N-Hydroxyisonicotinamidine

White to off-white solid or powder

3.4 g (0.024 mol) of pydridine-4-amidoxime in 100 ml of dimethyl formamide are introduced into the reactor, and 7.2 g (0.02 mol) of 4'-benzoxazolyl-2-stilbene-4-carboxylic acid chloride are added. Subsequently, the mixture is stirred for 1 hour at room temperature, and then refluxed for 2 hours. Suction-filtration is carried out at room temperature, and the filter residue is washed with dimethyl formamide and methanol. After drying, 7.8 g (87.6% of the theory) of the compound having the formula STR10 are obtained in the form of a light yellow powder, which, after recrystallization from N-methylpyrrolidone and clarification with animal charcoal has a liquid/crystalline transition temperature of 274-275 C. and a melting point of 281 C. Analysis: Calc.: C, 76.0%, H, 4.1%, N, 12.7%; Found: C, 75.8%, H, 4.2%, N, 12.8%. Absorption (in DMF): max=367 nm=74500. Fluorescence (in DMF): max=432 nm. The pyridine-4-amidoxime used is obtained in the following manner:General procedure: An amidoxime (30 mmol) and ester (36 mmol) was added to a suspension of powdered NaOH (36 mmol) in DMSO (10 mL). The reaction mixture was stirred at room temperature for 4 h. The reaction mixture was diluted with cold water (100 mL), and resulted precipitate was filtered off, washed with cold water (50 mL) and dried in air at room temperature. 5-Phenyl-3-(pyridin-4-yl)-1, 2, 4-oxadiazole (ODA-2, according to GP2): white solid; 4.42 g (66%) yieldGeneral procedure: An amidoxime (30 mmol) and ester (36 mmol) was added to a suspension of powdered NaOH (36 mmol) in DMSO (10 mL). The reaction mixture was stirred at room temperature for 4 h. The reaction mixture was diluted with cold water (100 mL), and resulted precipitate was filtered off, washed with cold water (50 mL) and dried in air at room temperature. 5-Methyl-3-(pyridin-4-yl)-1, 2, 4-oxadiazole (ODA-1, according to GP2): white solid; 3.77 g (78%) yield