| 摘要 |
<p>NEW MATERIAL:A compound expressed by formula I (R1-R4 are acyl; A is -CH2- or -OCH2-). EXAMPLE:(22R, 23R)-2alpha, 3alpha, 22, 23-Tetrahydroxy-24-nor-5alpha-cholestan-6-one. USE:A plant growth promoting agent. PREPARATION:A 3beta-tetrahydropyranyloxy-23, 24-bisnorchol-5-en-22-al expressed by formula II (THPO is tetrahydropyranyloxy) is converted into a thioketal, and the protecting group (THPO) is changed. The thioketal group is then removed, and the resultant compound is reacted with a Grignard reagent to aklylate the 22-position. OH groups at the 22- and 23-positions are then acetalized and protected, and the resultant compound is oxidized to remove the protecting groups. The OH groups are then acylated to give a compound expressed by formula III(Ac is acetyl), which is then oxidized to afford a compound expressed by formula IV. The protecting groups are, if necessary, removed to give the aimed compound expressed by formula I .</p> |
