CONVERSION OF ANILINES INTO N-METHYL-2-QUINOLONES VIA (2,3) SIGMATROPIC REARRANGEMENTS

A new general synthesis of o-(N-methylamino)-cinnamic acid, N-methyl-2-quinolone, and 3,4-dihydro-N-methyl-2-quinolone has been developed, which involves the sequential reaction of N-methylaniline with (i) t-butyl hypochlorite, (ii) ethyl 3-phenylthiopropionate, and (iii) sodium methoxide to produce the reactive intermediate o-(2-ethoxycarbonyl-1-phenylthioethyl)-N-methyl aniline, which is readily converted into the aforementioned products.