Abstract Reaction of 2-thioquinazolinone (1) with various alkylating agents like dimethyl sulphate, diethyl sulphate and benzyl chloride in the presence of K2CO3 as a mild base, by a simple physical grinding, microwave irradiation and PEG-600 under solvent-free conditions for 10-15 min at room temperature, followed by processing, gave respectively 2- methylsulfanyl-3H-quinazolin-4-one (2a, ie, R= CH3), 2-ethylsulfanyl-3H-quinazolin-4-one ...