350985-91-0

Upstream product

• 115540-15-3 (1S,5R)-5-acetoxy-1-ethynyl-3-hydroxy-2-methylcyclohex-1-ene 
• 62-23-7 4-nitro-benzoic acid 

Downstream Products

• 169437-97-2 (3R,5R)-1-ethynyl-3,5-dihydroxy-2-methylcyclohex-1-ene 
• 405197-18-4 (3R,5R)-5-acetoxy-1-ethynyl-3-hydroxy-2-methylcyclohex-1-ene 
• 405229-45-0 (3R,5R)-3,5-diacetoxy-1-ethynyl-2-methylcyclohex-1-ene 
• 497067-58-0 1α-[(tert-butoxycarbonyl)amino]-25-hydroxyvitamin D₃ 
• 497067-48-8 1α-[(tert-butoxycarbonyl)amino]-25-hydroxy-6,7-dehydroprevitamin D₃ 
• 1026086-72-5 1-α-[(tert-butoxycarbonyl)amino]-25-hydroxyprevitamin D₃ 
• 497067-24-0 (3S,5R)-3-[(tert-butoxycarbonyl)amino]-5-[(tert-butyldimethylsilyl)oxy]-1-ethynyl-2-methylcyclohex-1-ene 
• 497067-16-0 (3S,5R)-5-acetoxy-1-ethynyl-2-methyl-3-phthalimidocyclohex-1-ene 
• 497067-20-6 (3S,5R)-3-[(tert-butoxycarbonyl)amino]-1-ethynyl-5-hydroxy-2-methylcyclohex-1-ene 

Relevant academic research and scientific papers

CAL-B-catalyzed alkoxycarbonylation of A-ring stereoisomeric synthons of 1α,25-dihydroxyvitamin D3 and 1α,25-dihydroxy-19-nor-previtamin D3: A comparative study. First regioselective chemoenzymatic synthesis of 19-nor-A-ring carbonates

A comparative study of alkoxycarbonylation processes of both 19-nor-A-ring and A-ring stereoisomers of 1α,25-dihydroxyvitamin D3 analogues catalyzed by Candida antarctica lipase B (CAL-B) has been described. The presence of the methyl group in the A-ring at C-2, as in 3-6, has a determining role in the regioselectivity of the biocatalysis, mainly allowing the hydroxyl group at C-5 position to react. For the 19-nor-A-ring stereoisomers 7-10, which lack the C-2 methyl group, the configurations at C-3 and C-5 have a high influence in the selectivity exhibited by CAL-B. Thus, each couple of enantiomers showed opposing regioselectivities depending on the C-3 configuration. When C-3 possesses an (S)-configuration, enzymatic alkoxycarbonylations took place at the C-5-(R) or C-5-(S) hydroxyl groups. However, if the chiral centers at C-3 are (R), CAL-B alkoxycarbonylated the C-3-(R) hydroxyl group independently of the configuration at C-5. The corresponding carbonates are useful A-ring precursors of 1α,25-dihydroxyvitamin D3 analogues, selectively modified at the C-1 or C-3 positions. In addition, an improved synthesis of cis A-ring synthons 5 and 6 is described using a Mitsunobu methodology.

Efficient synthesis of novel 1α-amino and 3β-amino analogues of 1α,25-dihydroxyvitamin D3

Convenient synthetic routes to 1α-amino-25-hydroxyvitamin D3 (3) and 3β-amino-3-deoxy-1α,25-dihydroxyvitamin D3 (4), novel analogues of vitamin D3 bearing an amino group at the C-1 or C-3 position, have been developed starting from (S)-(+)-carvone. Construction of the A-ring fragments was accomplished by selective enzymatic hydrolysis of a diester intermediate and introduction of the amino group under Mitsunobu conditions.