Noteworthy Mechanistic Precedence in the Exclusive Formation of One Regioisomer in the Beckmann Rearrangement of Ketoximes of 4-Piperidones Annulated to Pyrazolo-indole Nucleus by Organocatalyst Derived from TCT and DMF

Abstract

Abstract Application of a very mild protocol to the Beckmann rearrangement of ketoximes of pyrazolo annulated oxocarbazole 5a and oxoazacarbazole 5b with the organocatalyst derived from 2,4,6-trichloro[1,3,5]triazine (TCT) and dimethylformamide (DMF) has been explored to provide a regioselective formation of the corresponding azepine 6a and 1,4-diazepine 6b respectively in good yield and purity. The mechanistic precedence for the exclusive formation of only one regioisomer has been discussed.