Sodium borohydride → N,2,2-trimethyl-3,4-dihydro-3-hydroxy-6-nitro-2H-1-benzopyran-4-carbothioamide

HRID 36071Notes

Reaction equation

HRID 36071 reaction equation
[CH3:1][NH:2][C:3]([C:5]1[C:10]2[CH:11]=[C:12]([N+:15]([O-:17])=[O:16])[CH:13]=[CH:14][C:9]=2[O:8][C:7]([CH3:19])([CH3:18])[C:6]=1[OH:20])=[S:4].[BH4-].[Na+]>CO>[CH3:1][NH:2][C:3]([CH:5]1[C:10]2[CH:11]=[C:12]([N+:15]([O-:17])=[O:16])[CH:13]=[CH:14][C:9]=2[O:8][C:7]([CH3:18])([CH3:19])[CH:6]1[OH:20])=[S:4]

Participants

4

Reactant 2

HCID 4311764Sodium borohydrideHCID 135720097HCID 135720097, compound

Product 1

HCID 15234732N,2,2-trimethyl-3,4-dihydro-3-hydroxy-6-nitro-2H-1-benzopyran-4-carbothioamideYield 28.6%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a mixture of 2.08 g of N-methyl-6-nitro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-carbothioamide and 50 ml of methanol was added 1.33 g of sodium borohydride at -10° C. while stirring. The mixture was stirred for 24 hours while slowly raising the temperature from -10° C. up to room temperature, followed by concentration under reduced pressure. Water was added to the residue, and the mixture was extracted with methylene chloride. The organic layer was washed with a saturated sodium chloride aqueous solution, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was recrystallized from a mixed solvent of methylene chloride and n-hexane to obtain 0.6 g of N-methyl-6-nitro-3,4-dihydro-3-hydroxy-2,2-dimethyl -2H-1-benzopyran-4-carbothioamide.

Workup

  1. stirringThe mixture was stirred for 24 hours
  2. temperaturewhile slowly raising the temperature from -10° C. up to room temperature
  3. concentrationfollowed by concentration under reduced pressure
  4. additionWater was added to the residue
  5. extractionthe mixture was extracted with methylene chloride
  6. washThe organic layer was washed with a saturated sodium chloride aqueous solution
  7. dry with materialdried over magnesium sulfate
  8. concentrationconcentrated under reduced pressure
  9. customThe residue was recrystallized from a mixed solvent of methylene chloride and n-hexane

Sources & evidence

ORD record
ord-713c8958f66b4cc2bad37f635a4314bd
Source dataset
uspto-grants-1995_05
Patent number
US05412117

Reaction notes

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