Tetrahydrofuran → 3-[2-Methyl-3,4-dihydro-3-oxo-4-(propynyl)-2H-1,4-benzoxazin-6-yl]-6-(trifluoromethyl)-2,4(1H,3H)-pyrimidinedione

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A slurry of 1.4 g. of sodium hydride in 25 ml. of dry tetrahydrofuran (THF) was cooled to -10° C. To the cooled and stirred slurry was added a solution of 10.0 g. of ethyl 3-amino-4,4,4-trifluoro-2-butenoate in 50 ml. of THF. The addition of this solution was made over a period of 30 minutes. The resultant light brown reaction mixture was cooled to -70° C. A solution of 13.3 g. of 6-isocyanato-2- methyl-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazine in 75 ml. of THF was added to the chilled reaction mixture over a period of 10 minutes. After stirring at -70° C. for 30 minutes, the temperature was allowed to rise slowly to 10° C. At that point 3.6 ml. of acetic acid was added to the mixture. A beige solid precipitated. 19.0 Grams of the solid was recovered by filtering it from the reaction mixture.

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