Pyridine-derivatives

Guo, Changchuan published the artcile[Determination of trace genotoxic impurities in nifedipine by ultra high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry]., Recommanded Product: Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, the publication is Se pu = Chinese journal of chromatography (2022), 40(3), 266-272, database is MEDLINE.

A method based on ultra high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry (UHPLC-Orbitrap HRMS) was established for the determination of genotoxic impurities 2, 6, and 12 in nifedipine. After extraction with methanol, the sample was injected into the UHPLC-Orbitrap HRMS system for analysis. An ACE EXCEL^TM 3 C18-AR column (150 mm×4.6 mm, 3 μm) was used for chromatographic separation. The mobile phase was methanol-0.1% formic acid aqueous solution (65âˆ?5, v/v). The flow rate was 0.6 mL/min, while the column temperature and autosampler temperature were set as 35 â„?and 8 â„? respectively. The divert valve switching technique was used to protect the mass spectrometer. The six-way valve was set to divert the eluent of 7.5-11.6 min to waste and the rest of the eluent into the mass spectrometer. The Orbitrap mass spectrometer was coupled with the UHPLC system by an electrospray ion (ESI) source. The sheath gas and auxiliary gas flow rates were 60 and 20 arb (arbitrary units), respectively. The spray voltage was 3.5 kV, while the capillary temperature and auxiliary gas heater temperature were set as 350 â„?and 400 â„? respectively. The positive ion parallel reaction monitoring (PRM) scanning mode was adopted, and the mass spectral resolution was set to 35000 FWHM. The accurate masses of the [M+H]⁺ precursor ions of impurities 2, 6, and 12 were m/z 347.1230, 361.1026, and 347.1230, respectively. The accurate masses of the extracted [M+H]⁺ fragment ions of impurities 2, 6, and 12 were m/z 315.0968, 298.1069, and 315.0968, respectively. The normalized collision energies (NCEs) were optimized to 10%, 42%, and 10% for impurities 2, 6, and 12, respectively. The external standard method was utilized for quantitative analysis. The established method was validated in detail by investigating the specificity, linear range, limit of detection (LOD), limit of quantification (LOQ), recovery, precision, and stability. This method had good specificity, and the solvent did not interfere with the determination of impurities. The peak areas of impurities 2, 6, and 12 as well as their concentrations showed good linear relationships in the ranges of 0.2-100 ng/mL, with all correlation coefficients (r)â‰?.9998. The recoveries of impurities 2, 6, and 12 at three levels (low, medium, and high) were in the range of 96.9%-105.0%, while the RSDs were between 1.21% and 5.12%. The LODs were 0.05 ng/mL and the LOQs were 0.2 ng/mL for all three impurities. This analytical method was used to determine impurities 2, 6, and 12 in three batches of nifedipine samples. Impurity 6 was not detected in the three batches, but impurities 2 and 12 were detected in all the three samples, and the detection amount was within the limit. The developed method is sensitive, fast, accurate, and easy to operate. It can provide a reference for the quality control of nifedipine by pharmaceutical companies and extend strong technical support for the supervision by drug regulatory authorities.

Se pu = Chinese journal of chromatography published new progress about 21829-25-4. 21829-25-4 belongs to pyridine-derivatives, auxiliary class Membrane Transporter/Ion Channel,Calcium Channel, name is Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, and the molecular formula is C17H18N2O6, Recommanded Product: Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Hayashi, Eri published the artcileBase-Assisted Aerobic C-H Oxidation of Alkylarenes with a Murdochite-Type Oxide Mg₆MnO₈ Nanoparticle Catalyst, Safety of Phenyl(pyridin-2-yl)methanone, the publication is ACS Applied Materials & Interfaces (2022), 14(5), 6528-6537, database is CAplus and MEDLINE.

