One‐Pot Catalytic Syntheses of Quinazolinones by Coupling of 2‐Aminobenzamide With Primary Alcohols Using a Nickel(II)‐ONO Pincer‐Like Complex

ABSTRACT One‐pot syntheses of biologically relevant quinazolinones using acceptorless dehydrogenative coupling (ADC) of 2‐aminobenzamide with various alcohols in the presence of a catalytic amount of [NiL(PPh 3 )] ( 1 ) (H 2 L represents N‐(2‐hydroxy‐1‐naphthylidene)‐N′‐(2‐thenoyl)hydrazine, where two Hs are the dissociable phenolic and amide protons) are reported. The identity and purity of 1 have been confirmed by infrared and 1 H NMR spectroscopic and X‐ray crystallographic studies. A variety of substituted derivatives of quinazolinones have been successfully synthesized using a diverse range of alcohols in 40%–83% yields using 5 mol% of 1 . The detailed mechanistic investigation has revealed that the presence of 1 leads to the dehydrogenation of alcohol into aldehyde, followed by the formation of a cyclic aminal via condensation of the aldehyde with 2‐aminobenzamide. Ultimately, the dehydrogenation of the aminal provides the desired quinazolinone, producing water and dihydrogen as the by‐products, thereby making the present catalytic method environmentally benign and sustainable.