An improved synthesis of [24‐ 14 C]cholic acid, and its application to the synthesis of [ 14 C]SCH 209702 (Syn3). Synthesis of [ 2 H 8 ]SCH 209702

An efficient synthesis of [24‐ 14 C]cholic acid from potassium [ 14 C]cyanide has been developed. The key intermediate, 23‐chloro‐3α, 7α, 12α‐triformyloxynorcholane, was synthesized by degradation of triformyl protected cholic acid. Different degradation conditions were explored. The synthesis of [ 14 C]SCH 209702 from 23‐chloro‐3α, 7α, 12α‐triformyloxynorcholane and potassium [ 14 C]cyanide is described. The synthesis of [ 2 H 8 ]SCH 209702 from [ 2 H 4 ]cholic acid is also presented. Copyright © 2008 John Wiley & Sons, Ltd.