Heterogeneously catalyzed aerobic oxidative C-H functionalization under mild conditions is a chem. process to obtain desired oxygenated products directly. Nanosized murdochite-type oxide Mg₆MnO₈ (Mg₆MnO₈-MA) was successfully synthesized by the sol-gel method using malic acid. The sp. surface area reached up to 104 m² g^-1, which is about 7 times higher than those (2-15 m² g^-1) of Mg₆MnO₈ synthesized by previously reported methods. Mg₆MnO₈-MA exhibited superior catalytic performance to those of other Mn- and Mg-based oxides, including manganese oxides with Mn-O-Mn active sites for the oxidation of fluorene with mol. oxygen (O₂) as the sole oxidant under mild conditions (40°C). The present catalytic system was applicable to the aerobic oxidation of various substrates. The catalyst could be recovered by simple filtration and reused several times without obvious loss of its high catalytic performance. The correlation between the reactivity and the pK_a of the substrates, basic properties of catalysts, and kinetic isotope effects suggest a basicity-controlled mechanism of hydrogen atom transfer. The ¹⁸O-labeling experiments, kinetics, and mechanistic studies showed that H abstraction of the hydrocarbon proceeds via a mechanism involving O₂ activation. The structure of Mg₆MnO₈ consisting of isolated Mn⁴⁺ species located in a basic MgO matrix plays an important role in the present oxidation

ACS Applied Materials & Interfaces published new progress about 91-02-1. 91-02-1 belongs to pyridine-derivatives, auxiliary class Pyridine,Benzene,Ketone, name is Phenyl(pyridin-2-yl)methanone, and the molecular formula is C12H9NO, Safety of Phenyl(pyridin-2-yl)methanone.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Hurh, Byungserk published the artcilePurification and characterization of nicotinic acid dehydrogenase from Pseudomonas fluorescens TN5, Synthetic Route of 636-73-7, the publication is Journal of Fermentation and Bioengineering (1994), 78(1), 19-26, database is CAplus.

Membrane-bound nicotinic acid dehydrogenase, an enzyme that catalyzes the formation of 6-hydroxynicotinic acid from nicotinic acid, was solubilized with Triton X-100, and then purified 126-fold with an 11.1% overall recovery from nicotinic acid-induced cells of Pseudomonas fluorescens TN5. The purified enzyme appeared to be homogeneous from anal. by polyacrylamide gel electrophoresis. The enzyme had a mol. mass of approx. 80 kDa and consisted of one subunit. Some electron acceptors, such as phenazine methosulfate, K₃Fe(CN)₆ and nitro blue tetrazolium, acted as electron acceptors. The purified enzyme catalyzed the hydroxylation of nicotinic acid to 6-hydroxynicotinic acid at a rate of 672 μmol min^-1 mg^-1 of protein at 35°. It also catalyzed the hydroxylation of pyrazinecarboxylic acid, 3-pyridinesulfonic acid, and 3-cyanopyridine. The purified enzyme exhibited an optimum pH of 8.3, and was sensitive to thiol reagents such as HgCl₂ and p-chloromercuribenzoate. A reduction in the amount of the cytochrome c-like component in the respiratory particles was observed during the hydroxylation reaction of nicotinic acid. Thus, nicotinic acid dehydrogenase appeared to be linked to the cytochrome respiratory chain in the cells of P. fluorescens TN5.

Journal of Fermentation and Bioengineering published new progress about 636-73-7. 636-73-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Sulfonic acid, name is Pyridine-3-sulfonic acid, and the molecular formula is C5H5NO3S, Synthetic Route of 636-73-7.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Talik, T. published the artcileReactivity of fluoronitropyridines. II. Derivates of fluoronitropyridines, Related Products of pyridine-derivatives, the publication is Bulletin de l’Academie Polonaise des Sciences, Serie des Sciences Chimiques (1968), 16(1), 7-12, database is CAplus.

Fluoronitropyridines and their derivatives were prepared as previously described (T. Talik and Z. Talik, 1964-7). Their reactivity could be compared as follows: 3,5-dinitro-2-fluoropyridine > 3-fluoro-4-nitropyridine N-oxide > 3-fluoro-5-methyl-4-nitropyridine N-oxide > 2-fluoropyridines with a Me group in the 3, 4, 5, or 6 position and a nitro group in the 3 or 5 position > 3-fluoro-4-nitropyridine > 3-fluoro-2-methyl-4-nitropyridine N-oxide > 2-fluoro-4-nitropyridine > 2,6-dimethyl-3-fluoro-4-nitropyridine N-oxide.

