Tandem Hydroformylation/Reductive Amination of 3‐Allyl‐2‐methylquinazolin‐4(3 H )‐one

The 3‐allyl‐2‐methylquinazolin‐4(3 H )‐one ( 1 ), a model functionalized terminal olefin, was submitted to hydroformylation and reductive amination under optimized reaction conditions. The catalytic carbonylation of 1 in the presence of Rh catalysts complexed with phosphorus ligands under different reaction conditions afforded a mixture of 2‐methyl‐4‐oxoquinazoline‐3(4 H )‐butanal ( 2 ) and α ,2‐dimethyl‐4‐oxoquinazoline‐3(4 H )‐propanal ( 3 ) as products of ‘linear’ and ‘branched’ hydroformylation, respectively ( Scheme 2 ). The hydroaminomethylation of quinazolinone 1 with arylhydrazine derivatives gave the expected mixture of [(arylhydrazinyl)alkyl]quinazolinones 5 and 6 , besides a small amount of 2 and 3 ( Scheme 3 ). The tandem hydroformylation/reductive amination reaction of 1 with different amines gave the quinazolinone derivatives 7 – 10 . Compound 10 was used to prepare the chalcones 11a and 11b and pyrazoloquinazolinones 12a and 12b ( Scheme 4 ).