Synthesis of linezolide like molecules and investigation of their antimicrobial activities

In the present study, first of all, 4-(2-Fluoro-4-nitrophenyl)morpholine (35) was synthesized from the reaction of 3,4-difluoronitrobenzene with morpholino. Then, the nitro group of this compound (35) was reduced to amine group. The treatment of amine (36) with indol-3-carbaldehyde, one by one afforded the corresponding Schiff base, N-((1H-indol-3-yl)methylene)-3-fluoro-4-morpholinobenzenamine (37). The reaction of compound 36 with 4-fluorophenylisothiocyanate led to the formation of 1-[3-Fluoro-4-morpholinphenyl]-3-(4-fluorophenyl)thiourea (38). Then, this urea derivative produced compounds 39 and 40 which are 1,3-thiazole derivatives, by the reaction with ethyl bromoacetate and 4-nitrophenacyl bromide, one by one. Compound 36 was converted to 1-(2-(3-Fluoro-4-morpholinophenylamino)acetyl)-4-(4-fluorophenyl)thiosemicarbazide (43) by the treatment with ethyl bromoacetate, hydrazyne hydrate and 4-fluorophenylisothiocyanate, respectively. The cyclization of compound 43 in basic media afforded 1,2,4-triazole derivative (44) while the cyclization of the same intermediate in acidic media afforded 1,3,4-thiadiazole ring (45). The condenzation of 43 with ethyl bromoacetate and 4-chlorophenacyl bromide, resulted the corresponding thiazole derivatives (46 and 47). The structures of the obtained compounds were confirmed on the basis of spectroscopic methods. The antimicrobial activities were screened by Şengül Alpay Karaoğlu (Rize University Department of Biology).