Water → 6-(2-Naphthalenylsulfonyl)-2,4-quinazolinediamine

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Reaction Steps

A solution of 2.0 grams (0.006 mole) of 2,4-diamino-6-(naphth-2-ylthio)quinazoline (prepared in Example 7) in 80 mL of acetic acid was stirred, and a solution of 2.0 grams (0.013 mole) of potassium permanganate in 75 mL of water was added dropwise during a 1 hour period. Upon completion of addition, the reaction mixture was stirred at ambient temperature for about 18 hours. After this time, the reaction mixture was filtered through diatomaceous earth. The filtrate was made basic by adding an excess amount of concentrated ammonium hydroxide. The resultant precipitate was collected by filtration and was washed in turn with water, methanol, and acetone. The precipitate was stirred in hot N,N-dimethylformamide and treated with decolorizing carbon. The mixture was filtered hot, and the filtrate was set aside. The residue collected by the filtration was again stirred with hot N,N-dimethylformamide and filtered. The two filtrates were combined and poured into 500 grams of ice. The resultant solid was collected by filtration, yielding 0.9 gram of 2,4-diamino-6-(naphth-2-ylsulfonyl)quinazoline, mp 300°-302° C. The NMR spectrum was consistent with the proposed structure.

Provenance & Evidence