4-CHLORO-7-SULFOBENZOFURAZAN AMMONIUM SALT synthesis

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Steps:

III 7-CHLORO-4-SULPHOBENZOFURAZAN (AMMONIUM SALT)

III 7-CHLORO-4-SULPHOBENZOFURAZAN (AMMONIUM SALT) 4-Chlorobenzofurazan (2.4 g, 16 mmole) was dissolved in oleum (7 ml) and the solution was heated at 150°-160° C. for 4 hours while protected from atmospheric moisture by a calcium chloride drying tube. The solution was then cooled and slowly poured onto ice (100 g.). The solution was then neutralized carefully with ammonium hydroxide until precipitation of the ammonium salt occurred. The precipitated salt was collected on a sintered glass funnel and recrystallized from water acetone (9:1). The product decomposes, without melting, above 330° C. Elemental analysis: calculated for C₆ H₆ N₃ O₄ SCl: C, 28.63; H, 2.41; N, 16.70; S, 25.43: Cl, 14.09%. Found: C, 28.40; H, 2.45; N, 16.37; S, 26.50; Cl, 13.90%.

References:

US4358595,1982,A