Diisopropylethylamine → 5-Amino-4-[3-(tert-butoxycarbonylamino)propionyl]amino-1-(2-hydroxyethyl)pyrazole

Participants

Reaction Steps

To a suspension of 4,5-diamino-1-(2-hydroxyethyl)pyrazole sulfuric acid salt (2.4 g) in methylene chloride (40 ml) were added N-ethyldiisopropylamine (2.1ml) and N-[3-(tert-butoxycarbonylamino)propionyloxy]succinimide (2.3 g) under ice-cooling, and the mixture was stirred at room temperature for 6 hours. To the reaction mixture were added brine (40 ml) and saturated aqueous sodium hydrogen carbonate solution (20 ml), and the mixture was extracted with a mixture of ethyl acetate and 2-propanol, (3:1, 60 ml). The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was triturated with diethyl ether to give 5-amino-4-[3-(tert-butoxycarbonylamino)propionyl]amino-1-(2-hydroxyethyl)pyrazole (1.65 g) as a solid.

Provenance & Evidence