Synthesis of putative metabolites of 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71)
摘要:
1 alpha,25-Dihydroxy-2 beta-(3-hydroxypropoxy)vitamin D-3 (ED-71), an analog of active vitamin D-3, 1 alpha,25-dihydroxyvitamin D-3 [1,25(OH)(2)D-3] is under phase III clinical trials in Japan for the treatment of osteoporosis and bone fracture prevention. Since ED-71 has a substituent at the 2 beta-position of the A-ring, it is recognized that the metabolic pathway of ED-71 might be more complicated than 1,25(OH)(2)D-3 because of metabolism at the 2 beta-position substituent in addition to the inherent metabolism of the side chain. To clarify the metabolism of hydroxypropoxy substituent of the 2 beta-positon and a combination of metabolism between side chain and 2 beta-positon, four putative metabolites of ED-71 have been prepared as authentic samples. The metabolites at the 2 beta-positon, the methyl ester derivative considered as an ester standard of the oxidized metabolite and the tetraol derivative as the truncated metabolite were synthesized from alpha-epoxide, a key intermediate of ED-71 synthesis. The combination metabolites between side chain and 2 beta-positon, the 24(S)- and 24(R)-pentaols were synthesized using Trost's convergent method. (c) 2006 Elsevier Inc. All rights reserved.
Synthesis of putative metabolites of 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71)
摘要:
1 alpha,25-Dihydroxy-2 beta-(3-hydroxypropoxy)vitamin D-3 (ED-71), an analog of active vitamin D-3, 1 alpha,25-dihydroxyvitamin D-3 [1,25(OH)(2)D-3] is under phase III clinical trials in Japan for the treatment of osteoporosis and bone fracture prevention. Since ED-71 has a substituent at the 2 beta-position of the A-ring, it is recognized that the metabolic pathway of ED-71 might be more complicated than 1,25(OH)(2)D-3 because of metabolism at the 2 beta-position substituent in addition to the inherent metabolism of the side chain. To clarify the metabolism of hydroxypropoxy substituent of the 2 beta-positon and a combination of metabolism between side chain and 2 beta-positon, four putative metabolites of ED-71 have been prepared as authentic samples. The metabolites at the 2 beta-positon, the methyl ester derivative considered as an ester standard of the oxidized metabolite and the tetraol derivative as the truncated metabolite were synthesized from alpha-epoxide, a key intermediate of ED-71 synthesis. The combination metabolites between side chain and 2 beta-positon, the 24(S)- and 24(R)-pentaols were synthesized using Trost's convergent method. (c) 2006 Elsevier Inc. All rights reserved.
The O-protected polyhydroxy ketones 9-14 and 39, 42 add sigma-type Grignard reagents with >90:10 stereoselectivity to give the 3,4-syn-adducts 17-28 and 43, 45, respectively, as the major diastereomers (Tables 1 and 2). The stereoselectivity is interpreted in terms of early transition states which are very close to the groundstate conformations shown in Figure 6 and 7. These demonstrate that the ''top face'' of the carbonyl group is much less shielded than the ''bottom'' face. Complexation phenomena are of minor importance. It is also shown that the classical transition state models (Felkin-Anh or chelate Cram) are not applicable to polyoxygenated ketones.
Synthesis of putative metabolites of 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3 (ED-71)
1 alpha,25-Dihydroxy-2 beta-(3-hydroxypropoxy)vitamin D-3 (ED-71), an analog of active vitamin D-3, 1 alpha,25-dihydroxyvitamin D-3 [1,25(OH)(2)D-3] is under phase III clinical trials in Japan for the treatment of osteoporosis and bone fracture prevention. Since ED-71 has a substituent at the 2 beta-position of the A-ring, it is recognized that the metabolic pathway of ED-71 might be more complicated than 1,25(OH)(2)D-3 because of metabolism at the 2 beta-position substituent in addition to the inherent metabolism of the side chain. To clarify the metabolism of hydroxypropoxy substituent of the 2 beta-positon and a combination of metabolism between side chain and 2 beta-positon, four putative metabolites of ED-71 have been prepared as authentic samples. The metabolites at the 2 beta-positon, the methyl ester derivative considered as an ester standard of the oxidized metabolite and the tetraol derivative as the truncated metabolite were synthesized from alpha-epoxide, a key intermediate of ED-71 synthesis. The combination metabolites between side chain and 2 beta-positon, the 24(S)- and 24(R)-pentaols were synthesized using Trost's convergent method. (c) 2006 Elsevier Inc. All rights reserved.