Diazomethane → Hexahydro-pyrrolo[3,2-b]pyrrole-1,3,4-tricarboxylic acid 1-benzyl ester 4-tert-butyl ester 3-methyl ester

Participants

Reaction Steps

To a solution of crude 72 (0.47 g) in EtOAc (10 mL) and Et2O (10 mL) was added an ethereal solution of diazomethane that was prepared by treatment of N-nitroso-N-methyl urea (0.5 g) in Et2O (10 mL) with 1M KOH (10 mL). After consumption of starting material (monitored by TLC), the reaction mixture was diluted with HOAc. The solution was extracted with EtOAc, washed with saturated NaHCO3, brine, dried over anhydrous Na2SO4, filtered and concentrated to give a dark oil that was purified by HPLC (2″ Dynamax® SiO2, 10% EtOAc/hexane to 100% EtOAc over 30 min) to give 76 (0.19 g) as a yellow-colored oil. 1H NMR (CDCl3, 300 MHz): δ7.40-7.29 (m, 5H), 5.23-5.09 (m, 2H), 4.56-4.52 (m, 2H), 4.11-4.04 (m, 1H), 3.69 (s, 3H), 3.45-3.42 (m, 1H), 3.22-3.12 (m, 1H), 2.27-2.10 (m, 1H), 1.96 (m, 1H), 1.47 (s, 9H) ppm. Mass spectrum, m/z [405.2] (M+H)+.

Provenance & Evidence