反应详情

The product from Example 6 is dissolved in 900 ml. of water and 350 ml. of concentrated hydrochloric acid, heated on a steam bath for 5 hours and then chilled. The solution is concentrated in vacuo and a mixture of 100 ml. of acetone and 100 ml. of ethanol is added. The mixture is filtered. The filtrate is evaporated and the residue is dissolved in 50 ml. of water and neutralized with a concentrated solution of K2CO3, until bubbling ceases. The top layer is separated and combined with 5 ml. of methanol. On standing, a precipitate forms. The solid is collected and the filtrate is diluted with acetone to give a second precipitate which is also collected. The solids are combined and recrystallized from hot acetone giving the desired product, m.p. 134°-136° C.

1. temperaturechilled
2. concentrationThe solution is concentrated in vacuo
3. additiona mixture of 100 ml
4. additionof ethanol is added
5. filtrationThe mixture is filtered
6. customThe filtrate is evaporated
7. dissolutionthe residue is dissolved in 50 ml
8. customuntil bubbling ceases
9. customThe top layer is separated
10. customThe solid is collected
11. additionthe filtrate is diluted with acetone
12. customto give a second precipitate which
13. customis also collected
14. customrecrystallized from hot acetone giving the desired product, m.p. 134°-136° C.