Tag: 100-200

σ-Adducts of heterocycles with nucleophiles. XXII. Nuclear magnetic resonance data of pyrido[2,3-b]pyrazines and their σ-adducts with amide ion and water was written by Nagel, A.;Van der Plas, H. C.;Geurtsen, G.;Van Veldhuizen, A.. And the article was included in Journal of Heterocyclic Chemistry in 1979.HPLC of Formula: 322-46-3 This article mentions the following:

The ¹³C NMR of I [R = R¹ = R² = H (II); R = 3-Ph, O-Me₃C, 2-Cl (III), R¹ = R² = H; R = R¹ = H, R² = 6-Cl (IV), 6-NH₂; R = 2-Cl (V), 3-Ph, 3-Me₃C, 2-Me₃C, 2-NH₂NH, R¹ = H, R² = 6-Cl; R = 2-Ph, R¹ = 3-Ph, R² = H, 6-F, 6-Cl, 6-Br], II-2-¹³C, III–2–¹³C, IV–2–¹³C, V–2–¹³C, VI (R = H, Cl), and VII are used to assign the spectrum of II. ¹³C NMR established the structure and the formation of VIII (R = H, Me₃C) from the addition of KNH₂-NH₃ to the corresponding I; ¹H NMR established the formation of IX under these conditions. ¹³C NMR also indicated that II is not hydrated in neutral aqueous solution; II in N HCl gives X. The ring contraction mechanism of I with NH₂^– to give 1H-imidazo[4,5-b]pyridine is discussed. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3HPLC of Formula: 322-46-3).

Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine has the elements of symmetry for the point group D2h. It has three mutually perpendicular two-fold axes. It also has three mutually perpendicular planes of symmetry. As a result, pyrazine also has a centre of symmetry. Pyrazines undergo nearly all of the same reactions as pyrimidines, from nucleophilic substitution (SNAr) to palladium-catalyzed cross coupling reactions.HPLC of Formula: 322-46-3

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Experimental and theoretical studies on the magnetic circular dichroism of azanaphthalenes. Use of the CNDO/S-CI approximation was written by Kaito, Akira;Hatano, Masahiro. And the article was included in Journal of the American Chemical Society in 1978.Recommanded Product: 322-46-3 This article mentions the following:

The magnetic CD spectra of quinoline, isoquinoline, quinoxaline, phthalazine, quinazoline, cinnoline and pyrido[2,3-b]pyrazine were measured in the waveno. region 20,000-50,000 cm^-1. The transition energies, oscillator strengths and Faraday B terms calculated within the framework of the CNDO/S-Cl approximation agree with the exptl. results. The signs of the Faraday B terms of 2 lowest π^* ← π transitions change according to whether the aza substitution occurs at the α or β position. The origins for the Faraday B terms of the lowest allowed π^* ← n transition and the 2 lowest π^* ← π transitions were also investigated. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Recommanded Product: 322-46-3).

Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine has the elements of symmetry for the point group D2h. It has three mutually perpendicular two-fold axes. It also has three mutually perpendicular planes of symmetry. As a result, pyrazine also has a centre of symmetry. Pyrazine-based skeletons were incorporated into agents targeting a range of ailments. Many derivatives were synthesized and evaluated as potential cancer treatments.Recommanded Product: 322-46-3

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Regioselectivity in the catalytic hydrogenation of some pyrido[2,3-b]pyrazines was written by Cosmao, Jean Marie;Collignon, Noel;Queguiner, Guy. And the article was included in Canadian Journal of Chemistry in 1982.Category: pyrazines This article mentions the following:

Catalytic hydrogenation of pyridopyrazines I (R = H, R¹ = Me, Ph; R = R¹ = Me) on Pd-C in EtOH gave mixtures of the 1,2,3,4- and 5,6,7,8-tetrahydro derivatives Similar reduction of I (R = R¹ = H) takes place on the pyrazine ring and, in the case of I (R = R¹ = Ph) (II) the pyridine ring is reduced. In pure AcOH this reduction provides only 1,2,3,4-tetrahydropyrido[2,3-b]pyrazines. A study of the reduction of II and several di- and tetrahydro derivatives as a function of solvent acidity suggests that the observed selectivity could result from the isomerization of partially hydrogenated intermediates. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Category: pyrazines).

Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazines are volatile compounds that are used in the cosmetic, food, flavor, and fragrance industries. Substituted pyrazines have been found as subunits of multiple synthetically constructed therapeutic agents, as well as several natural products.Category: pyrazines

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Scaffold evaluation of liguzinediol analogs as novel cardiotonic agents was written by Liu, Z.;Li, W.;Qin, K.;Wen, K.;Zhu, C. J.;Li, N. G.;Bian, H. M.;Wen, H. M.;Chen, L.. And the article was included in Pharmazie in 2013.Reference of 75907-74-3 This article mentions the following:

Liguzinediol (LZDO) could mediate the pos. inotropic effects through sarcoplasmic reticulum Ca²⁺ ATPase-dependent mechanism without the risk of arrhythmia. However, the pharmacophore of LZDO contributed to the activities was not clear. The aim of this work was to explore the relationship between pos. inotropic effect and scaffold of LZDO as well as to check whether the pharmacophore of LZDO on anti-heart failure activity was located at the pyrazine ring. A series of LZDO analogs (3a-b, 4a-b, 9-19) were designed and synthesized, and their activities were evaluated on isolated heart contractility by Lan- gendorff perfusion. The results showed that the efficacy of LZDO was reduced when the hydroxyl, carboxyl or ester moieties at the side chain position of LZDO were induced, and the para-dihydroxy in LZDO was necessary for its activity. Thus, the pharmacophore of the pos. inotropic effect might be located at the whole scaffold of LZDO, but not at the pyrazine ring. The finding may provide an important clue of the pharmacophore for the development of novel cardiotonic agents. In the experiment, the researchers used many compounds, for example, (3,5,6-Trimethylpyrazin-2-yl)methanol (cas: 75907-74-3Reference of 75907-74-3).

(3,5,6-Trimethylpyrazin-2-yl)methanol (cas: 75907-74-3) belongs to pyrazine derivatives. Pyrazine has the elements of symmetry for the point group D2h. It has three mutually perpendicular two-fold axes. It also has three mutually perpendicular planes of symmetry. As a result, pyrazine also has a centre of symmetry. A large number of pyrazine derivatives are known for their antitumor, antibiotic, anticonvulsant, antituberculosis, and diuretic activities.Reference of 75907-74-3

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Catalytic hydrogenation of pyrazinecarboxylic acids was written by Felder, E.;Maffei, S.;Pietra, S.;Pitre, D.. And the article was included in Helvetica Chimica Acta in 1960.Quality Control of Ethyl pyrazine-2-carboxylate This article mentions the following:

Reduction of several pyrazinecarboxylic acids and derivatives over Pd-C generally gave piperazines. Reduction of 3.1 g. pyrazine-2-carboxylic acid (I) in 200 ml. H₂O containing 1.6 g. KOH at 50° and atm. pressure over 10% Pd-C gave in 90 min. 94% piperazine-2-carboxylic acid (II), resolved into optical isomers through its 1:2 salt with (+)-10-camphorsulfonic acid; (-)-II camphorsulfonate m. 264-5° (decomposition), [α]²⁵_D 14.9° (c 5, H₂O); (-)-II m. 291-3° (decomposition), [α]²⁰_D -3.9° (c 6.5, H₂O), obtained by anion exchange of the salt. Similar reduction of pyrazine-2,3-dicarboxylic acid (di-Et ester b₂ 138-40°) gave 83% piperazine-2,3-dicarboxylic acid (III); resolution through the 1:1 salt with (+)-10-camphorsulfonic acid gave (+)-III camphorsulfonate, m. 233° (decomposition), [α]²²_D 14.08° (c 6, H₂O); (+)-III, m. 296° (decomposition), [αa]²⁰_D 0.32° (c 21, N NH₄OH). In similar reductions were prepared the following piperazines (substituents, m.p., and % yield given): 2,5-(CO₂H)₂, 205-7°, 93 [di-HCl salt m. 278° (decomposition)]; 2,6-(CO₂H)₂, 305-6°, 96 [di-HCl salt m. 242-3° (decomposition)]; 2,3-(CO₂Me)₂, -, 50 (di-HCl salt m. 199°; picrate m. 192°); 2,3-(CO₂Et)₂, 55°, 57 (picrate m. 182°); 2-CONH₂, 143-4° (decomposition), 83 [di-HCl salt m. 132-4° (decomposition)]; 2 (or 3)-CO₂H, 3 (or 2)-CONH₂ (IV), 189-90°, 74; 2,3-(CONH₂)₂, 204-8° (decomposition), 65. Reduction in EtOH of pyrazine-2,3-dicarboxylic acid imide gave 50% tetrahydropyrazine-2,3-dicarboxylic acid imide, red solid, m. 217-18° (decomposition), reduced in alk. solution to IV. I Me ester and I Et ester, m. 49°, b₆ 120-2, gave no isolable reduction products. Pyrazine-2,3-dicarboxamide gave the monoamide, m. 170-1°, by partial saponification with NaOH solution In the experiment, the researchers used many compounds, for example, Ethyl pyrazine-2-carboxylate (cas: 6924-68-1Quality Control of Ethyl pyrazine-2-carboxylate).

