Sulfuric Acid → 4-(7,12-Dihydroxy-3-methanesulfonyloxy-10,13-dimethylhexadecahydrocyclopenta[a]phenanthren-17-yl) pentanoic acid

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Reaction Steps

100 g of cholic acid are dissolved in 500 ml of pyridine and 23.1 ml of mesyl chloride are added dropwise over a period of 30 minutes at 0° C. The mixture is stirred at RT for 3 hours, then poured into a solution of 400 ml of H2SO4 in 3 l of water at 0° C. and extracted 4 times using 750 ml of EA each time. The extract is dried over Na2SO4 and the solvent is removed in vacuo. The residue is crystallized using diisopropyl ether and 117.1 g are obtained; m.p. 121° C. (with decomposition).

Provenance & Evidence