The reaction of methyl sterculate and malvalate with silver nitrate‐silica gel and its use as a basis for the estimation of cyclopropene fatty acids

When in contact with silver nitratesilica gel, methyl esters of cyclopropene fatty acids undergo ring opening to yield pairs of isomers with methylene, hydroxymethyl, or nitratomethyl side‐chains at the original ring positions. Thus the main products from methyl sterculate were the methyl 9 (or 10)‐methylene octadec‐10 (or 8)‐enoates, and, in lesser quantities, the methyl 9 (or 10)‐(nitratomethyl)‐octadec‐9‐enoates and the methyl 9 (or 10)‐(hydroxymethyl)‐octadec‐9‐enoates. Hydrogenation quantitatively converted this mixture of isomeric pairs to a mixture of methyl 9‐ and methyl 10‐methyloctadecanoates. Chromatography on silver nitrate‐silica gel, followed by gas chromatography of the hydrogenated products, has been used as the basis of a new method for estimating individual cyclopropene and cyclopropane acids in lipids.