COMPARISON OF SOLUTION AND SOLID-STATE STRUCTURE OF 2,3-DIYDROBENZOFURAN DERIVATIVES .7.

The molecular structure of xyphenyl)-5-hydroxy-3-methyl-2,3-dihydroben zofuran 3E-i-PR) and xyphenyl)-5-hydroxy-3-methyl-2,3-dihydrobenzofura n (3E-ET) have been determined by X-ray diffraction methods. The latte r compound was examined in solution by H-1 and C-13 NMR in order to as sign H-1 and C-13 spectra and extract the spin-spin coupling constants used in a conformational analysis of the single bonds at the C2 subst itutent. The low energy conformations, found by means of molecular mod eling for 3E-ET, are analysed using the recently modified Karplus equa tions. The NMR data, together with molecular mechanics calculations, i ndicate that the conformations established in the crystal, around C2-N and N-C16 bonds, also predominate in solution.