Synthesis of 3- [(8Z, 11E, 13Z) -8, 11, 13-pentadecatrienyl] catechol and Analysis of the Triene Urushiol Fraction of the Sap of Rhus vernicifera

An efficient method for synthesizing 3- [(8Z, 11E, 13Z) -8, 11, 13-pentadecatrienyl] catechol, the main component in urushiol, was established. Good yield was attained via the Wittig reaction of ylides derived from (3E, 5Z) -3, 5-heptadienyltriphenylphosphonium iodide with 3- (8-oxo-1-octyl) catechol diacetate in a stepwise procedure of repeated protection and deprotection of the hydroxyl group of catechol. Quantitative analysis of the triene urushiol of saps from of different origin was conducted for comparison with the synthesized triene urushiol as reference. In this manner, sap performance could be assessed best, since each sap with good performance as lacquer coating material was high in triene urushiol content. This content was found to depend on the growing conditions of the Rhus vernicifera tree and on the particular seasons for obtaining sap.