Paal-Knorr缩合法合成N-烷氧羰基-2,5-二甲基吡咯

Synthesis of N-carboalkyloxy-2,5-dimethylpyrroles by the Paal-Knorr condensation of carbamate with diketone

用对甲苯磺酸作催化剂、甲苯为溶剂，使氨基甲酸酯和2，5-己二酮进行Paal—Knorr缩合反应，拭沸脱水6h，合成出了5种N-烷氧羰基-2，5-二甲基吡咯，产率为76％～89％。探讨了氨基甲酸酯和2，5-己二酮进行Paal—Knorr缩合反应的机理，研究了催化剂种类及用量、反应溶剂和氨基甲酸酯的结构对缩合反应产率的影响。

Five N-carboalkyloxy-2,5-dimethylpyrroles were synthesized by Paal-Knorr condensation from carbamate and 2,5-hexanedione in toluene at the reflux temperature for 6 h. The yields of the condensation reaction were 76% - 89%. The mechanism of Paal-Knorr reaction between a carbamate and 2,5-hexanedione to form a pyrrole was explored. The influences of category and dose of catalysts, solvents and the structure of carbamates on the yields of the condensation reaction were also studied.