Experimental R(M) values of a series of 3-(4-alkylphenyl)-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and 3-(4-alkylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dithiones were obtained by a reversed-phase TLC system. The mobile phase was a phosphate buffer with volume fractions of acetone between 80 and 60%.
The retention constants R(M)(0) were compared with the partition coefficients calculated using different software products. The lipophilicity contributions of the sub-stituents were compared with the pi constants.