Reaktion #570797

Reaktionsgleichung

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

p-toluenesulfonic acid

1,4-butanediol

sodium bicarbonate

→

title compound

Ausbeute 62.0%

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

Ausbeute 62.0%

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux temperature for 2 hours
2. 2
   Sonstige30 minutes
3. 3
   Einengenconcentrated in vacuo
4. 4
   Sonstigeto give a liquid
5. 5
   SonstigeThe liquid is partitioned between methylene chloride and 5% sodium bicarbonate solution
6. 6
   SonstigeThe layers are separated
7. 7
   Extraktionthe aqueous layer is extracted with methylene chloride
8. 8
   Trocknenthe combined methylene chloride extracts are dried over anhydrous magnesium sulfate
9. 9
   Einengenconcentrated in vacuo
10. 10
    Sonstigeto give an oil
11. 11
    SonstigeThe oil is chromatographed

Vorschrift

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.

Quelle