Ethyl orthoformate → Ethyl 2-(2,6-dichloropyridine-3-carbonyl)-3-ethoxyprop-2-enoate

Ethyl 2-(2,6-dichloronicotinoyl)acetate (7.03 g, 26.8 mmol) was dissolved in acetic anhydride (30 ml), and after adding triethyl orthoformate (60 ml) thereto, it was stirred in an oil bath of 140° C. for 2 hours. After letting the reaction solution cool, it was concentrated under a reduced pressure, and after adding toluene (50 ml) to the residue obtained, a concentration operation under a reduced pressure was performed. This operation was repeated 3 times, and the residue obtained was dried under a reduced pressure. 8.42 g of ethyl 2-(2,6-dichloronicotinoyl)-3-ethoxyacrylate was thereby obtained in the form of a yellow oily substance.