Trimethylaluminum → HCID 178489779, compound

Participants

Reaction Conditions

Reaction Steps

2M Trimethylaluminium (1.250 ml, 2.50 mmol) in toluene, was added dropwise to a stirred solution of tert-butyl 4-(5-(methoxycarbonyl)thiophen-2-yl)piperazine-1-carboxylate (0.326 g, 1 mmol) and 5-[2-(3,5-dimethoxyphenyl)ethyl]-2H-pyrazol-3-amine (0.247 g, 1.00 mmol) in toluene (7.14 ml) at 20° C. under nitrogen. The reaction mixture was stirred at 20° C. for 20 h. The temperature was increased to 60° C. and the reaction mixture was stirred for 20 h and then allowed to cool. The reaction mixture was diluted with acetone (10 ml) and quenched with damp solid sodium sulphite. The mixture was stirred for 30 mins, and then a solution of 10% methanol in DCM (10 mL) was added and the mixture stirred for a further 30 mins. The suspension was filtered and the solid washed with 10% methanol in DCM (20 mL); the combined filtrates were evaporated to give a yellow foam. The crude product was purified by silica column chromatography, eluting with a gradient of 1 to 10% 2M ammonia/methanol in DCM. Pure fractions were evaporated to dryness to afford the crude product. This was further purified by preparative HPLC, using decreasingly polar mixtures of water (containing 1% NH3) and MeCN as eluents. Fractions containing the desired compound were evaporated to dryness to afford tert-butyl 4-[5-[[5-[2-(3,5-dimethoxyphenyl)ethyl]-2H-pyrazol-3-yl]carbamoyl]thiophen-2-yl]piperazine-1-carboxylate (0.272 g, 50.2%) as a white dry film. 1H NMR (500.13 MHz, DMSO-d6) δ 1.46 (9H, s), 2.89-2.90 (6H, m), 3.22 (4H, t), 3.52 (4H, t), 3.75 (6H, s), 6.18 (1H, d), 6.27 (1H, s), 6.34 (1H, t), 6.42-6.42 (2H, m), 7.72 (1H, d), 9.81 (1H, s), 11.71 (1H, s); MS: m/z 542 (MH+)

Provenance & Evidence