Comparative conventional and microwave assisted synthesis of heterocyclic oxadiazole analogues having enzymatic inhibition potential

Article abstract of DOI:10.1002/jhet.4150

A comparative microwave assisted and conventional synthetic strategies were applied to synthesize heterocyclic 1,3,4-oxadiazole analogues as active anti-enzymatic agents. Green synthesis of compound 1 was achieved by stirring 4-methoxybenzenesulfonyl chloride (a) and ethyl piperidine-4-carboxylate (b). Compound 1 was converted into respective hydrazide (2) by hydrazine and then into 1,3,4-oxadiazole (3) by CS₂ on reflux. The electrophiles, N-alkyl/aralkyl/aryl-2-bromopropanamides (6a–p) were synthesized and converted to N-alkyl/aralkyl/aryl-2-propanamide derivatives (7a–p) by reaction with 3 under green chemistry. Microwave assisted method was found to be effective relative to conventional method. ¹³C-NMR, ¹H-NMR and IR techniques were availed to corroborate structures of synthesized compounds and then subjected to screening against lipoxygenase (LOX), α-glucosidase, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. A number of compounds presented better potential against these enzymes. The most active compounds against LOX and α-glucosidase enzymes were subjected to molecular docking study to explore their interactions with the active sites of the enzymes.