2,4(1 H,3H)-Quinazolinediones and 2-Thioxo-4(3H}-quinazolin-4-ones represent one of the most active classes of heterocycles possessing a wide spectrum of industrial [1] and biological activities [2]; therefore, considerable attention has been focused on their synthesis [3]. The most accessible method has proven to be the one based on the reaction of anthranilic acid or its functional derivatives with a source of NH and carbonyl or thiocarbonyl groups such as thiocyanate salts and isothiocyanates. In this work, we wish to report a convenient and simple procedure for the one-pot synthesis of 2,4(1 FL3H)-quinazolinediones and 2-thioxo-4(3H)- quinazolin-4-ones 2 by direct cyciocondensation reaction of anthranilic acid derivatives I with urea and thiourea in. polyethyleneglycole (PEG). The reaction proceeds in neutral media and without use of any catalyst.
