反应详情

To a solution of 5′-amino-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4,6′-dicarboxylic acid 4-tert-butyl ester (510 mg, 1.6 mmol; see Example 16 (e) above) in benzene (4 mL) and methanol (4 mL) was added a solution of trimethylsilyldiazomethane (2 M in hexane, 2 mL). The reaction was stirred at room temperature for overnight. The solvent was then removed in vacuo and the residue was purified by flash chromatography using ethyl acetate/hexanes (40:60) as eluant to afford 5′-amino-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4,6′-dicarboxylic acid 4-tert-butyl ester 6′-methyl ester as a yellow solid (520 mg, 96%). 1H NMR (300 MHz, CDCl3) δ1.49 (s, 9H), 3.40 (s, 4H), 3.59 (s, 4H), 3.95 (s, 3H), 8.01 (s, 1 H); 13C NMR (100 MHz, CDCl3) δ 28.41, 46.30, 52.52, 80.05, 119.69, 135.58, 148.24, 150.00, 154.70, 167.10.

1. customThe solvent was then removed in vacuo
2. customthe residue was purified by flash chromatography