TY - JOUR
T1 - An efficient and short degradation of the cholic acid side chain
T2 - A new method for the preparation and dehydrogenation of 4,5-dihydro-oxazoles
AU - Barton, Derek H.R.
AU - Motherwell, William B.
AU - Wozniak, Jocelyne
AU - Zard, Samir Z.
PY - 1985/1/1
Y1 - 1985/1/1
N2 - 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)].
AB - 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)].
U2 - 10.1039/p19850001865
DO - 10.1039/p19850001865
M3 - Article
AN - SCOPUS:37049091445
SN - 1472-7781
SP - 1865
EP - 1869
JO - Journal of the Chemical Society. Perkin Transactions 1
JF - Journal of the Chemical Society. Perkin Transactions 1
ER -