Iodine → Ethyl 2-amino-2-cyanoacetate

Beteiligte Stoffe

Reaktionsschritte

Combine ethyl cyanoglyoxylate-2-oxime (20.0 g, 141 mmol) and 5% Pt/C (2.0 g, 10% wt. load) in acetic acid (120 mL) and EtOAc (60 mL) and hydrogenate under 40 psi H2 overnight until the reaction is complete by TLC (5:1/heptane:EtOAc, I2 stain). Carefully filtered the spent catalyst using partial vacuum through glass fiber paper, and rinse with HOAc/EtOAc without allowing the cake to dry out. Concentrate the filtrate in vacuo on a rotovapor to an oil, leaving 25.5 g (96%) of crude amino-cyano-acetic acid ethyl ester as the HOAc salt. Partition a portion (13.0 g) of the HOAc salt between EtOAc (70 mL) and water (35 mL). Stir the biphasic solution and add dropwise aqueous 5N NaOH (16.5 mL) to adjust the pH to 8.0-8.2. Separate the layers, and extract the aqueous layer with more EtOAc (3×25 mL). Combine the organic layer, dry (MgSO4), filter, and concentrate the filtrate to dryness in vacuo on a rotovapor at low bath temperature (30-35° C.) to afford 5.68 g (65%) crude amino-cyano-acetic acid ethyl ester which was used immediately in the next reaction.

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