115540-15-3Relevant academic research and scientific papers
Synthesis of monoacyl A-ring precursors of 1α,25-dihydroxyvitamin D3 through selective enzymatic hydrolysis
Gotor-Fernandez, Vicente,Ferrero, Miguel,Fernandez, Susana,Gotor, Vicente
, p. 1266 - 1270 (2007/10/03)
An efficient synthesis of monoacylated 1α,25-dihydroxyvitamin D3 A-ring precursors 15, 16, 18, and 19 has been described through an enzymatic hydrolysis process. Candida antarctica A lipase (CAL-A) hydrolyzes the C-5 acetate ester in trans stereoisomers 9 and 13, with complete and high selectivity, respectively. In the case of cis isomers 11 and 14, Chromobacterium viscosum lipase (CVL) is the enzyme of choice, exhibiting opposite selectivity for these two enantiomers. This lipase selectively catalyzes the hydrolysis at the C-3 acetate in diester 11 and at C-5 position in diester 14. It is noteworthy that through a hydrolysis reaction CAL-A and CVL allow the synthesis of the four A-ring monoacetylated precursors of 1α,25-dihydroxyvitamin D3, precursors which are complementary to those obtained by the enzymatic acylation process. In addition, with excellent yield CVL selectively hydrolyzes the C-3 chloroacetate ester instead of the C-5 acetate in diester 22, a key intermediate in the synthesis of new A-ring modified 1α,25-dihydroxyvitamin D3 analogues.
Selective acylation of A-ring precursors of vitamin D using enzymes in organic solvents
Fernandez,Ferrero,Gotor,Okamura
, p. 6057 - 6061 (2007/10/03)
Whereas Chromobacterium viscosum lipase (CVL) catalyzes selectively the acylation of the C-5 hydroxyl of the three stereoisomeric vitamin D A-ring precursors 2a, 3a and 3b, only the C-3 hydroxyl of the fourth stereoisomer 2b is acylated under the same conditions in organic solvent. In a convenient application, the racemic vitamin D A-ring precursor 4, possessing only the C-5 hydroxyl, was resolved using suitable conditions identified from the studies of 2 and 3.
Synthesis and Biological Activity of 9,11-Dehydrovitamin D3 analogues: Stereoselctive Preparation of 6β-Vitamin D Vinylallenes and a Concise Enynol Synthesis for Preparing the A-Ring
Okamura, William H.,Aurrecoechea, J. Miguel,Gibbs, Richard A.,Norman, Anthony W.
, p. 4072 - 4083 (2007/10/02)
The Δ9(11)-unsaturated vitamin D analogues 5a and 5b are of biochemical interest because they are incapable of tautomerizing via a sigmatropic hydrogen shift to a previtamin structure related to 3 and also becouse they possess a perturbed
A SHORT, ENANTIOSPECIFIC SHYNTHESIS OF THE 1α-HYDROXYVITAMIN D ENYNE A-RING SYNTHON
Aurrecoechea, J. Miguel,Okamura, William H.
, p. 4947 - 4950 (2007/10/02)
The vitamin D A-ring synthon, the enyne 3b, was synthesized in 5 steps (37percent overall yield) from (S)-(+)-carvone (5).The key step was the SmI2-Pd0 mediated transformation of epoxypropargyl ester 6 to 3b.
