81702-92-3Relevant articles and documents
AMBERLYST 15: A PRACTICAL, MILD AND SELECTIVE CATALYST FOR METHYL ESTERIFICATON OF CARBOXYLIC ACIDS
Petrini, Marino,Ballini, Roberto,Marcantoni, Enrico
, p. 847 - 854 (2007/10/02)
Mild and selective methyl esterification of carboxylic acids are realized using Amberlyst 15 as acid catalyst in methanol.No racemization, epimerization or ketalization products have been observed with this method.Excellent results are obtained in the esterifications of bile acids.
Potential bile acid metabolites. 1. The epimeric 3ε{lunate},7α,12β-trihydroxy-5β-cholanic acids. Raney nickel as an epimerizing catalyst.
Chang, Frederic C
, p. 2085 - 2088 (2007/10/15)
The epimeric 3α,7α,12β- and 3β,7α,12β-trihydroxy-5β-cholanic acids have been prepared. Under ambient hydrogenation conditions with Raney nickel as catalyst the axial 3β-ester (4b) is epimerized to the 3α-compound (2b).
Introducing Δ11 unsaturation into steroid compounds
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, (2008/06/13)
A process for the introduction of Δ11 unsaturation into steroid compounds having a C-12 sulfonate ester group is described. Dehydrosulfonation is carried out by reacting the sulfonate with a hexaalkylphosphoric triamide. The process is particularly useful with steroid compounds that also contain a blocked C-7 hydroxy group. The process yields the 11-enate in preference to the 6,11-dienate. The yield of the process can be increased by carrying out the reaction in the presence of a weak base.