Synthesis and antibacterial activity of 2-hydrazino5-bromomethyl-4,5-dihydrothiazole hydrazones

A series of 2-hydrazino-5-bromomethyl-4,5-dihydrothiazole hydrazones based on substituted N 4 -allylthiosemicarbazones was synthesized. Some of these hydrazones were found to have moderate antibacterial activity against Staphylococcus aureus 209P, 1 and Shigella flexneri. Previous reports have described the synthesis of imidazolinylhydrazones, which included compounds with antitumor [1], mutagenic [2, 3], and other [4] biological activities. The literature contains reports of biologically active 2-amino- and 2-hydrazino-4,5-dihydrothiazole derivatives [5 – 9] whose structures contain an isothioureido system, which is largely responsible for their biological activities [5]. Bromination of N 4 -allylthiosemicarbazones is known to be accompanied by cyclization to form thiazoline rings [10]. This method was used here for the synthesis of 2-hydrazino5-bromomethyl-4,5-dihydrothiazole hydrazones, obtained by the action of bromine on the corresponding N 4 -allylthiosemicarbazones (I) as shown in Scheme 1.