Selective removal of phenolic hydroxyl groups of morphinan derivatives synthesis of rac. N‐formyl‐3‐methoxy‐6‐oxomorphinan (1)

The hydroxyl group of N-formyl-2-hydroxy-3-methoxy-6-oxomorphinan (7) can be readily etherified with 5-chloro-1-phenyltetrazole. The etherification of isomers with the hydroxyl group in position 4 scarcely takes place, if at all. Catalytic hydrogenolysis of the ether of 7 gives dehydroxylation of 7 to N-formyl-S-methoxy-6-oxomorphinan (1).