Stereocontrolled synthesis of the four possible 3-methoxy and 3-benzyloxy-16-triazolyl-methyl-estra-17-ol hybrids and their antiproliferative activities.

The four possible isomers of each of 3-methoxy- and 3-benzyloxyestra-1,3,5(10)-trien-17-ols (5-8 and 9-12) were converted through 16-p-tosyloxymethyl- or 16-bromomethyl derivatives into their 3-methoxy- and 3-benzyloxy-16-azidomethylestra(1,3,5(10)-triene derivatives (13-16 and 17-20). The regioselective Cu(I)-catalyzed 1,3-dipolar cycloaddition of these compounds with different terminal alkynes afforded novel 1,4-disubstituted diastereomers (21a-f, 22a-f, 23a-f, 24a-f and 25a-f, 26a-f, 27a-f, 28a-f). The antiproliferative activities of the structurally related triazoles were determined in vitro with the microculture tetrazolium assay on four malignant human cell lines of gynecological origin (Hela, SiHa, MCF-7 and MDA-MB-231).