中文摘要：

本文对雷尼替丁的传统化学合成方法进行优化和改进,提高了收率和纯度。氮气保护下,以蒸馏水为溶剂,将N-甲基-1-甲硫基-2-硝基乙烯胺（简称侧三）和2-[[[5-（二甲氨基）甲基-2-呋喃基]甲基]硫基]乙胺（简称氨乙基硫醚）按照摩尔比1.156：1投料,36℃下反应4h。反应结束后,对反应液调酸至 pH=3.5~4,经二氯甲烷萃取,得到有机相和水相。有机相回收侧三,回收率高达98.9%。水相调碱至pH=9~10,经萃取、干燥、过滤、浓缩、重结晶,得到雷尼替丁,收率最高达89.7%,熔点：68-70℃。

英文摘要：

The traditional chemical synthesis methods have been optimized to get high yield and purity of ranitidine in this paper. Under the protection of nitrogen, N-methyl-1-alkylthio-2-nitroethenamines （referred to as “three side”） and 2-[[[5-（dimethylamine）methyl-2-furanyl]methyl]thio]ethylamine（referred to as“thiobisethylamine”） as raw material in the mole ratio of 1.156：1 was added to the water, keep the temperature at 36 ℃ for 4 h. The reaction mixture can be acidified to a pH= 3.5~4 and extracted with dichloromethane. The organic phase can be used to recycle three side with high recovery rate of 98.9%. Water phase can be basified to a pH=9~10, then it was extracted with dichloromethane again, dried, filtered, evaporated, recrystallised to get the ranitidine with yield of 89.7% and melting point of 68-70 ℃.