Réaction #64345

Équation de réaction

N,2-dimethyl-6-cyano-2-ethyl-3-hydroxy-2H-1-benzopyran-4-carbothioamide

sodium borohydride

→

N,2-dimethyl-6-cyano-3,4-dihydro-2-ethyl-3-hydroxy-2H-1-benzopyran-4-carbothioamide

Rendement 53.4%

Solvants

methanol

Conditions de réaction

Traitement

1. 1
   Températurecooling
2. 2
   workup.STIRRINGby stirring at room temperature for 2 hours
3. 3
   workup.DISTILLATIONThe reaction mixture was distilled under reduced pressure, and water
4. 4
   workup.ADDITIONwas added to the residue
5. 5
   ExtractionThe residue was extracted with diethyl ether
6. 6
   Lavagethe organic layer was washed with water
7. 7
   Autredried
8. 8
   AutreThe solvent was removed by distillation

Mode opératoire

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.

Source