Category: pyridazine

Nakagome, Takenari published the artcile< Syntheses of pyridazine derivatives. IV. Synthesis of 4-aminopyridazines.>, Reference of 20744-39-2, the main research area is AMINES/chemistry; HEXAMETHONIUM COMPOUNDS/chemistry.

Pyridazine 1-oxide (5.1 g.) in 10 ml. concentrated H2SO4, 12 ml. 12% fuming H2SO4, and 7.5 ml. fuming HNO3 heated 5 hrs. at 105-10°, the product poured into ice-H2O, taken up in CHCl3 and washed with NaHCO3 and concentrated gave 8% 4-nitropyridazine I-oxide; picrate m. 81-2°. Similarly were prepared the following nitro compounds (compound, % yield and m.p. given): 4-nitro-6-methylpyridazine 1-oxide, 56, 120-1°; 3,6-dimethyl-4-nitropyridazine 1-oxide, 83, 117-18°; 3-methoxy-4-nitro-6-methylpyridazine 1-oxide, 81, 114-15°; 3-chloro-4-nitro-6-methylpyridazine 1-oxide (I), 46, 103°. The above 4-NO2 compounds (0.04) mole in 30 ml. MeOH and 1 ml. 4N NaOMe refluxed 1 hr., the MeOH removed, the residue extracted with CHCl3 and chromatographed on Al2O3 gave the following 4-MeO compounds (product, % yield and m.p. given): 4-methoxypyridazine 1-oxide, 30, 123-4°; 4-methoxy-3-methylpyridazine 1-oxide, 0.4, 105-6°; 3-methyl-4,6-dimethoxypyridazine 1 oxide, 40, 148-9°. Catalytic reduction of 4-nitro compds, in MeOH with Raney Ni gave the following amino compounds (product, % yield and m.p. given): 4-aminopyridazine, 75, 131-2°; 3-methyl-4-aminopyridazine, 70, 162-3°; 3,6-dimethyl-4-aminopyridazine, 91, 162-3°; 3-methyl-4-amino-6-chloropyridazine, 70, 158-9°.

Yakugaku Zasshi published new progress about 20744-39-2. 20744-39-2 belongs to class pyridazine, and the molecular formula is C4H5N3, Reference of 20744-39-2.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Ueda, Shigeyuki; Amano, Takahumi published the artcile< The pKa calculations of N-heteroaromatic compounds by Hueckel MO method>, Formula: C4H5N3, the main research area is heteroaromatic compound pK HMO; nitrogen heterocycle pK MO; pyridine amino hydroxy MO; pyridazine amino hydroxy MO; pyrimidine amino hydroxy MO; pyrazine amino hydroxy MO; LFER pK nitrogen heteroaromatic.

The HMO energies of pyridine, pyridazine, pyrimidine, pyrazine, and their monamino and monohydroxy derivatives were calculated taking account of σ-polarity. The protonation energies of the ring nitrogens and the dissociation energies of the OH group were evaluated and showed a linear relationship with their pKa values except for compounds showing ortho effects.

Kyushu Sangyo Daigaku Kogakubu Kenkyu Hokoku published new progress about Acidity. 20744-39-2 belongs to class pyridazine, and the molecular formula is C4H5N3, Formula: C4H5N3.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

El Akkaoui, Ahmed; Berteina-Raboin, Sabine; Mouaddib, Abderrahim; Guillaumet, Gerald published the artcile< Direct Arylation of Imidazo[1,2-b]pyridazines: Microwave-Assisted One-Pot Suzuki Coupling/Pd-Catalyzed Arylation>, Related Products of 64067-99-8, the main research area is imidazo pyridazine microwave preparation; microwave Suzuki coupling aryl heterocyclic halide arylboronic acid.

Direct intermol. C-H arylation of 6-chloroimidazo[1,2-b]pyridazine in its 3-position was achieved, and the tolerance to reaction conditions in the presence of chloro groups was investigated. Various 3-(hetero)arylimidazo[1,2-b]pyridazines were synthesized in good to excellent yields. This methodol. was successfully applied to the synthesis of 3,6-di- and 2,3,6-trisubstituted imidazo[1,2-b]pyridazines by a microwave-assisted, one-pot, two-step Suzuki cross-coupling/palladium-catalyzed arylation process.

