Hydrochloric Acid → 2,4-Diamino-6-methyl-5-(m-chlorophenylazo) pyrimidine

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Reaction Conditions

Reaction Steps

A solution of 2,4-diamino-6-methyl pyrimidine (1.0 gm) in water (60 ml) was cooled to 0° C in ice-salt bath and stirred mechanically. m-Chloro aniline (1.02 gm) was dissolved in ethanol (10 ml). To this solution 3 N HCl (30 ml) was added and the solution was cooled to -5° C. A solution of sodium nitrite (0.552 gm) in water (5 ml) was also cooled to 0° C. The cold sodium nitrite solution was then added to the cold m-chloro aniline solution. After shaking thoroughly, excess sodium nitrite was decomposed with a trace of urea. The diazotized m-chloro aniline solution was then added to the pyrimidine solution. After stirring for 10 minutes, the pH of the combined solution was adjusted to 7.0 with 30 percent sodium hydroxide solution. A precipitate appeared. After stirring for two hours more, the product was separated by filtration, washed well with water, dried in a vacuum desiccator, and crystallized from ethanol. M.P. 249° C. Yield: 1.65 grams (85 percent).

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