反应详情

温度

50 °C

A solution of 305 mg (1.74 mmol) of methyl 3-cyano-4-methylbenzoate and excess Et3O+BF4− in 7 mL of CH2Cl2 was stirred at 45° C. After 13 h and about 24 h more Et3O+BF4− was added and after a further 20 min. the temperature was increased to 50° C. After 37 h, the temperature was increased to 55° C. and heating was continued for 1.5 h. After this time, the crude solution was added with 3 mL of CH2Cl2 to 0.16 mL of Et3SiH in 5 mL of CH2Cl2. After the solution was stirred at 55° C. for 2 h, 10 mL of H2O was added, and the mixture was stirred at 120° C. for 15 min. and the temperature was decreased to 115° C. for 1 h, stopped for 2 h, and then resumed for 17 h. EtOAc was added, and the layers were separated. The organic layer was washed with brine, dried over Na2SO4, filtered, and concentrated. Purification by flash silica gel chromatography (7.5% EtOAc/hexanes) provided 25 mg of methyl 3-formyl-4-methylbenzoate as colorless oil with some impurity. 5-(methoxycarbonyl)-2-methylbenzoic acid was synthesized from the aldehyde following the general procedure as described above for the methyl substituted benzoic acid.

1. waitAfter 37 h
2. temperaturethe temperature was increased to 55° C.
3. temperatureheating
4. waitwas continued for 1.5 h
5. stirringthe mixture was stirred at 120° C. for 15 min.
6. waitthe temperature was decreased to 115° C. for 1 h
7. waitstopped for 2 h
8. waitresumed for 17 h
9. customthe layers were separated
10. washThe organic layer was washed with brine
11. dry with materialdried over Na2SO4
12. filtrationfiltered
13. concentrationconcentrated
14. customPurification by flash silica gel chromatography (7.5% EtOAc/hexanes)