Substituted pyrrolidines have been prepared in good yields by heating N-chlorine derivatives of secondary amines with a mixture of sulfuric acid and water. Amines such as methyl-n-butylamine, ethyl-n-butylamine, methyl-n-amylamine, and di-n-butyl amine have been used. The optimal conditions for ring closure are not the same for all amines. Varying amounts of secondary amines are usually recovered. In this reaction an intermediate compound is formed with sulfuric acid. The compound from N-chloro-di-n-butylamine has been isolated as a white solid and analyzed. With N-chloro-N-methyl-n-octylamine ring closure apparently occurs with the fifth carbon from nitrogen to form a substituted piperidine. However, complete identification of the compound has not yet been made. In the application of this method to primary amines n-butylamine was converted to N-chloro-N-n-butyl-p-toluenesulfonamide. Under the usual conditions of ring closure there was formed from this compound a 50% yield of pyrrolidine with a 35% recovery of N-n-butyl-p-toluenesulfonamide.
Proceedings of the Iowa Academy of Science
©1939 Iowa Academy of Science, Inc.
Coleman, George H.
"Ring Compunds from Chloroamines and Amides,"
Proceedings of the Iowa Academy of Science, 46(1), 217-218.
Available at: https://scholarworks.uni.edu/pias/vol46/iss1/44