Sulfuric Acid → Ethyl 3-carbamoyl-4-chloropyrrolo[1,2-b]pyridazine-6-carboxylate

HRID 1507898Notes

Reaction equation

HRID 1507898 reaction equation
[Cl:1][C:2]1[C:3]2[N:4]([CH:10]=[C:11]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:12]=2)[N:5]=[CH:6][C:7]=1[C:8]#[N:9].[OH:18]S(O)(=O)=O>>[C:8]([C:7]1[CH:6]=[N:5][N:4]2[CH:10]=[C:11]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:12]=[C:3]2[C:2]=1[Cl:1])(=[O:18])[NH2:9]

Participants

3

Reactant 2

HCID 1118Sulfuric AcidHCID 69326995Ethyl 4-chloro-3-cyanopyrrolo[1,2-b]pyridazine-6-carboxylate

Product 1

HCID 68290691Ethyl 3-carbamoyl-4-chloropyrrolo[1,2-b]pyridazine-6-carboxylateYield 70%

Procedure

To a round bottom flask was added concentrated H2SO4 (100 mL) followed by ethyl 4-chloro-3-cyanopyrrolo[1,2-b]pyridazine-6-carboxylate (10 g, 40 mmol). The reaction was stirred at room temperature under nitrogen overnight. The reaction mixture was poured onto ice cold saturated sodium carbonate solution. The aqueous solution was extracted with EtOAc (4×) and the combined organic layer was concentrated to yield 7 g (70%) of the title compound as a yellow solid. HPLC (condition S): retention time=8.04 min. LCMS (condition A): m/z=268.0 +ve. 1H NMR (400 MHz, CDCl3) δ ppm: 8.49 (1H, d, J=1.6 Hz), 8.40 (1H, s), 8.08 & 7.98 (1H, two br s), 7.12 (1H, d, J=1.6 Hz), 4.34 (2H, q, J=7.2 Hz), 1.34 (3H, t, J=7.2 Hz).

Workup

  1. additionThe reaction mixture was poured onto ice cold saturated sodium carbonate solution
  2. extractionThe aqueous solution was extracted with EtOAc (4×)
  3. concentrationthe combined organic layer was concentrated

Sources & evidence

ORD record
ord-c04d6f6fb7df4c3582aceb5dde984b26
Source dataset
uspto-grants-2015_12
Patent number
US09221826B2

Reaction notes

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