Bulletin de l’Academie Polonaise des Sciences, Serie des Sciences Chimiques published new progress about 3726-08-7. 3726-08-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Fluoride,Bromide, name is 4-Bromo-3-fluoro-2,6-dimethylpyridine, and the molecular formula is C6H17NO3Si, Related Products of pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Talik, Zofia published the artcile2,6-Dimethyl-3-fluoro-4-nitropyridine N-oxide, Category: pyridine-derivatives, the publication is Roczniki Chemii (1965), 39(4), 601-6, database is CAplus.

Reactivity of the fluorine atom in I was found to be lower than in the 3-fluoro-4-nitropyridine N-oxide. A series of substitution reactions of F or NO₂-group was carried out. A mixture of 25 g. 2,6-dimethyl-3-aminopyridine in 150 ml. EtOH, 150 ml. HBF₄, prepared from 140 ml. 48% HF and 45 g. H₃BO₃, was treated at 0°, during 90 min. with EtONO, kept 10 min. at 50°, cooled to 0°, treated again during 2 hrs. with EtONO, and distilled under reduced pressure to remove EtOH. The residue was made alk. with aqueous KOH and steam-distilled The distillate saturated with NaCl and extracted with Et₂O gave 11 g. 2,6-dimethyl-3-fluoropyridine (II), b. 136-8°. A cold solution of 25 g. II in 150 ml. Ac₂O was treated with 150 ml. 30% H₂O₂, left for a few hrs. at room temperature, then kept 30 hrs. at 60° and distilled under reduced pressure to remove AcOH and AcOOH. The whole was dissolved, below 10° in 30 ml. concentrated H₂SO₄ and 30 ml. 20% oleum, then added carefully to 60 ml. 20% oleum and 90 ml. HNO₃ (d. 1.52), kept 1 hr. on a water bath, poured onto 300 g. ice, and neutralized with solid (NH₄)₂CO₃ to give 24 g. I, m. 136° (H₂O). I (1 g.) and 30 ml. alc. NH₃, saturated at 0°, was autoclaved 4 hrs. at 120-30° and evaporated to dryness. The residue triturated with small amount H₂O, cooled, and filtered gave 0.8 g. 2,6-dimethyl-3-amino-4-nitropyridine N-oxide (III), m. 189-90° (H₂O). III (0.4 g.), 1 ml. PCl₃, in 15 ml. CHCl₃ was refluxed 1 hr., evaporated, and the residue neutralized with aqueous KHCO₃ to afford 0.3 g. 2,6-dimethyl-3-amino-4-nitropyridine, m. 112° (H₂O). III (0.3 g.) reduced in 10 ml. of boiling AcOH with 0.6 g. Fe dust, kept 30 min. on a water bath, made alk. with 50% KOH, and extracted with Et₂O gave 0.2 g. 2,6-dimethyl-3,4-diaminopyridine, m. 181° (C₆-H₆-EtOH); picrate m. 215°. Similarly, reduction of 1 g. I with 2 g. Fe in 25 ml. AcOH afforded 0.7 g. 2,6-dimethyl-3-fluoro-4-aminopyridine, m. 92° (H₂O); picrate m. 235° (alc.). Heating of 0.5 g. I and 5 ml. PhNH₂ during 2 hrs. at 120-30°, followed by pouring into H₂O and acidifying with HCl, yielded 90.3% 2,6-dimethyl-3-phenylamino-4-nitropyridine N-oxide, m. 146° (EtOH-H₂O). A solution of 1.5 g. KOH in 13 ml. H₂O, treated successively with 2 ml. 30% H₂O₂ and 1 g. I, kept 30 min. on a water bath, cooled, and filtered, gave 0.8 g. 2,6-dimethyl-8-hydroxy-4-nitropyridine N-oxide, m. 99° (H₂O). A mixture of 1 g. I and MeONa, prepared from 0.15 g. metallic Na and 20 ml. MeOH, refluxed 1 hr., evaporated, and extracted with CHCl₃, afforded 0.9 g. 2,6-dimethyl-3-methoxy-4-nitropyridine N-oxide, m. 137° (H₂OEtOH). Similarly, substitution of F atom in I using EtONa yielded 94.2% 2,6-dimethyl-3-ethoxy-4-nitropyridine N-oxide, m. 103° (aqueous alc.). I (5 g.) refluxed 1 hr. with 10 ml. PCl₃ in 10 ml. CHCl₃, evaporated, and the residue decomposed with ice and neutralized with Na₂CO₃ was steam-distilled to give in the distillate 2.5 g. 2,6-dimethyl-3-fluoro-4-chloropyridine, b. 174-5°; picrate m. 125° (alc.). Similarly, I and PBr₃ yielded 54.7% 2,6-dimethyl-3-fluoro-4-bromopyridine, m. 67° (ligroine); picrate m. 140° (alc.).

