Butanedione → 1H-Imidazole-4-methanol, 5-methyl-2-phenyl-

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Reaction Steps

Benzamidine hydrochloride (100 g) is dissolved in a minimum of water (350 ml) at room temperature. Freshly distilled 2,3-butanedione (67 g) is added giving a yellow solution. Adjusting the pH to 6-7 with 2N sodium hydroxide gives a solid which is allowed to stand at 0° C for 2 hours, collected, pressed dry and then washed with acetone (100 ml). This material is heated with stirring on a steam bath with concentrated hydrochloric acid (855 ml) and water (2437 ml) for 4 hours giving a solution. Cooling to room temperature overnight and then to 0° C produces a solid which is collected and air dried. This solid is dissolved in ethanol (350 ml), filtered and cooled producing a gel, which is taken up in 250 ml of 50°-60° C water, adjusted to pH 5.5 with concentrated sodium hydroxide and then to pH 7-8 with solid potassium bicarbonate. The mixture is cooled to 0° C and the product is collected, washed with water, and air dried. This product is recrystallized from methanol (1000 ml) giving the title product, m.p. 197°-199° C.

Provenance & Evidence