Benzoyl chloride → pyridinium 3-hydroxy-4-(N-benzoylamino)-1-naphthalenesulfonate

Beteiligte Stoffe

Reaktionsschritte

Benzoyl chloride (1.8 ml) was added portionwise to a vigorously stirred suspension of 2.39 g 4-amino-3-hydroxy-1-napthalenesulfonic acid in a mixture of 50 ml pyridine and 20 ml water with cooling in an ice bath. The mixture was stirred for 2 hours at room temperature. The solid product was collected and washed with 10 ml of ice-cold water. Drying in a vacuum oven gave crude pyridinium 3-hydroxy-4-(N-benzoylamino)-1-naphthalenesulfonate (2.55 g, 60%); an analytical sample was prepared by recrystallization from a mixture of tetrahydrofuran and water (9:1), m.p. 225° C.

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