54512-75-3

95-92-1

78834-75-0

The general procedure for the synthesis of ethyl 7-chloro-2-oxoheptanoate from 1-bromo-5-chloropentane and diethyl oxalate is as follows (Example 1): 1. Reaction apparatus preparation: the reaction apparatus 10 shown in Figure 1 was used, wherein the main flow channel 12 was a circular tube made of stainless steel, and the introduction points 12o and 12p were 180-degree T-shaped mixture flow channels. 2. Grignard reagent preparation: 1-bromo-magnesium-5-chloropentane Grignard reagent (0.45 mol/L) was prepared by adding magnesium powder to 1-bromo-5-chloropentane and diluted with tetrahydrofuran solvent, and the resulting diluted solution was used as feedstock M2. 3. Raw material preparation: Undiluted diethyl oxalate (7.4 mol/L) was used as raw material M1. 4. Reactant delivery: Feedstock M2 and feedstock M1 were delivered to a flow-type microfine reaction flow path 32 via smooth flow pumps 20 and 26 manufactured by TACMINA CORPORATION at flow rates of 110 mL/min and 5.1 mL/min, respectively. 5. Control of reaction conditions: Feedstock M2 (Grignard reagent) and feedstock M1 (diethyl oxalate) were controlled at 10 °C and room temperature, respectively, and the thermostatic liquid tank 28 was charged with methanol as refrigerant 30 and controlled at -15 °C. 6. Reaction process: Under the above conditions, the residence time of the reactants in the flow-type fine reaction flow channel 32 was about 14 seconds. 7. Product treatment: The liquid from the reaction was collected and the reaction was quenched with dilute hydrochloric acid to give the target product ethyl-7-chloro-2-pentyl oxalate in 90% yield.