1,2-Dichloroethane → tert-butyl 2,4-dioxo-5,6,7,7a-tetrahydro-4aH-cyclopenta[b]pyridine-1-carboxylate

Participants

Reaction Steps

To a stirred solution of 2-[(tert-butoxycarbonyl)amino]cyclopentanecarboxylic acid (0.24 g, 1.06 mmol) in DCM (4.5 mL) was added EDC (0.31 g, 1.59 mmol), DMAP (0.19 g, 1.59 mmol) and Meldrum's acid (0.15 g, 1.06 mmol). After stirring for 18 h at r.t., the reaction mixture was poured into aqueous 1M NaHSO4 solution (5 mL) and extracted with DCM (3×20 mL). The combined organics were dried over MgSO4, filtered and concentrated in vacuo to give a clear yellow oil which was dissolved in EtOAc (5 mL) and heated to 80° C. for 18 h. The reaction mixture was then cooled and concentrated in vacuo to give the title compound (0.25 g, 42%) as a yellow solid that was used without further purification. δH (CDCl3) 4.64-4.55 (1H, m), 2.98-2.92 (1H, m), 2.37-2.20 (2H, m), 1.99-1.60 (6H, m), 1.58 (9H, s). LCMS (ES+) 198.0 ((M−tBu)+H)+.

Provenance & Evidence