Reaktion #1370874

Reaktionsgleichung

p-toluene sulphonic acid

t-Butyl 3-p-fluorobenzyl-7-triphenylmethylamino-3-cephem-4-carboxylate

p-Toluene sulphonic acid

( IX )

t-Butyl 3-p-fluorobenzyl-7-triphenylmethylamino-3-cephem-4-carboxylate

→

t-butyl 7-amino-3-p-fluorobenzyl-3-cephem-4-carboxylate

Ausbeute 64.7%

Lösungsmittel

acetone

acetone

acetone

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe solution cooled to 0°
2. 2
   workup.WAITthe solution left
3. 3
   SonstigeAfter 2.5 hours a solid had formed
4. 4
   TemperaturThe mixture was again cooled to 0°
5. 5
   SonstigeAfter leaving at room temperature for a further 1.5 hours
6. 6
   Filtrationthe white solid was filtered off
7. 7
   workup.ADDITIONtreated with saturated sodium bicarbonate solution
8. 8
   WaschenThe organic layer was washed with brine
9. 9
   Sonstigedried
10. 10
    Sonstigeevaporated

Vorschrift

t-Butyl 3-p-fluorobenzyl-7-triphenylmethylamino-3-cephem-4-carboxylate (IX) (72 mg) was dissolved in acetone and the solution cooled to 0°. p-Toluene sulphonic acid (25 mg) in acetone (0.5 ml) was added dropwise over a few minutes and the solution left to warm to room temperature with stirring. After 2.5 hours a solid had formed but t.l.c. still showed some unchanged (IX) to be present. The mixture was again cooled to 0° and a further quantity of p-toluene sulphonic acid (5 mg) in acetone added. After leaving at room temperature for a further 1.5 hours, the white solid was filtered off. This solid was suspended in ethyl acetate and treated with saturated sodium bicarbonate solution. The organic layer was washed with brine, dried and evaporated to give t-butyl 7-amino-3-p-fluorobenzyl-3-cephem-4-carboxylate (XI) (28 mg) shown to be pure by t.l.c. ##SPC17##

Quelle