European Journal of Organic Chemistry published new progress about Arylation. 64067-99-8 belongs to class pyridazine, and the molecular formula is C9H8ClN3O2, Related Products of 64067-99-8.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Joshi-Pangu, Amruta; Cohen, Ryan D.; Tudge, Matthew T.; Chen, Yonggang published the artcile< Dearomatization of Electron-Deficient Nitrogen Heterocycles via Cobalt-Catalyzed Asymmetric Cyclopropanation>, Recommanded Product: Ethyl 6-chloroimidazo[1,2-b]pyridazine-2-carboxylate, the main research area is dearomatization electron deficient nitrogen heterocycle cobalt catalyst stereoselective cyclopropanation.

The dearomatization of a series of electron-deficient nitrogen heterocycles has been achieved through a cobalt-catalyzed asym. cyclopropanation reaction. This reaction proceeds with high levels of enantio- and diastereoselectivity to afford unique cyclopropanes that can be further functionalized to provide complex heterocyclic building blocks.

Journal of Organic Chemistry published new progress about Cyclopropanation catalysts, stereoselective. 64067-99-8 belongs to class pyridazine, and the molecular formula is C9H8ClN3O2, Recommanded Product: Ethyl 6-chloroimidazo[1,2-b]pyridazine-2-carboxylate.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Wetzel, B.; Woitun, E.; Reuter, W.; Maier, R.; Lechner, U.; Goeth, H.; Werner, R. published the artcile< Pyrimidinylureidopenicillins. Synthesis and structure-activity relationships>, Safety of Pyridazin-4-amine, the main research area is pyrimidylureidopenicillin preparation bactericide activity; condensation amoxicillin aminopyrimidine; penicillin pyrimidylureido.

The ureidopenicillin VX-VC 43 (I), prepared from the aminopyrimidine II by cyclization and condensation with amoxicillin and Et3N, showed outstanding in vitro and potent in vivo activity in mice. The mean minimal inhibitory concentrations of I against 59 strains of Pseudomonas aeruginosa, 50 strains of Escherichia coli, Klebsiella, and Enterobacter cloacae were 0.62, 0.16, 3.28, and 0.92 μg/mL, resp. The antimicrobial activity of 18 other heterocyclic substituted ureidopenicillins is also reported.

Special Publication – Royal Society of Chemistry published new progress about Condensation reaction. 20744-39-2 belongs to class pyridazine, and the molecular formula is C4H5N3, Safety of Pyridazin-4-amine.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Liu, Yu-Xiu; Wei, Deng-Guo; Zhu, Ye-Rong; Liu, Shao-Hua; Zhang, Yong-Lin; Zhao, Qi-Qi; Cai, Bao-Li; Li, Yong-Hong; Song, Hai-Bin; Liu, Ying; Wang, Yong; Huang, Run-Qiu; Wang, Qing-Min published the artcile< Synthesis, Herbicidal Activities, and 3D-QSAR of 2-Cyanoacrylates Containing Aromatic Methylamine Moieties>, Electric Literature of 120276-59-7, the main research area is hetarylmethylaminoacrylate cyano preparation herbicidal; aminoacrylate cyano preparation herbicidal; arylmethylaminoacrylate cyano preparation herbicidal; cyanoacrylate aromatic methylamine preparation herbicidal.

A series of novel 2-cyanoacrylates containing different aromatic rings, e.g. I (R = MeS, Et, Me2CH; R1 = 4-ClC6H4, 6-bromo-3-pyridinyl, 2-ethoxy-5-thiazolyl, etc) were prepared, and their structures were characterized by 1H NMR, elemental anal., and single-crystal X-ray diffraction anal. Their herbicidal activities against four weeds and inhibition of photosynthetic electron transport against isolated chloroplasts (the Hill reaction) were evaluated. Both in vivo and in vitro data showed that the compounds containing benzene, pyridine, and thiazole moieties gave higher activities than those containing pyrimidine, pyridazine, furan, and THF moieties. To further explore the comprehensive structure-activity relationship on the basis of in vitro data, comparative mol. field anal. (CoMFA) was performed, and the results showed that a bulky and electroneg. group around the para-position of the aromatic rings would have the potential for higher activity, which offered important structural insights into designing highly active compounds prior to the next synthesis.

