ChemInform Abstract: Stereochemical Issues Related to the Synthesis of 7,10-Dimethyl-7,10,16,16a-tetrahydro-11H-quinazolino [2′,3′:3,4]pyrazino[1,2-b]β-carboline-5,8-diones.

Abstract

Abstract Condensation reactions between anthranilic acid and iminoethers derived from 2,3,6,7,12,12a-hexahydropyrazino[1,2- b ]β-carboline-1,4-diones 3 – 8 to give the title hexacyclic compounds were studied from a stereochemical point of view. The configuration was retained in the formation of iminoethers, but inversion of the tryptophan sterocenter C-16a took place in the condensation process. Epimerization also occurred in an alternative procedure that involves acylation at N-2 with o -azidobenzoyl chloride, followed by intramolecular aza-Wittig reaction.