p-Toluenesulfonic acid monohydrate → HCID 67212603, compound

Participants

Reaction Steps

A mixture of 3-[2-(2,4-dimethyl-phenyl)-1-methyl-2-oxo-ethoxy]-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (273 mg, 0.83 mmol), para-toluenesulfonic acid mono-hydrate (160 mg, 0.83 mmol) in toluene (15 ml) and AcOH (5 ml) is refluxed for 3 days. The reaction mixture is concentrated in vacuo and the residue is dissolved in EtOAc (40 ml). The organic solution is washed successively with Na2CO3 2M in water (2×20 ml) and brine (20 ml), dried over Na2SO4, filtered and concentrated to dryness. The resulting crude residue is purified by Combi-Flash Companion™ (Isco Inc.) column chromatography (SiO2; gradient elution, iso-hexane/TBME 98:2→7:3) to yield the title compound (227 mg, 0.73 mmol, 88%) as a colorless oil. TLC: RF=0.81 (iso-hexane/TBME 1:1); HPLC: AtRet=2.85; MS: m/z 313.2 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ 1.30 (t, J 7.1, 3H), 2.20 (s, 3H), 2.34 (s, 3H), 2.36 (s, 3H), 2.41 (s, 3H), 4.26 (q, J 7.1, 2H), 7.17 (m, 1H), 7.24 (br. s., 1H), 7.31 (m, 1H).

Provenance & Evidence