Synthesis and Biological evalution of some substituted 2-dibenzyl amino 1,3,4-oxadiazoles , thiadiazoles and 1,2,4-triazoles

Abstract

ABSTRACT In this paper the synthesis of some substituted 2-dibenzyl 1,3,4-oxadiazole, thiadiazole and 1,2,4-triazoles derived from dibenzyl amine is reported scheme-1. Dibenzyl amine was treated with chloroacetic acid to give N,N –dibenzyl glycine (1) which was converted to its methyl/ ethyl esters (2,3) .The esters were treated with hydrazine hydrate in ethanol to give hydrazide (4)which was reacted with ammounium thiocyanate to give thiosemicarbazide(5).Treatment of thiosemicarbazid(5)with concentrated sulfuric acid , hydrazine hydrate, 4% sodium hydroxide and with potassium iodide / iodine to gave substituted 1,3,4-thiadiazole (6) 1,2,4- triazole (7) 1,2,4-triazole -3-thiol (8) and 5-amino1,3,4-oxadiazole (9) respectively. The acid (1) was treated with polyphosphoric acid and hydrazine hydrate to give 2,5- disubstituted oxadiazole (10), sulfonation of (10) gave disubstituted 1,3,4- thiadiazole (11). Hydrazides (4) was treated with acid chlorides to give thediketones (12-14) which cyclized to substituted oxadiazoles (15-17) and thiadiazoles (18-20) by their reaction with phosphorus pentoxideand phosphorus pentasulfide respectively.Some of the synthesized compounds were tested against various types of bacteria. The structures of the synthesized compounds were confirmed by physical and spectral methods.

Keywords

• synthesis
• biological evaluation
• 2-dibenzyl amino 1
• 3
• 4-oxadiazoles
• thiadiazoles
• 1
• 2
• 4-triazoles