HCID 86619018, compound → ethyl 7-chloro-1H-pyrrolo(2,3-c)pyridine-2-carboxylate
Reaction equation
[Cl:1][C:2]1[C:7]([N+:8]([O-])=O)=[C:6](/[CH:11]=[C:12](\[O-])/[C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:5]=[CH:4][N:3]=1.[K+]>C(O)(=O)C.[Fe]>[Cl:1][C:2]1[N:3]=[CH:4][CH:5]=[C:6]2[CH:11]=[C:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[NH:8][C:7]=12Participants
4
Reactant 1
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 60 °C
Procedure
Potassium (1Z)-1-(2-chloro-3-nitropyridin-4-yl)-3-ethoxy-3-oxoprop-1-en-2-olate (19.8 g, 63.6 mmol) was dissolved in acetic acid (908 mL) and the solution was treated with iron powder (14.6 g, 280.9 mmol). The reaction mixture was warmed to 60° C. and stirred overnight (18.5 h). TLC analysis indicated consumption of the starting material, therefore the reaction mixture was filtered through diatomaceous earth to remove the catalyst. The filtrate was concentrated to dryness. The residue was treated with methylene chloride (ca. 400 mL) and filtered through a plug of silica. Eluting with methylene chloride removed insolubles, and further elution with methylene chloride/ethyl acetate (50:50) provided ethyl 7-chloro-1H-pyrrolo[2,3-c]pyridine-2-carboxylate (10.3 g, 45.8 mmol, yield 72%) as a yellow solid after concentration: Rf 0.80 (silica gel, 50:50 hexanes/ethyl acetate); mp 152-157° C.; 1H NMR (300 MHz, CD3OD) δ1.43 (3H, t, J=7.0 Hz), 4.44 (2H, q, J=7.1 Hz), 7.27 (1H, s), 7.65 (1H, d, J=5.7 Hz), 7.95 (1H, d, J=5.4 Hz); ESI MS m/z 224 [C10H9ClN2O2+H]+; HPLC (Method A) >99% (AUC), tR=16.6 min.