Producing Alkoxy Malonic Acid Dinitriles

Patent Method for Producing Alkoxy Malonic Acid Dinitriles 

Bartek etal, US Patent 6,673,957 (January 6, 2004) Assignee Lonsa AG Utility Anesthetic Intermediate 

Phosphorous oxychloride (87.0 mmol) and AICI3 (2.3 mmol) were added to a solution of methoxymalonamide (75.5 mmol) dissolved in 50ml CH3CN and refluxed 4 hours. Thereafter, the solvent was distilled off, water added, the product extracted 3 times with 50 ml diethyl ether, dried, and the solvent removed. The product was purified by Kugelrohr distillation at 100 °C at 20 mbar and the product isolated in 61% yield as a colorless oil. H- and C-NMR data supplied. 

Trifluoroacetic anhydride can be used as an alternative dehydrating agent for phosphorous oxychloride as described below by the author  

Methoxymalonamide (75.5 mmol) was dissolved in 100ml dioxane containing pyridine (278 mmol). The solution was cooled to 2-5 °C, trifluoroacetic anhydride (230 mmol) added, and the mixture reacted at ambient temperature for 24 hours. Thereafter, 200 ml apiece water and CH2CI2 were added at 10 °C, the mixture extracted with 200 ml CH2CI2, and the product isolated by distillation at 27-30 °C at 1.6 mbar in 33% yield. 

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