Does anyone know of a good compilation of 1J(CH) values which
includes examples of epoxides? I have a carotenoid with a CH group which
has the following characteristics:
singlet in 1H at 3.92 ppm
carbon shift 57.76 ppm
1J(CH) = 195 Hz
The large 1J value especially caught my eye. Maybe it's some familiar
impurity, but it has the right intensity and appears to connect by HMBC
crosspeaks to other carbons in the molecule. The solvent is CDCl3 and the
Temp. is 30 C. My first guess is an epoxide, possibly CH(-O-)-C(CH3)-. Any
suggestions?
Neil E. Jacobsen
NMR Facility Manager
Department of Chemistry
University of Arizona
Tucson, AZ 85721
520-621-8146
Fax 520-621-8407