(E)-3-(dimethylamino)prop-2-enenitrile

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of oxalyl chloride (13.1 mL, 0.15 mol) in 1,2-dichloroethane is added dropwise to a solution of N,N-dimethylformamide (11.6 mL, 0.15 mol) in 1,2-dichloroethane while maintaining the reaction mixture temperature below 0° C. The reaction mixture is stirred for 45 minutes, treated with a solution of trans-3-dimethylaminoacrylonitrile (16.4 mL, 0.15 mol) in 1,2-dichloroethane, stirred at room temperature for 16 hours, refluxed for two hours and concentrated in vacuo to obtain a semi-solid residue. A solution of the residue in 2-propanol is treated with a solution of oxalic acid dihydrate (18.9 g, 0.15 mol) in 2-propanol and warmed until a clear solution is obtained. The clear solution is cooled to and held at room temperature for several hours, cooled in a freezer for two hours and filtered. The filter cake is washed sequentially with 2-propanol and ether and dried in a vacuum desiccator at 50° to give the title product (28.6 g, 79%). while maintaining the reaction mixture temperature below 0° C stirred at room temperature for 16 hours refluxed for two hours concentrated in vacuo to obtain a semi-solid residue warmed until a clear solution is obtained The clear solution is cooled to and held at room temperature for several hours cooled in a freezer for two hours filtered The filter cake is washed sequentially with 2-propanol and ether dried in a vacuum desiccator at 50°

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of cyanoacetic acid (2.0 g, 23.53 mmol) in 1,4-dioxane (10 mL) was added N,N-dimethylformamide dimethylacetal (3.35 g, 28.23 mmol) and the reaction mixture was heated at 80° C. for 4 h. Then the reaction mixture was concentrated, diluted with Et2O and filtered through a pad of silica. The filtrate was concentrated to afford 2.37 g of (E)-3-(dimethylamino)acrylonitrile which was taken to the next step without further purification. To a solution of (Z)-ethyl 2-(ethoxymethylene)-4,4-difluoro-3-oxobutanoate (5.5 g, 24.77 mmol) in DMF (15 mL) at 65° C. was added (E)-3-(dimethylamino)acrylonitrile (2.37 g, 24.77 mmol) dropwise and the reaction mixture was heated at the same temperature for 5 h. Then NH4OAc (2.86 g, 37.15 mmol) was added to the reaction mixture and heating was continued for 12 h. Then the reaction mixture was quenched with water at rt and was extracted with Et2O. The organic layer was separated, dried, filtered and concentrated. The residue was purified by column chromatography to afford 1.3 g of the title product. 1H NMR (300 MHz, DMSO-d6): δ 9.09 (s, 1H), 8.60 (s, 1H), 7.62-7.26 (t, J=54 Hz, 1H), 4.51-4.44 (q, J=7.2 Hz, 2H), 1.46-1.42 (t, J=7.2 Hz, 3H); MS [M+H]+: 227.38. was taken to the next step without further purification the reaction mixture was heated at the same temperature for 5 h heating Then the reaction mixture was quenched with water at rt was extracted with Et2O The organic layer was separated dried filtered concentrated The residue was purified by column chromatography