Journal of Agricultural and Food Chemistry published new progress about Herbicides. 120276-59-7 belongs to class pyridazine, and the molecular formula is C5H4Cl2N2, Electric Literature of 120276-59-7.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

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

Itai, Takanobu; Natsume, Sachiko published the artcile< Potential anticancer agents. IX. Nitration of pyridazine 1-oxide>, Related Products of 20744-39-2, the main research area is .

Preceding abstract To 5 g. pyridazine 1-oxide (I) in 40 cc. cold CHCl3 was added 6 cc. BzCl, followed portionwise by 9.7 g. finely powd. AgNO3 at below – 10° with stirring, the mixture stirred 4 hrs. at below – 10°, kept 4 days at room temperature, the precipitate (II) (mixture of AgCl and a yellow solid) filtered off, washed twice with cold CHCl3 [the combined filtrate and washings (III) were kept], extracted with hot CHCl3, and the extract concentrated to dryness to give 2.15 g. 3-NO2 derivative (IV) of I, m. 166° (MeOH), ν (KBr) 1543, 1523, 1337, 1324 cm.-1, (95% EtOH) 232, 281, and 350 mμ (log ε 4.02, 3.99, and 3.73); the MeOH mother liquor evaporated, the residue chromatographed on SiO2, and the column eluted gave the following fractions: (1) with 9:1 C6H6CHCl3, 50 mg. BzOH; (2) with same solvent mixture, 22 mg. 5-NO2 derivative (V) of I, m. 142-3° (MeOH); (3) with same solvent mixture, 45 mg. IV, m. 167-9° (MeOH); (4) with CHCl3, 100 mg. sirupy mixture; and (5) with CHCl3, 270 mg. unchanged I (perchlorate m. 184°). The residue remaining after extracting II with hot CHCl3 extracted with hot MeOH gave 0.06 g. IV; III evaporated, the residue treated with 30 cc. H2O and 60 cc. Et2O, and the precipitate filtered off [the filtrate (VI) was kept] gave 0.12 g. IV, m. 169° (MeOH); VI extracted with Et2O and the extract dried and evaporated gave 5.9 g. BzOH; the remaining aqueous layer evaporated in vacuo, the residue extracted repeatedly with CHCl3, the combined extracts dried, evaporated, and the residue chromatographed on SiO2 as above gave 40 mg. V, m. 142-3°, 45 mg. IV, m. 169°, and 1.12 g. unchanged I. I (5 g.) in 50 cc. cold CHCl3 treated with 4.1 cc. AcCl followed portionwise by 9.7 g. finely powd. AgNO3 at below -10° with stirring, the mixture stirred 1.5 hrs. at below – 10°, kept 3 days at room temperature, and worked up as above gave 1.26 g. IV, 57 mg. V, and 1.72 g. unchanged I. V (0.042 g.) in 15 cc. 50% MeOH containing 1 cc. concentrated HCl hydrogenated over 20% Pd-C, when 4 equivalents H were absorbed the solution filtered, the filtrate evaporated, the residue dissolved in a little MeOH, and the solution treated with MeOH-Na picrate (VIa) gave 4-aminopyridazine (VII) picrate, m. 226-8° (decomposition) (MeOH), converted by passage in MeOH through Amberlite IRA-410 (OH form) into VII, m. 127-9°. IV (145 mg.) suspended in 30 cc. MeOH and 30 cc. 4% aqueous HCl hydrogenated over 20% Pd-C (prepared from 4.2 cc. 1% aqueous PdCl2 and 0.1 g. C) (the reduction was interrupted after rapid absorption of 4 equivalents H), the product (100 mg.) isolated as usual, and treated with 1 equivalent VIa gave 100 mg. 3-aminopyridazine (VIII) picrate (IX), m. 248-9° (EtOH), converted as above into VIII, m. 170°. IV (1.08 g.) and 20% Pd-C (prepared from 0.2 g. C and 8.4 cc. 1% aqueous PdCl2) in 100 cc. MeOH shaken in a stream of H until 2 equivalents H were absorbed (H was absorbed rapidly), the mixture warmed, the catalyst filtered off hot, washed with hot MeOH, and the combined filtrate and washings evaporated gave 0.74 g. 3-hydroxyaminopyridazine 1-oxide (X), m. 184° (decomposition) (EtOH);λ (95% EtOH) 229,262, and 341 mμ (log ε 4.17, 4.14, and 3.63); ν (KBr) 3160 cm.