Moreover, coupling of 3-(3-methyl-1H-indol-2-yl)-3-oxopropanenitrile (2) with the diazonium salts of 3-phenyl-5-aminopyrazole 16 or 3-amino-1,2,4-triazole 17 gave the corresponding hydrazones 18 and 19, respectively. Cyclization of the latter hydrazones yielded the corresponding pyrazolo[5,1-c]-1,2,4-triazine and 1,2,4-triazolo[5,1-c]-1,2,4-triazine derivatives 20 and 21, respectively. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, $^1H$ NMR and mass spectral data. All the synthesized compounds were tested for in vitro activities against certain strains of fungi such as Aspergillus niger, Aspergillus nodulans, Alternaria alternate. Compounds showed marked inhibition of fungal growth nearly equal to the standards.

Analysis of Volatiles in Sesame Oil Collected by Simultaneous Distillation/Extraction(SDE) and Dynamic Headspace Sampling (DHS) (연속수증기증류법(SDE)과 동적헤드스페이스법(DHS)에 의한 참기름 중의 향기성분의 분석)

  • Ha, Jaeho
    • Analytical Science and Technology
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    • v.9 no.4
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    • pp.399-405
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    • 1996
  • The flavor compounds of the oil from roasted sesame seeds were collected by simultaneous steam distillation/ extraction(SDE) and dynamic headspace sampling(DHS) and were analyzed using a gas chromatograph equipped with a flame ionization detector and connected into a mass spectrometer. Among the flavor compounds collected by the SDE method, 46 compounds were identified. They consisted of 6 alcohols, 6 aldehydes, 5 ketones or acids, 4 furans or phenols, 12 pyrazines, 4 pyridines or thiazoles, and others. Thirty six compounds were identified by DHS and many of them were the same as those identified by the SDE method. However, some compounds such as 1-hexanol, pentanal, and dimethylsulfide were identified only by the DHS method.

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Volatile Flavor Components in Green Tea Blended with Parched Naked Barley (볶은 쌀보리를 혼합한 녹차의 휘발성 향기성분)

  • Choi, Sung-Hee
    • Journal of Life Science
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    • v.22 no.7
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    • pp.981-986
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    • 2012
  • To produce a new tea with a good flavor and functional properties using green tea of low quality, naked barley and barley were selected to blend with the green tea. The simultaneous distillation extraction method (SDE) using Likens and Nickerson's extraction apparatus was used to extract the volatile flavor compounds from the samples. The concentrated flavor extracts were analyzed and identified by GC and GC-MS. The GC patterns of the flavor components in two parched barleys were very different. The main volatile flavor components in two of the samples were alkyl pyrazines. Compounds including 3-methylbutanal, 2-methylbutanal, dihydro-2-methyl-3(2H)-furanone, 2,5-dimethyl pyrazine, and 3-ethyl-2.5-dimethyl pyrazine were isolated from the naked barley. Compounds including thiophenes, thiazoles, sulfides, and pyrroles with burnt odor were isolated from the barley. The parched naked barley was better than barley for adding to green tea. The main aroma components of the green tea blended with the naked barley were hexanol, hexanal, trans-2-hexenal, ${\beta}$-ionone, ${\alpha}$-ionone, alkyl pyrazines, 3-methylbutanal, 2-methylbutanal, and furfural.