D-ring allyl derivatives of 17 beta- and 17 alpha-estradiols: Chemical synthesis and C-13 NMR data

We report the C-13 NMR data for 17 beta-estradiol, 17 alpha-estradiol, and a series of ten 17 beta- or 17 alpha-estradiol derivatives bearing an allyl group On the D-ring (at C-17, C-16, and C-15 positions). The target 17 beta-OH estradiol derivatives were synthesized from estrone by well known methods to ensure the accuracy of the allyl stereochemistry. The 17 alpha-estradiol derivatives were obtained by a modified Mitsunobu alcohol inversion of 17 alpha-analogs. The carbon assignments were done using 1D and 2D NMR experiments. Six positions of the allyl group (17 alpha, 17 beta, 16 alpha 16 beta, 15 alpha, and 15 beta) and two alcohol stereochemistries (17 beta and 17 alpha) of the D-ring ware studied, resulting in an important source of data. The effect of allyl-positioning and alcohol stereochemistry on C-13 NMR chemical shifts was also identified producing important points of comparison for other steroid analogs. (C) 1997 by Elsevier Science Inc.