Abstract: A compound represented by the following Formula (1) that is effective for the treatment of Paget's disease of bone or hypercalcemia or a medically acceptable solvate thereof; [wherein R1 refers to hydrogen atom, C1-C6 alkyl group optionally substituted with hydrogen group or C1-C6 alkoxy group optionally substituted with hydroxyl group, R2a and R2b refer to hydrogen atom, C1-C10 alkyl group optionally substituted with hydroxyl group, C6-C10 aryl group optionally substituted with hydroxyl group or C7-C12 aralkyl group optionally substituted with a hydroxyl group, or are combined to represent ethylene group. However, a compound in which R1 is a hydrogen atom or a methyl group and R2a and R2b are hydrogen atoms is excluded].

Abstract: The object of the present invention is to synthesize novel vitamin D derivatives. According to the present invention, there are provided vitamin D derivatives represented by the following general formula (1): wherein R1 and R2 may be the same or different, and each represents a straight chain or branched chain alkyl group optionally substituted by a hydroxyl group, and R3 represents a straight chain or branched chain alkyl group optionally substituted by a hydroxyl group.

Abstract: A compound represented by the following Formula (1) that is effective for the treatment of Paget's disease of bone or hypercalcemia or a medically acceptable solvate thereof; [wherein R1 refers to hydrogen atom, C1-C6 alkyl group optionally substituted with hydrogen group or C1-C6 alkoxy group optionally substituted with hydroxyl group, R2a and R2b refer to hydrogen atom, C1-C10 alkyl group optionally substituted with hydroxyl group, C6-C10 aryl group optionally substituted with hydroxyl group or C7-C12 aralkyl group optionally substituted with a hydroxyl group, or are combined to represent ethylene group. However, a compound in which R1 is a hydrogen atom or a methyl group and R2a and R2b are hydrogen atoms is excluded].

Abstract: The object of the present invention is to synthesize vitamin D derivatives in which the 3-position is substituted with methyl and the steric configuration at the 20-position is epimerized. The present invention provides vitamin D derivatives of Formula (1): wherein R is straight or branched alkyl optionally substituted with hydroxy.

Abstract: Provided are 1,25-dihydroxy-2-methylvitamin D3 derivatives expressed by the general formula (I), [wherein each of R1 and R2 is independently a hydrogen atom or a tri(C1 to C7 alkyl)silyl group; herein configurations of asymmetric carbons at the 1-, 2- and 3-positions are each independently ?-configuration or ?-configuration] and their production methods. The compound is useful as a treating agent for osteoporosis, rickets, hyperthyroidism, etc.

Abstract: According to the present invention, there are provided vitamin D derivatives represented by the following general formula (1): wherein R1 and R2 may be the same or different, and each represents a straight chain or branched chain alkyl group optionally substituted by a hydroxyl group, and R3 represents a straight chain or branched chain alkyl group optionally substituted by a hydroxyl group.

Abstract: A vitamin D derivative which has a methyl group in the 1-position and has an epi form in the 20-position. The vitamin D derivative is represented by the general formula (1): wherein R represents linear or branched alkyl optionally substituted by hydroxy.

Abstract: An object of the present invention is to synthesize a novel vitamin D3 derivative having a substituent at the 2?-position. The present invention provides vitamin D derivatives represented by-Formula (I): wherein R1 represents a saturated aliphatic C1-15hydrocarbon group optionally substituted with 1 to 3 hydroxy or protected hydroxy groups; and R2 represents a saturated aliphatic C1-10hydrocarbon group optionally substituted with one or more substituents, which may be the same or different and which are selected from the group consisting of a hydroxy group, a halogen atom, a cyano group, a lower alkoxy group, an amino group and an acylamino group, provided that when R2 represents a saturated aliphatic C1hydrocarbon group, R2 is substituted with at least one substituent.

Abstract: Object of the present invention is to synthesize novel vitamin D derivatives. The present invention provides 5,6-trans-2-alkyl-substituted vitamin D derivatives of Formula (1): wherein R1 is straight or branched-chain alkyl; and R2 is straight or branched-chain alkyl optionally substituted with hydroxy.

Abstract: The object of the present invention is to synthesize vitamin D derivatives in which the 3-position is substituted with methyl and the steric configuration at the 20-position is epimerized.

Abstract: Object of the present invention is to synthesize novel vitamin D derivatives.

Abstract: An object of the present invention is to synthesize a novel vitamin D derivative having a substituent at the 2&agr;-position.