2-Amino-6-methylpyridine → 2-Amino-6-methylpyridine

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Reaction Steps

The intermediate 2-amino-6-methylpyridine is prepared as follows: To a solution of 68 g. (0.63 mole) of 2-amino-6-methylpyridine in about 500 ml. of glacial acetic acid, cooled to 10°-15° C., is added a mixture of 170.2 g. (2.1 moles) of sodium thiocyanate suspended in about 570 ml. of glacial acetic acid. A solution containing 30.5 ml. of bromine in about 60 ml. of glacial acetic acid is then added, and the mixture is stirred at 10°-15° C. for 1 hour and then at 75°-80° C. for 1/2 hour. The solution is filtered, and the solvent is removed from the filtrate under reduced pressure. The residue is recrystallized from isopropyl alcohol containing activated charcoal. The 2-amino-5-methylthiazolo[4,5-b]pyridine thus obtained melts at 150°-160° C. The product is hydrolyzed by refluxing 8 g. of the material in 120 ml. of 20 percent aqueous sodium hydroxide solution for 6 hours. The resulting cloudy solution is filtered, and the filtrate is acidified and reduced to dryness. The residue is extracted with hot ligroin to yield 2-amino-6-methyl-3-pyridinethiol, melting at 133°-138° C.

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