ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Transformation of (20S)-20-(Hydroxymethyl)pregna-1,4-dien-3-one into (20S)-20-(p-Toluene-sulfonyloxymethyl)pregna-1,5-dien-3β-ol and -3α-ol: Intermediates of Vitamin D DerivativesEfficient three-step approaches to the two 3-epimeric 22-tosylated 1,5-diene-3,22-diols 6 and 7 starting with (20S)-20-(hydroxymethyl)pregna-1,4-dien-3-one (1) were developed and optimized. Isomerization of 1 to the 1,5-dien-3-one 3 and subsequent tosylation furnished the deconjugated 3-ketone 4. The 3β-alcohol 6 was available from 4 by means of in situ generated calcium borohydride. Treatment of 4 with lithium trisiamylborohydride (LS-Selectride) afforded the highest yield of the hitherto unknown 3α-epimer 7. Following the optimized synthesis, 6 and 7 were obtained from 1 in 60 % and 50 % overall yield, respectively.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19963380145
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