4-Oxo-pyrrolidine-1,3-dicarboxylic acid diethyl ester → HCID 178473309, compound

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Reaction Steps

A suspension of intermediate (f) (14.05 g) and guanidine carbonate (g) (16.6 g, 91.9 mmol) was refluxed in t-butanol (147 mL) for about 6 h. The mixture was allowed to cool to ambient temperature for about 2 h. The volatile components were removed under vacuum and water was added. The pH was adjusted to about 6-7 using KHSO4. The resulting slurry was filtered to collect the solids which were washed with water followed by EtOAc. The solids were dried under vacuum to afford intermediate (h) as cream solids (11.9 g, 53.1 mmol) in 87% yield. 1H NMR (400 MHz, DMSO-D6) δ ppm 11.01 (s, 1H), 6.97 (s, 0.5H, possible tautomer), 6.70 (s, 2H), 4.25 (s, 4H), 4.13-4.03 (m, 2H), 1.22 (t, 3H). LCMS (M+H)+: 225.2.

Provenance & Evidence