Phosphorus oxychloride → Ethyl 4-chloro-3-cyanopyrrolo[1,2-b]pyridazine-6-carboxylate

HRID 1507897Notes

Reaction equation

HRID 1507897 reaction equation
[C:1]([C:3]1[CH:8]=[N:7][N:6]2[CH:9]=[C:10]([C:12]([O:14][CH2:15][CH3:16])=[O:13])[CH:11]=[C:5]2[C:4]=1O)#[N:2].O=P(Cl)(Cl)[Cl:20]>>[Cl:20][C:4]1[C:5]2[N:6]([CH:9]=[C:10]([C:12]([O:14][CH2:15][CH3:16])=[O:13])[CH:11]=2)[N:7]=[CH:8][C:3]=1[C:1]#[N:2]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178468548HCID 178468548, compound

Product 1

HCID 69326995Ethyl 4-chloro-3-cyanopyrrolo[1,2-b]pyridazine-6-carboxylateYield 48%

Conditions

Temperature
75 °C

Procedure

To a round bottom flask was added POCl3 (200 mL) and ethyl 3-cyano-4-hydroxypyrrolo[1,2-b]pyridazine-6-carboxylate (20 g, 80 mmol). The reaction was heated under nitrogen at 75° C. for 2 hours. The reaction was cooled to room temperature and POCl3 was removed under vacuum. The residue was poured onto ice-water. The aqueous solution was extracted with CH2Cl2. The organic layer was washed with saturated sodium carbonate solution, dried and concentrated. The resulting residue was purified by flash silica gel column chromatography to yield 10 g (48%) of the title compound as a yellow solid. 1H NMR (400 MHz, CDCl3) δ ppm: 8.33 (1H, d, J=1.3 Hz), 8.11 (1H, s), 7.41 (1H, d, J=1.6 Hz), 4.41 (2H, q, J=6.8 Hz), 1.41 (3H, t, J=6.8 Hz).

Workup

  1. temperatureThe reaction was cooled to room temperature
  2. customPOCl3 was removed under vacuum
  3. additionThe residue was poured onto ice-water
  4. extractionThe aqueous solution was extracted with CH2Cl2
  5. washThe organic layer was washed with saturated sodium carbonate solution
  6. customdried
  7. concentrationconcentrated
  8. customThe resulting residue was purified by flash silica gel column chromatography

Sources & evidence

ORD record
ord-7000723fff9f45cf9f2c75a58b17ac57
Source dataset
uspto-grants-2015_12
Patent number
US09221826B2

Reaction notes

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