An efficient and short degradation of the cholic acid side chain: a new method for the preparation and dehydrogenation of 4,5-dihydro-oxazoles
- 1 January 1985
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- No. 9,p. 1865-1869
- https://doi.org/10.1039/p19850001865
Abstract
11 -Oxolithocholic acid (2) and other unhindered aliphatic carboxylic acids undergo an efficient, boric acid mediated, condensation with 2-amino-2-methylpropan-1-ol (3) to give the corresponding 4,5-dihydro-oxazoles. The latter can be dehydrogenated in high yield to the α,β-unsaturated derivatives (e.g.18) with benzeneseleninic acid or anhydride. Acylation with trichloroacetyl chloride in the case of (18) followed by ozonolysis and saponification furnishes the 20-oxopregnane derivative (21) in over 80% overall yield. The side chain can also be cleaved in one step by benzeneseleninic acid albeit in relatively low yield [10–40% from (4) or (5)].This publication has 1 reference indexed in Scilit:
- A practical catalytic method for the preparation of steroidal 1,4-dien-3-ones by oxygen atom transfer from iodoxybenzene to diphenyl diselenideJournal of the Chemical Society, Perkin Transactions 1, 1982