Synthesis of specifically deuterated decanoic acids and decanols

Abstract

Methyl [7- 2H 2]-, [9- 2H 2]- and [10- 2H 3]decanoates and the corresopnding deuterated decanols have been synthesized. The 7,7-dideuterodecanoate was prepared starting from methyl 7-oxodecanoate. Reduction with sodium borodeuteride to methyl 7-hydroxy-[7- 2H]decanoate followed by bromination yielded methyl 7-bromo-[7- 2H]decanoate, further reduction with sodium borodeuteride in hexamethylphosphoramide gave methyl [7- 2H 2]decanoate with only 7% reduction of the ester group. [7- 2H 2]Decanol was also prepared from the bromo ester by lithium aluminum hydride reduction followed by lithium aluminum deuteride-lithium deuteride reduction. Exchange of sodium 10-undecanoate in deuterium oxide gave 10-[2- 2H 2]undecenoic acid without double bond migration. [9- 2H 2]Decanoic acid was obtained by two-stage reduction of the carboxyl to CH 3 and oxidative cleavage of the double bond. [10- 2H 3]Decanol was prepared from 10-hydroxydecanoic acid by protecting the hydroxyl as the methoxyethoxymethoxy ether and reducing the carboxyl to CD 3, in two stages, with lithium aluminum deuteride; chromic acid oxidation gave [10- 2H 3]decanoic acid. The 7- 2H 2- and 9- 2H 2-labelled acids and alcohosl were at least 96% dideuterated and [10- 2H 3]acid and alcohol were 97% trideuterated.