C-13 NMR ASSIGNMENTS OF CONFORMATIONALLY DEFINED 6-S-TRANS-RETINOIDS

A new class of vitamin A analogs (retinoids) was synthesized containin g a dimethylene bridge to maintain a 6-s-trans conformation of the ter minal double bonds. The H-1 and C-13 NMR spectra were assigned for 15 new compounds, including E-Z isomers (all-E, 13Z, 9Z, and 9Z,13Z) of r etinoids containing an ethyl ester and carboxylic acid polar end group s, and also the (all-E)-isomer of the retinoids with an alcohol and al dehyde polar end-groups and five C-15 intermediates. The assignments w ere based on long-range H-1-C-13 heteronuclear 2D experiments.