Isolation and characterisation of impurities in adapalene.

摘要

Three impurities of structure 2-4 were isolated and characterised during the optimisation of a synthetic procedure to adapalene. Impurity 1 was a by-product of the Friedel-Crafts reaction of adamantanol with 4-bromoanisole. Impurities 3 and 4 were due to side reactions of the final Negishi coupling.