1,2-Pyrrolidinedicarboxylic acid, 1-(1,1-dimethylethyl) ester, (2S)- → (S)-tert-Butyl 2-(2-carbamoyl-1H-pyrrol-1-ylcarbamoyl)pyrrolidine-1-carboxylate

Participants

Reaction Steps

A mixture of 1-amino-1H-pyrrole-2-carboxamide (3.00 g, 24.0 mmol) and (S)-1-(tert-butoxycarbonyl)pyrrolidine-2-carboxylic acid (7.18 g, 28.8 mmol) was dissolved in THF (240 mL). To this solution was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (5.52 g, 28.8 mmol). The reaction was stirred overnight at rt, then concentrated in vacuo. The crude residue was dissolved in CH2Cl2 then washed with water (3×200 mL) and brine (200 mL). The organic layer was dried (MgSO4), filtered, and concentrated in vacuo to a sticky gum, which was dissolved in a 1:1 solution of CH2Cl2/Hex, then concentrated in vacuo to remove most of the CH2Cl2. The precipitate that formed was filtered and dried to give 1A (6.68 g, 78%). 1A had an analytical HPLC retention time=2.132 min (Phenomenex Luna 3.0×50 mm, 10-90% aqueous MeOH over 5 min containing 0.1% TFA) and a LC/MS M++1=357.

Provenance & Evidence