Synthesis of all-trans-Parinaric Acid-d8 Specifically Deuterated at All Vinyl Positions

Article abstract of DOI:10.1021/jo00249a005

Parinaric acid is a widely used fluorescent probe of biological systems.The all-trans isomer (9(E),11(E),13(E),15(E)-octadecatetraenoic acid) specifically deuteriated at all vinyl positions was prepared by using the Wittig reaction to couple a diene phosphorane with an α,β-unsaturated aldehyde-ester.The preparation of each component included the stereoselective reduction of a substituted propynoic ester with lithium aluminum deuteride (LAD), introducing the trans double bond as well as most of the deuterium in one step, in high isotopic purity without unwanted hydrogen-deuterium exchange.By inclusion of deuterium, the probe can be used with other techniques, such as deuterium NMR and neutron diffraction, further increasing its utility.The synthesis can be used to prepare other tetraenes by correct choice of starting propynoic esters.