Hydrochloric Acid → HCID 86597118, compound

Participants

Reaction Conditions

Reaction Steps

To a suspension of methoxymethyl-triphenyl-phosphonium chloride (2.06 g, 6.00 mmol) in dry THF (20 mL) cooled at −15° C. (ethyl glycol/dry ice) was added LDA (2.0 M in THF, 3.1 mL, 6.2 mmol) slowly. After the addition the mixture was stirred at −15° C. for 30 min, and a solution of 2-benzyl-1H-pyrazole-4-carbaldehyde (1.00 g, 5.37 mmol) (Werner, A., et al., Tetrahedron (1995) 51:4779-4800) in THF (15 mL) was added. The reaction mixture was stirred at room temperature for 16 h. Water (30 mL) was added, and the mixture was extracted with EtOAc (30 mL) and CH2Cl2 (2×30 mL). The extracts were combined and dried over Na2SO4. After filtration the solvent was removed by evaporation under vacuum, and the residue was purified by flash chromatography on a silica gel column (CH2Cl2) to afford a colorless oil. The oil was dissolved in THF (3 mL) and aqueous HCl (4 N, 15 mL) was added. After being stirred for 72 h, the mixture was neutralized with saturated aqueous K2CO3, and extracted with CH2Cl2 (3×30 mL). The extracts were combined and dried over Na2SO4. After filtration the solvent was removed by evaporation under vacuum, and the residue was purified by flash chromatography on a silica gel column (2:1 CH2Cl2/Et2O), affording (2-benzyl-1H-pyrazol-4-yl)-acetaldehyde as a colorless oil (0.548 g, 51%). 1H NMR (CDCl3) δ 3.56 (d, 2H, J=2.1 Hz), 5.29 (s, 2H), 7.21-7.24 (m, 2H), 7.28-7.39 (m, 4H), 7.45 (s, 1H), 9.70 (t, 1H, J=2.1 Hz).

Provenance & Evidence