Homonuclear Overhauser 1H-NMR. Experiments on the Carotenoid Pigments Lycopene and Prolycopene

The recently proposed structure of the carotenoid pigment prolycopene as the 7,9,7′,9′-tetra-cis isomer of lycopene has been unambiguously confirmed by a series of homonuclear Overhauser ¹H-NMR. experiments at 270 MHz. Comparative measurements are reported for lycopene.