New parameters for predicting 1H NMR chemical shifts of protons attached to carbon atoms

A parameter set has been compiled for predicting the 1H NMR chemical shifts of protons attached to carbon atoms. It is based on simple additivity rules and currently comprises 728 base values and about 2000 increments. For methyl groups, increments for α- and β-substituents have been developed and parameter sets previously reported for methylene and methane groups have been amended. New rules have been added for allenes and acetylenes. The parameter set is part of a recently published computer program for estimating proton chemical shifts [1]that automatically searches for appropriate substructures and applies various strategies to find suitable parameters for lacking substituents.