Mechanism of unusual formation of 3-(5-phenyl-3H-[1,2,4]dithiazol-3-yl)chromen-4-ones and 4-oxo-4H-chromene-3-carbothioic acid N-phenylamides and their antimicrobial evaluation
摘要:
6/6,7-Substituted 3-formylchromones (9a-e) react with 2 equivalents of 2-phenyl-4-dimethylamino-1-thia-3-azabuta-1,3-diene (10) or thiobenzamide (11) in refluxing toluene to furnish novel substituted 3-(5-phenyl-3H-[1,2,4]dithiazol-3-yl)chromen-4-ones (12a-e). However, reactions of substituted 2-anilino-3-formylchromones (15a-d) with thiobenzamide (11, 2 equivalents) in refluxing xylene furnish 4-oxo-4H-chromene-3-carbothioic acid N-phenylamide (17a-d) in high yields. A mechanistic rationalization of the conversion of 2-anilino-3-formylchromones (15a-d) to N-phenylamides (17a-d), and 3-formylchromones (9a-e) to the corresponding thioaldehydes, is proffered. All the compounds (12a-e, 17a-d) display very high antifungal and antibacterial activities against a number of strains. Dithiazole 12d exhibits a very high antifungal activity (MIC 5 mu g/ml) against Geotrichum candidum, better than fluconazole (MIC 09 mu g/ml) and also possesses good antibacterial activity (MIC 52 mu g/ml) against Shigella flexneri. (C) 2009 Elsevier Masson SAS. All rights reserved.
Reduction of chromano–piperidine-fused isoxazolidines: Tandem intramolecular rearrangements leading to 2-(methylamino)-4-oxo- N -phenyl- N -propyl-4 H -chromene-3-carboxamide
作者:Gagandeep Singh、Naman Gupta、Vivek Gupta、Mohan Paul Singh Ishar
DOI:10.1016/j.tetlet.2017.05.032
日期:2017.6
Reductive ring opening of isoxazolidine moiety of chromano–piperidine-fused isoxazolidines (3a–c) with HCOONH4 and 10% Pd/C in a mixture of solvents (THF/MeOH) at ambient temperature, affords novel 2-(methylamino)-4-oxo-N-phenyl-N-propyl-4H-chromene-3-carboxamide (4), which is apparently derived from reductive NO bond cleavage followed by tandem intramolecular rearrangements. Plausible mechanistic
Domino routes to substituted benzoindolizines: tandem reorganization of 1,3-dipolar cycloadducts of nitrones with allenic esters/ketones and alternative cycloaddition–palladium catalyzed cyclization pathway
作者:Ashish Kapur、Kamal Kumar、Lakhwinder Singh、Parminder Singh、Munusamy Elango、Venkatesan Subramanian、Vivek Gupta、Priyanka Kanwal、Mohan Paul S. Ishar
DOI:10.1016/j.tet.2009.03.076
日期:2009.6
intramolecular aza Diels–Alderreaction in the intermediate C. DFT calculations of various parameters for diene and dienophile components in the proposed intermediate C have revealed that conformational constraints imposed by the alkyl groups (R=Me, Et) favor intramolecular aza-Diels–Alder cycloaddition. An alternative domino route to benzoindolizines (9a,d,g) involving sequential one-pot cycloaddition of azadienes
6/6,7-Substituted-3-formylchromones (8a-g) were reacted with 2 equivalents thiobenzamide (9) in refluxing toluene to furnish substituted -3-(5-phenyl-3H-[1,2,4]dithiazol-3-yl)chromen-4-ones (10a-g) in high yields. Similarly, when substituted-2-anilino-3-formylchromones (8a-d) were reacted with thiobenzamide (9, 2 equivalents) in refluxing xylene, 4-oxo-4H-chromene-3-carbothioic acid N-phenylamides (11a-d) were obtained in high yields. All the compounds (10a-g) and (11a-d) display significant cytotoxic activity against a number of human cancer cell lines. Among these compounds 10e (IC50 = 10 mu M), 10b (IC50 = 14.6 mu M) and 10a (IC50 = 10.5 mu M) showed maximum cytotoxic activity on neuroblastoma. Also, the compound 10c (IC50 = 10.5 mu M) showed maximum cytotoxic activity on ovarian cancer cell line. (C) 2009 Elsevier Masson SAS. All rights reserved.