Sodium borohydride → HCID 13290180, compound

HRID 370978Notes

Reaction equation

HRID 370978 reaction equation
[Cl-].[Al+3].[Cl-].[Cl-].[BH4-].[Na+].[CH2:7]([CH:11]1[S:15][C:14]2[C:16]([Cl:23])=[C:17]([Cl:22])[C:18]([O:20][CH3:21])=[CH:19][C:13]=2[C:12]1=[O:24])[CH2:8][CH2:9][CH3:10]>ClCCl.C(O)C>[CH2:7]([CH:11]1[S:15][C:14]2[C:16]([Cl:23])=[C:17]([Cl:22])[C:18]([O:20][CH3:21])=[CH:19][C:13]=2[CH:12]1[OH:24])[CH2:8][CH2:9][CH3:10]

Participants

6

Reactant 3

HCID 4311764Sodium borohydrideHCID 6451240Aluminum(III) ChlorideHCID 20197880HCID 20197880, compound

Product 1

HCID 13290180HCID 13290180, compound

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 6344DichloromethaneSolvent

Procedure

A mixture of 1.62 g of α-[(2,3-dichloro-4-methoxy)phenylthio]hexanoic acid and 8 ml of thionyl chloride in 50 ml dichloromethane is refluxed for 30 minutes. The cooled solution is concentrated in vacuo to dryness at 60°, leaving the acid chloride as a yellow solid. The residue is dissolved in 100 ml dichloromethane, cooled to -70° and the solution is treated with 0.73 g of aluminum chloride in small portions. The cooling bath is removed after the addition is complete and the reaction mixture is stirred for 11/2-2 hours. The mixture is decomposed with water and the aqueous solution is extracted with 3×100 ml portions of dichloromethane. The organic layers are combined, dried over anhydrous magnesium sulfate, filtered, and the filtrate is concentrated under reduced pressure to give a dark oil. The oil is dissolved in 100 ml of 100% ethanol and stirred under a nitrogen atmosphere. To this mixture is slowly added 1.0 g of sodium borohydride. Stirring is continued until the disappearance of the ketone intermediate, 2-n-butyl-6,7-dichloro-5-methoxybenzo[b]thiophen-3(2H)-one, is shown by a thin layer chromatography. The reaction mixture is quenched with 100 g ice-water and extracted with 3×100 ml-portions of diethyl ether. The organic layers are combined and washed with 1×100 ml-portions of water. The organic layer is dried, filtered, and the solvent removed in vacuo. The residue is chromatographed on 60 g of silica gel using dichloromethane as the eluant to give 0.76 g of 2-n-butyl-6,7-dichloro-2,3-dihydro-3-hydroxy-5-methoxybenzo[b]thiophene as an oily epimeric mixture. Upon standing, crystals form from the isolated oil. Recrystallization from ether-hexane gives an isomer which melts at 95°-96°.

Workup

  1. temperaturecooled to -70°
  2. customThe cooling bath is removed
  3. additionafter the addition
  4. extractionthe aqueous solution is extracted with 3×100 ml portions of dichloromethane
  5. dry with materialdried over anhydrous magnesium sulfate
  6. filtrationfiltered
  7. concentrationthe filtrate is concentrated under reduced pressure
  8. customto give a dark oil
  9. stirringstirred under a nitrogen atmosphere
  10. stirringStirring
  11. customThe reaction mixture is quenched with 100 g ice-water
  12. extractionextracted with 3×100 ml-portions of diethyl ether
  13. washwashed with 1×100 ml-portions of water
  14. customThe organic layer is dried
  15. filtrationfiltered
  16. customthe solvent removed in vacuo
  17. customThe residue is chromatographed on 60 g of silica gel

Sources & evidence

ORD record
ord-d67f5f74b44147a8a74f3c594d53bb88
Source dataset
uspto-grants-1985_07
Patent number
US04528399

Reaction notes

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