Sodium methanethiolate → 3-Pyridinecarboxamide, 5-mercapto-N,N-dimethyl-

Sodium thiomethoxide (3 g) was added to a stirred solution of 5-bromo-N,N-dimethyl-3-pyridinecarboxamide (2.5g, WO2000055168) in N,N-dimethylformamide (40 ml) and the suspension stirred at 100° C. for 4 h. The solvent was concentrated in vacuo, the residue dissolved in 2M sodium hydroxide (35 ml) and water (50 ml), and the solution washed with chloroform (4×75 ml). The aqueous layer was acidified with 2M hydrochloric acid to pH 4 and extracted with chloroform (5×80 ml), and the combined organic layers were washed with brine (20 ml), dried over magnesium sulphate and concentrated in vacuo to give the title compound as an orange oil (1.8 g).