Nakagome, Takenari published the artcile< Syntheses of pyridazine derivatives. II. 3-Methoxy-6-pyridazinol 1-oxide>, Recommanded Product: Pyridazin-4-amine, the main research area is HETEROCYCLIC COMPOUNDS/chemistry.
3-Chloro-6-methoxypyridazine (I) (7.3 g.) in 50 mL. AcOH treated with 24 mL. 30% H2O2, kept 5 h. at 70°, the solution concentrated in vacuo, the residue made alk. with Na2CO3 and the product extracted with CHCl3 gave 1.4 g. 3-methoxy-6-chloropyridazine 1-oxide (II), m. 157-8° (C6H6). The mother liquor from washing II with 2N NaOH gave 0.4 g. 3-methoxy-6(1H)-pyridazinone (III), plates, m. 162-3° (AcOEt). A solution of 18 g. BzO2H in 337 mL. CHCI3 treated with 14.5 g. I, kept 3 days at room temperature and the product treated as above gave 14.3 g. II, m. 157-8°. I (3 g.), 20 mL. AcOH, and 3.4 g. AcOK in a sealed tube heated 1.5 h. at 140-50° and the AcOH removed gave 3.6 g. III, m. 162-3°. III (4 g.) and 30 mL. POCl3 heated 30 min. at 100° the product poured into ice-H2O and extracted with Et2O gave 1.5 g. 3,6-dichloropyridazine (IV), m. 68-9°. Catalytic reduction of 0.5 g. II in 3 mL. 28% NH4OH and 30 mL. MeOH with 0.05 g. 10% Pd-C absorbed 77 mL. H and gave 0.35 g. 3-methoxypyridazine 1-oxide (V), m. 79-80°. Catalytic reduction of 0.5 g. II in 3 mL. 28% NH4OH and 30 mL. MeOH with Pd-C (from 10 mL. 1% PdCl2 and 0.5 g. C) absorbed 160 mL. H in 15 min. and gave 0.5 g. 3-methoxypyridazine; picrate m. 111°. II (3.2 g.), 12 mL. AcOH, and 1.64 g. AcONa in a sealed tube heated 1 h. at 150-60° and the product concentrated gave 1.64 g. 1-hydroxy-3-methoxy-5(1H)-pyridazinone (VI), m. 178-9°. A solution of 29.5 g. 3,6-dimethoxypyridazine I-oxide in 400 mL. 2N HCl heated 20 min. at 80-90° and the solution concentrated gave 25.3 g. VI, m. 178-9°. VI (2.8 g.), 2.54 g. BzCl, 0.46 g. Na and 30 mL. MeOH in a sealed tube heated 2 h. at 100° the solution concentrated and the residue extracted with CHCl3 gave 3.1 g. 1-benzoyloxy-3-methoxy-6(1H)pyridazinone (VII), m. 86.5-87°. VI (2 g.), 2.5 g. MeI, Ag2O (from 3 g. AgNO3), and 20 mL. MeOH in a sealed tube heated 2 h. at 100° and the solution concentrated gave 100% 1,3-dimethoxy-6(1H)-pyridazinone, m. 66-7°. A solution of 250 mL. dry C6H6, 20.6 g. PhCH2OH, and 4.4 g. Na, refluxed 1 h., after disappearance of Na, with 20 g. 3-chloropyridazine, and the product distilled gave 18 g. 3-benzyloxypyridazine (VIII), b0.15 120-5°, m. 49-50°. VIII (6 g) and 84.5 mL. CHCl3 containing 4.46 g. BzO2H kept 2 days at room temperature gave 100% VIII I-oxide (VIIIa), m. 118-18.5°. Catalytic reduction of 0.5 g. VIIIa in 30 mL. MeOH with 0.05 g. 10% Pd-C absorbed 64 mL. H in 5 min.and gave 3-pyridazinol 1-oxide, m. 201-2° (decomposition). Catalytic reduction of 0.5 g. VIIIa in 30 mL. MeOH with 0.2 g. 10% Pd-C absorbed 128 mL. H in 15 min. and gave 0.25 g. 3(2H)-pyridazinone-H2O, m. 74°. IV (21 g.) and 240 mL. CHCl3 containing 18.7 g. BzO2H kept 2 days at room temperature and the product concentrated gave 10.4 g. IV 1-oxide, m. 110-12°. IV 1-oxide (1 g.) and 0.33 g. 22.6% MeONa-MeOH heated several min. on a water bath, the solution acidified with AcOH and the product extracted with CHCl3 gave 0.6 g. II, m. 155-7°.
Yakugaku Zasshi published new progress about 20744-39-2. 20744-39-2 belongs to class pyridazine, and the molecular formula is C4H5N3, Recommanded Product: Pyridazin-4-amine.
Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem