22-May-2013
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Indian Journal of Chemistry -Section B (IJC-B) >
IJC-B Vol.45B [2006] >
IJC-B Vol.45B(07) [July 2006] >
| Title: | Synthesis and antibacterial activity of new oxadiazolo[1,3,5]-triazine, 1,2,4 triazolo and thiadiazolo 1,3,4 oxadiazole derivatives |
| Authors: | Mulwad, V V
Chaskar, Atul C |
| Keywords: | 3-formyl 4-hydroxycoumarin
semicarbazide
regioselective condensation
phenyl isothiocynate |
| Issue Date: | Jul-2006 |
| Publisher: | CSIR |
| IPC Code: | Int.Cl.8C07D |
| Abstract: | 3-Formyl-4-hydroxycoumarin has been treated with semicarbazide to give 4-hydroxy-2-oxo-2H[1]-benzopyran-3-aldehyde semicarbazone 1a-d, which on oxidative cyclization with bromine in glacial acetic acid in the presence of anhydrous sodium acetate gives 3-(5-amino-1,3,4-oxadiazol-2-yl)-4-hydroxy-2H[1]-benzopyran-2-one 2a-d. 3-(5-amino-1,3,4-oxadiazol-2-yl)-4-hydroxy-2H[1]-benzopyran-2-one on reaction with benzaldehyde gives 4-hydroxy-3-(5-benzylidine imino 1,3,4-oxadiazol-2-yl)-2H[1]-benzopyran-2-one 3a-d. 3a-d on (4+2) cycloaddition with phenyl isothiocynate gives 3-(6,7-diphenyl-5-thioxo-6,7-dihydro-5H-[1,3,4]oxadiazolo[3,2- ][1,3,5]triazin-2-yl)-4-hydroxy-2H[1]-benzopyran-2-one 4a-d. 2a-d undergoes regioselective condensation with KSCN in methanol to give N-[5-(4-hydroxy-2-oxo-2H[1]-benzopyran-3-yl)-1,3,4,-oxadiazol-2-yl]thiourea 5a-d whereas with phenyl isothiocynate it gives N-[5-(-4-hydroxy-2-oxo-2H[1]benzopyran-3-yl)-1,3,4-oxadiazole-2-yl]-N'-phenylthiourea 7a-d. 5a-d reacts with thionyl chloride in pyridine to give 4-hydroxy-3-(6-thioxo-5,6-dihydro[1,2,4]triazolo[5,1-b][1,3,4]oxadiazol-2-yl)-2H[1]-benzopyran-2-one 6a-d. 7a-d on treatment with ethanol and iodine yields 4-hydroxy-3-[6-phenylimino-6H-[1,2,4]-thiadiazolo[3,2-b][1,3,4]-oxadiazol-2-yl]-2H[1]benzopyran-2-one 8a-d. |
| Page(s): | 1710-1715 |
| ISSN: | 0975-0983(Online); 0376-4699(Print) |
| Source: | IJC-B Vol.45B(07) [July 2006]
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