THE SYNTHESIS OF A COUMARIN ANALOG OF RETINAL

A new coumarin analogue of retinal was synthesised by Wittig condensat ion of (2-oxo-2H-chromen-3-yl)methyltriphenylphosphonium chloride and (2E,6Z) imethyl-8-triphenylsilyloxyocta-2,6-dien-4-yn-1-al in high yie ld. Subsequent triphenylsilyl group removal, MnO2 oxidation, followed by hydrogenation over Lindlar catalyst and isomerization in the presen ce of traces of iodine furnished the desired polyenal. This ail-trans coumarin analogue of retinal was used for study of the bacteriorhodops in chromophore binding site. Copyright (C) 1996 Elsevier Science Ltd