Reacción #155422

Ecuación de reacción

4-hydroxybenzaldehyde

tetrahydro-pyran-4-carboxylic acid

thionyl chloride

pyridine

→

4-formylphenyl tetrahydro-2H-pyran-4-carboxylate

Rendimiento 87.4%

Disolventes

water

CH2Cl2

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroTo a 100 mL dry round bottom flask
2. 2
   TemperaturaThe mixture was refluxed for 45 minutes
3. 3
   Otroall the volatile materials were rotary-evaporated
4. 4
   workup.ADDITIONTo the residue, anhydrous CH2Cl2 (10 mL) was added
5. 5
   Temperaturawarmed from 0° C. to room temperature slowly
6. 6
   Otroat room temperature
7. 7
   Otroovernight
8. 8
   Otrothe CH2Cl2 layer was separated
9. 9
   ExtracciónThe aqueous layer was extracted continually with CH2Cl2 (50 mL×3)
10. 10
    LavadoThe combined CH2Cl2 solution was washed with a cold aqueous solution of saturated NaHCO3 (80 mL)
11. 11
    OtroAfter drying
12. 12
    Otroremoval of the solvent
13. 13
    Otrothe residue was purified with a silica gel chromatography (heptane/ethyl acetate, gradient eluting)

Procedimiento

To a 100 mL dry round bottom flask were added tetrahydro-pyran-4-carboxylic acid (2.8 g, 21.5 mmol), thionyl chloride (2.8 mL, 34.4 mmol). The mixture was refluxed for 45 minutes, then all the volatile materials were rotary-evaporated. To the residue, anhydrous CH2Cl2 (10 mL) was added. The resulting solution was cooled to 0° C., and pyridine (2.63 g, 21.5 mmol) was added, followed by a solution of 4-hydroxybenzaldehyde (2.04 g, 25.8 mmol) in anhydrous CH2Cl2 (30 mL). The reaction mixture was stirred and warmed from 0° C. to room temperature slowly, then at room temperature overnight. To the reaction mixture, water (60 mL) was added and the CH2Cl2 layer was separated. The aqueous layer was extracted continually with CH2Cl2 (50 mL×3). The combined CH2Cl2 solution was washed with a cold aqueous solution of saturated NaHCO3 (80 mL). After drying and removal of the solvent, the residue was purified with a silica gel chromatography (heptane/ethyl acetate, gradient eluting) to give 4-formylphenyl tetrahydro-2H-pyran-4-carboxylate (4.40 g) as colorless oil. Yield: 87%. 1H NMR (CDCl3, 300 MHz): δ=9.97 (s, 1H), 7.91 (d, J=8.7 Hz, 2H), 7.27 (d, J=8.4 Hz, 2H), 4.06-4.00 (m, 2H), 3.55-3.47 (m, 2H), 2.88-2.81 (m, 1H), 2.03-1.88 (m, 4H). 13C NMR (CDCl3, 75.5 MHz): δ=190.9, 172.2, 155.3, 133.9, 131.1, 122.2, 115.9, 66.8, 40.1, 28.4.

Fuente