4-Chlorobenzoyl chloride → methyl 2-(1-(4-chlorobenzoyl)-1H-indazol-3-yl)acetate

Reaction equation

[NH:1]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[C:3]([CH2:10][C:11]([O:13][CH3:14])=[O:12])=[N:2]1.CC([O-])(C)C.[Na+].[Cl:21][C:22]1[CH:30]=[CH:29][C:25]([C:26](Cl)=[O:27])=[CH:24][CH:23]=1>C1COCC1>[Cl:21][C:22]1[CH:30]=[CH:29][C:25]([C:26]([N:1]2[C:9]3[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=3)[C:3]([CH2:10][C:11]([O:13][CH3:14])=[O:12])=[N:2]2)=[O:27])=[CH:24][CH:23]=1

Participants

Procedure

To a cooled solution (ice bath, 0-5° C.) of methyl 2-(1H-indazol-3-yl)acetate (80 mg, 0.42 mmol) in THF (2.5 mL) was added tBuONa (2 M in THF, 252.4 μL, 0.50 mmol), and the mixture was stirred for 25 min at the low temperature. 4-Chlorobenzoyl chloride (88.3 mg, 0.50 mmol) was added and the reaction was aged overnight at room temperature. The reaction was quenched with saturated aqueous NH4Cl (provided in a commercial phase separator syringe) and the organic compound was extracted with CH2Cl2, washed with brine and water, dried over Na2SO4, filtered and concentrated in vacuo. The crude residue was subjected to flash chromatography (SiO2, ethyl acetate/hexane gradient) to afford the title compound as yellow oil, which permanently crystallized upon drying at high vacuum and storage at −20° C. Yield: 51 mg (37%). C17H13ClN2O3, Mr=328.75; 1H NMR (400 MHz, DMSO-d6) d: 3.65 (s, 3H), 4.16 (s, 2H), 7.50 (td, J=0.8/7.6 Hz, 1H), 7.63-7.66 (m, 2H), 7.71 (td, J=1.0/7.6 Hz, 1H), 7.91 (d, J=8.0 Hz, 1H), 8.00-8.03 (m, 2H), 8.41 (d, J=8.4 Hz, 1H); LCMS (ESI) tR: 2.80 min (>99%, ELSD), m/z: 329.0 [M+1]+.