title: Synthesis of 9-alkylated calcitriol and two 1α,25-dihydroxy-9-methylene-10,19-dihydrovitamin D3 analogues with a non-natural triene system by thermal sigmatropic rearrangements.
abstract: 1α,25-(OH)(2)-9α-Methylvitamin D(3) (4), the first known analogue of the natural hormone 1α,25-(OH)(2)D(3) (3) with an alkyl substituent at C-9, and two 1α,25-(OH)(2)-9-methylene-10,19-dihydrovitamin D(3) analogues (7 and 8) with an unprecedented non-natural triene system were synthesized by thermal isomerization of 1α,25-(OH)(2)-9-methylprevitamin D(3) (6). Three alternative approaches (Sonogashira, Stille, or stereoselective dehydration of a tertiary propargyl alcohol) have been successfully used to construct the dienyne precursors of previtamin 6 possessing two methyl groups capable of participating in the [1,7]-sigmatropic hydrogen shift.
authors: Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
authors: Urszula
authors: U
authors: Kulesza
authors: Rita
authors: R
authors: Sigüeiro
authors: Antonio
authors: A
authors: Mouriño
authors: Rafal R
authors: RR
authors: Sicinski
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D000478:Alkylation; D002117:Calcitriol / Q000138:chemical synthesis* / Q000737:chemistry; D006887:Hydroxycholecalciferols / Q000138:chemical synthesis* / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure
chemical_list: C581726:1alpha,25-dihydroxy-9-methylene-10,19-dihydrovitamin D3; D000473:Alkanes; D006887:Hydroxycholecalciferols; C091176:dihydroxycarbene; D002117:Calcitriol; D008697:Methane