Solvent-Free Condensation Reactions To Synthesize Five-Membered Heterocycles Containing the Sulfamide Fragment (original) (raw)
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Synthesis and Reactions of New Thiazoles and Pyrimidines Containing Sulfonate Moiety
Journal of Heterocyclic Chemistry, 2018
Treatment of 2-tosyloxybenzylidinethiosemicarbazone (2) with active halo compounds afforded thiazoles 3-5. Moreover, reaction of compound 2 with acetic anhydride or dimethylformamide dimethylacetal gave N,N diacetyl 6 and dimethylamino derivatives 7, respectively. Cyclization of thiazole derivatives 3 with some arylidenemalononitriles yielded thiazolo[2,3-d]pyrans 8-12. Multicomponent reaction of 2-tosyloxybenzaldehyde (1) with urea, thiourea, or compound 2 and ethyl acetoacetate or acetylacetone afforded pyrimidines 13-14. The structures of compounds were elucidated by elemental and spectral analyses.
Organic Magnetic Resonance, 1981
The conformational preferences in solution of eight new open-chain and cyclic aromatic sdphides containing pyridine or 1,3,4-thiadiazole nnits have been investigated, parallel to those of some structurally related phenyl sulphides, by means of 'H NMR spectroscopy. The results obtained have shown that replacement of phenyl by the pyridyl or the 1,3,4-thia&azolyl moieties induces slightly different propeller arrangements, ascriied to the higher conjugative tendency of both electron-defiaent heteroaromatic rings, in all open-chain mixed sulphides, in opposition to the skew arrangements observed for phenyl sulphide derivatives. No prominent differences have been found for cydic sulphides, which preferentially adopt the sterically unhindered saddle shape conformation.
Islamic Azad University Of Qaemshahr, 2016
The present study describes the synthesis of some novel arylidene cyclic chalcones 2-(4-substituted benzylidene)-6,6-diphenylimidazo[2,1-b][1,3]thiazole-3,5-diones and their transformation to 3-(4-substitutedphenyl)-6,6-diphenyl-3,3adihydroimidazo[2',1':2,3][1,3]thiazolo[4,5-c][1,2]oxazol-7(6H)-ones via cyclization using hydroxylamine hydrochloride. The starting chalcones have been synthesized by the condensation of various aromatic aldehydes and methylene entity of synthesized imidazothiazole-3,5-diones which were obtained by the cyclization of 5,5-diphenyl-2-thioxoimidazolidin-4-ones and chloroacetic acid. The intermediate 5,5-diphenyl-2-thioxoimidazolidin-4-ones have been synthesized by the condensation of α-diketone (benzil) with thiourea in presence of ethanolic alkali followed by Pinacol-Pinacolone rearrangement. Structures of all the newly synthesized compounds were confirmed by chemical, analytical and spectral data.
Journal of Physical Organic Chemistry, 2003
Although 2-mercapto-5-methyl-1,3,4-thiadiazole (mmtd) is commonly thought of as a thione tautomer, electrophilic substitution occurs on the thiol moiety. The tautomeric ability of mmtd allows a substitution reaction to take place at the sulphur; this is shown by reaction with Cl3−nFnCSCI compounds (n = 0–2) to give perhalomethyldithio thiadiazole derivatives. Three novel perhalomethylsulphenyl compounds, which exhibit a wide range of potentially interesting applications, were obtained and characterized by x-ray crystal diffraction, mass spectrometry, IR and Raman spectroscopy and density functional theory calculations. Copyright © 2002 John Wiley & Sons, Ltd.
European Journal of Medicinal Chemistry, 2012
Some new 5-(4-(4-X-phenylsulfonyl)phenyl)-4-(R)-2H-1,2,4-triazol-3(4H)-thiones 4a,b; 5a,b and 5-(4-(4-X-phenylsulfonyl)phenyl)-N-(R)-1,3,4-thiadiazol-2-amines 6a,b; 7a,b were obtained by cyclization of new N 1 -[4-(4-X-phenylsulfonyl)benzoyl]-N 4 -(R)-thiosemicarbazides 2a,b; 3a,b (X ¼ H, Br). The 1,2,4triazoles were synthesized by intramolecular cyclization of acylthiosemicarbazides, in basic media. On the other hand, 1,3,4-thiadiazoles were obtained from same acylthiosemicarbazides, in acidic media. These new intermediates from thiosemicarbazide class were afforded by the reaction of 4-(4-X-phenylsulfonyl)benzoic acids hydrazides (X ¼ H, Br) 1a,b with 4-trifluoromethoxyphenyl or 3,4,5trimethoxyphenyl isothiocyanate. The newly synthesized compounds were characterized by IR, 1 H NMR, 13 C NMR, MS and elemental analysis. All the new compounds were screened for their antimicrobial activity against some bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 13061, Escherichia coli ATCC 25922, Enterobacter cloacae ATCC 49141, Acinetobacter baumannii ATCC 19606 and Pseudomonas aeruginosa ATCC 27853) and yeasts (Candida albicans ATCC 90028 and Candida parapsilosis ATCC 22019).
