Phenyl isocyanate → HCID 57075789, compound

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Reaction Steps

1.92 ml of phenyl isocyanate are added at a temperature in the region of 20° C. to a solution of 1.5 g of 7-amino-1,4-dihydro-5H-indeno [1,2-b]pyrazine-2,3-dione hydrochloride and 2.48 ml of triethylamine in 20 ml of dimethylformamide. After overnight stirring at the same temperature, the precipitate formed is filtered off, washed with water and dried under a partial vacuum (1 mm Hg; 0.13 kPa) at 40° C. to yield 1.4 g of 7-(3-phenylureido)-1,4-dihydro-5H-indeno[1,2-b]pyrazine-2,3-dione in the form of a greenish solid, the melting point of which is above 260° C. (Analysis C18H14N4O3 ; 4.0 H2O; % calculated C: 64.66; H: 4.22; N: 16.76; % found C: 64.4; H: 4.5; N: 16.8; 1H NMR spectrum [250 MHz, (CD3)2SO-d6, δ in ppm]: 3.58 (s, 2H CH2 9); 7.00 (t, J=7.5 Hz, 1H: aromatic H of the phenyl at para with respect to the ureido); 7.30 (t, J=7.5 Hz, 2H: aromatic H of the phenyl at meta with respect to the ureido); 7.50 (d, J=7.5 Hz, 2H: aromatic H of the phenyl at ortho with respect to the ureido); from 7.20 to 7.60 (mt, 2H: H 5 and H 6); 7.72 (s broad, 1H: H 8); 8.80 (s broad, 2H: ArNHCONH); 12.00 and 12.28 (2 unres. comp. 1H each: NHCOCONH).

Provenance & Evidence