Reaktion #64341

Reaktionsgleichung

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

tetrahydrofuran

sodium borohydride

→

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

Ausbeute 7.1%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGby stirring at -10° C. for 2 hours
2. 2
   workup.DISTILLATIONThe reaction mixture was distilled under reduced pressure, ice-water
3. 3
   workup.ADDITIONadded to the residue
4. 4
   Extraktionextracted with diethyl ether and ethyl acetate
5. 5
   TrocknenThe organic layer combined was dried over Na2SO4
6. 6
   workup.DISTILLATIONfollowed by distillation

Vorschrift

To a mixture of 1.4 g of N-methyl-6-cyano-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-carbothioamide, 15 ml of tetrahydrofuran, and 15 ml of methanol was added 0.23 g of sodium borohydride (NaBH4) at -10° C. with stirring, followed by stirring at -10° C. for 2 hours and then at room temperature for 2 hours. The reaction mixture was distilled under reduced pressure, ice-water added to the residue, and the mixture made acidic with acetic acid and extracted with diethyl ether and ethyl acetate. The organic layer combined was dried over Na2SO4, followed by distillation. The residue was subjected to silica gel column chromatography (developing solution: CH2Cl2 :AcOEt=2:1). From the first fraction was obtained 0.1 g of cis-N-methyl-6-cyano-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-carbothioamide represented by formula shown below.

Quelle