反应详情

The product of example 1B (3.5 g, 4.91 mmoles) was suspended in 50 ml of ethanol. Concentrated hydrochloric acid (2.1 ml) was added and the mixture was stirred for 11/2 hours at room temperature. The solution was concentrated under vacuum and the resulting residue was diluted with water. Potassium acetate was added in portions until the pH was neutral. Ether (5 ml) was added and the mixture was stirred. The sticky solid which formed was dissolved in chloroform. The chloroform solution was dried over sodium sulfate and then concentrated. The resulting residue was crystallized from ether to provide 2.08 g of the desired product. M.p. 164°-166° C. 1H NMR (CDCl3) δ0.85 (t, 3H, J=7 Hz), 1.25 (m, 2H), 1.32 (t, 3H, J=7 Hz), 1.50 (m, 2H), 2.24 (s, 3H), 3.38 (t, 2H, J=7 Hz), 4.30 (q, 2H, J=7 Hz), 4.73 (s, 2H), 7.00 (m, 4H), 7.42 (dd, 1H, J=8 Hz, J=1Hz), 7.50-7.62 (m, 2H), 7.75 (dd, 1H, J=8 Hz, J= 1Hz), 8.02 (s, 1H).

1. concentrationThe solution was concentrated under vacuum
2. additionthe resulting residue was diluted with water
3. additionPotassium acetate was added in portions until the pH
4. additionEther (5 ml) was added
5. stirringthe mixture was stirred
6. customThe sticky solid which formed
7. dry with materialThe chloroform solution was dried over sodium sulfate
8. concentrationconcentrated
9. customThe resulting residue was crystallized from ether