Search results for "Diazodiphenylmethane"

Linear free energyortho-correlations in the thiophene series. Part IX . Kinetics of esterification with diazodiphenylmethane of some 3-, 4-, and 5-su…

1981

The rate constants for the esterification of some 3-, 4-, and 5-substituted thiophene-2-carboxylic acids with diazodiphenylmethane in methanol at 25° have been measured. The reactivity of some para- and ortho-substituted benzoic acids has also been determined. Logarithmic kinetic constants for ortho-, meta-, and para-like substituted thiophene-2-carboxylic acids furnish an excellent linear free energy relationship when plotted versus Δpka (β 0.89, r 0.989, C.L. > 99.9%, n 18, i 0.04), thus confirming the peculiar behaviour of five-membered ring derivatives. The correlation with σH values offers an additional proof of the hyper-ortho character of the 2,3-relation in thiophene derivatives. pa…