| 摘要 |
<p>Compounds of the general formula <IMAGE> I wherein R represents a hydrogen atom or a hydroxyl protecting group, Y represents a hydrogen atom or an optionally protected hydroxyl group, X represents the residue of a dienophile and either R1 represents a halogen atom a hydrocarbylsulphonyloxy group or a group of the formula -Z-R3 (in which Z represents -O-, -S-, -SO-, -NR4- or -CR4R5- and R3, R4 and R5, which may be the same or different, each represent a hydrogen atom or a straight or branched aliphatic group having 1-12 carbon atoms and which may optionally carry one or more substituents) and R2 represents a hydrogen atom or R1 and R2 together represent an oxo group or an optionally substituted alkylidene group, except that R1 and R2 together with the group -CH(CH3)CH- to which they are attached do not represent a group having the branched 17 beta -hydrocarbyl side chain skeleton of vitamin D2 or vitamin D3 or use in the preparation of novel vitamin D analogues.</p> |
