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

HRID 1408905Notes

Reaction equation

HRID 1408905 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-842523514e384641a53b1e80f68a6164
Source dataset
uspto-grants-2014_12
Patent number
US08921368B2

Reaction notes

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