Study on the Preparation Process of Nevirapine Intermediate
Using 2,6-dichloro-4-methylpyridine as raw material,2-chloro-3-amino-4-methyl pyridine can be obtained through nitration reaction,and "one-pot method" which including the selective reduction and dechlorination.The nitration reactions through traditional method of mixed acid and micro-channel reactor have been investigated respectively.Wilkinson catalyst has been used in the selective reduction and dechlorination which were names as"one-pot method".This catalyst has the advantages of high selectivity,good stability and repeated application.The optimum nitrification conditions were micro-channel reactor,reaction temperature was 15℃,residence time was 60 seconds,the molar ratio of fuming nitric acid to 2,6-dichloro-4-methyl was 1.2 ∶ 1,and the yield was 93%.The optimum conditions of "one-pot method" were as below:the amount of catalyst added was 1.2%,reaction temperature was 90℃,pressure was 1.1 MPa and the yield was 92%.
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