Triethylamine → 3-ethoxy-4-{[1-methyl-5-(tritylamino)-1H-pyrazol-4-yl)amino}-3-cyclobutene-1,2-dione

Participants

Reaction Steps

To a suspension of 1-methyl-N5-trityl-1H-pyrazole-4,5-diamine (1.60 g) in ethanol (50 ml) were added triethylamine (0.627 ml) and diethyl squarate (0.858 ml), and the mixture was stirred at room temperature for 22 hours. To the reaction mixture were added ethyl acetate (200 ml) and hexane (100 ml), and the solution was washed successively with water, 5% aqueous citric acid solution and brine. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crystalline residue was washed with diethyl ether and dried in vacuo to give 3-ethoxy-4-{[1-methyl-5-(tritylamino)-1H-pyrazol-4-yl]amino}-3-cyclobutene-1,2-dione (1.45 g) as a solid.

Provenance & Evidence