Sulfamic Acid → 2-[5-(2,4Dioxopent-3-ylazo)-2-propoxyphenyl]-8-azapurin-6-one

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Reaction Conditions

Reaction Steps

2-(5-Amino-2-propoxyphenyl)-8-azapurin-6-one (1.5 g) was dissolved in a hot mixture of concentrated hydrochloric acid (4 ml) and water (20 ml). The solution was then cooled to 0° C. to give a suspension of 2-(5-amino-2-propoxyphenyl)-8-azapurin-6-one hydrochloride. The stirred suspension was treated with a solution of sodium nitrite (0.5 g) in water (2 ml) during 10 minutes. After stirring for one hour at 0° C., a sufficient quantity of sulphamic acid was added to decompose the excess of nitrous acid. The resulting ice-cold solution was then added, dropwise, to a stirred mixture of acetylacetone (2 ml), ethanol (20 ml), water (10 ml) and sodium acetate (5 g) at 0° C. during 30 minutes. After a further 30 minutes, the thick yellow mixture was filtered, and the precipitate was washed with water and sucked dry. Recrystallisation from a mixture of dimethylformamide and methanol gave 2-[5-(2,4dioxopent-3-ylazo)-2-propoxyphenyl]-8-azapurin-6-one (1.4 g), m.p. 288°-290° C. (with decomposition).

Provenance & Evidence