Roczniki Chemii published new progress about 3726-08-7. 3726-08-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Fluoride,Bromide, name is 4-Bromo-3-fluoro-2,6-dimethylpyridine, and the molecular formula is C17H20ClN3, Category: pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Fujisawa, Hidehito published the artcileSimple procedure for preparation of α-fluoro esters by fluorination of ester enol silyl ethers with perchloryl fluoride, Application In Synthesis of 107263-95-6, the publication is Journal of Fluorine Chemistry (2002), 117(2), 173-176, database is CAplus.

A practical method for general preparation of α-fluoro esters by fluorination of the corresponding enol silyl ethers using diluted FClO₃ in the presence of suitable amount of amine is described. Fluorination of ester enol silyl ethers in THF at room temperature using diluted perchloryl fluoride (FClO₃) in the presence of ca. 0.5 M eq. of t-BuNH₂ as an additive produced the corresponding α-fluoro esters in over 80% yields. For example, fluorination of [(1-ethoxy-2-phenylethenyl)oxy]trimethylsilane with perchloryl fluoride gave α-fluorobenzeneacetic acid Et ester.

Journal of Fluorine Chemistry published new progress about 107263-95-6. 107263-95-6 belongs to pyridine-derivatives, auxiliary class Fluorination reagent, name is 1-Fluoropyridiniumtriflate, and the molecular formula is C6H5F4NO3S, Application In Synthesis of 107263-95-6.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Iwata, Naoko published the artcileClassification of pacemaker dynamics in the mouse intestine by field potential microimaging, HPLC of Formula: 21829-25-4, the publication is Biosensors and Bioelectronics: X (2022), 100111, database is CAplus.

The flexible and sophisticated movement of the gastrointestinal (GI) tract implies the involvement of mechanisms other than enteric neural circuits, to coordinate excitation in microregions. We thus performed microimaging of pacemaker dynamics in the small intestine of mice since it contains typical network-forming pacemaker cells. A dialysis membrane-reinforced low-impedance microelectrode array (MEA) enabled field potentials over a wide frequency range to be stably measured in microregions. The pacemaker dynamics were classified into basic patterns despite large variations. In the developmental process, pacemaker activity was categorized as either an ‘expanding’ or a ‘migrating’ pattern that was initiated in or propagated to the MEA sensing area, resp. The intercellular current of the volume conductor complicated the waveform of both activities. The existence of ‘expanding’ and ‘migrating’ patterns was attributable to duplicated pacemaker systems such as intracellular Ca2+ oscillation-activated and voltage-gated mechanisms. Addnl., from the spatio-temporal feature during the period of pacemaker events, the ‘bumpy/aberrant’ pattern was defined by aberrant, incoherent propagation, and associated with local impairment of excitability, while the ‘colliding/converging’ pattern involved the interaction of multiple activities in the MEA area. Interconversion between the four micro-coordination patterns occurred in the same microregion. 5-Hydroxytryptamine (5-HT) promoted ‘migrating’ activity, implying an improvement or restoration of spatial conductivity These results agree well with the action of 5-HT to change GI movement toward propulsion. In conclusion, our MEA method of microimaging classification enables the quant. assessment of spatio-temporal elec. coordination underlying GI motility, suggesting its application to small model animals.

