396716-28-2

Upstream product

• 396716-18-0 N-methyl-N-(2-thiocarbamoyl-phenyl)-benzamide 
• 98-88-4 benzoyl chloride 
• 32600-73-0 2-methylaminothiobenzamide 

Downstream Products

• 22686-80-2 1-Methyl-2-phenyl-4(1H)-quinazolinone 

Relevant academic research and scientific papers

Kinetics and mechanism of the base-catalysed cyclisation of 2-(substituted benzoylamino)benzamides giving quinazolin-4-one and quinazolin-4-thione derivatives

Acylation of 2-aminobenzamide and 2-(methylamino)benzamide with substituted benzoyl chlorides in acetone has been used to prepare the respective 2-(substituted benzoylamino)benzamides 1a-i, which were then subjected to sodium methoxide catalysed ring closure to give the respective 2-(substituted phenyl)quinazolin-4 -ones 2a-i. The kinetics of the cyclisation reactions were monitored by UV/Vis spectroscopy at 25 °C in methanolic solutions of sodium methoxide. In the case of 2-(substituted benzoylamino)benzamides 1a-i and 2-(substituted benzoylamino)thiobenzamides 3a-j, non-linear dependences of observed rate constants κobs on the sodium methoxide concentrations were obtained, the shape of them being typical of a reaction with rapid pre- equilibrium. All the cyclisation reactions satisfactorily obeyed the Hammett correlation. In the case of 2 - [(benzoyl) (methyl) amino] benzamides 1e-i, increasing sodium methoxide concentration resulted in a progressive increase in κobs values which is probably due to formation of dianion. In the case of 2-(substituted benzoylamino)thiobenzamides 3b and 3h, which differ in the presence of a methyl group on the nitrogen atom the values of the activation Gibbs energy ΔG? 25 °C, activation enthalpy ΔH? 25 °C, and activation entropy ΔS? 25 °C for their respective cyclisations to 2-(substituted phenyl)quinazoline-4-thiones 4b and 4h were determined. Whereas the ΔG? 25 °C values were very close for the two substances, the ΔH? 25 °C and ΔS? 25 °C distinctly differed. This was interpreted by the enthalpy and entropy factors operating against each other in the cyclisation. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

Synthesis of substituted 2-benzoylaminothiobenzamides and their ring closure to substituted 2-phenylquinazoline-4-thiones

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 ring closure 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 has been discussed on the basis of their 13C-NMR, IR and Raman spectra. It has been found that in the given medium 1-methyl-quinazoline-4-thiones undergo a replacement of the sulphur substituent by oxygen giving 1-methyl-quinazoline-4-ones. In strong acid media, 2-benzoylaminothiobenzamide is cyclised through its sulphur atom to give 2-phenylbenzo[d-1,3]thiazin-4-one.