Reaktion #582258

Reaktionsgleichung

crotonaldehyde

HBr

1,3-propanediol

→

title compound

Ausbeute 1.4%

2-(2-Bromopropyl)-1,3-dioxane

Ausbeute 1.4%

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGthe reaction was stirred at 5° C. for further 0.5 h
2. 2
   Temperaturwarm to rt
3. 3
   workup.STIRRINGfinally stirring it at rt for 2 h
4. 4
   SonstigeThe crude reaction mixture
5. 5
   Extraktionn-heptane extracted (2×200 mL)
6. 6
   Sonstigedried
7. 7
   Sonstigeevaporated in vacuo
8. 8
   Sonstige121JP80 was isolated by Kugelrohr distillation (75° C., 0.18 mmHg)

Vorschrift

Adapting a procedure of Büchi and Wüest (J. Org. Chem, 1969, 34, 1122-1123), crotonaldehyde (3 g, 43 mmol) was added dropwise to conc. aq. HBr (5.2 g, 64 mmol) over 5 min at 5° C. under air atmosphere. After 15 min of stirring at 5° C., during which time the mixture changed from colourless to brownish, 1,3-propanediol (8.1 g, 107 mmol) was added and the reaction was stirred at 5° C. for further 0.5 h before allowing it warm to rt, and finally stirring it at rt for 2 h. The crude reaction mixture was then n-heptane extracted (2×200 mL), the combined n-heptane extracts were Na2SO4 dried, evaporated in vacuo and 121JP80 was isolated by Kugelrohr distillation (75° C., 0.18 mmHg) to obtain 124 mg (1.4%) of the title compound as a colourless liquid.

Quelle