Reaktion #215076

Reaktionsgleichung

potassium persulfate

sodium monohydrogen phosphate

methyl 3-t-butoxycarbonylamino-1-(2,4-dimethoxybenzyl)-4-oxoazetidine-2-carboxylate

→

title compound

Ausbeute 31.0%

Methyl cis-3-t-Butoxycarbonylamino-4-oxoazetidine-2-carboxylate

Ausbeute 31.0%

Lösungsmittel

water

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwarmed to 80°
2. 2
   Sonstigeis consumed (tlc)
3. 3
   TemperaturThe reaction mixture is cooled
4. 4
   Einengenconcentrated in vacuum
5. 5
   workup.STIRRINGshaken with ethyl acetate-water
6. 6
   WaschenThe organic phase is washed with dilute HCl, NaHCO3 solution and brine
7. 7
   Trocknendried over magnesium sulfate
8. 8
   Sonstigeevaporated to dryness
9. 9
   SonstigeThe residue is chromatographed over silica gel with 1:1 benzene-ethyl acetate
10. 10
    Sonstigeto afford pure product which
11. 11
    Sonstigecrystallized from ethyl acetate-hexane

Vorschrift

A solution of 10.5 g (26.7 mmole) of methyl 3-t-butoxycarbonylamino-1-(2,4-dimethoxybenzyl)-4-oxoazetidine-2-carboxylate in 500 ml of acetonitrile is degassed with argon and warmed to 80°. A degassed solution of 15 g (55.5 mmole) of potassium persulfate and 7.5 g (28 mmole) of sodium monohydrogen phosphate in 150 ml of water is added in five portions over 1 hr. The reaction is stirred at 80°-85° under argon for 2-3 hrs until all starting material is consumed (tlc). The reaction mixture is cooled, concentrated in vacuum, shaken with ethyl acetate-water. The organic phase is washed with dilute HCl, NaHCO3 solution and brine; dried over magnesium sulfate and evaporated to dryness. The residue is chromatographed over silica gel with 1:1 benzene-ethyl acetate to afford pure product which crystallized from ethyl acetate-hexane to yield 2.0 g (31%) of the title compound. A less pure fraction from the column, is crystallized from ethyl acetate-hexane to give an additional 0.5 g of product, overall yield, 38%.

Quelle