3,4-Diaminopyridine → 6,7,8,9-Tetrahydropyrido[3,4-b]quinoxaline

HRID 1670653Notes

Reaction equation

HRID 1670653 reaction equation
[C:1]1(=O)[CH2:6][CH2:5][CH2:4][CH2:3][C:2]1=O.[NH2:9][C:10]1[CH:11]=[N:12][CH:13]=[CH:14][C:15]=1[NH2:16].CN1CCN(C)C2C=NC=CC1=2.[K+].[Br-]>C(O)C.CCOC(C)=O.CCCCCC>[CH:11]1[C:10]2=[N:9][C:2]3[CH2:3][CH2:4][CH2:5][CH2:6][C:1]=3[N:16]=[C:15]2[CH:14]=[CH:13][N:12]=1

Participants

7

Reactant 4

HCID 59183,4-DiaminopyridineHCID 130061,2-CyclohexanedioneHCID 253877Potassium BromideHCID 441857941,4-Dimethy-1,2,3,4-tetrahydropyrido[3,4-b]pyrazine

Product 1

HCID 574357846,7,8,9-Tetrahydropyrido[3,4-b]quinoxaline

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 21226206Ethyl acetate hexaneSolvent

Conditions

Temperature
70 °C

Procedure

1,2-Cyclohexanedione (1.52 g, 13.93 mmol) was added to a suspension of 1.56 g (13.93 mmol) of 3,4-diaminopyridine in 50 ml of ethanol. The reaction mixture was subsequently heated at an oil bath temperature of 70° C. for 5 hours, then cooled to room temperature and the solvent was then distilled off on a rotary evaporator. The product obtained was purified by flash chromatography using ethyl acetate as eluent. This gave 1.84 g (71%) of a white solid which was stored in a refrigerator and processed further after 1-2 days. Allowing the solid to stand in an open flask in sunlight resulted in the color changing to greyish green. Rf=0.25 (EtOAc/hexane, 20:1). 1H NMR: (200 MHz, CDCl3): δ=2.05 (m, 4H, H-7,8), 3.18 (m, 4H, H-6,9), 7.79 (d, 3J=5.8 Hz, 1H), 8.72 (d, 3J=5.8 Hz, 1H), 9.38 (s, 1H) ppm. 13C NMR (75 MHz, CDCl3): δ=22.8 (CH2, C-7,8), 33.7 (CH2, C-6,9), 121.2 (CH), 136.9 (Cq), 144.1 (Cq), 146.8 (CH), 153.9 (CH), 156.8 (Cq) 159.9 (Cq) ppm. GC-MS (EI): RT 8.44 min, m/e (%) 186 (11), 185 (M+, 100), 184 (39), 183 (3), 182 (3), 171 (2), 170 (21), 169 (4), 158 (2), 157 (5), 156 (5) 131 (2), 104 (2), 103 (4), 78 (3), 76 (4), 67 (2), 64 (2), 51 (2), 50 (6); IR (KBr): ν=3435 (vs), 2947 (s), 2864 (m), 1594 (s), 1557 (w), 1461 (w), 1421 (m), 1385 (s), 1365 (w), 1330 (w), 1297 (m), 1211 (m), 1140 (w), 979 (m), 949 (w), 901 (m), 849 (m), 679 (w), 629 (w), 570 (w), 412 (w) cm−1. HRMS (EI): calculated for C11H11N3 185.0953 [M+], found: 185.0935

Workup

  1. temperaturecooled to room temperature
  2. distillationthe solvent was then distilled off on a rotary evaporator
  3. customThe product obtained
  4. customwas purified by flash chromatography
  5. customAllowing the solid to stand in an open flask in sunlight
  6. customresulted in the color

Sources & evidence

ORD record
ord-2305a970020642f7bf8f0f752da22096
Source dataset
uspto-grants-2011_08
Patent number
US07994169B2

Reaction notes

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