Tag: 100-200

The tautomerism of N-heteroaromatic hydroxy compounds. III. Ionization constants was written by Mason, S. F.. And the article was included in Journal of the Chemical Society in 1958.Category: pyridazine This article mentions the following:

Acidic and basic ionization constants are reported for a number of N-heteroaromatic hydroxy compounds and their O- and N-Me derivatives From the measured and from published values, tautomeric equilibrium constants (K_t = [NH form]/[OH form]) were estimated for the monoaza compounds, and for the diaza compounds with not more than one N atom conjugated with the OH group. For the diazacompds. with a ring-N atom placed both ortho and para to the OH group, the equilibrium constant (K_op = [ο-quinonoid NH form]/[p-quinonoid NH form]) was similarly estimated Such constants agree, to within an order of magnitude, with those determined spectrophotometrically. The ionization and tautomeric constants vary with the π-electron energies of the species in equilibrium Absorption spectra were measured with a Hilger Uvispek H700/305 Quartz Spectrophotometer, and aqueous solutions with pH values 2 units less than pK₁ value of the 63 compounds examined Ionization constants were determined by potentiometric titration at 20° under N, a Cambridge pH meter being used with glass and calomel electrodes. The ionization constants of the N-heteroaromatic hydroxy compounds were measured at 0.004M and those of the O- and N-Me derivatives at 0.01M. In the experiment, the researchers used many compounds, for example, 3-Methoxypyridazine (cas: 19064-65-4Category: pyridazine).

3-Methoxypyridazine (cas: 19064-65-4) belongs to pyridazine derivatives. Pyridazines are rare in nature, possibly reflecting the scarcity of naturally occurring hydrazines, common building blocks for the synthesis of these heterocycles. Pyridazine is bioavailable (especially in the CNS) and can reduce toxicity. Pyridazine is a component of several drug molecules, and the pyridazine pharmacophore has contributed to a variety of pharmacologically active compounds.Category: pyridazine

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Syntheses of pyridazine derivatives. II. 3-Methoxy-6-pyridazinol 1-oxide was written by Nakagome, Takenari. And the article was included in Yakugaku Zasshi in 1962.COA of Formula: C5H6N2O This article mentions the following:

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), b_0.15 120-5°, 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°. In the experiment, the researchers used many compounds, for example, 3-Methoxypyridazine (cas: 19064-65-4COA of Formula: C5H6N2O).

3-Methoxypyridazine (cas: 19064-65-4) belongs to pyridazine derivatives. Pyridazine and phthalazine have quite different spectroscopic properties compared with their isomers, pyrazine and quinoxaline. Pyridazine compounds have attracted interest in various fields like medicinal, industrial, and agricultural research as they are used for numerous biological activities and other applications.COA of Formula: C5H6N2O

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Synthesis and herbicidal activity of 3-aryloxy-6-substituted pyridazines was written by Yang, Hua-Zheng;Wang, Xiang;Hu, Fang-Zhong;Yang, Xiu-Feng. And the article was included in Gaodeng Xuexiao Huaxue Xuebao in 2002.Safety of 3,6-Difluoropyridazine This article mentions the following:

A series of 3-aryloxy-6-substituted pyridazines have been synthesized and their herbicidal activity have been studied. All of above pyridazines have been confirmed by ¹H NMR and elemental analyses, and some of them have been characterized by IR and MS. The bioassay result indicated that some of the title compounds have a high herbicidal activity. In addition, the structure-activity relationship was discussed. In the experiment, the researchers used many compounds, for example, 3,6-Difluoropyridazine (cas: 33097-39-1Safety of 3,6-Difluoropyridazine).

3,6-Difluoropyridazine (cas: 33097-39-1) belongs to pyridazine derivatives. The pyridazine structure is also found within the structure of several drugs such as cefozopran, cadralazine, minaprine, pipofezine, and hydralazine. Pyridazine is bioavailable (especially in the CNS) and can reduce toxicity. Pyridazine is a component of several drug molecules, and the pyridazine pharmacophore has contributed to a variety of pharmacologically active compounds.Safety of 3,6-Difluoropyridazine

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

The tautomeric properties of 6-(2-pyrrolyl)pyridazin-3-one and 6-(2-pyrrolyl)pyridazin-3-thione was written by Jones, R. Alan;Whitmore, Alexander. And the article was included in ARKIVOC (Gainesville, FL, United States) in 2007.Recommanded Product: 19064-65-4 This article mentions the following:

The pyrrolyl substituent enhances the electron densities on the pyridazine ring and has the effect of shifting the positions of the tautomeric equilibrium for 1c,d ⇌ 2c,d, which exist predominantly as the pyridazin-3-one and -3-thione forms, towards the hydroxyl (thiol) structures, compared with those of those for the parent unsubstituted systems. In the experiment, the researchers used many compounds, for example, 3-Methoxypyridazine (cas: 19064-65-4Recommanded Product: 19064-65-4).

