反应详情

温度

60 °C

(S)-2-tert-Butoxycarbonylamino-3-{2-[4-(3,4-dichloro-benzyloxy)-phenyl]-2,3-dihydro-benzo[1,4]dioxin-6-yl}-propionic acid methyl ester (2.1 g) was deprotected according to General Procedure C. The resulting material was dissolved in dioxane (20 mL) and TFA (4 mL) and solid paraformaldehyde (300 mg) added. The reaction mixture was heated for 2 h at 60° C. and concentrated. The resulting material was dissolved in DCM and aqueous sodium bicarbonate and ditert-butyl pyrocarbonate (1.5 g) added. The layers of the reaction mixture were separated and the aqueous layer was extracted twice with 50. mL of DCM. The combined organic extracts were dried over sodium sulfate, filtered, and concentrated to provide a yellow solid. The residue was purified by silica gel chromatography (10/90 to 30/70 ethyl acetate/hexanes in 10% increments) to obtain the desired product. 1H NMR (400 MHz, CDCl3): 7.54 (d, 1H), 7.45 (d, 1H), 7.32 (d, 2H), 7.24 (m, 2H), 6.96 (d, 2H), 6.77 (s, 1H), 6.72 (d, 2H), 5.04 (m, 1H), 5.02 (s, 2H), 4.73 (m, 1H), 4.60 (m, 1H), 4.40 (m, 1H), 4.26 (m, 1H), 3.97 (m, 1H), 3.64 (d, 3H), 3.02-3.20 (m, 2H), 1.54 and 1.44 (s, 9H).

1. concentrationconcentrated
2. dissolutionThe resulting material was dissolved in DCM
3. additionaqueous sodium bicarbonate and ditert-butyl pyrocarbonate (1.5 g) added
4. customThe layers of the reaction mixture were separated
5. extractionthe aqueous layer was extracted twice with 50
6. dry with materialThe combined organic extracts were dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated
9. customto provide a yellow solid
10. customThe residue was purified by silica gel chromatography (10/90 to 30/70 ethyl acetate/hexanes in 10% increments)