Studies on 1,2,3-benzothiadiazoles. Part II. The nuclear magnetic resonance spectra of the nitro-, bromo-, and methoxy-1,2,3-benzothiadiazoles

Abstract

The 100 MHz proton magnetic resonance spectra of the nitro-, bromo-, and methoxy-1,2,3-benzothiadiazoles were recorded and analysed as ABC systems. Additivity rules for chemical shifts and coupling constants have been applied; deviations from the observed chemical shifts are rationalised in terms of mesomeric and field effects. Syntheses of the four methoxy-1,2,3-benzothiadiazoles are described.