| abstract |
Cpds. of formulae I, II or III: where R1 is alkyl (C2-C8, cycloalkyl, aralkyl, N,N-dialkylamino, or polymethyleneimino; R2 is H, Et, -CH=CH2, -C=CH, -C=C-Cl; R3 is OH, -o. acyl, -O-alkyl, -O.SiMe3; R2+R3 are =O; R4 = H, Cl; R5 = H, Me; R6 = H2 or =O; R7 = alpha-H, beta-O.SO2R1 or alpha-OH, beta-CO.CH2O.SO2.R1; R8 = CO.Me or C8H17. They are prepared by esterification of the corresp. 3-, 17- or 21-ols with R1.SO2.X where X is halogen. |