Ethyl α-(hexahydroazepinylidene-2)acetate could be produced through the following synthetic routes.

A. Isopropylidene α-(hexahydroazepinylidene-2)malonate (CAS NO.: ). In a 1-L, round-bottomed flask fitted with an efficient reflux condenser and equipped with a magnetic stirrer are placed 50.8 g (0.40 mol) of O-methylcaprolactim, 57.6 g (0.40 mol) of , and 0.25 g of nickel acetylacetonate monohydrate (Note 3) in 500 mL of anhydrous chloroform. The reaction mixture is refluxed for 12 hr. The solvent is removed with a rotary evaporator and the bright-yellow precipitate is recrystallized from absolute ethanol to give 77–78 g (81–82%) of pale-yellow crystals, mp 147–149°C.

B. Ethyl α-(hexahydroazepinylidene-2)acetate. A solution of sodium ethoxide is prepared from 8.3 g (0.36 mol) of freshly cut sodium and 600 mL of freshly distilled absolute ethanol in a 1-L, round-bottomed flask equipped with a magnetic stirrer and fitted with a reflux condenser. To the stirred solution is added in one portion 71.7 g (0.30 mol) of freshly recrystallized isopropylidene α-(hexahydroazepinylidene-2)malonate. The mixture is refluxed and a white precipitate begins to appear. Refluxing is continued for 12 hr. The solvent is removed with a rotary evaporator and the white precipitate is placed in a 2-L beaker. (300 mL) is added and a 1 N hydrochloric solution is added dropwise to pH 6. The reaction mixture is extracted with four 100-mL portions of chloroform. The extracts are dried over anhydrous sodium sulfate and the solvent is removed with a rotary evaporator. The yellow solid residue is recrystallized from methanol to give 43–44 g (78–80%) of white powder, mp 55–56°C.