1,2-Dibromoethane → Ethyl 2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylate

HRID 468306Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 468306
C([O-])([O-])=O.[Cs+].[Cs+].[CH2:7]([O:9][C:10](=[O:19])[C:11]1[CH:16]=[CH:15][C:14]([OH:17])=[C:13]([OH:18])[CH:12]=1)[CH3:8].Br[CH2:21][CH2:22]Br>CN(C=O)C>[CH2:7]([O:9][C:10]([C:11]1[CH:16]=[CH:15][C:14]2[O:17][CH2:21][CH2:22][O:18][C:13]=2[CH:12]=1)=[O:19])[CH3:8]

Komponenten

5

Edukt 3

HCID 78391,2-DibromoethaneHCID 10796Cesium carbonateHCID 77547Ethyl 3,4-Dihydroxybenzoate

Produkt 1

HCID 16648286Ethyl 2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylateAusbeute 29,8 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 6228DimethylformamideLösungsmittel

Reaktionsbedingungen

Temperatur
80 °C

Versuchsvorschrift

To a suspension of Cs2CO3 (270 g, 1.49 mol) in DMF (1000 mL) were added 3,4-dihydroxybenzoic acid ethyl ester (54.6 g, 0.3 mol) and 1,2-dibromoethane (54.3 g, 0.29 mol) at room temperature. The resulting mixture was stirred at 80° C. overnight and then poured into ice-water. The mixture was extracted with EtOAc (200 mL×3). The combined organic layers were washed with water (200 mL×3) and brine (100 mL), dried over Na2SO4 and concentrated to dryness. The residue was purified by column (petroleum ether/ethyl acetate 50:1) on silica gel to obtain 2,3-dihydro-benzo[1,4]dioxine-6-carboxylic acid ethyl ester (18 g, 29%). 1H NMR (300 MHz, CDCl3) δ 7.53 (dd, J=1.8, 7.2 Hz, 2H), 6.84-6.87 (m, 1H), 4.22-4.34 (m, 6H), 1.35 (t, J=7.2 Hz, 3H).

Aufarbeitung

  1. extractionThe mixture was extracted with EtOAc (200 mL×3)
  2. washThe combined organic layers were washed with water (200 mL×3) and brine (100 mL)
  3. dry with materialdried over Na2SO4
  4. concentrationconcentrated to dryness
  5. customThe residue was purified by column (petroleum ether/ethyl acetate 50:1) on silica gel

Quellen und Nachweise

ORD-Eintrag
ord-207ed2100719455fa4924dcd2616e69c
Quelldatensatz
uspto-grants-2014_01
Patentnummer
US08623905B2

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