Surfactant based nanoreactor micellar assembly: An innovative route for synthesis of 2-thioxo-2,3-dihydroquinazolin-4(1H)-ones

Abstract

• Synthesis of an efficient surfactant, 4-(dimethylamino)-1-hexadecylpyridinium hydroxide [DAHP] + [OH]-. • A novel route for the synthesis of 2-thioxo-2,3-dihydroquinazolin-4(1 H )- ones. • The micelle size by SAXS found to be 14.8 nm (diameter) and 2.6 nm (the spacing between two micelles). • High yield, water as a solvent, short reaction time, easy separation of products are remarkable properties. We described an innovative route for synthesis of 2-thioxo-2,3-dihydroquinazolin-4(1 H )-ones using isatoic anhydride and phenyl isothiocyanate via in situ formation of anthranilic acid. The reaction was performed in the nano-micellar assembly of surfactant, 4-(dimethylamino)-1-hexadecylpyridinium hydroxide [DAHP] + [OH] - as a nano-reactor. The micelle concentration of surfactant is found to be 0.002 mol.dm −3 using the conductivity data. The micellar particle dimensions were demonstrated from small-angle X-ray scattering (SAXS) analysis viz. micelle diameter and the interspacing between two micelles which were found to be 14.8 nm and 2.6 nm, respectively. From the TGA analysis, the surfactant is thermally stable up to 250 °C with 76.01 % weight loss. The practical simplicity, atom economy, good to high yields, ease of product isolation and purification, water as eco-benign solvent and catalyst recyclability are the remarkable aspects of the present methodology.