反应详情

To a solution of 0.465 mL DMF (6 mmol) in 10 mL acetonitrile at 0° C. was added 0.48 mL (5.5 mmol) of oxalyl chloride. A white precipitate formed immediately and was accompanied by gas evolution. When complete, a solution of 1.2 g (5 mmol) of (2S)-1-(1,2-dioxo-3,3-dimethylpentyl)-2-pyrrolidinecarboxamide (from Example 2) in 2.5 mL acetonitrile was added. When the mixture became homogeneous, 0.9 mL (11 mmol) pyridine was added. After 5 min., the mixture was diluted into water and extracted by 200 mL ethyl acetate. The organic layer was concentrated and further purified by silica gel to give 0.8 g product as a white solid (72% yield). 1H NMR (CDCl3): δ 0.87 (t, 0.3H, J=7.5); 1.22 (s, 3H); 1.24 (s, 3H); 1.80 (m, 2H); 2.03–2.23 (m, 4H); 3.55 (m, 2H); 4.73 (m, 1H).

1. customA white precipitate formed immediately
2. extractionextracted by 200 mL ethyl acetate
3. concentrationThe organic layer was concentrated
4. customfurther purified by silica gel