1,3-Dibromopropane → 3,4-dihydro-2H-1,5-benzodioxepine-7-carbaldehyde

HRID 2264143

Reaction equation

HRID 2264143 reaction equation
O[C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([OH:10])[CH:9]=1)[CH:5]=[O:6].Br[CH2:12][CH2:13][CH2:14]Br.C(=O)([O-])[O-:17].[Cs+].[Cs+]>C(#N)C>[O:17]1[C:9]2[CH:2]=[CH:3][C:4]([CH:5]=[O:6])=[CH:7][C:8]=2[O:10][CH2:14][CH2:13][CH2:12]1

Participants

5

Reactant 3

HCID 80011,3-DibromopropaneHCID 10796Cesium carbonateHCID 943653,5-Dihydroxybenzaldehyde

Product 1

HCID 27763883,4-dihydro-2H-1,5-benzodioxepine-7-carbaldehyde

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Conditions

Temperature
60 °C

Procedure

A mixture of 35 g of 3,5-dihydroxybenzaldehyde, 50 g (0.97 equiv) of 1,3-dibromopropane and 127 g (1.5 equiv) of cesium carbonate in 1 L of anhydrous acetonitrile was heated under nitrogen to 60° C. overnight. The mixture was allowed to cool, then filtered and concentrated under reduced pressure. The residue was partitioned between 500 mL of ethyl acetate and 100 mL of saturated sodium carbonate then dried over magnesium sulfate and concentrated under reduced pressure. Purification by flash chromatography (0-20% ethyl acetate in hexanes) gave the product as clear oil. MS (m+1)=179.1; 1H NMR (400 MHz, CDCl3) 9.82 (s, 1H), 7.42 (m, 2H), 7.02 (m, 1H), 4.32 (t, 2H), 4.24 (t, 2H), 2.22 (m, 2H).

Workup

  1. temperatureto cool
  2. filtrationfiltered
  3. concentrationconcentrated under reduced pressure
  4. customThe residue was partitioned between 500 mL of ethyl acetate and 100 mL of saturated sodium carbonate
  5. dry with materialthen dried over magnesium sulfate
  6. concentrationconcentrated under reduced pressure
  7. customPurification by flash chromatography (0-20% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-f4145d78c7d3416390d338d79fdb3716
Source dataset
uspto-grants-2010_12
Patent number
US07855201B2

Linked notes

Loading…