3-Methoxypyridazine (cas: 19064-65-4) belongs to pyridazine derivatives. The pyridazine derivatives are mostly present in biologically active compounds and are also present with different pharmacophores. The unsubstituted pyridazines are more resistant to eletrophilic substitution due to the nature of withdrawal of electron density from the ring by two heteroatoms, while the related electron deficiency of the ring makes pyridazine more easily attacked by nucleophiles.Recommanded Product: 19064-65-4

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

The proton sponge-triethylamine tris(hydrogen fluoride) system as a selective nucleophilic fluorinating reagent for chlorodiazines was written by Darabantu, M.;Lequeux, T.;Pommelet, J.-C.;Ple, N.;Turck, A.;Toupet, L.. And the article was included in Tetrahedron Letters in 2000.Reference of 33097-39-1 This article mentions the following:

The proton sponge-triethylamine tris(hydrogen fluoride) mixture provides a mild and efficient fluorinating reagent for the selective introduction of a fluorine atom, by halogen exchange, into dichlorodiazines. In the experiment, the researchers used many compounds, for example, 3,6-Difluoropyridazine (cas: 33097-39-1Reference of 33097-39-1).

3,6-Difluoropyridazine (cas: 33097-39-1) belongs to pyridazine derivatives. Pyridazine-based compounds continued to be a great source of biologically active compounds as evidenced by the number of publications which emerged in 2021. In the past decade, X-ray data were reported with regard to the characterization and structural elucidation of a number of pyridazine-metal complexes, including pyridazine ligands with zinc, nickel, copper, cadmium and ruthenium.Reference of 33097-39-1

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

The tautomerism of N-heteroaromatic hydroxy compounds. II. Ultraviolet spectra was written by Mason, S. F.. And the article was included in Journal of the Chemical Society in 1957.Synthetic Route of C5H6N2O This article mentions the following:

The UV spectra of 68 N-heteroaromatic hydroxy compounds and their O- and N-Me derivatives with fixed structures have been measured. These were measured with a Hilger Uvispek H700/305 quartz spectrophotometer in buffered aqueous solutions The buffer solutions were 0.01M acetate for pH 3.8-5.7; 0.01M phosphate for pH 6.0-7.9, and 10.3-11.3; and 0.01M borate for pH 8.2-10.0. The variations of the spectra with temperature were measured by means of a water-jacketed cell-holder maintained at a constant temperature (±0.05°) with H₂O circulated from a thermostat. By comparing spectra, it was found that tautomerism from O-H to N-H forms in general among the monoaza and some diaza heterocyclic hydroxy compounds Equilibrium constants (K_t = [N-H form]/[O-H form] have been estimated from the spectra, and they have been found to increase with conjugation between the O and N atom, and with the addition of fused benzene rings, and to decrease with aza substitution, with a rise in temperature, and with a fall in the dielec. constant of the solvent. In the experiment, the researchers used many compounds, for example, 3-Methoxypyridazine (cas: 19064-65-4Synthetic Route of C5H6N2O).

3-Methoxypyridazine (cas: 19064-65-4) belongs to pyridazine derivatives. Pyridazine and phthalazine have quite different spectroscopic properties compared with their isomers, pyrazine and quinoxaline. Specifically, the pyridazine moiety is an important structural feature of various pharmacologically important compounds with activities like antimicrobial, analgesic, anti-inflammatory, antiplatelet, anticancer, antisecretory, antiulcer, antidepressant, cardiotonic, vasodilator, antiarrhythmic, and hypocholesterolaemic.Synthetic Route of C5H6N2O

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Studies on pyridazines. XXVI. The reaction of substituted N-acetyliminopyridazinium ylides with benzyne was written by Hasegawa, Hiroshi;Arai, Heihachiro;Igeta, Hiroshi. And the article was included in Chemical & Pharmaceutical Bulletin in 1977.Electric Literature of C5H6N2O This article mentions the following:

Reaction of N-acetyliminopyridazinium ylides I (R = Me, MeO, EtO, Ph, piperidino; R1 = R2 = H; R = MeO, R1 = Me, R2 = H; R = MeO, R1 = H, R2 = Me) with benzyne gave 1,3-dipolar cycloadducts II. Photolysis of II (R = MeO, EtO; R1 = R2 = H) gave α-alkoxynaphthalene and 3-(2-acetamidophenyl)pyridazines. Photolysis of II (R = Me, R1 = R2 = H) gave the indazolo[2,3-b]pyridazine (III). Reaction of II (R = MeO, Ph; R1 = R2 = H) with base gave 3-vinylindazole and the dihydroindazolopyridazine IV (R3 = MeO, Ph). Reaction of 3-pyridazinol 1-oxide with benzyne gave a 1,3-cycloadduct, which underwent N-O bond fission to give the pyridazinone V. In the experiment, the researchers used many compounds, for example, 3-Methoxypyridazine (cas: 19064-65-4Electric Literature of C5H6N2O).

