4-(10,11-dibromo-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene)-piperidine → Desloratadine impurity 24

Participants

Reaction Steps

In accordance with the process of the present invention, the starting material, i.e., the 4-(10,11-dibromo-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene)-piperidine (I) is treated in an inert polar solvent with hydroxide ion, but preferably by dissolving the salt in water, to produce the biologically active 10,11-dihydroxy derivative of 4-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene)-piperidine (II). The product produced in this manner is biologically active and is a mixture of primarily the cis and trans isomers, the major portion being present in the cis configuration. The cis isomer of the compound may be isolated by selective fractional crystallization.

Provenance & Evidence