Reaktion #64340

Reaktionsgleichung

potassium t-butoxide

6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-one

methyl isothio-cyanate

N,N-dimethylformamide

→

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

Ausbeute 68.5%

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling
2. 2
   workup.STIRRINGby stirring for 4 hours under ice-
3. 3
   Temperaturcooling
4. 4
   Extraktionextracted with diethyl ether
5. 5
   WaschenThe ether layer was washed with water
6. 6
   Trocknendried over sodium sulfate
7. 7
   SonstigeThe ether layer was removed by distillation
8. 8
   Sonstigethe residue was recrystallized from ethanol

Vorschrift

To a mixture of 1.5 g of 6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-3-one, 0.6 g of methyl isothio-cyanate, and 15 ml of dried N,N-dimethylformamide was added 0.93 g of potassium t-butoxide with stirring under ice-cooling, followed by stirring for 4 hours under ice-cooling. Ice-water was added to the reaction mixture, and the mixture was made acidic with acetic acid and then extracted with diethyl ether. The ether layer was washed with water and dried over sodium sulfate. The ether layer was removed by distillation, and the residue was recrystallized from ethanol to yield 1.4 g of N-methyl-6-cyano-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-4-carbothioamide represented by formula shown below.

Quelle