p-Toluenesulfonic acid monohydrate → HCID 19006957, compound

Participants

Reaction Steps

A solution of ethyl 2-amino-4-(acetylamino)benzoate (4.03 g, 18.13 mmol, Example 4, Step A), p-toluenesulfonic acid, monohydrate (0.5 g, 2.63 mmol) and methyl 6-chloro-3-pyridazinecarboxylate [3.13 g, 18.14 mmol, prepared according to the procedure of Barlin, G. B. and Yap, C. Y. (Aust. J. Chem. 1977, 30, 2319-2322)] in 500 mL of toluene was refluxed under Dean-Stark conditions for 12 h. The mixture was concentrated, dissolved into chloroform, washed with saturated sodium bicarbonate solution, dried (MgSO4), filtered and concentrated. Medium pressure chromatography (silica gel, 5% methanol in chloroform) afforded methyl 7-acetylamino-10-oxo-10H-pyridazino[6,1-b]-quinazoline-2-carboxylate as a yellow solid, mp 281°-285° C., dec.

Provenance & Evidence