Calculation of ~(17)O-NMR Chemical Shifts of Carbonyl Groups in Carboxylic Methyl and Ethyl Esters

An equation: δ_(cal)=360.0+Δα+Δβ+Δγ for calculating ~(17)O-NMR chemical shifts of carbonyls in carboxylic methyl and ethyl esters was provided.Twenty two substituent parameters for the equation were obtained with least-square linear regression.Experimentally measured ~(17)O chemical shifts from 52 carboxylic esters were used as the test set to examine the accuracy of the calculated results.The confidence limit was found to be 99.5 % and the calculating errors for almost all the compounds were less than 5.0(relative errors ≤0.5 %).