C(3)-alkylation and cyclization of pyrazino[1,2-b]isoquinolin-4-ones |
| |
Authors: | Irene Ortí n |
| |
Affiliation: | Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad Complutense, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain |
| |
Abstract: | To avoid the epimerization of the C(11a)-stereocenter previously observed in 6,11a-cis-pyrazino[1,2-b]isoquinolin-1,4-diones, we present in this paper the C(3)-alkylation of 1-methoxy-pyrazino[1,2-b]isoquinolin-4-ones to obtain all-cis derivatives through a very reliable protocol. The success of the acid-promoted cyclization to get pentacyclic (R3=arylmethyl) or tetracyclic (R3=2-bromo-2-propenyl) compounds is dependent on the nature of the C(3)-unsaturated chain and of the N-substituent, but these limitations have been overcome by using trifluoromethanesulfonic as a superacid catalyst. The C-(3)-alkylation of pyrazino[1,2-b]isoquinolin-4-one is also studied. |
| |
Keywords: | Diastereoselective alkylation Tetrahydroisoquinolines Pictet-Spengler Superacid catalysis |
本文献已被 ScienceDirect 等数据库收录! |
|