Collect. Czech. Chem. Commun. 1994, 59, 1833-1840

An Analysis of Substituent Effects on the Proton and Carbon-13 Chemical Shifts of 2-Substituted 9-Isothiocyanatoacridines

Ivan Danihela, Ján Imricha, Pavol Kristiana, Tibor Liptajb and Dana Mazagováa

a Department of Organic Chemistry, P. J. Šafárik University, 041 54 Košice, Slovak Republic
b Central NMR laboratory, Slovak Technical University, 812 37 Bratislava, Slovak Republic


Proton and 13C NMR chemical shifts and coupling constants J(H,H) of a series of 2-substituted 9-isothiocyanatoacridines and their 4-methyl and 4-methoxy analogs were determined. The obtained values were utilized in analysis of substituent effects using empirical equations based on two- and three-parameter linear correlations. It was found that short-range interactions (positions ipso, ortho and meta) are well described by the three-parameter model of Reynolds whereas long-range effects are satisfactorily compatible with the two-parameter model. The dominant direction of conjugation in the acridine skeleton was derived from changes in chemical shifts due to substitution (SCS).