An Efficient Synthesis of New Thiazole Based Heterocycles
HETEROCYCLES, 2010
Synthesis of new aminopyrazole, pyrazolo[3,4-d]-1,2,3-triazine, 1,3,4thiadiazole, thiophene and 1,2-dihydropyridine derivatives containing thiazole template has been carried out by simple, efficient and good yielding routes starting from the versatile and readily accessible 2-cyano-N-(thiazol-2-yl)acetamide. Thiazoles and their derivatives have attracted continuing interest over the years because of their diverse biological activities. 1,2 They found application in drug development for the treatment of allergies, 3 hypertension, 4 inflammation, 5 schizophrenia, 6 bacterial 7 and HIV infections. 8 They are also used as hypnotics, 9 for the treatment of pain, 10 and as inhibitors of LFA-1/ICAM-1 mediated cell adhesion. 11 In addition, thiazole derivatives show strong FabI and FabK inhibitory effects with potent antibacterial activity. 12 In view of the above mentioned findings, and as a continuation of our interest in the synthesis of a variety of heterocyclic ring systems for biological evaluation, 13-28 we report in the present work the synthesis of some heterocycles containing thiazole template. During our search, we have found that 2-cyano-N-(thiazol-2-yl)acetamide (1) 29 is a versatile, readily accessible building block for synthesis of the target compounds. Treatment of the acetamide 1 with 2-oxo-N'-phenylpropanehydrazonoyl chloride (2) 30 in ethanolic sodium ethoxide, at room temperature, furnished a single product identified as the aminopyrazole derivative 4a. The IR spectrum of the reaction product exhibited absorption bands at 3443, 3331, 3191, 1692 and 1638 cm-1 due to amino, amide-NH and two carbonyl groups, respectively. Prompted by the foregoing results and to generalize this reaction, we have also studied the behaviour of the acetamide 1 towards the 2-oxo-2-(phenylamino)-N'-p-tolylacetohydrazonoyl chloride (5a), 31 under the same experimental
Molecules, 2003
Condensation of 4,4'-diacetyldiphenyl sulphide (2) with variable amounts of thiosemicarbazide (3) in refluxing ethanol and in the presence of catalytic amounts of dry piperidine afforded only 4-acetylthiosemicarbazone-4'-acetyldiphenyl sulphide (5). Condensation of 2 with excess semicarbazide hydrochloride (4) in the presence of fused sodium acetate and/or piperidine yielded 4,4'-diacetylsemicarbazone diphenyl sulphide (6), whereas use of equimolar amounts of 2 and 4 afforded 4-acetyl-semicarbazone-4'acetyldiphenyl sulphide (7). 4-Acetylsemicarbazone-4'-acetylthiosemicarbazone diphenyl sulphide (8) was also obtained via two different routes. The effect of tautomeric structure 5d is discussed. 4-(4"-phenyl-∆ 3-thiazoline-2"-acetylazino)-4'-acetyldiphenyl sulphide (9), 4-(5"-carboxyethyl-4"-thiazolidinone-2"-acetylazino)-4'-acetyldiphenyl sulphide (10), 4-(4"-thiazolidinone-2'-acetylazino)-4'-acetyldiphenyl sulphide (11) and 4-(4"-methyl-∆ 3-thiazoline-2"-acetylazino)-4'-acetyldiphenyl sulphide (12) were prepared by interaction of 5 with phenacylbromide, bromodiethylmalonate, chloro ethylacetate and chloroacetone, respectively. Sulphides 9-12 were easily condensed with 3 to afford the corresponding 4-(heterocyclic moiety-2"-acetylazino)-4'-acetylthiosemicarbazone diphenyl sulphides 23-26. Oxidation of the prepared sulphides 5-7, 9-12, 23 and 25-26 using H 2 O 2 /glacial AcOH mixtures yielded only 4,4'-diacetyldiphenyl sulphone (13) as the main product in every case, besides 3 and 4 in certain cases. Unsymmetrical and symmetrical sulphones 14-22 were obtained starting from 13. The structures of the synthesized compounds are based on IR, 1 H-NMR, 13 C-NMR and mass spectral data. A Molecules 2003, 8 623 theoretical study on some of the prepared compounds using molecular modeling was carried out.
Synthesis and characterization of new pyrazole-based thiazoles
Synthetic Communications, 2017
Melting points were measured on an Electrothermal IA 9000 series digital melting point apparatus. IR spectra were recorded in potassium bromide discs on PyeUnicam SP 3300 and Shimadzu FTIR 8101 PC infrared spectrophotometers. 1 H-NMR and 13 C-NMR spectra were recorded in deuterated dimethyl sulfoxide (DMSO-d6) using a Varian Gemini 300 NMR spectrometer (300 MHz for 1 H-NMR and 75 MHz for 13 C-NMR). Chemical shifts were related to that of the solvent. Mass spectra were recorded on a Shimadzu GCMS-QP1000 EX mass spectrometer at 70 eV. Elemental analyses were measured by using a German made Elementarvario LIII CHNS analyzer. Synthesis of thiazoles 3a-e General method: To a solution of thiosemicarbazone 2 (0.273 g, 1 mmol) in ethanol (20 mL), bromoacetyl derivatives 2a-e (l0 mmol) were added. The mixture was refluxed for 4-8 h (monitored by TLC), then left to cool. The solid product was filtered off, washed with ethanol and recrystalized from ethanol or dioxane to afford the thiazole derivatives 3a-e, respectively. The products 3a-e together with their physical constants are listed below.