Hydrochloric Acid → 6-tert-Butyl 3-methyl (S)-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-3,6-dicarboxylate

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Reaction Conditions

Reaction Steps

A solution of freshly prepared sodium methoxide (Na, 50% by weight in paraffin, 0.084 g, 1.84 mmol, 2.25 mL anh MeOH) was added slowly to a solution of (S)-2-amino-3,4-dihydro-5H-pyrrole-5-carboxylic acid t-butyl ester.HCl (0.41 g, 1.84 mmol) in 2.25 mL anh MeOH cooled to -10° C. After 1 h, the resulting white precipitate (NaCl) was filtered, and the solution of this free base was slowly added to a solution of dimethylmethoxymethylene malonate (0.32 g, 1.84 mmol) in 2.25 mL anh MeOH at -10° C. The reaction mixture was stirred at 0° C. overnight at which time it was concentrated under vacuum, and the residue was purified by column chromatography on silica gel (2% MeOH/CHCl3) to afford (S)-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-α]pyrimidine-3,6-dicarboxylic acid 6-t-butyl ester 3-methyl ester (0.22 g, 40%) as a yellow oil. 1H NMR (CDCl3) δ 1.49 (s, 9H), 2.31 (m, 1H), 2.57 (m, 1H), 3.09-3.33 (m, 2H), 3.90 (s, 3H), 5.03 (m, 1H), 8.69 (s, 1H). MS calcd C14H18N2O5 +295, found 295.

Provenance & Evidence