A New Domino Reaction under Microwave Irradiation for the Synthesis of Pyrazolo[5,1- b ]quinazolinones.

When the reaction of anthranilic acid hydrazide with methyl 2-cyano-3,3-bis(methylthio)acrylate ( B 6a b ) was performed in methanol at 130 °C for 1 minute, 1,3,4-oxadiazoline B 8a b precipitated from the reaction mixture instead of expected pyrazolo[5,1- I b i ]quinazolinone B 7a b . Keywords: pyrazoles; quinazolines; domino reaction; oxadiazolines; anthranilates; microwave-assisted synthesis EN pyrazoles quinazolines domino reaction oxadiazolines anthranilates microwave-assisted synthesis 2691 2701 11 08/17/23 20230901 NES 230901 Graph The pyrazolo[5,1- I b i ]quinazolinone ring system serves as a scaffold for the construction of bioactive molecules with a diverse range of potential applications. Microwave-assisted reactions were performed in a CEM Discover SP microwave reactor operating at a maximal microwave power of 150 W and pressure of 435 psi. [22][23][24] The pathway of the reaction between anthranilic acid hydrazide and alkyl 2-cyano-3,3-bis(methylthio)acrylates B 6 b can be explained by the insufficient nucleophilicity of the aromatic amino group of anthranilic acid hydrazide. [Extracted from the article]