Sulfapyridine → Homosulphasalazine

Participants

Reaction Steps

12 g sulfapyridine was dissolved with cooling to 0° C. in 40 ml water and 12 ml conc. hydrochloric acid. 3.5 g sodium nitrite in 20 ml water was added to the sulfapyridine solution during about 15 minutes with stirring and cooling. The diazonium salt solution was added to 7.6 g 2-hydroxy-benzeneacetic acid and 7 g sodium hydroxide in 50 ml water at 0°-10° C. After stirring for 1.5 h the solution was acidified by hydrochloric acid. The precipitating product was filtered off and washed with water. Yield 18.1 g. The product was dissolved in acetic acid and treated with 5 g decolourizing coal. The solution was filtered and evaporated in vacuum. This was repeated once, a pure product being obtained, which during partial melting at about 135° C. was converted into another crystal modification of melting point 185°-187° C. with decomposition.

Provenance & Evidence