-1 IV (1.06 g.) and 20% Pd-C (prepared from 0.2 g. C and 8.4 cc. 1% aqueous PdCl2) in 200 cc. MeOH hydrogenated as above until uptake of 3 equivalents H, the mixture worked up as above, and the residue recrystallized from MeOH gave 0.2 g. X, m. 182° (decomposition). The mother liquor evaporated, the residue dissolved in MeOH, the solution treated with MeOH-picric acid, and the precipitate filtered off gave 0.25 g. IX, m. 248-9° (MeOH); the filtrate kept overnight with Amberlite IRA-410 (OH form), the resin filtered off, and the filtrate evaporated gave 0.27 g. VIII 1-oxide (XI), m. 139-41° (EtOAc); λ (95% EtOH) 217, 246-8, and 338-40 mμ (log ε 4.23, 4.13, and 3.74); ν (KBr) 3340, 3300, 3210, 1632 cm.-1 X (0.2 g.) and 0.12 g. 20% Pd-C in 50 cc. MeOH shaken in a stream of H until 1 equivalent H was absorbed and treated as above gave 60 mg. IX, m. 245-9°, and 75 mg. XI, m. 139-41°. IV (0.2 g.) suspended in 70 cc. anhydrous MeOH treated with NaOMe solution (prepared from 40 mg. Na and 7 cc. MeOH), the mixture kept 1.5 hrs. at 30° (IV dissolved slowly), and the precipitate filtered off and washed with C6H6 gave 30 mg. unchanged IV, m. 168-9°; the combined filtrate and washings evaporated in vacuo, the residue treated with a little H2O, and the product isolated with CHCl3 gave 137 mg. 3-OMe derivative (XII) of I, m. 79-80° (C6H6). IV (0.4 g.) in 50 cc. hot MeOH mixed with 10 cc. MeONa solution (prepared from 80 mg. Na) and the solution refluxed 1 hr. and treated as above gave 0.26 g. XII. IV (0.59 g.) suspended in 15 cc. AcCl refluxed until solution occurred (9 hrs.), the AcCl removed in vacuo, and the residue recrystallized from (iso-Pr)2O gave 0.36 g. 3-Cl derivative (XIII) of I, m. 93°, λ (95% EtOH) 266 mμ (log ε 4.00), ν (KBr) 1340 cm.-1 ; the mother liquor evaporated and the residue chromatographed on Al2O3 with CHCl3 gave 80 mg. XIII. IV (0.1 g.) suspended in 1 cc. AcCl kept 3 hrs. at 35°, the mixture evaporated in vacuo, and the residue extracted repeatedly with (iso-Pr)2O gave (as insoluble product) 90 mg. unchanged IV, m. 167-9°; the combined extracts evaporated and the residue chromatographed on Al2O3 with CHCl3 gave 2 mg. XIII. IV (0.15 g.) added to 0.4 g. Na dissolved in 0.7 g. PhOH by warming, the mixture heated 1 hr. at 100°, the PhOH removed in vacuo, the residue treated with H2O, the product isolated with CHCl3, the residue dissolved in CHCl3, the solution passed through Al2O3, and the eluate evaporated gave 100 mg. 3-OPh derivative of I, m. 115-16° (C6H6). HONH2.HCl (0.27 g.) in MeOH (saturated solution) treated with 0.27 g. K2CO3 in a little H2O, the precipitate filtered off, the filtrate treated with 80 mg. XIII in 3 cc. MeOH, refluxed 5.5 hrs., evaporated to dryness, the residue treated with a little H2O, the mixture extracted with CHCl3, and the extract evaporated gave 22 mg. unchanged XIII, m. 90-2° (iso-Pr)2O; the product insoluble in CHCl3 and H2O filtered off and recrystallized from EtOH gave 6 mg. X, m. 182-3° (decomposition). XIII (0.2 g.), 5 cc. EtOH, and 3 cc. 28% aqueous NH3 heated 4 hrs. at 120° in a sealed tube, the mixture treated with C, the solution evaporated in vacuo, the residue extracted repeatedly with hot EtOAc, and the combined extracts evaporated gave 0.05 g. XI, m. 140-1° (EtOAc). XIII (0.17 g.) in 10 cc. MeOH treated with NaOMe solution (prepared from 30 mg. Na and 5 cc. MeOH), the mixture kept overnight at room temperature, evaporated in vacuo, the residue treated with a little H2O, the mixture extracted with CHCl3, the extract dried, evaporated, and the residue chromatographed on Al2O3 with C6H6 gave 130 mg. XII, m. 78-80°. XIII (0.05 g.) and 0.04 cc. 80% N2H4.H2O in 1 cc. 95% EtOH refluxed 1 hr., cooled, evaporated in vacuo, the residue dissolved in 1 cc. AcOH, the solution treated with 0.03 g. NaNO2 in H2O with cooling, and the precipitate collected gave 30 mg. 3-azido derivative of I, m. 155-6° (99% MeOH), ν (KBr) 2180, 2150, and 1250 cm.-1 IV shown no activity of Ehrlich ascite carcinoma in vivo, it showed strong activity against Staphylococcus aureus, Escherichia coli, Shigella flexneri, and Candida albicans in vitro.

