Calcium Carbonate → 4-Amino-2,6-dimethyl-3-iodopyridine

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Reaction Steps

Benzyltrimethylammonium dichloroiodate (6 g) was added to 4-amino-2,6-dimethylpyridine (2.1 g) and calcium carbonate (2.25 g) in dichloromethane/methanol (55 ml) (8:3 v/v) and the mixture was stirred for 16 hours. Solvent was removed by evaporation and the residue partitioned between 5% sodium metabisulphite solution and dichloromethane. The aqueous phase was separated and washed with dichloromethane. The aqueous phase was then basified with sodium carbonate and extracted with dichloromethane. The organic phase was washed with water, saturated sodium chloride solution and dried (MgSO4). Solvent was removed by evaporation and the residue purified by flash chromatography eluting with dichloromethane/methanol (9:1 v/v) to give 4-amino-2,6-dimethyl-3-iodopyridine (B) (1.7 g) as a light yellow solid, m.p. 103°-110° C.; NMR (CDCl3): 2.3(s,3H), 2.7(s,3H), 4.6(br s,2H), 6.3(s,1H); mass spectrum (chemical ionisation): 249 (M+H)+.

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