Analogues of brassinolide and castasterone, containing an ester functionality with four carbon atoms in the position 20 of the pregnane skeleton, have been prepared. In the bean second internode assay the most effective compounds were (20R)-2α,3α,20-trihydroxy-5α-pregnan-6-one 20-isobutyrate (6d) and (20R)-2α,3α,20-trihydroxy-B-homo-7-oxa-5α-pregnan-6-one 20-isobutyrate (7d). On the other hand, (20R)-2α,3α,20-trihydroxy-B-homo-6-oxa-5α-pregnan-7-one 20-heptafluorobutyrate (8) was the first compound with the retarding effect in the same test.
含有孕烷骨架中20位的四个碳原子的酯官能团的油菜素内酯和卡斯特龙类似物已经制备。在豆类第二节间隔试验中,最有效的化合物是(20R)-2α,3α,20-三羟基-5α-孕烷-6-酮20-异丁酸酯(6d)和(20R)-2α,3α,20-三羟基-B-同型-7-氧杂-5α-孕烷-6-酮20-异丁酸酯(7d)。另一方面,(20R)-2α,3α,20-三羟基-B-同型-6-氧杂-5α-孕烷-7-酮20-庚氟丁酸酯(8)是在同一测试中具有减缓效果的第一个化合物。