Method I. Ethyl chloroformylacetate, also known as ethyl 3-chloro-3-oxopropionate, ethyl malonate monochloride, can be obtained by chlorination of 3-ethoxy-3-oxopropionic acid, and the chlorination reagent can be selected from sulfoxide chloride and oxalyl chloride.
To a solution of toluene (226 mL) containing 3-ethoxy-3-oxopropionic acid (14.9 g, 112.8 mmol) was added dichlorosulfoxide (26.6 g, 225.6 mmol). The reaction solution was heated and stirred at 110C for 4 hours and then concentrated under reduced pressure to give ethyl chloroformylacetate as a brown oil.
Method II, ethyl malonate (13.2g,100.0mmol) and N,N-dimethylformamide (0.05mL) were stirred and dissolved in dichloromethane (200mL), cooled to 0C in an ice-water bath, oxalic acid chloride (25.4g,200mmol) was added dropwise, and the mixture was stirred at room temperature for 2h, and concentrated to obtain ethyl chloroformyl acetate (14.5g,97%) as a white oily material.
