Studies on the syntheses of heteroeyelie compounds. Part DV . Cyclization products of i‐substituted 2‐benzyl‐1,2,5,6‐tetrahydropyridines [syntheses of analgesics. Part XXXV ]

Treatment of 1,2,5,6‐tetrahydro‐2‐(4‐hydroxy‐ and/or 4‐methoxybenzyl)‐3,4‐dimethyl‐I‐(3‐methyl‐2‐butenyl)pyridines (IV and V) and 2‐(4‐methoxybenzyl)‐3,4‐dimethyl‐1‐(3‐methyl‐2‐butenyl)‐4‐piperidinol (X) with acid afforded 9‐(4‐hydroxy‐ and/or 4‐methoxybenzyl)‐4,4,5,6‐tetramethyl‐1‐azabicyelo[3,3,1]non‐6‐ene (XIII and XIV). In contrast, the corresponding 1‐allyl‐substituted derivatives VI, VII, and XI were converted into the expected 3‐allyl‐1,2,3,4,5,6‐hexahydro‐8‐hydroxy‐ and/or 8‐methoxy‐6,11‐dimethyl‐2,6‐methano‐3‐benzazocine (II and III).