反应详情

A solution of the product from Example 19 (0.70 g, 1.74 mmol) in 20 mL of methanol and 0.5 mL acetic acid was treated with zinc dust (1.58 g, 320 mesh) and the resulting suspension stirred at room temperature for three hours. The reaction mixture was filtered and the filtrate concentrated. The residue was dissolved in ether (30 mL) and extracted with aqueous 1N HCl (3×15 mL). The combined acid extracts are made basic (pH=11) with potassium carbonate and the resulting aqueous solution was extracted with CH2Cl2 (5×15 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated. The residue (0.30 g) was converted to its HCl salt by dissolution in ether and treatment with a saturated solution of HCl (gas) in ether. The solid which formed was collected by filtration and dried under vacuum (100° C.) to give the title compound (0.25 g, 54%) as a white solid mp >270° C.

1. filtrationThe reaction mixture was filtered
2. concentrationthe filtrate concentrated
3. dissolutionThe residue was dissolved in ether (30 mL)
4. extractionextracted with aqueous 1N HCl (3×15 mL)
5. extractionthe resulting aqueous solution was extracted with CH2Cl2 (5×15 mL)
6. dry with materialThe combined organic extracts were dried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated
9. dissolutionThe residue (0.30 g) was converted to its HCl salt by dissolution in ether
10. customThe solid which formed
11. filtrationwas collected by filtration
12. customdried under vacuum (100° C.)