Ethyl pyrazine-2-carboxylate (cas: 6924-68-1) belongs to pyrazine derivatives. Pyrazine is an N-heterocyclic moiety, and it can be easily prepared from ethylenediamine and 1,2-diketone, α-hydroxyketone, α-methyl ketone. Substituted pyrazines have been found as subunits of multiple synthetically constructed therapeutic agents, as well as several natural products.Quality Control of Ethyl pyrazine-2-carboxylate

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Correlation and Estimation of Gas-Chloroform and Water-Chloroform Partition Coefficients by a Linear Free Energy Relationship Method was written by Abraham, Michael H.;Platts, James A.;Hersey, Anne;Leo, Albert J.;Taft, Robert W.. And the article was included in Journal of Pharmaceutical Sciences in 1999.Reference of 6924-68-1 This article mentions the following:

A linear free energy relation, LFER, has been used to correlate 150 values of gas-chloroform partition coefficients, as log L^chl with a standard deviation, sd, of 0.23 log units, a correlation coefficient r² of 0.985, and an F-statistic of 1919. The equation reveals that bulk chloroform is dipolar/polarizable, of little hydrogen-bond basicity, but as strong a hydrogen-bond acid as bulk methanol or bulk ethanol. However, the main influence on gaseous solubility in chloroform is due to solute-solvent London dispersion interactions. A slightly modified LFER has been used to correlate 302 values of water-chloroform partition coefficients, as log P_chl. The correlation equation predicts log P_chl for a further 34 compounds not used in the equation with sd = 0.17 log units. When the LFER is applied to all 335 log P_chl values, the resulting equation has sd = 0.25, r² = 0.971, and F = 2218. The importance of these results lies in the recent use of the water-chloroform system as a measure of solute lipophilicity and of recent calculations of the transfer of nucleic acids from water to chloroform. Furthermore if the water-chloroform system is to be generally used as a measure of solute lipophilicity in drug design, it will be of very considerable help to have a predictive procedure available. The authors have shown that the multiple linear regression anal. (MLRA) method is capable of correlating log P_chl values rather better than computational methods although the present MLRA method suffers from the possible lack of availability of the required descriptors. In the experiment, the researchers used many compounds, for example, Ethyl pyrazine-2-carboxylate (cas: 6924-68-1Reference of 6924-68-1).

Ethyl pyrazine-2-carboxylate (cas: 6924-68-1) belongs to pyrazine derivatives. Pyrazine derivatives have antitumor, antibiotic, anticonvulsant, antituberculous and diuretic effects as well as kinase, enzymatic and potent tubulin and FtsZ polymerization inhibitory activities. Pyrazines undergo nearly all of the same reactions as pyrimidines, from nucleophilic substitution (SNAr) to palladium-catalyzed cross coupling reactions.Reference of 6924-68-1

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Design, synthesis and antitrypanosomal activity of heteroaryl-based 1,2,4-triazole and 1,3,4-oxadiazole derivatives was written by Shaykoon, Montaser Sh.;Marzouk, Adel A.;Soltan, Osama M.;Wanas, Amira S.;Radwan, Mohamed M.;Gouda, Ahmed M.;Youssif, Bahaa G. M.;Abdel-Aziz, Mohamed. And the article was included in Bioorganic Chemistry in 2020.Application of 6924-68-1 This article mentions the following:

