Reaktion #1676049

Reaktionsgleichung

ethyl chloroformate

9-hydroxy-9-fluorenecarboxylic acid, methyl ester

potassium tert.-butoxide

phenylhydrazine

carbon disulfide

→

3'-(Phenylamino)-2'-thioxo-spiro(9H-fluorene-9,5'-oxazolidin)-4'-one

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter 6 minutes the solution was cooled in an ice bath
2. 2
   Sonstigethe mixture was evaporated under reduced pressure to a yellow syrup
3. 3
   workup.ADDITIONThe syrup was treated with 1-chlorobutane and water
4. 4
   Waschenthe organic layer was washed with saturated sodium bicarbonate solution, water, 1N HCl, and water
5. 5
   TrocknenThe dried (magnesium sulfate) solution
6. 6
   Filtrationwas filtered
7. 7
   Sonstigeevaporated under reduced pressure to an oil
8. 8
   SonstigeThe oil was crystallized from carbon tetrachloride/hexane
9. 9
   Sonstigethe solid product further purified
10. 10
    workup.DISSOLUTIONwithout dissolution of all solid),
11. 11
    Temperaturcooling
12. 12
    Filtrationfiltering
13. 13
    SonstigeThe product was obtained as 3.56 g (27% of theoretical) of analytically-pure white solid, m.p. 187°-189° C.

Vorschrift

A solution of 9-hydroxy-9-fluorenecarboxylic acid, methyl ester (8.91 g, 0.0371 mole) in tetrahydrofuran (89 ml) was treated with potassium tert.-butoxide (4.16 g, 0.0371 mole). After 6 minutes the solution was cooled in an ice bath and carbon disulfide (2.3 ml, 0.038 mole) was added. After 7 minutes ethyl chloroformate (3.6 ml, 0.038 mole) was added to the cold solution. After 7 minutes 97% phenylhydrazine (3.9 ml, 0.038 mole) was added. After 3 minutes, the mixture was evaporated under reduced pressure to a yellow syrup. The syrup was treated with 1-chlorobutane and water, and the organic layer was washed with saturated sodium bicarbonate solution, water, 1N HCl, and water. The dried (magnesium sulfate) solution was filtered and evaporated under reduced pressure to an oil. The oil was crystallized from carbon tetrachloride/hexane, and the solid product further purified by boiling with isopropanol (without dissolution of all solid), cooling, and filtering. The product was obtained as 3.56 g (27% of theoretical) of analytically-pure white solid, m.p. 187°-189° C.

Quelle