Sodium borohydride → HCID 19939981, compound

HRID 36067Notes

Reaction equation

HRID 36067 reaction equation
[CH3:1][NH:2][C:3]([C:5]1[C:10]2[CH:11]=[C:12]([C:15]#[N:16])[CH:13]=[CH:14][C:9]=2[O:8][C:7]([CH3:19])([CH2:17][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]([C:15]#[N:16])[CH:13]=[CH:14][C:9]=2[O:8][C:7]([CH3:19])([CH2:17][CH3:18])[CH:6]1[OH:20])=[S:4]

Participants

4

Reactant 2

HCID 4311764Sodium borohydrideHCID 135720098HCID 135720098, compound

Product 1

HCID 19939981HCID 19939981, compoundYield 53.4%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a mixture of 0.8 g of N,2-dimethyl-6-cyano-2-ethyl-3-hydroxy-2H-1-benzopyran-4-carbothioamide and 20 ml of methanol was added 0.24 g of sodium borohydride (NaBH4) while stirring under ice-cooling, followed by stirring at room temperature for 2 hours. The reaction mixture was distilled under reduced pressure, and water was added to the residue. The residue was extracted with diethyl ether, and the organic layer was washed with water and dried. The solvent was removed by distillation to obtain 0.43 g of N,2-dimethyl-6-cyano-3,4-dihydro-2-ethyl-3-hydroxy-2H-1-benzopyran-4-carbothioamide. The resulting product were added 0.1 g of p-toluenesulfonic acid monohydrate and 30 ml of toluene, followed by heating at reflux for 3 hours. The solvent was removed by distillation, and the residue was purified by silica gel column chromatography (developing solution: CH2Cl2) to obtain 0.2 g of N,2-dimethyl-6-cyano-2-ethyl-2H-1-benzopyran-4-carbothioamide represented by formula shown below.

Workup

  1. temperaturecooling
  2. stirringby stirring at room temperature for 2 hours
  3. distillationThe reaction mixture was distilled under reduced pressure, and water
  4. additionwas added to the residue
  5. extractionThe residue was extracted with diethyl ether
  6. washthe organic layer was washed with water
  7. customdried
  8. customThe solvent was removed by distillation

Sources & evidence

ORD record
ord-c2913d5dd4c74ad7a260fa4d91c99cd2
Source dataset
uspto-grants-1995_05
Patent number
US05412117

Reaction notes

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