3-Methoxypyridazine (cas: 19064-65-4) belongs to pyridazine derivatives. Pyridazine-based compounds continued to be a great source of biologically active compounds as evidenced by the number of publications which emerged in 2021. Pyridazine and derivatives coordinate readily with transition metals to form complexes and catalysts with synthetic utility.Electric Literature of C5H6N2O

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Preparation of 3,6-difluoro- and 3-chlorofluoropyridazines and their nucleophilic reactions was written by Ishikawa, Nobuo;Kuroda, Katsuhiko;Onodera, Nobuo. And the article was included in Kogyo Kagaku Zasshi in 1971.Related Products of 33097-39-1 This article mentions the following:

3,6-Dichloropyridazine was treated with KF in DMF to give 3-fluoro-6-chloropyridazine (I) which was further treated with KF in Me2SO to give 3,6-difluoropyridazine (II). Treatment of II with 1 mole of various phenols (PhOH, o-, m-, p-ClC6H4OH, o-, m-, p-MeC6H4OH, etc.) in MeCN gave the corresponding 3-aryloxy-6-fluoropyridazines in 64-89% yields. 3,6-Diphenoxy- and 3-(dimethylamino)-6-fluoropyridazines were also prepared, and treatment of I with PhOK in MeCN gave 3-chloro-6-phenoxypyridazine. The 3-aryloxy-6-fluoropyridazines showed herbicidal activities (barnyard grass). In the experiment, the researchers used many compounds, for example, 3,6-Difluoropyridazine (cas: 33097-39-1Related Products of 33097-39-1).

3,6-Difluoropyridazine (cas: 33097-39-1) belongs to pyridazine derivatives. Pyridazines are rare in nature, possibly reflecting the scarcity of naturally occurring hydrazines, common building blocks for the synthesis of these heterocycles. Pyridazine can act as a hydrogen bond acceptor to improve the physicochemical properties of drug molecules by increasing their water solubility, and has a high affinity for complexing with targets due to its dipole moment.Related Products of 33097-39-1

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

Halogen-exchange fluorination of aromatic halides with HF or HF-base was written by Fukuhara, Tsuyoshi;Yondea, Norihiko. And the article was included in Chemistry Letters in 1993.Product Details of 33097-39-1 This article mentions the following:

Heteroaromatic halides such as 2-chloropyrimidines and 2-chloropyridines, and 2,4-dinitrochlorobenzene underwent halogen-exchange fluorination with the treatment of HF or HF-base solutions to afford the corresponding fluorides in good yields. In the experiment, the researchers used many compounds, for example, 3,6-Difluoropyridazine (cas: 33097-39-1Product Details of 33097-39-1).

3,6-Difluoropyridazine (cas: 33097-39-1) belongs to pyridazine derivatives. Pyridazine-based compounds continued to be a great source of biologically active compounds as evidenced by the number of publications which emerged in 2021. Specifically, the pyridazine moiety is an important structural feature of various pharmacologically important compounds with activities like antimicrobial, analgesic, anti-inflammatory, antiplatelet, anticancer, antisecretory, antiulcer, antidepressant, cardiotonic, vasodilator, antiarrhythmic, and hypocholesterolaemic.Product Details of 33097-39-1

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem

The oxidation of s-triazolo[4,3-b]pyridazines with selenium dioxide was written by Iwao, Masatomo;Kuraishi, Tsukasa. And the article was included in Journal of Heterocyclic Chemistry in 1976.COA of Formula: C5H3ClN4O This article mentions the following:

The s-triazolo[4,3-b]pyridazines I (R = Me, MeO, Cl, H, R1 = H; R = Cl, R1 = AcNH) were oxidized to the s-triazolo[4,3-b]pyridazin-3-ones II with SeO2 in PhNO2 at 160-165° for 1-2 hr in 30-40% yields. In the experiment, the researchers used many compounds, for example, 6-Chloro-[1,2,4]triazolo[4,3-b]pyridazin-3(2H)-one (cas: 33050-32-7COA of Formula: C5H3ClN4O).

6-Chloro-[1,2,4]triazolo[4,3-b]pyridazin-3(2H)-one (cas: 33050-32-7) belongs to pyridazine derivatives. The pyridazine structure is a popular pharmacophore which is found within a number of herbicides such as credazine, pyridafol and pyridate. Pyridazine is bioavailable (especially in the CNS) and can reduce toxicity. Pyridazine is a component of several drug molecules, and the pyridazine pharmacophore has contributed to a variety of pharmacologically active compounds.COA of Formula: C5H3ClN4O

Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem