ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
J(13C1H) coupling constants for some methyl- and aminopyrimidines have been determined by 13C NMR. Both the one-bond and long-bond and long-range coupling constants follow general trends which can be summarized in a few simple rules. In particular, the 3J(C-i,H) coupling constants between a ring carbon C-i and the ring protons are larger than the 2J(C-i,H) coupling constants. The opposite is observed for the couplings between the ring carbons and the methyl protons: 3J(C,Me). These general rules are very useful for the assignment of resonances in complex 13C spectra of pyrimidines and seem to be valid for other 6-membered aromatic nitrogen heterocycles. Furthermore, the additivity of substituent effects on 1J (CH) for monosubstituted pyrimidines allows the estimation of 1J (CH) for polysubstituted pyrimidines with a very good accuracy.
Additional Material:
5 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1270150105
