1(2H)-Pyridazinecarboxylic acid, tetrahydro-, ethyl ester → 2-[7-fluoro-2H-1,4-benzoxazin-3(4H)-on-6-yl]-hexahydro-1H-(1,2,4)-triazolo (1,2-a) pyridazine-1,3-dione

Participants

Reaction Steps

A mixture composed of 6-isocyanato-7-fluoro-2H-1,4-benzoxazin-3(4H)-one (2.14 g), 1-ethoxycarbonylhexahydropyridazine (1.62 g) and dioxane (30 ml) is treated with a few drops of triethylamine, stirred at an ambient temperature for 2 hours, and left overnight. The reaction mixture is made free from dioxane by evaporation in vacuo, mixed with methanol (30 ml) containing a catalytic amount of sodium, and refluxed for 2 hours. After removal of methanol by evaporation in vacuo, the resultant solid is collected, and washed with water to obtain an end product 2-[7-fluoro-2H-1,4-benzoxazin-3(4H)-on-6-yl]-hexahydro-1H-(1,2,4)-triazolo (1,2-a) pyridazine-1,3-dione (2.45 g).

Provenance & Evidence