Total Synthesis and Cytotoxic Activity of 6,8-Dimethoxy-1,3-dimethylisoquinoline Isolated from Ancistrocladus tectorius: A 6π-Azaelectrocyclization Approach

Abstract

A facile and convenient approach toward the total synthesis of 1,3-dimethyl-6,8-dimethoxyisoquinoline from phloroacetophenone is reported. The sequence entailed the selective 2,4-di-O-methylation and further triflation of the resulting phenolic product. This was followed by a Stille-type allylation, an allyl-to-propenyl isomerization, and the methoximation of the carbonyl moiety. A final microwave-assisted 6π-azaelectrocyclization completed the sequence. Functionalized derivatives on C-1 were also prepared. The heterocycles exhibited cytotoxic activity.

Eco-friendly methoximation of aromatic aldehydes and ketones using MnCl 2 .4H 2 O as an easily accessible and efficient catalyst

“…The synthesis of methoximes is a highly relevant transformation with both theoretical and practical implications in the chemistry of carbonyl compounds [1]. Methoximation has been used for characterization and purification of carbonyl compounds, for the protection or activation of carbonyl groups in multistep synthesis [2][3][4][5]; the reaction has also found use in Heck-type and C-H bond activation reactions, as well as in O-H and N-O bond cleavage, followed by coupling or C-N bond formation [6].…”