Reduction of indole compounds to indoline compounds
申请人:McNeil Laboratories, Incorporated
公开号:US04210590A1
公开(公告)日:1980-07-01
A method for reducing indole compounds to the corresponding indoline compounds substantially free of undesirable side reactions is described. The method involves contacting an indole compound with a borane complex reagent in the presence of trifluoroacetic acid. The method is rapidly and readily carried out and provides an excellent method for preparing certain indoline compounds from the corresponding indole compounds. A novel dioxyborane useful as a borane reagent is also disclosed.
A new convenient three-step synthesis of the privileged CNS scaffold 1,2,3,4,10,10a-hexahydropyrazino[1,2-a]indoles has been developed. The method makes use of an intramolecular carbene-mediated C-H insertion in phenylpiperazine-derived tosylhydrazones made from 2-fluorobenzaldehydes. Notably, the piperazine can be replaced with other cyclic nitrogen bases and the methodology is successfully extended to pyrrolidine, piperidine, azepane, morpholine, and homopiperazine.