Unusual Conformation and Photoisomerization of Retinochrome Analogues with 11-Methylretinals
Three kinds of 11-methylretinals were synthesized for elucidating effect of methyl substitution on formation of retinochrome-analogues and their properties. The stable conformation of 11-methylretinal was found as 6,10,12-tri-<I>S</I>-cis conformation based on NOESY measurement. The formed retinochrome-analogues with 11-Me-, 11-Me-13-deMe- and 11-Me-9,13-dideMe-retinals showed their absorption maxima at 450, 470 and 470 nm, respectively. The enzymatic photoisomerization of their retinochrome-analogues gave the 11-cis isomers in 90-91 % regioselectivity. The CD spectra of 11-methylretinochrome exhibited the intense β-band with extremely weak α-band.
- Chemistry letters
Chemistry letters 1997(8), 813-814, 1997-08
The Chemical Society of Japan