SYNTHESIS OF (R,S)-10-METHYLOCTADECANOIC ACID (TUBERCULOSTEARIC ACID)AND KEY CHIRAL 2-METHYL BRANCHED INTERMEDIATES

Tuberculostearic acid, (R)-10-methyloctadecanoic acid, is a characteri stic component of pathogenic mycobacteria and related organisms. Sensi tive detection of this acid in infected material allows rapid detectio n of mycobacterial disease. A novel, convergent synthesis of tuberculo stearic acid and key chiral intermediates is described in this communi cation, to provide a reference compound. Racemic and (R)- and (S)-1-io do-2-methyldecanes were synthesised from 1-octanal and 1-carboethoxyet hylidenetriphenylphosphorane as initial starting materials. 1-Hydroxyo ct-7-yne was made from 1,6-hexanediol by two alternative methods and c oupled with the above racemic iodide. Hydrogenation and oxidation of t he resulting (R,S)-10-methyloctadec-7-yn-1-ol gave racemic tuberculost earic acid.