A new class of dihaloquinolones bearing N'-aldehydoglycosylhydrazides, mercapto-1,2,4-triazole, oxadiazoline and a-amino ester precursors: synthesis and antimicrobial activity

Abstract

Reaction of the quinolones 6-8 with hydrazine afforded the hydrazide 9-11 in moderate yields. Condensation of 9 and 11 with CS2 /KOH furnished the potassium salts 13 and 14, respectively, which spontaneously afforded the 3-(1,2,4-triazolyl)-quinolones 15 and 16, respectively, on treatment with hydrazine. Reaction of 9 in refluxing CS2 /KOH gave the 3-(1,2,4-oxadiazolyl)-quinolone 17. Alternatively, 15 was prepared from 17. The azide derivative 12, obtained from 10, furnished the a-amino ester derivative 18, on reaction with the glycine ethyl ester. Coupling of 10 with various sugars gave the N'-aldehydoglycosyl-quinolone-3-yl)carbohydrazides 19a-e. The newly synthesized compounds were screened for their antibacterial activity.

Keywords

• antimicrobial activity
• hydrazides
• quinolones