Synthesis and antimicrobial activity of new 1,2,4‐triazole, 1,3,4‐oxadiazole, 1,3,4‐thiadiazole, thiopyrane, thiazolidinone, and azepine derivatives

Abstract

Abstract4‐oxo‐4‐phenylbutanehydrazide 3 was reacted with aryl or alkyl isothiocyanates to give the corresponding N‐substituted‐2‐(4‐oxo‐4‐phenylbutanoyl) hydrazine‐1‐carbothioamide 4a‐c. Cyclization of thiosemicarbazides 4a‐c with sodium hydroxide led to the formation of 3‐(4‐sub‐5‐thioxo‐1,2,4‐triazol‐3‐yl)‐propanone 5a‐c. Desulfurization of thiosemicarbazides 4a‐c by mercuric oxide afforded 3‐(5‐(sub‐amino)‐1,3,4‐oxadiazol‐2‐yl)‐propanone 6a‐c. The reaction of 4a‐c with phosphorus oxychloride gave 3‐(5‐(sub‐amino)‐1,3,4‐thiadiazol‐2‐yl)‐propanone 7a‐c. Treatment of 4a‐c with ethyl‐bromoacetate or α‐bromopropionic acid gave N′‐(3‐sub‐thiazolidin‐2‐ylidene)‐butanehydrazide 8a‐c and (N′‐(3‐sub‐oxothiazolidin‐2‐ylidene)‐butanehydrazide 9a‐c. Chlorination of oxothiazolidine‐hydrazide 9a‐c by phosphorus oxychloride afforded N‐(3‐sub‐4‐oxothiazolidine)‐butane‐hydrazonoyl‐chloride 10a‐c. The reaction of 10a‐c with mercaptoacetyl‐chloride yielded 2‐((4‐benzoyl‐thiopyrane) hydrazono)‐3‐sub‐thiazolidinone 11a‐c. Also, reacted of 10a‐c with hydrazine hydrate afforded N″‐(3‐sub‐oxothiazolidine)‐butane‐hydrazon‐hydrazide 12a‐c. The 3‐sub‐2‐((pyridazine) hydrazono) thiazolidinone 13a‐c was obtained by cyclization of 12a‐c via refluxing in DMF. The reaction and cyclized of 9a‐c with chloroacetyl‐chloride in ethanolic KOH afforded 1‐((3‐sub‐4‐oxothiazolidine) amino)‐azepine‐dione 14a‐c. The chemical structures of the new compounds have been confirmed by diverse spectroscopy analyses such as IR, NMR, MS, and elemental analysis. The synthesized compounds were tested for their antimicrobial activity and these compounds were considered (Pyridazin‐hydrazono‐thiazolidinone 13a‐c, oxothiazolidin‐azepinedione 14a‐c, N‐thiazolidin‐hydrazon‐hydrazide 12a‐c, and thiopyran‐hydrazono‐thiazolidinone 11a‐c) the most effective as antimicrobial activity.