Specific branched fatty acids are of great interest in the search of a
new type of drug penetration enhancers across human skin for transder
mal drug delivery and in gaining an understanding of structure-activit
y relationships with skin lipids. A convenient synthesis thesis has th
erefore been developed especially for ethyloctade-canoic acids. The su
ccessful syntheses of 6- and 9-ethyloctadecanoic acids are reported he
re.