Novel synthesis of piperazine ring

摘要

A novel process for preparing a compound of the formula I:whereinR1 denotes substituted or unsubstituted alkyl, alkoxy, aryl, aryloxy or arylalkoxy; R2 denotes substituted or unsubstituted alkyl, alkoxy, aryl, aryloxy, arylalkoxy, tosyl, formyl, acetyl or amine; and R3 denotes substituted or unsubstituted alkyl, alkoxy, aryl, aryloxy or arylalkoxy is disclosed. These compounds are useful in the synthesis of the antidepressant mirtazapine and other tetracyclic compounds.