Trityl chloride → 1-methyl-4-(trityl-amino)-1H-pyrazole-3-carboxylic acid methyl ester

Participants

Reaction Steps

A solution of 4-amino-1-methyl-1H-pyrazole-3-carboxylic acid methyl ester (160 mg, 1.03 mmol) in N,N-dimethylformamide (1.0 mL) at 25° C. was treated with triethylamine (0.35 mL, 2.6 mmol) and triphenylmethylchloride (316 mg, 1.13 mmol). Additional N,N-dimethylformamide (2.0 mL) was added to the reaction to aid stirring. The reaction was stirred at 25° C. for 18 h. At this time, the reaction was concentrated in vacuo. The residue was dissolved in dichloromethane (50 mL) and then was washed with a IN aqueous hydrochloric acid solution (1×10 mL), a saturated aqueous sodium bicarbonate solution (1×10 mL), and a saturated aqueous sodium chloride solution (1×10 mL). The organics were dried over magnesium sulfate, filtered, and concentrated in vacuo to afford 1-methyl-4-(trityl-amino)-1H-pyrazole-3-carboxylic acid methyl ester (373 mg, 91.1%) as an off-white solid: 1H NMR (DMSO-d6, 300 MHz) δ7.25 (m, 16H), 3.74 (s, 3H), 3.53 (s, 3H).

Provenance & Evidence