Hydrochloric Acid → 1,3-Dihydroisobenzofuran

HRID 1659602Notes

Reaction equation

HRID 1659602 reaction equation
[H-].[Al+3].[Li+].[H-].[H-].[H-].[C:7]1([C:16]2[C:11](=[CH:12][CH:13]=[CH:14][CH:15]=2)[CH2:10][O:9]1)=O.Cl>O1CCCC1.CCOCC.O.C(OC(=O)C)C>[CH2:7]1[O:9][CH2:10][C:11]2[C:16]1=[CH:15][CH:14]=[CH:13][CH:12]=2

Participants

8

Reactant 3

HCID 313Hydrochloric AcidHCID 6885PhthalideHCID 21226445Aluminium lithium hydride3×

Product 1

HCID 103271,3-Dihydroisobenzofuran

Reagents, catalysts & solvents 4

HCID 962WaterSolvent2×HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent2×HCID 8857Ethyl AcetateSolvent

Procedure

Lithium aluminum hydride (0.2 g) was added to approximately 40 ml of dry tetrahydrofuran at room temperature under nitrogen. 3-[4'-(dimethyl)amino-1'-phenyl]-3-(3",5"-diisopropyl-4"-oxo-1"-phenyl)phthalide (1.0 g) was dissolved in 40 ml dry tetrahydrofuran and the solution added dropwise to the lithium aluminum hydride suspension. The temperature rose to about 30° C. Upon completion of addition, a sample of the reaction mixture was poured into water and extracted with ether. TLC on silica gel with 1:1 ether/petroleum ether showed completion of the reaction and no unreacted phthalide. After neutralizing the lithium aluminum hydride with ethylacetate, the reaction mixture was poured into 200 ml water, the pH adjusted to 3 with HCl and extracted with ether. The ether layer was washed with 200 ml of 5% aqueous sodium hydroxide, dried over sodium sulfate and the ether evaporated to leave a pink-red residue. The residue was dissolved in about 20 ml ether, and petroleum ether was added to precipitate a white solid. The solution after filtering was evaporated to give the corresponding phthalan as a pink solid.

Workup

  1. customrose to about 30° C
  2. additionUpon completion of addition
  3. extractionextracted with ether
  4. customTLC on silica gel with 1:1 ether/petroleum ether showed completion of the reaction
  5. extractionextracted with ether
  6. washThe ether layer was washed with 200 ml of 5% aqueous sodium hydroxide
  7. dry with materialdried over sodium sulfate
  8. customthe ether evaporated
  9. customto leave a pink-red residue
  10. customto precipitate a white solid
  11. filtrationThe solution after filtering
  12. customwas evaporated

Sources & evidence

ORD record
ord-06bbd41ec00a4840b2a25d2549c4bd80
Source dataset
uspto-grants-1981_12
Patent number
US04304833

Reaction notes

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