277. Synthesis of diaminoxanthones

Canscora decussata (Gentianaceae) Xanthones III: Pharmacological Studies

“…Synthetic xanthones carrying basic substituents are known t o possess oral schistosomicidal activity in experimental animals (1)(2)(3)(4)(5). Several investigations have also shown: (a) an analeptic effect in the treatment of respiratory depression, (b) a CNS stimulant effect (4), and (c) a tuberculostatic effect with synthetic xanthones ( 3 , 4, 6).…”

Photophysics of Aminoxanthone Derivatives and Their Application as Binding Probes for DNA†

“…The synthesis of MAX and DAX was achieved by standard nitration of xanthone (38, 39), followed by reduction of the nitro groups to amino moieties (39, 40) (Scheme 1). The degree of nitration was controlled by optimizing the KNO 3 /xanthone concentration ratio.…”

“…2,7‐Dinitroxanthone . Nitration was carried out following standard aromatic nitration procedures (38, 39). A solution of KNO 3 (2.34 g, 23.2 mmol) in concentrated sulfuric acid (100 mL) was added slowly to a solution of xanthone (1.52 g, 7.77 mmol) in concentrated sulfuric acid (20 mL).…”

“…DAX . Reduction of nitro to amino groups was carried out following known procedures (39, 40). A solution of stannous chloride (9.60 g, 50.6 mmol) in concentrated HCl (100 mL) was added dropwise to a solution of 2,7‐dinitroxanthone (1.29 g, 4.50 mmol) in concentrated HCl (100 mL).…”

“…The reaction mixture was allowed to stir at 20°C for 2 h and then the mixture was placed in an ice bath and slowly diluted with water (T 5 50°C). The pale yellow solid was isolated via vacuum filtration and recrystallized from cold acetone and water, yielding 1.47 g (66%) of product, mp 261-263°C (literature values: 264°C [32], 262-265°C [39]). 'H NMR (300 MHz) 7.72 (d, J = 9.6 Hz; 2H).…”