Dien‐Synthesen auf dem Fettgebiet, III.: Über das Oiticica‐Öl (Studien auf dem Fettgebiet, XXXI. Mitteil.)

The Diels-Alder Diene Synthesis.

“…A typical sample gave the following analysis: 74.5 per cent eleostearic acid, 9.7 per cent linolic acid, 8 per cent oleic acid, 3.3 per cent saturated acids, 0.1 per cent unsaponifiable matter, and 4.5 per cent glycerol residues (258). The oil of the pits of the oiticaca tree showed a similar discrepancy between the results obtained by the diene analysis method and those obtained by the iodine or thiocyanogen method (259). Further analysis of a sample showed 70 per cent licanic acid, 15.2 per cent unsaturated nonconjugated acids, 9.9 per cent saturated acids, 0.4 per cent nonsaponifiable matter, and 4.5 per cent glycerol residues.…”

“…There is also a possibility that the dienic esters which might be present in the original fat undergo alteration on saponification, for the acids obtained by the saponification of such fats do not show diene numbers. The method is more reliable for dienic glycerides than analysis of fats with iodine or thiocyanogen, for these two methods show other unsaturated acids as well as conjugated dienic acids (258,259).…”

“…The glycerides of (3-eleostearic acid and licanic acid have been shown to add maleic anhydride (258,259). The reaction of /3-eleostearic acid itself ( , ,µoctadecatrienoic acid) has been reported ( 257) to give a product to which structure I has been assigned, although no evidence appears to have been advanced…”

“…Two equivalents of thiosulfate are required per mole of excess anhydride used (257, 260). Diene numbers have been determined for a number of fats and terpinoid bodies (233,257,258,259,260,261,262). These range from zero for synthetic triolein, palm-kernel oil, and cacao butter to 46.0 for bay oil.…”