Reacción #570797

Ecuación de reacción

5-formyl-2,3-pyridinedicarboxylic acid, dimethyl ester

p-toluenesulfonic acid

1,4-butanediol

sodium bicarbonate

→

title compound

Rendimiento 62.0%

Dimethyl 5-(1,3-Dioxepan-2-yl)-2,2-pyridinedicarboxylate

Rendimiento 62.0%

Disolventes

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturaat reflux temperature for 2 hours
2. 2
   Otro30 minutes
3. 3
   Concentraciónconcentrated in vacuo
4. 4
   Otroto give a liquid
5. 5
   OtroThe liquid is partitioned between methylene chloride and 5% sodium bicarbonate solution
6. 6
   OtroThe layers are separated
7. 7
   Extracciónthe aqueous layer is extracted with methylene chloride
8. 8
   Secadothe combined methylene chloride extracts are dried over anhydrous magnesium sulfate
9. 9
   Concentraciónconcentrated in vacuo
10. 10
    Otroto give an oil
11. 11
    OtroThe oil is chromatographed

Procedimiento

A solution of 5-formyl-2,3-pyridinedicarboxylic acid, dimethyl ester, 5-dimethyl acetal (1.3 g, 0.0048 mol), a catalytic amount of p-toluenesulfonic acid, 1,4-butanediol and toluene is heated at reflux temperature for 2 hours and 30 minutes. The reaction mixture is cooled to room temperature, made basic with sodium bicarbonate and concentrated in vacuo to give a liquid. The liquid is partitioned between methylene chloride and 5% sodium bicarbonate solution. The layers are separated and the aqueous layer is extracted with methylene chloride, the combined methylene chloride extracts are dried over anhydrous magnesium sulfate and concentrated in vacuo to give an oil. The oil is chromatographed using silica gel and hexanes/ethyl acetate (2:1 to 1:1) as eluant to give the title compound as a clear oil (0.88 g, 62%), identified by IR and NMR spectral analyses.

Fuente