with TLC on silica gel with dimethylformamide (Rf 0.9) or aqueous 80% methanol (Rf 0.8). Attempted recrystallization usually resulted in partial decomposition, as shown by TLC. The analytical sample was dried for 9 h at 0.1 Torr at 100 °C. The compound darkened above 240 °C but did not melt up to 400 °C; 100-MHz !H NMR (Me2SO-d8) 8.55 (s, 1, NCHN), 8.10 (s, 1, CH=CB2), 7.64 (broadened s, 1, NH), 7.18 (broadened s, 1, NH), 3.42 (s, ~10, NH, BOH, and H20 from solvent); on addition of methanol dropwise, the 7.64 peak broadened, shifted downfield, and disappeared, and the 7.18 peak broadened somewhat without shifting; NMR (CD3OD)8.31 (brd s.

A preparatively useful method for the synthesis of 3‐cyano‐4‐phenyl‐2‐pyridone (I) is described. Reaction of 2‐cyano‐3‐methylcinnamamide (VII) with N,N‐dimethylformamide dimethyl acetal affords the corresponding dimethylaminomethylidene amide VIII which in turn, is thermally cyclized to I in DMF solvent. The advantages of this method include mild reaction conditions for short periods to give good yields of I on large scales without chromatographic purification.

Aus dem Anhydrid (I) erhält man mit o‐Chlorphenylmagnesiumehlorid das Keton (III), das über das Säurechlorid zu (IV) umgesetzt wird.

Aus dem Anhydrid (I) erhält man mit o‐Chlorphenylmagnesiumehlorid das Keton (III), das über das Säurechlorid zu (IV) umgesetzt wird.

Dimethylformamid‐acetal (II) reagiert mit dem ungesättigten Amid (I) über (III) zum Pyridon (IV), das eine Zwischenstufe bei der Herstellung von Komplexen und Naturstoffen darstellt.