Studies on the Syntheses of Heterocyclic Compounds. LXXIX

Synthesis of Cularine and Related Compounds. (2). The Products of N-[3-(2-Formyl-4, 5-dimethoxyphenoxy)-4-methoxyphenethyl]acetamide by Pictet-Spengler Reaction. (A Synthesis of C-nor-Cularine)

Abstract

Condensation of N-(3-hydroxy-4-methoxyphenethyl)acetamide (VIII) prepared from iso-vaniline and 6-bromoveratraldehyde by Ullmann reaction afforded N-[3-(2-formyl-4, 5-dimethoxyphenoxy)-4-methoxyphenethyl]acetamide (IX). By Pictet-Spengler reaction with 20% hydrochloric acid, acetamide (IX) was cyclized and dehydrogenated to give isoquinoline (XI), the structure of which was established by various physical and chemical methods. Next, C-nor-cularine (1-methyl-6, 9, 10-trimethoxy-1, 2, 3, 11b-tetra-hydropyrido[4, 3, 2-kl]xanthene was synthesized by preparing methiodide (XII) and its reduction with NaBH₄.