Carbon Dioxide → 2-Methyl-5-nitroquinoline

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Reaction Steps

2-Methylquinoline (108.3 ml, 0.80 mol) is added in drops to 65% nitric acid (61 ml, 0.88 mol) at an internal temperature of 0-10° C. (dry ice cooling) within 45 minutes. After 1 hour, the precipitated nitrate is suctioned off and introduced in portions at an internal temperature of 0-6° C. in concentrated sulfuric acid (240 ml). After 30 minutes, potassium nitrate (6 g, 60 mmol) is added thereto, and it is stirred for 16 hours at room temperature. The batch is slowly poured onto ice/water, and a pH of 1.5 is set with 40% NaOH (˜500 ml). The precipitate is suctioned off, the filtrate is made alkaline with 25% ammonia water (pH 10) and filtered. The filter residue is dissolved in hot methanol (500 ml). During cooling, the 8-nitro-isomer crystallizes out. The mother liquor is concentrated by evaporation and purified by column chromatography on silica gel with hexane-ethyl acetate, whereby 53 g of the 2-methyl-5-nitroquinoline accumulates.

Provenance & Evidence