The Turpethinic Acids of Ipomoea turpethum L.

Abstract
The main glycosidic acids from the alcohol–soluble resin of Ipomoea turpethum L. have been isolated and their structures elucidated as gluco–gluco–gluco–rhamnosides of 11–hydroxy palmitic acid (Jalapinolic acid), 3,12–dihydroxy pentadecanoic acid (Operculinolic acid) and the hitherto unknown 3, 12–dihydroxy palmitic acid, 4, 12–dihydroxy pentadecanoic acid and 4, 12–dihydroxy palmitic acid by GLC and MS of the derivatized components. The structure of 3,12–dihydroxy pentadecanoic acid methylester could be confirmed by synthesis. The petrol ether– and ether–soluble part of the resin contained glycosidic acids consisting of jalapinolic acid, glucose and rhamnose only.