57333-97-8Relevant articles and documents
Novel 1α,24-dihydroxycholecalciferol compositions, novel precursors thereof, and processes for preparing them
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, (2008/06/13)
Novel 1α, 24-dihydroxycholecalciferol and derivatives thereof which are useful with reduced side-effects for the treatment of abnormal metabolism of calcium and phosphorus caused by liver failure, renal failure, gastrointestinal tract failure and parathyroid failure, and related bone diseases. Preparation of the novel 1α, 24-dihydroxycholecalciferol and their derivatives starts from 1α, 24-dihydroxycholesterol prepared by reacting 1α, 2α-epoxy-24-keto-cholesta-4,6-dien-3-one with an alkali metal and a proton donor in the presence of liquid ammonia or a liquid amine. Reaction of the 1α, 24-dihydroxycholesterol with an allylic brominating agent, followed by contacting with a dehydrobrominating agent, affords 1α,3β, 24-trihydroxycholesta-5,7-diene derivative, which can then be converted to 1α, 24-dihydroxycholocalciferol by ultraviolet irradiation in a organic solvent, followed by isomerization. Processes are also provided for separating 1α, 24-dihydroxycholesterol into an (S)-epimer and an (R)-epimer, and also for separating at least one of 1α, 3β, 24(S)-and 1α, 3β, 24(R)-trihydroxycholesta-5,7-dienes from trihydroxycholesta-4,6-diene.
