Synthesis of Tetracyclic Heterocompounds as Selective Estrogen Receptor Modulators. Part 1. Process Development for Scale-up of 2,5,8-Substituted 5,11-Dihydrochromeno[4,3-c]chromene Derivatives

Unsymmetrical benzopyranobenzopyran compounds are novel selective estrogen receptor modulators (SERMs). A reproducible and nonchromatographic process was developed to prepare multihundred gram quantities of 5-(4-(2-(piperidin-1-yl)ethoxy)phenyl)-5,11-dihydrochromeno[4,3-c]chromene-2,8-diyl-bis(2,2-dimethylpropanoate) (14). The overall yield of this 11-step synthesis was improved from 0.17% to 7.1% after three scale-up campaigns.