Stannous chloride dihydrate → 5-Amino-6,7-dichloro-1,4-dihydro-2,3-quinoxalinedione

HRID 53756Notes

Reaction equation

[N+:1]([C:4]1[C:13]([Cl:14])=[C:12]([Cl:15])[CH:11]=[C:10]2[C:5]=1[NH:6][C:7](=[O:17])[C:8](=[O:16])[NH:9]2)([O-])=O.O.O.Cl[Sn]Cl>C(O)C>[NH2:1][C:4]1[C:13]([Cl:14])=[C:12]([Cl:15])[CH:11]=[C:10]2[C:5]=1[NH:6][C:7](=[O:17])[C:8](=[O:16])[NH:9]2

Participants

Conditions

Temperature: 90 °C

Procedure

To a stirred mixture of 5-nitro-6,7-dichloro-1,4-dihydro-2,3-quinoxalinedione (110 mg, 0.40 mMol) in ethanol (6 mL) was added SnCl2.2H2O (448 mg, 2.0 mMol) in one portion. The mixture was refluxed at 80° C. (oil bath 90° C.) with stirring for 1 h to form a clear solution and continually refluxed for another 3 h. The mixture was then cooled to room temperature and the yellow precipitate was collected by filtration and washed with cold ethanol (2×1 mL) to give 61 mg (62%) of crude title compound (contains minor impurities by NMR). Crystallization from DMSO/H2O gave 43 mg of pure title compound as bright yellow needles, mp >350° C. (dec.), changed color from 320° C. IR (KBr, cm-1): 3468; 3389; 3057; 1695; 1636; 1596; 1397. NMR (1H, DMSO-d6): δ 5.935 (s, 2H); 6.595 (s, 1H); 11.317 (s, 1H); 11.868 (s, 1H). Purity >98.95% by HPLC. HRMS: calcd for C8H5N3O2Br2 (M+) m/z: 244.9757; found 244.9740. Potency relative to DCK: 323%.

Workup

customto form a clear solution
temperaturecontinually refluxed for another 3 h
temperatureThe mixture was then cooled to room temperature
filtrationthe yellow precipitate was collected by filtration
washwashed with cold ethanol (2×1 mL)
customto give 61 mg (62%) of crude title compound (contains minor impurities by NMR)
customCrystallization from DMSO/H2O

Sources & evidence

ORD record: ord-a3aa65e9579f4732b1cd7a6749f0ea78
Source dataset: uspto-grants-1997_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05620979

Reaction notes

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