Synthesis and Antibacterial Activity of some Hdrazides, Substituted Thiosemicarbazide, 1,3,4-Oxadiazoles, Thiadiazoles and 1,2,4- Triazoles

Abstract

In the present work five ethyl esters (1-5) were treated with hydrazine hydrate in
ethanol to give the corresponding acid hydrazides (6-10). The hydrazides were
converted to substituted thiosemicarbazides (11-14) by their reaction with phenyl
isothiocyanate, while on heating at 150-200 °C substituted 1,2,4-triazole was obtained
(15). The thiosemicarbazides were converted to substituted 1,2,4-triazoles (16-19),
1,3,4-oxadiazoles (20-22) and 1,3,4-thiadiazoles (23-26) by their reaction with
sodium hydroxide, mercuric oxide in methanol and concentrated sulfuric acid
respectively. The synthesized compounds (7, 11, 15, 18, 20, 22, 24 and 26) were
tested against Staph. Aureus, Bacillus subtilis, Proteus mirabilis, E. coli, K.
pneumonia and Pseudomonas aeroginosa, and the compounds (10, 16, 17, 19, 23 and
25) against E. coli, Pseudomonas aeroginosa, Proteus mirabilis and Staph. aureus.
The structures of the synthesized compounds were established by physical and
spectral methods.