Acylation of 2-aminothiobenzamide or 2-methylaminothiobenzamide with substituted benzoyl chlorides has been used to synthesise the corresponding 2-benzoyl-aminothiobenzamides whose subsequent sodium methoxide-catalysed ringclosure gives the corresponding quinazoline-4-thiones. These compounds were characterised by means of their 1H- and 13C-NMR spectra. The preferred tautomeric form of selected compounds