An Efficient Synthesis of ( 1‐Methyl )‐2‐phenyl‐4‐quinolones from ( N ‐Methyl )isatoic Anhydride

The acyl substitution of ( N ‐methyl)isatoic anhydride with N , O ‐dimethylhydroxylamine hydrochloride in CH 3 CN gave N ‐methoxy‐ N ‐methyl 2‐( N ‐methyl)aminobenzamide, which was treated with ethynyllithium reagents to afford 1‐[2‐( N ‐methyl)amino]‐3‐phenyl‐2‐propyn‐1‐ones. The 6‐ endo cyclization of 1‐[2‐( N ‐methyl)amino]‐3‐phenyl‐2‐propyn‐1‐ones using NaOCH 3 in CH 3 OH at 65 °C gave various (1‐methyl)‐2‐phenyl‐4‐quinolone derivatives in high yields.