Strukturanalytische Untersuchungen an Folgeprodukten aus Sulfonamiden. V. Infrarotspektroskopische und thermoanalytische Untersuchungen an polymorphen Modifikationen von N-substituierten S-Methyl-N′-tosyl-isothioharnstoffen

Structure-Analytical Investigations of Consecutive Products of Sulphonamides. V. Infrared Spectroscopic and Thermoanalytical Studies of Polymorphic Modifications of N-Substituted S-Methyl-N′-tosyl-isothioureas Four compounds ( 1d, 1e, 1h, 1p ) out of twelve N-substituted S-methyl-N′-tosylisothioureas were shown to form polymorphic modifications. Attempts were made to isolate each single specimen and to characterize it by means of differential scanning calorimetry and infrared spectroscopy. The results clearly revealed that both different hydrogen bonding and conformational effects are responsible for the formation of the polymorphic species. With the help of ¹⁵N labeled compounds the presence of the sulphonylimino structure in any modification was proved. The v(NH) and δ_s(SO₂) band positions are used to divide the polymorphs into two groups A and B.