反应详情

To a solution of 0.66 g of 8 and 0.2 g of sodium hydrogen carbonate in 20 ml of water and 2 ml of dioxane there is added a suspension of platinum prepared by hydrogenation of 313 mg of platinum oxide in 50 ml of water. In a cylindrical apparatus, oxygen is passed through the mixture from bottom to top at 55° by means of a glass frit, with vigorous stirring. The mixture is filtered and washed with water, and the filtrate is extracted five times with 100-150 ml of ethyl acetate each time. Concentration of the extracts by evaporation yields 220 mg of educt 5. 1 gof Amberlyst® 15 (strongly acidic) is added to the aqueous phase, whichis then filtered and concentrated by evaporation in vacuo at 40°. Purification as in f,a) yields 156 mg of 9. 1H-NMR (300 MHz, CDCl3): 1.43 (s, (CH3)3C); 1.96 (d, J=3 Hz, CH3 --C(4)); 2.55 and 2.71 (2 d×d, J=22 and 15, 2H--C(5)); 3.75 and 3.76(2 d, J=11, 2 OCH3); 4.97 (m, H--C(2)); 5.25-5.45 (m, NH and H--C(3)).

1. customto top at 55° by means of a glass frit, with vigorous stirring
2. filtrationThe mixture is filtered
3. washwashed with water
4. extractionthe filtrate is extracted five times with 100-150 ml of ethyl acetate each time
5. customConcentration of the extracts by evaporation
6. customyields 220 mg of educt 5
7. addition1 gof Amberlyst® 15 (strongly acidic) is added to the aqueous phase, whichis
8. filtrationthen filtered
9. concentrationconcentrated by evaporation in vacuo at 40°
10. customPurification as in f,a)