2-Mercapto-isonicotinic acid Methyl ester synthesis

Yield:74470-33-0 227 mg

Reaction Conditions:

with Lawessons reagent in toluene; for 0.666667 h;Reflux;

Steps:

33-1.1 [2-(Ethanesulfonyl)pyridin-4-yl]methanol

(1)
Lawesson's reagent (6.34 g) was added to a solution of commercially available methyl 2-oxo-1,2-dihydropyridine-4-carboxylate (2.00 g) in toluene (26.1 mL), and the mixture was stirred under heated reflux for 40 minutes.
The mixture was cooled to room temperature, then the precipitate was collected by filtration, and the solid was roughly purified by silica gel column chromatography (chloroform only, to chloroform/methanol = 19:1).
The obtained roughly purified substance was suspended in ethyl acetate (1 mL), and the suspension was stirred under heated reflux for 30 minutes.
The suspension was cooled to room temperature, and then the precipitate was collected by filtration to give methyl 2-sulfanylidene-1,2-dihydropyridine-4-carboxylate (227 mg) as an orange solid.

References:

EP3418276,2018,A1 Location in patent:Paragraph 0668; 0669