81522-68-1Relevant articles and documents
PROCESS FOR PRODUCING PHOSPHINE OXIDE VITAMIN D PRECURSORS
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Page/Page column 4, (2009/01/20)
A process for producing a compound of the formula: including reacting of a compound of the formula: with diphenyl phosphine oxide using a binary phase reaction mixture including diphenyl phosphine oxide in an organic solvent, a basic aqueous solution, and a phase transfer catalyst, to obtain the compound of formula 1, wherein Ph is phenyl, X1 and X2 are both hydrogen or X1 and X2 taken together are CH2, R1 is a protecting group, R2 is fluorine, hydrogen, or OR3, wherein R3 is a protecting group, and the squiggly line represents a bond that results in the adjacent double bond being in either the E or Z configuration, is disclosed.
Efficient synthesis of the A-ring phosphine oxide building block useful for 1α,25-dihydroxy vitamin D3 and analogues
Daniewski, Andrzej R.,Garofalo, Lisa M.,Hutchings, Stanley D.,Kabat, Marek M.,Liu, Wen,Okabe, Masami,Radinov, Roumen,Yiannikouros, George P.
, p. 1580 - 1587 (2007/10/03)
The 1α-hydroxy A-ring phosphine oxide 1, a useful building block for vitamin D analogues, was synthesized from (S)-carvone in nine synthetic operations and a single chromatographic purification in 25% overall yield. The synthesis features two novel efficient synthetic transformations: the Criegee rearrangement of α-methoxy hydroperoxyacetate 10 in methanol to obtain directly the desired secondary 3β-alcohol 11 and the highly chemo- and stereoselective isomerization of dieneoxide ester (E)-7 to the 1α-allylic alcohol with an exocyclic double bond (E)-8. Further insight into the selectivity control of the latter rearrangement was obtained from the reactions of (Z)epimeric substrates. The new synthetic approach leading to the 1α-hydroxy epimers complements our previously reported synthesis of the corresponding 1β-epimers, thus producing all stereoisomers of these versatile building blocks efficiently from carvone.
Parallel synthesis of a vitamin D3 library in the solid-phase
Hijikuro,Doi,Takahashi
, p. 3716 - 3722 (2007/10/03)
A highly efficient synthesis of the vitamin D3 system on solid support is described. Two synthetic strategies for the solid-phase synthesis of vitamin D3 were developed. One is for 11-hydroxy analogues, and the other is for most other synthetic analogues. In the latter strategy, the sulfonate-linked CD-ring 58 was initially immobilized on PS-DES resin to give solid-supported CD-ring 63 (Scheme 10). Similarly, solid-supported CD-ring 63 was prepared by attachment of the CD-ring 10 to the chlorosulfonate resin 64. The vitamin D3 system was synthesized by Horner-Wadsworth-Emmons reaction of the A-ring phosphine oxide to a solid-supported CD-ring, followed by simultaneous introduction of the side chain and cleavage from resin with a Cu1-catalyzed Grignard reagent. Parallel synthesis of the vitamin D3 analogues was accomplished by a split and pool methodology utilizing radio frequency encoded combinatorial chemistry, and a manual parallel synthesizer for side chain diversification and deprotection. Additionally, we demonstrated the synthesis of various A-rings in a similar protocol for efficient preparation of building blocks.