反应详情

6′-(4-Methyl-thiazol-2-ylmethoxy)-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid tert-butyl ester (I-3u) (376 mg, 0.96 mmol) was dissolved in dry 1,4-dioxane (4 mL) and 4 M HCl in 1,4-dioxane (4 mL, 16 mmol) was added with stirring. A gummy solid immediately precipitated. Methanol (2 mL) was added to solubilize the solid. The resulting solution was stirred at room temperature for 4 h and concentrated to a gummy yellow solid. The residue was basified by addition of 1 M NaOH (15 mL) and extracted with CH2Cl2 (3×20 mL). The combine extracts were dried over Na2SO4 (anhydrous), filtered, and concentrated in vacuo to an amber oil. The oil solified on drying in vacuo to give the title compound 3-Q (274 mg, 98% yield).

1. customA gummy solid immediately precipitated
2. additionMethanol (2 mL) was added
3. stirringThe resulting solution was stirred at room temperature for 4 h
4. concentrationconcentrated to a gummy yellow solid
5. additionThe residue was basified by addition of 1 M NaOH (15 mL)
6. extractionextracted with CH2Cl2 (3×20 mL)
7. dry with materialThe combine extracts were dried over Na2SO4 (anhydrous)
8. filtrationfiltered
9. concentrationconcentrated in vacuo to an amber oil
10. customon drying in vacuo