反应详情

温度

0 °C

Cyclohexanoyl chloride (7 mL, 47 mmole) was added dropwise to a stirred solution of dry pyridine (400 mL) and O-benzyltyrosine benzyl ester (25 g, 46.8 mmole). The reaction temperature was maintained at 0° C. throughout the addition. The reaction mixture was stirred for an additional 2 hours after the addition was complete. The reaction mixture was concentrated to dryness in vacuo to provide a solid material. The solid was washed with aqueous hydrochloric acid (1N, 4×400 mL). The residue was dissolved in ethyl acetate (300 mL), washed with aqueous hydrochloric acid (1N, 2×500 ml), aqueous sodium bicarbonate (2×300 mL), and dried over magnesium sulfate. Filtration, followed by concentration in vacuo, provided an oil which was dissolved in methanol/tetrahydrofuran (400 mL/70 mL) and was hydrogenated at atmospheric pressure and room temperature over 10% palladium on carbon (600 mg). The reaction mixture was filtered through Celite and concentrated in vacuo to provide a solid which was recrystallized from ethyl acetate/hexane. The crystals were collected to provide the N-cyclohexanoyl-(L)-tyrosine (8.7 g, 64%) as a white solid.

1. additionafter the addition
2. concentrationThe reaction mixture was concentrated to dryness in vacuo
3. customto provide a solid material
4. washThe solid was washed with aqueous hydrochloric acid (1N, 4×400 mL)
5. dissolutionThe residue was dissolved in ethyl acetate (300 mL)
6. washwashed with aqueous hydrochloric acid (1N, 2×500 ml), aqueous sodium bicarbonate (2×300 mL)
7. dry with materialdried over magnesium sulfate
8. filtrationFiltration
9. concentrationfollowed by concentration in vacuo
10. customprovided an oil which
11. filtrationThe reaction mixture was filtered through Celite
12. concentrationconcentrated in vacuo
13. customto provide a solid which
14. customwas recrystallized from ethyl acetate/hexane
15. customThe crystals were collected