Methyl Isocyanate → ethyl 8-(3-methylureido)-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazine-2-carboxylate

Beteiligte Stoffe

Reaktionsschritte

0.44 ml of methyl isocyanate is added dropwise with stirring to a suspension of 580 mg of ethyl 8-amino-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazine-2-carboxylate in 10 ml of dimethylformamide and stirring is continued for 12 hours at a temperature close to 20° C. The reaction mixture is then filtered, rinsed with dimethylformamide and dried at 35° C. under vacuum (1 mm Hg; 0.13 kPa). 320 mg of ethyl 8-(3-methylureido)-4,5-dihydro-4-oxo-10H-imidazo[1,2-a]indeno[1,2-e]pyrazine-2-carboxylate are obtained as a dihydrate in the form of a beige solid melting above 260° C. (analysis % calculated C: 53.59, H: 5.25, N: 17.36; % found C: 53.2, H: 4.7, N: 17.7).

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