SYNTHESIS OF METHYL 3-(2-OCTADECYLCYCLOPROPEN-1-YL)PROPANOATE AND METHYL 3-(2-OCTADECYLCYCLOPROPEN-1-YL)PENTANOATE AND CYCLOPROPANE FATTY-ACIDS AS POSSIBLE INHIBITORS OF MYCOLIC ACID BIOSYNTHESIS

(Z)-Tetracos-5-enoic acid is a key intermediate in the biosynthesis of mycobacterial mycolic acids. Recently the methyl ester of its cyclopr opene analogue, methyl 4-(2-octadecylcyclopropen-1-yl)butanoate, was s hown to act as an inhibitor of mycolic acid biosynthesis. The related analogues methyl 5-(2-octadecylcyclopropen-1-yl)pentanoate and methyl 3-(2-octadecylcyclopropen-1-yl)propanoate have been synthesised, as we ll as the related cyclopropane esters methyl (Z)-4-(2-octadecylcyclopr opan-1-yl)butanoate and methyl (Z)-5-(2-octadecylcyclopropan-1-yl)pent anoate. The synthesis of methyl 3-(2-octadecylcyclopropen-1-yl)propano ate involved protection of the cyclopropene ring by iodination to allo w oxidation of an alcohol to a carboxylic acid; the diiodocyclopropane was deprotected by a new mild procedure using activated zinc.