由邻二甲氧基苯(Ⅰ)经硝化成4-硝基-1,2-二甲氧基苯(Ⅱ),还原成3,4-二甲氧基苯胺(Ⅲ),与光气反应得异氰酸-3,4-二甲氧基苯酯(Ⅳ)与氰胺缩合成N-3,4-二甲氧基苯基-N′-氰基代脲(Ⅴ)再用PCl_5/POCl_3闭环成2-氯-4-氨基-6,7-二甲氧基喹唑磷酸酰胺酯(Ⅵ)及水解成盐酸盐(Ⅶ)再碱化等八步反应合成哌唑嗪的药效关键结构2-氯-4-氨基-6,7-二甲氧基喹唑(Ⅷ),总产率按邻二甲氧基苯计为38.2％。其另一片段糠甲酰基哌嗪(Ⅸ)用哌嗪单盐酸盐代替单氢溴酸盐与糠甲酰氯反应获同样结果。 From o-dimethoxybenzene (Ⅰ) by nitration into 4-nitro-1,2-dimethoxybenzene (Ⅱ), reduced to 3,4-dimethoxyaniline (Ⅲ), and phosgene reaction 3,4-dimethoxyphenyl isocyanate (IV) is condensed with cyanamide to form N-3,4-dimethoxyphenyl-N’-cyanuuoride (V) POCl_3 ring closure into 2-chloro-4-amino-6,7-dimethoxyquinazole phosphate ester amide (Ⅵ) and hydrolysis into hydrochloride (Ⅶ) realkalization and other eight-step reaction prazosin efficacy The key structure of 2-chloro-4-amino-6,7-dimethoxyquinazole (Ⅷ), the total yield of o-dimethoxybenzene 38.2%. The other fragment furfural piperazine (IX) was reacted with furfural chloride by piperazine monohydrochloride instead of monohydrobromide to obtain the same result.