2-bromo-1-(2,4-dimethylphenyl)propan-1-one

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: To a well stirred mixture of 5-methyl-3-oxo-2,3-dihydro-1H-pyrazole4-carboxylic acid ethyl ester (200 mg, 1.18 mmol, 1 eq.) and K2CO3 (179 mg, 1.29 mmol, 1.1 eq.) in DMF (5 ml) is added dropwise a solution of 2-bromo-1-(2,4-dimethyl-phenyl)-propan-1-one (Intermediate BA) (298 mg, 1.23 mmol, 1.05 eq.) in DMF (2.5 ml) at 50° C. After the addition, the reaction mixture is further stirred at 50° C. for 1 h then poured into water (50 ml) and extracted with EtOAc (2×25 ml). The combined organic fractions are dried over Na2SO4, filtered and concentrated to dryness under reduced pressure. The resulting crude residue is purified by Combi-Flash Companion™ (Isco Inc.) column chromatography (SiO2; gradient elution, [iso-hexane/DCM 1:1]/TBME 95:5→7:3) to yield the title compound as a white solid. TLC: RF=0.74 (iso-hexane/DCM/TBME 1:1:2); HPLC: AtRet=2.30; MS: m/z 331.3 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ 1.24 (t, J 7.1, 3H), 1.43 (d, J 6.8, 3H), 2.31 (s, 6H), 2.33 (s, 3H), 4.15 (m, 2H), 5.75 (q, J 6.8, 1H), 7.13 (m, 2H), 7.83 (m, 1H), 12.24 (br. s., 1H). After the addition the reaction mixture is further stirred at 50° C. for 1 h extracted with EtOAc (2×25 ml) The combined organic fractions are dried over Na2SO4 filtered concentrated to dryness under reduced pressure The resulting crude residue is purified by Combi-Flash Companion™ (Isco Inc.) column chromatography (SiO2; gradient elution, [iso-hexane/DCM 1:1]/TBME 95:5→7:3)