Studies on the syntheses of heterocyclic compounds. Part CDLXVI. Synthesis of narwedine-type enones by photochemical cyclisation
Abstract
Irradiation of 4-benzyloxy-2-bromo-3-hydroxy-N-(4-hydroxyphenethyl)-N-methylbenzamide (26) and of 2-bromo-3-hydroxy-N-(4-hydroxyphenethyl)-4-methoxy-N-methylbenzamide (28) afforded the narwedine-type enones (4) and (3), respectively. The former enone (4) was also synthesised by phenolic oxidation of 4-benzyloxy-3-hydroxy-N-(4-hydroxyphenethyl)-N-methylbenzamide (24).