Ethyl chloroformate → ethyl pyrrole-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of compound ◯3 (10.43 g, 20 mmol.) in dichloromethane (100 ml) at 0° C. was added DBN (1,5-diazabicyclo[4,3,0]non-5-ene) (4.96 g, 40 mmol.) followed by a solution of ethyl chloroformate (3.42 g, 32 mmol.) in dichloromethane (20 ml). After completion of the transformation to the N-carboethoxy derivative 4 (approximately 1 hour), an additional equivalent of DBN (2.48 g, 20 mmol.) was added and the reaction mixture was stirred at 25° C. for 20 hours and evaporated to dryness. Chromatographic purification of the residue on silica gel (chloroform/ethyl acetate; 9/1) afforded the N-carboethoxy pyrrole ◯5 (α, β-anomeric mixture) as a white foam (10 g, 84% from ◯3 ). The structure was confirmed by CHN elemental analysis and NMR spectroscopy.

Provenance & Evidence