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S050 3,5-二苯基吡唑的一步合成法刘源发等〔农药(5):10,1982〕标题化合物(Ⅰ)是吡唑鎓盐类如野燕枯等除草剂的重要中间体。原制法是用查耳酮(Ⅱ)与水合肼(Ⅲ)生成3,5-二苯吡唑啉再催化脱氢而得。缺点为周期长并需惰性气体保护。经改进为:将Ⅱ、Ⅲ和钯催化剂同时加入二甲苯中回流脱水,一步完成缩合和脱氢。操作简便,不需惰性气体。收率约90％,纯度近100％。〔王其灼摘〕 S051 硼氢化钠-叔丁醇-甲醇用作酯
S050 One-step synthesis of 3,5-diphenylpyrazole Liu Yuanfa et al [Pesticide (5): 10, 1982] The title compound (I) is an important intermediate of pyrazolium salts such as wild yam and other herbicides. The original method is to use chalcone (Ⅱ) and hydrazine hydrate (Ⅲ) generated 3,5-diphenylpyrazoline derived catalytic dehydrogenation. Disadvantages of long cycle and the need for inert gas protection. The improvement is as follows: the II, III and Pd catalysts are simultaneously added to xylene for reflux dehydration to complete the condensation and dehydrogenation in one step. Easy to operate without inert gas. Yield of about 90%, purity of nearly 100%. [Wang Qi burning pick] S051 sodium borohydride - tert-butanol - methanol as an ester