2-Butenoic acid, 3-amino-, ethyl ester, (2Z)- → ethyl 6-hydroxy-2-methyl-4-oxo-1H-pyridine-3-carboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of malonic acid (20 g, 192 mmol), 2,4,6-trichlorophenol (72 g, 365 mmol), and phosphorus oxychloride (38 mL, 403.2 mmol) was stirred at reflux for 12 h. The reaction mixture was cooled to 70° C. and poured into ice water. The solid was collected by filtration, washed with water, and air-dried to give malonic acid bis-(2,4,6-trichloro-phenyl)ester (85 g, 95%). A solution of malonic acid bis-(2,4,6-trichloro-phenyl)ester (85 g, 183.6 mmol) and ethyl 3-aminocrotonate (26.1 g, 202 mmol) in bromobenzene (100 mL) was stirred at reflux for 50 min. The reaction mixture was cooled to 50° C. and diluted with EtOAc (260 mL). The solid was collected by filtration, washed with water, and air-dried, to give 4,6-dihydroxy-2-methyl nicotinic acid ethyl ester (31 g, 86%).

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