Hydrochloric Acid → 1H-Pyrrole-2-acetonitrile, 1-methyl-

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Reaction Steps

N-methylpyrrole (4 g, 0.049 mole) is dissolved in 40 ml of dry (ethanol-free) chloroform in a dry, 200 ml, 3-necked round-bottomed flask and flushed with a stream of dry nitrogen. The temperature of the solution is lowered to 0° C and cyanogen (3.25 g, 0.063 mole) is added. Hydrogen chloride (dried through sulfuric acid) is introduced in a slow steady stream with mechanical stirring at 0° C for 4 hrs at which time all the N-methylpyrrole has been consumed. The hydrogen chloride flow is stopped; the chloroform is evaporated to 1/2 its volume at reduced pressure and room temperature; and the temperature is then lowered to -40° C. Dry pyridine (25 ml) is added dropwise with rapid stirring. The rest of the chloroform is evaporated at reduced pressure and then 25 mls of additional pyridine is added. The reaction mixture is allowed to warm to room temperature and hydrogen sulfide is introduced in a slow stream for 20 minutes. Chloroform (200 ml) is added and the reaction solution is washed with 35% aqueous potassium carbonate solution, followed by a 3N hydrochloric acid wash which is backwashed with chloroform. The combined chloroform extracts are washed with 5% aqueous sodium bicarbonate solution and dried over anhydrous MgSO4 powder. The mixture is filtered and the filtrate evaporated in vacuo to a brown oil. The oil is distilled under high vacuum to give 840 mg of N-methylpyrrole-2-acetonitrile, bp 61°-65° C at 0.04 Torr.

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