Regioselective formation of new 3- S -alkylated-1,2,4-triazole-quinolones

Abstract

Regioselective synthesis of quinolone-1,2,4-triazoles was established starting from 4-hydroxyquinol-2-ones. The strategy started by the reaction of ethyl bromoacetate with 4-hydroxyquinoline to give the corresponding ethyl oxoquinolinyl acetates, which reacted with hydrazine hydrate to afford the hydrazide derivatives. Subsequently, hydrazides reacted with isothiocyanate derivatives to give the corresponding acyl thiosemicarbazides. Finally, subjecting the thiosemicarbazide derivatives with ethyl bromoacetate, reaction underwent internal cyclization and alkylation processes. Alkylation occurred regioselectivity to sulfur atom of thione group and not to amino group. Thus 3-S-1,2,4-triazole-quinolones were obtained in good yields. The structure of the obtained compounds was proved by different spectroscopic together with elemental analysis and Xray crystallography.

Synthesis and Identification of New N,N-Disubstituted Thiourea, and Thiazolidinone Scaffolds Based on Quinolone Moiety as Urease Inhibitor

“…For the synthesis of new 4-oxothiazolidin-quinolone hybrids 7a – l , we planned to prepare the N , N -disubstituted thiourea derivatives 5a – g as precursors for functionalized 4-oxothiazolidine derivatives. To approach these targets, the reaction of compounds 4a – c and isothiocyanate derivatives in refluxing ethanol yielded the reported N , N -disubstituted thiourea derivatives 5a , b , d – f [ 37 ]. All the newly synthesized compounds gave satisfactory analyses for the proposed structures, which were confirmed based on their IR, NMR, mass spectra, and elemental analyses.…”

“…N -Allyl-2-(2-((6-methyl-2-oxo-1,2-dihydroquinolin-4-yl)oxy)acetyl)hydrazine-1-carbothioamide (5d) [ 37 ]…”