C-13 NMR CHEMICAL-SHIFTS OF HETEROCYCLES - EMPIRICAL SUBSTITUENT EFFECTS IN 5-HALOMETHYL-5-HYDROXY-4,5-DIHYDROISOXAZOLES

Evaluation by empirically derived equations for the substituent effect (alpha, beta, gamma, delta) on the C-13 NMR chemical shifts far C-3, C-4, C-5 and halomethyl-substituent carbon (C-6) in 5-halomethyl-5-hyd roxy-4,5-dihydroisoxazoles (where C-3 substituent = H, alkyl or phenyl , C-4 substituent = H, alkyl or heteroalkyl and C-5 substituent (= di- or trihalomethyl), taking as reference 5-trichloromethyl-5-hydroxy-4, 5-dihydroisoxaxole, is reported. From the calculated values for the al pha, beta, gamma and delta effects for each substituent it was possibl e to estimate the chemical shift of each carbon of the compounds.