Facile synthesis of 4-phenylquinolin-2(1H)-one derivatives from N-acyl-o-aminobenzophenones

An efficient synthesis of 4-phenylquinolin-2(1H)-one derivatives has been achieved in a one-pot reaction from N-acyl-o-aminobenzophenones (: acyl=acetyl; : acyl=propanoyl; : acyl=heptanoyl) using NaH as a base. Treatment of with NaH provided the quinolones with 62–83% yields, whereas the reaction in the presence of alkyl iodide (alkyl=methyl, ethyl, n-octyl) gave the corresponding N-alkylated quinolones in 75–95% yields. The alkylation reaction of 4-phenylquinolin-2(1H)-one with alkyl halide gave a mixture of N-alkylated and O-alkylated products. Comparison of IR and NMR data of the N-alkylated and O-alkylated compounds with those of indicated that exist as the lactam form.