Diisobutylaluminum hydride → 2,3-Dihydro-1,4-benzodioxin-2-ol

HRID 1722829Notes

Reaction equation

HRID 1722829 reaction equation
CC(C[AlH]CC(C)C)C.[O:10]1[C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][C:14]=2[O:13][CH2:12][C:11]1=[O:20]>C1(C)C=CC=CC=1>[OH:20][CH:11]1[O:10][C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][C:14]=2[O:13][CH2:12]1

Participants

4

Reactant 2

HCID 14487Diisobutylaluminum hydrideHCID 46854502,3-dihydro-1,4-benzodioxin-2-one

Product 1

HCID 1107112,3-Dihydro-1,4-benzodioxin-2-olYield 90.9%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Conditions

Temperature
-70 °C

Procedure

The mixture is warmed at room temperature, then heated to reflux for 2 hours. The organic phase is washed with water, 5% aqueous sodium hydroxyde and then with water. After drying on Na2SO4, the solvent is evaporated to dryness under vacuum and the crude material is crytallized from cyclohexane--Et2O to give 1,4-benzodioxan-2-one (10 g) m.p. 52°-54° C. A molar solution of DIBAH in toluene (73 ml) is added dropwise to a stirred solution of 1,4-benzodioxan-2-one (8.9 g) in dry toluene (100 ml), cooled at -70° C. during 40 minutes. Stirring at this temperature is continued for 15 minutes, then the excess reagent is destroyed by adding 2N-isopropanol in toluene (75 ml), under stirring, at -70°+-60° C. The mixture is warmed at room temperature and treated with 30% NaH2PO4 aqueous solution (6 ml) and 25 g of anhydrous Na2SO4, for 4 hours, under stirring. The inorganic material is filtered out and the eluate is evaporated to dryness to give 8.2 g of 2-hydroxy-1,4-benzodioxan. A stirred solution of this δ-lactol (7.8 g) in ethanol (30 ml) is treated with a solution of cysteamine hydrochloride (7.36 g) and potassium acetate (6.5 g) in water (12 ml). Stirring is continued for 45 minutes, then a crystalline precipitate of 2-[(o-hydroxyphenoxy)methyl]thiazolidine(8.1 g) is obtained. M.p. 76°-78° C.

Workup

  1. customthe excess reagent is destroyed
  2. additionby adding 2N-isopropanol in toluene (75 ml)
  3. stirringunder stirring, at -70°+-60° C
  4. temperatureThe mixture is warmed at room temperature
  5. additiontreated with 30% NaH2PO4 aqueous solution (6 ml) and 25 g of anhydrous Na2SO4, for 4 hours
  6. stirringunder stirring
  7. filtrationThe inorganic material is filtered out
  8. customthe eluate is evaporated to dryness

Sources & evidence

ORD record
ord-698727ea8f6f44a7b54bdf322fd8f84b
Source dataset
uspto-grants-1989_08
Patent number
US04857643

Reaction notes

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