Reaktion #564667

Reaktionsgleichung

methyl 5-chloro-2-hydroxy-3-(2-propenyl)benzoate

methyl 5-chloro-2-hydroxy3-(2-propenyl)benzoate

ether

sodium periodate

→

5c

3-carbomethoxy-5-chloro2-hydroxy-phenylacetaldehyde

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe mixture was stirred at room temperature for another 21 hours
2. 2
   SonstigeThe layers were separated
3. 3
   Extraktionthe aqueous layer extracted with ethyl ether (2×400 ml)
4. 4
   Trocknendried over anhydrous Na2SO4
5. 5
   Filtrationfiltered through a column of Florisil (85 g)
6. 6
   Sonstigeto remove inorganic impurity
7. 7
   SonstigeEvaporation of the ether

Vorschrift

Osmium tetroxide (1.0 g, 3.9 mmol) was added to a mixture of methyl 5-chloro-2-hydroxy-3-(2-propenyl)benzoate (4c) (22.7 g, 0.1 mol), ether (400 ml), and water (400 ml). After stirring at room temperature for 5 minutes, sodium periodate (47.06 g, 0.22 mol) was added in portions. The mixture was stirred at room temperature for another 21 hours, and then poured into 800 ml of water. The layers were separated and the aqueous layer extracted with ethyl ether (2×400 ml). The organic layers were combined, dried over anhydrous Na2SO4 and then filtered through a column of Florisil (85 g) to remove inorganic impurity. Evaporation of the ether yielded 5c quantitatively as a brown solid, m.p. 49°-59° C., which appeared hygroscopic. The crude product was used for the next reaction without purification. NMR (CDCl3) δ 10.90 (s, 1H, OH), 9.67 (t, 1H, J= 1.5 Hz, CHO), 7.70 (d, 1H, J=3 Hz, aromatic proton), 7.23 (d, 1H, aromatic proton), 3.97 (s, 3H, CH3) and 3.70 (d, 2H, CH2).

Quelle