4-甲基-2-肼基苯并噻唑合成工艺研究

Synthesis of 4-methyl-2-hydrazinobenothiazole

研究了4-甲基-2-肼基苯并噻唑改进合成工艺.邻甲基苯基硫脲(简称苯基硫脲)溶于二氯乙烷中,然后通入氯气,生成4-甲基-2-氨基苯并噻唑盐酸盐(简称AMBT盐酸盐).然后以AMBT、AMBT盐酸盐和水合肼为原料,乙二醇为反应溶剂,通过取代反应合成4-甲基-2-肼基苯并噻唑.产品及重要中间体经红外光谱、核磁共振确定并经气相色谱测定产品纯度为98.2%,收率达到90.3%.综合考虑了影响反应的因素:成环反应试剂的选择、投料比、溶剂量、反应时间和反应温度.最佳反应条件:采用氯气来替代SOCl2或KBr,AMBT与水合肼的摩尔比为1∶6.5,乙二醇15 mL,取代反应时间为7 h,反应温度115℃.该路线工艺条件温合,操作简单,产品含量高,具有较好的社会效益和经济效益,适合工业化生产.

An improved process was developed for the synthesis of 4-methyl-2-hydrazinobenothiazole. 4-methyl-2-aminobenzothiazole hydrochloride （AMBT· HCl） was synthesized by N-（2-methylphenyl） thiourea and chlorine. 4-methyl-2-hydrazinobenothiazole was synthesized by substitution reaction with AMBT and AMBT · HCl as raw materials and ethylene glycol as solvent. The target compound and key intermediate were separated and characterized by gas chromatography （GC）, infrared spectrum （IR）, nuclear magnetic resonance （NMR）. The yield of the target compound can be reached 90.3% （purity of 98.2%）. The factors of reaction include the confirmation of reagent, feed molar ratio, solvent, quantity reaction time and reaction temperature. The preferred reaction conditions include that taking chlorine instead of SOCl2 or KBr, the molecular ratio between AMBT and hydrazine hydrate is 1 ： 6.5, glycol 15 mL, the reaction period is seven hours and the reaction temperature is 115 ℃. The advantages of synthetic route proposed are easy operation, mild reaction condition, high yield and suitable for industrialization.