| 摘要 |
<p>Pregnane derivatives represented by general formula (I) (wherein A1 represents a hydrogen atom or a hydroxy group, A2 represents a substituent such as a hydroxy group when A1 represents a hydrogen atom, or A2 represents a hydrogen atom when A1 represents a hydroxy group, or A?1 and A2¿ are combined together to form an oxo group; D1 represents a substituent such as a hydroxy group, and D2 represents a hydrogen atom, or D?1 and D2¿ are combined together to form an epoxy group or a single bond; D?3, D5 and D7¿ each represents a hydrogen atom, D4 represents a hydroxy group, and D6 represents a substituent such as a hydroxy group, or D?3 and D4¿ may be combined together to form an epoxy group or a single bond, or D?4 and D5¿ may be combined together to form a single bond, D?5 and D6¿ may be combined together to form an epoxy group or a single bond, or D?6 and D7¿ may be combined together to form a single bond; and X?1 and X2¿ each represents a lower alkoxy group or, when combined together, they represent a lower alkylenedioxy or oxo group) and a process for their preparation. The pregnane derivatives are useful as intermediates for synthesizing vitamin D¿3? having a hydroxy group in the 1α-position.</p> |
