ABSTRACT
Some derivatives of pyridazine are reported to exhibit broad spectrum biologic effect [1,2]. Moreover substituted 1,3,4-oxadiazoles have been mentioned to exert wide variety of application in medicine and agriculture[3,4]. On the basis of these findings we wish to report here the synthesis of some substituted [pyridazin-3-yl] thiomethyl, -1,3,4-oxadiazole derivatives and the evaluation of some of their antimicrobial activity. The starting material in this work is ethyl S-[substituted- pyridazin-3-yl] thioglycolate [II] which was obtained either by the reaction of the corresponding 3-thiopyridazine [I[a]] with ethyl chloroacetate [5] or the reaction of the corresponding 3-chloropyridazine [I[b]] with ethyl thioglycolate[6]. II [Ar = Ph, 'Ar = H] showed i.r. absorption bands at 1740 cm[-1] [ester c=o] and 1445 cm[-1] [S-CH2]. The [1] H-NMR spectrum of [II] showed signals at sigma1.2 [CH[3],t, 3H], sigma 4,2 [CH[2]m,4H] and sigma 7.5-8. 2 [Ar-H, m, 7H]. The hydrazides III were prepared by treating the ethyl ester [II] with hydrazine hydrate. Ill [Ar=Ph, R=H] showed i.r absorption bands at 3400-3210 cm[-1] [NH], 1660 cm[-1] [CONH amide 1] and 1390 cm[-1] [S-CH[2]]. The [1]H-NMR spectrum of compound III [Ar=Ph, R=H] showed signals at sigma 4.0 [CH[2],s, 2H], sigma 4.4 [NH, bs, 2H], sigma 7.5-8.2 [Ar-H, m, 7H] and sigma 9.4 [NH, s, 1H]. Mass spectrum of III [Ar=Ph, R=H] showed the following ion fragments m/z [Peak/relative abundance]: 260/20.3 [M[+]], 243/3.8, 201/3.16, 147/7.59, 105/14.87, 103/17.6, 77/100, 73/17.09, 56/29.11, 55/31.01 and 51/14.56