Biosensors and Bioelectronics: X published new progress about 21829-25-4. 21829-25-4 belongs to pyridine-derivatives, auxiliary class Membrane Transporter/Ion Channel,Calcium Channel, name is Dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate, and the molecular formula is C17H18N2O6, HPLC of Formula: 21829-25-4.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Tsukada, Tomoharu published the artcileStructure-based drug design of tricyclic 8H-indeno[1,2-d][1,3]thiazoles as potent FBPase inhibitors, SDS of cas: 197958-29-5, the publication is Bioorganic & Medicinal Chemistry Letters (2010), 20(3), 1004-1007, database is CAplus and MEDLINE.

With the goal of improving metabolic stability and further enhancing FBPase inhibitory activity, a series of tricyclic 8H-indeno[1,2-d][1,3]thiazoles was designed and synthesized with the aid of structure-based drug design. Extensive SAR studies led to the discovery of 19a (I) with an IC₅₀ value of 1 nM against human FBPase. X-ray crystallog. studies revealed that high affinity of 19a was due to the hydrophobic interaction arising from better shape complementarity and to the hydrogen bonding network involving the side chain on the tricyclic scaffold.

Bioorganic & Medicinal Chemistry Letters published new progress about 197958-29-5. 197958-29-5 belongs to pyridine-derivatives, auxiliary class Pyridine,Boronic acid and ester, name is 2-Pyridinylboronic acid, and the molecular formula is C2H8Cl2N4S2, SDS of cas: 197958-29-5.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Sadler, Scott A. published the artcileIridium-catalyzed C-H borylation of pyridines, Formula: C11H14BCl2NO2, the publication is Organic & Biomolecular Chemistry (2014), 12(37), 7318-7327, database is CAplus and MEDLINE.

The iridium-catalyzed C-H borylation is a valuable and attractive method for the preparation of aryl and heteroaryl boronates. However, application of this methodol. for the preparation of pyridyl and related azinyl boronates can be challenged by low reactivity and propensity for rapid protodeborylation, particularly for a boronate ester ortho to the azinyl nitrogen. Competition experiments have revealed that the low reactivity is due to inhibition of the active catalyst through coordination of the azinyl nitrogen lone pair at the vacant site on the iridium. This effect can be overcome through the incorporation of a substituent at C-2. Moreover, when this is sufficiently electron-withdrawing protodeborylation is sufficiently slowed to permit isolation and purification of the C-6 boronate ester. Following functionalization, reduction of the directing C-2 substituent provides the product arising from formal ortho borylation of an unhindered pyridine ring.

Organic & Biomolecular Chemistry published new progress about 1622217-00-8. 1622217-00-8 belongs to pyridine-derivatives, auxiliary class Boronic acid and ester,Boronic Acids,Boronate Esters, name is 2,4-Dichloro-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine, and the molecular formula is C11H14BCl2NO2, Formula: C11H14BCl2NO2.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Ishida, Akiharu published the artcileDiscovery and SAR Studies of Orally Active Somatostatin Receptor Subtype-2 (SSTR2) Agonists for the Treatment of Acromegaly, COA of Formula: C7H10BNO3, the publication is ACS Chemical Neuroscience (2020), 11(10), 1482-1494, database is CAplus and MEDLINE.

Acromegaly is a disease caused by the oversecretion of growth hormone. It is currently treated by i.v. injection with cyclic peptide drugs that activate somatostatin receptor subtype 2 (SSTR2). Here, novel nonpeptidic, small-mol., and orally active SSTR2 agonists were identified from a hit compound (13). Pharmacophore studies enabled scaffold hopping to obtain a unique 3,4,5-trisubstituted pyridine motif. Further optimization conferred potent SSTR2 agonistic activity and metabolic stability. Several compounds were evaluated and these showed good oral pharmacokinetic profiles in rats, and one representative compound (25)(I) showed highly potent inhibition of growth hormone secretion induced by growth hormone-releasing hormone in rats. Based on these results, 25 was identified as a promising lead for further optimization. A structure-activity relationship (SAR) study and the metabolic stability data for this compound are also described.

ACS Chemical Neuroscience published new progress about 612845-44-0. 612845-44-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Boronic acid and ester,Ether,Boronic Acids,Boronic acid and ester, name is (6-Ethoxypyridin-3-yl)boronic acid, and the molecular formula is C7H10BNO3, COA of Formula: C7H10BNO3.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem