反应详情

2-(3-pyridinyl)-3-tert-butoxycarbonyl-4-thiazolidinecarboxylic acid (78 g, 251 mmol), prepared as in Example 1, step 2, and 4-methylmorpholine (43 g, 427 mmol) were dissolved in tetrahydrofuran (500 mL ), and cooled in the ice bath. Isobutylchloroformate (38 g, 276 mmol) was added and the yellow suspension was stirred for 0.5 hours. Methanol (250 mL) was added, the cold bath was removed, and the reaction mixture was stirred for 60 hours at ambient temperature. The reaction mixture was concentrated in vacuo and the residue was partitioned between ethyl acetate and saturated aqueous NaHCO3. The aqueous phase was extracted twice with ethyl acetate. The combined organic extracts were washed twice with brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by chromatography on silica gel to give Methyl-2-(3-pyridinyl)-3-tert-butoxycarbonyl-4-thiazolidinecarboxylate (38 g).

1. customthe cold bath was removed
2. stirringthe reaction mixture was stirred for 60 hours at ambient temperature
3. concentrationThe reaction mixture was concentrated in vacuo
4. customthe residue was partitioned between ethyl acetate and saturated aqueous NaHCO3
5. extractionThe aqueous phase was extracted twice with ethyl acetate
6. washThe combined organic extracts were washed twice with brine
7. dry with materialdried over MgSO4
8. filtrationfiltered
9. concentrationconcentrated in vacuo
10. customThe crude product was purified by chromatography on silica gel