Aniline → 1-[[(o-Tolylamino)carbonyl]amino]-1,4-dihydro-2,3-quinoxalinedione

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Reaction Conditions

Reaction Steps

To a stirred solution of 1-carboxymethyl-1,4-dihydroquinoxaline-2,3-dione (100 mg, 0.450 mmol) and aniline (62 mg, 0.66 mmol) in dry DMF (2 mL) under N2 at 28° C., DCC (95 mg, 0.46 mmol, Aldrich) was added in one portion. The solution was stirred for 4 h at 28° C. The insoluble solid was filtered and washed with DMF (1 mL). The clear filtrate was poured into water (30 mL). The solid thus obtained was filtered and dried under vacuum (water aspirator) to yield 133 mg crude product as a grey powder. It was purified by Soxhlet extraction in boiling ethanol (20 mL), keeping the oil bath temperature at 120° C., for 4 h. The insoluble material (in the thimble) was dried under vacuum to obtain 55 mg of pure (1H NMR) N-(N'-phenylcarboxamidyl)methyl-1,4-dihydroquinoxaline-2,3-dione as a white solid (some of the product also ends up being extracted by hot ethanol which accounts for the low yield of the pure product). M.p.>300° C. (decomposes). 1H NMR: δ4.92 (s, 2H), 7.01-7.30 (m, 7H); 7.51 (d, 2H, J=6.9 Hz), 10.26 (s, 1H) 12.13 (s, 1H). IR (KBr, cm-1): 3148, 1715, 1671, 1600, 1557. HRMS: Calculated for C16H13N3O3, 295.0951; Observed, 296.1033.

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