5-chloro-6-[4-(ethoxycarbonyl)piperidino]nicotinic acid synthesis

Yield:931395-73-2 88%

Reaction Conditions:

in tetrahydrofuran; for 3 h;Reflux;Solvent;

Steps:

1.2 Preparation of intermediate 2

Dichloronicotinic acid (250 g) and ethyl 4-piperidinecarboxylate (210 g) were dissolved in THF (1.25 L) and refluxed. The mixture was stirred for 3 h and the reaction was complete by HPLC followed by addition of sodium bicarbonate and stirring at room temperature 0.5 hours. Further, a maleic acid aqueous solution was added dropwise to the reaction mixture to adjust ph to 1, and the mixture was extracted with methylene chloride (1 L × 2) and washed with water. Concentrate and add n-hexane 2L to precipitate a solid. Intermediate 2 was obtained as a white solid in 88% yield. HPLC purity 99.89%.

References:

CN107383000,2017,A Location in patent:Paragraph 0037; 0038; 0050; 0062