Abstract: An equation: δ_cal=360.0+Δα+Δβ+Δγ for calculating ¹7O-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 ¹⁷O 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 %).

Key words: ¹⁷O-NMR, chemical shift, substituent effect, ester, carbonyl