Reaktion #218540

Reaktionsgleichung

I2

sodium bicarbonate

ethyl cyanoglyoxylate-2-oxime

sodium dithionite

→

amino-cyano-acetic acid ethyl ester

Ausbeute 31.0%

Lösungsmittel

water

EtOAc

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengensaturate the solution with sodium chloride (400 g)
2. 2
   Extraktionextract the product CH2Cl2 (1×500 mL, 3×250 mL)
3. 3
   workup.ADDITIONmore added if necessary)
4. 4
   Extraktionduring the extractions
5. 5
   TrocknenCombine the organic layers, dry over (MgSO4)
6. 6
   Filtrationfilter
7. 7
   Einengenconcentrate the filtrate to dryness in vacuo on a rotovapor at low bath temperature (30-35° C.)

Vorschrift

Dilute aqueous saturated sodium bicarbonate (560 mL) with deionized water (700 mL). and stir the solution while addinng ethyl cyanoglyoxylate-2-oxime (70.0 g, 493 mmol), in portions (note: some off-gassing and a gentle endotherm were observed). Add sodium dithionite (238 g, 1.37 mol, 2.8 eq.) in portions and stir at rt. After 2.5-3 hours, during this time the reaction was monitored by TLC (EtOAc, I2 stain), saturate the solution with sodium chloride (400 g), and extract the product CH2Cl2 (1×500 mL, 3×250 mL), making sure solid NaCl was visible (more added if necessary) during the extractions. Combine the organic layers, dry over (MgSO4), filter, and concentrate the filtrate to dryness in vacuo on a rotovapor at low bath temperature (30-35° C.) to afford 19.6 g (31%) crude amino-cyano-acetic acid ethyl ester which was used immediately in the next reaction.

Quelle