Chemical & Pharmaceutical Bulletin published new progress about IR spectra. 20744-39-2 belongs to class pyridazine, and the molecular formula is C4H5N3, Related Products of 20744-39-2.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Kosary, Judit; Kasztreiner, Endre; Rabloczky, Gyorgy; Kurthy, Maria published the artcile< Synthesis and cardiotonic activity of 2,4-diamino-1.3,5-triazines>, Formula: C9H8ClN3O2, the main research area is aminotriazine heteroaryl preparation cardiotonic; triazine diaminoheteroaryl preparation cardiotonic.

Thirty-two diaminotriazine derivatives, e.g., I (R = NH2, NHBu, NMe2, morpholino, 4-methylpiperazino; R1 = indol-3-yl, imidazo[1,2-a]pyridin-2-yl, imidazo[1,2-b]pyridazin-2-yl, imidazo[1,2-a]pyrazin-2-yl, etc.] were prepared and tested for cardiotonic activity in cats. There was no correlation between the cardiotonic activity of these compounds and their inhibitory effect on cardiac phosphodiesterase.

European Journal of Medicinal Chemistry published new progress about Cardiotonics. 64067-99-8 belongs to class pyridazine, and the molecular formula is C9H8ClN3O2, Formula: C9H8ClN3O2.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Mason, S. F. published the artcile< The electronic spectra of N-heteroaromatic systems. VI. The π → π transitions of monocyclic amino- and mercaptoazines>, Recommanded Product: Pyridazin-4-amine, the main research area is .

Ultraviolet absorption spectra are reported for 2-(I), 3-, and 4-aminopyridine (II), 2-(III), 4-(IV), and 5-aminopyrimidine, 4-aminopyridazine, 2-aminopyrazine, and 3-amino-6-methylpyridazone (V), in approx. neutral solution (pH about 7-9.5) and in acid (pH 1), and the 1-methochlorides of I, II, III, and IV, and the 2-methochloride of V, at pH 12-14. Most of the neutral spectra are repeated in EtOH and cyclohexane, and spectra of 1-methyl-2-, and -4-pyridone imine, 1-methyl-2-, and -4-pyrimidone imine and 2,6-dimethyl-3-pyridazone imine are reported in H2O and cyclohexane. Spectra are also reported for 2-, 3-, and 4-methylthiopyridine and for 4-methyl-2-methylthio-, 2-mercapto-4-methyl-, 6-methyl-4-methylthio-, and 4-mercapto-6-methylthiopyrimidine in neutral, acidic, and basic solution The spectra are discussed in relation to a benzyl anion model (loc. cit.) and a substituted benzene charge transfer model (Murrell, C.A. 53, 6749b). The latter model is more consistent with the exptl. data.

Journal of the Chemical Society published new progress about Azines. 20744-39-2 belongs to class pyridazine, and the molecular formula is C4H5N3, Recommanded Product: Pyridazin-4-amine.

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem