Cesium carbonate → (1,4,6,7-Tetrahydro-pyrazolo[4,3-c]pyridin-5-yl)acetic acid benzyl ester

Participants

Reaction Steps

To a solution of 4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine (300 mg) in MeCN (10 mL) was added Cs2CO3 (1.49 g) followed by benzyl bromoacetate (0.253 mL). The reaction mixture was stirred at RT overnight and evaporated to dryness. The residue was taken up in EA and washed with water and brine. The aq. layers were extracted with EA, the combined org. layers were dried (MgSO4), filtered off and evaporated in vacuo. The residue was purified by CC (Biotage, SNAP 10 g cartridge, solvent A: DCM; solvent B: DCM/MeOH 8/2; gradient in % B: 15 for 7CV, 15 to 25 over 3CV, 25 for 5CV) to afford (1,4,6,7-tetrahydro-pyrazolo[4,3-c]pyridin-5-yl)acetic acid benzyl ester (218 mg, pale yellow oil). LC-MS (B): tR=0.50 min; [M+H]+: 272.12. 1H-NMR (CDCl3): 7.40-7.33 (m, 5H); 7.30 (s, 1H); 5.21 (s, 2H); 3.73 (s, 2H); 3.52 (s, 2H); 3.50 (s, 1H); 2.98 (t, 2H, 6.0 Hz); 2.85 (t, 2H, 5.8 Hz).

Provenance & Evidence