反应详情

温度

65 °C

A mixture of 3-chloro-4-hydroxy-5-methyl-benzonitrile (1.15 g, 6.87 mmol) and Cs2CO3 (13.43 g, 41.2 mmol) in DMF (45 mL) is stirred at rt for 30 min before tert.-butyl 4-bromobutanoate (1.55 g, 6.95 mmol) is added. The orange suspension is stirred at 65° C. for 72 h. Another portion of tert.-butyl 4-bromobutanoate (1.55 g, 6.95 mmol) is added and stirring is continued at 65° C. for 24 h. The mixture is dilued with water (150 mL) and extracted three times with DCM (3×50 mL) and EA (3×50 mL). The org. extracts are combined, dried over MgSO4, filtered and concentrated. The crude product is purified by MPLC on silica gel eluting with heptane:EA:methanol to give tert-butyl 4-(2-chloro-4-cyano-6-methylphenoxy)butanoate (645 mg) as a colourless oil; LC-MS: tR=1.01 min, [M+H]+=no mass detectable; 1H NMR (D6-DMSO): δ 7.94 (d, J=1.7 Hz, 1H), 7.75 (d, J=1.3 Hz, 1H), 3.95 (t, J=6.3 Hz, 2H), 2.46 (t, J=7.2 Hz, 2H), 2.30 (s, 3H), 1.98 (quint, J=6.6 Hz, 2H), 1.41 (s, 9H).

1. additionis added
2. stirringstirring
3. waitis continued at 65° C. for 24 h
4. extractionextracted three times with DCM (3×50 mL) and EA (3×50 mL)
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude product is purified by MPLC on silica gel eluting with heptane