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

The 3-allyl-2-methylquinazolin-4(3H)-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(4H)-butanal (2) and ,2-dimethyl-4-oxoquinazoline-3(4H)-propanal (3) as products of linear' and branched' hydroformylation, respectively (Scheme2). 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 (Scheme3). 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 (Scheme4).