Ammonia → 2-Amino-7-nitroacridin-9(10H)-one

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Reaction Steps

See Korolev et al., 1976. Polyphosphoric acid was freshly prepared by slowly adding, with stirring, 85% orthophosphoric acid (360 mL) to phosphorus pentoxide (600 g). The mixture was then heated on a steam bath with stirring until a clear viscous liquid was obtained. 2-(-4-amino-phenylamino)-5-nitrobenzoic acid 10 (107.76 g, 0.394 mol) was added with stirring over the course of 5 min. Heating on the steam bath was continued for 6 hr, the mixture being stirred occasionally. Whilst still hot, the mixture was poured into 4 L of ice-water, stirred for 30 min, and allowed to stand overnight. The mixture was adjusted to pH 8.0 by the addition of 0.88 s.g. aqueous ammonia, chilled for 2 hr, and the crude product collected on a glass sinter. It was washed with dilute ammonia (1% 0.88 s.g. aqueous ammonia in water, 250 mL) followed by water (3×250 mL), ice-cold ethanol (2×250 mL), dry ether (2×250 mL) and finally hexane (250 mL). The product, 11, was dried over P2O5 under vacuum to yield a red-brown solid (97.04 g, 96%).

Provenance & Evidence