Design, synthesis, and urease inhibition studies of some 1,3,4-oxadiazoles and 1,2,4-triazoles derived from mandelic acid

Abstract

Some new structural type inhibitors of urease, i.e. 2,5-disubstituted-1,3,4-oxadiazoles (4a–e) and 4,5-disubstituted-1,2,4-triazole-3-thiones (5a–e) were synthesized in two steps from mandelic acid hydrazides (2a–e) and aryl isothiocyantes. The hydrazides in turn were synthesized from mandelic acid via esterification. Compounds 4a–e and 5a–e were evaluated against jack bean urease. Compounds 4d, 5b, and 5d were found to be more potent, with IC₅₀ values of 16.1 ± 0.12 µM, 18.9 ± 0.188 µM, and 16.7 ± 0.178 µM, respectively, when compared to the standard (thiourea; IC₅₀ = 21.0 ± 0.011 µM). These compounds may be subjected to further investigations for the development of antiulcer drugs.

Keywords::

• Triazoles
• oxadiazoles
• urease inhibition
• mandelic acid
• thiosemicarbazides