Cularine and Related Compounds. V. Investigation of the Ullmann Reaction Products of Methyl (2-Bromo-4, 5-dimethoxyphenyl) acetate with Phenolic Compounds, and an Approach to the Total Synthesis of Cularine.

Abstract

Preparation of the cyclic amide (II) as the key intermediate for the synthesis of cularine was elaborated. Bischler-Napieralski cyclization of this amide appeared to proceed as expected to give the desired isoquinoline derivative, didehydronorcularine, in a crude state, which, however, was readily oxidized and turned during purification into the corresponding ketone derivative, which was characterized as its picrate.