Two series of novel 1,2,4-triazol-3-yl-thioacetamides I [X = O, NOH; R = 4-pyridyl, 2-pyrazinyl] and 5-pyrazin-2-yl-3H-[1,3,4]oxadiazole-2-thiones II [R¹ = 4-Me, 2-F, 3,4,5-tri-MeO, etc.] were synthesized. The prepared compounds I and II were identified using ¹H NMR, ¹³C NMR and elemental anal. The synthesized compounds I and II [R¹ = 2-F, 4-F, 4-Me, 2-MeO, 4-MeO] were evaluated with α-difluoromethylornithine (DFMO) as a control drug for their in-vitro antitrypanosomal activity against Trypanosoma brucei. Results showed that compound I [X = O, R = 4-pyridyl (III)] was the most active compound in general and also more potent than control DFMO. Compound III was 8 folds more potent than the reference with IC₅₀ of 0.79μM and IC₉₀ of 1.35μM, resp. compared to DFMO (IC₅₀ = 6.10μM and IC₉₀ of 8.66μM). The tested compounds showed moderate cytotoxicity with selectivity indexes ranging from 12 to 102 against L6 cells. Docking study was performed into ten of T. brucei enzymes which have been identified as potential/valid targets for most of the antitrypanosomal agents. The results of the docking study revealed high binding scores toward many of the selected enzymes. A good correlation was observed only between log (IC₅₀) of antitrypanosomal activity of the new compounds and their calculated Ki values against TryR enzyme (R² = 0.726). Compound III, the most active as antitrypanosomal agents exhibited similar binding orientation and interaction to those of WP6 against TryR enzyme. However, in a next round of work, a complementary studies will be carried out to clarify the mechanism of action of these compounds In the experiment, the researchers used many compounds, for example, Ethyl pyrazine-2-carboxylate (cas: 6924-68-1Application of 6924-68-1).

Ethyl pyrazine-2-carboxylate (cas: 6924-68-1) belongs to pyrazine derivatives. Pyrazines are part of several biologically active polycyclic compounds; examples are quinoxalines, phenazines; and the bio-luminescent natural products pteridines, flavins, and their derivatives. Substituted pyrazines have been found as subunits of multiple synthetically constructed therapeutic agents, as well as several natural products.Application of 6924-68-1

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Some 5-azaquinoxalines and 4-azabenzimidazoles was written by Petrow, V.;Saper, J.. And the article was included in Journal of the Chemical Society in 1948.Application In Synthesis of Pyrido[2,3-b]pyrazine This article mentions the following:

3-Nitro-2-aminopyridine (2.5 g.), 7.5 g. reduced Fe, 15 mL. EtOH, 8 mL. H₂O, and 0.5 mL. concentrated HCl, refluxed 1 h., give 75% 2,3-diaminopyridine (I), m. 118.5-19.5° (m.ps. corrected). I (1.5 g.) and 4 g. (CHO)₂.NaHSO₃ (II) in 20 mL. aqueous EtOH, refluxed 1 h., give 17% 5-azaquinoxaline (III), m. 147-8°; I and Ac₂, refluxed 1.5 h. in C₆H₆, give 40% of the 2,3-di-Me derivative of III, straw, m. 148-9°. 5-Bromo-2-aminopyridine (20 g.), slowly added to 120 mL. H₂SO₄ (d. 1.4) at 0°, the solution treated dropwise with 3.4 mL. fuming HNO₃, and the mixture kept 1 h. at 0°, 1 h. at room temperature, and 1 h. at 50-60°, gives 49% of the 3-NO₂ derivative, m. 211-12°; reduction with Fe as above gives 70% 5-bromo-2,3-diaminopyridine (IV), m. 214-15°, decompose 255°. IV (1.9 g.) and 2.6 g. II in 20 mL. EtOH, heated 1 h. on the water bath, give 36% of the 7-Br derivative (V) of III, m. 167°; 1 g. Ac₂ and 1.9 g. IV in 40 mL. EtOH, refluxed 30 min., give 66% of the 7-bromo-2,3-dimethyl derivative of III, light gray, m. 150° (decomposition); 2.2 g. Bz₂ and 2 g. IV in 60 mL. C₆H₆, refluxed 1.5 h., give 65% of the 7-bromo-2,3-diphenyl derivative of III, yellow, m. 156-8° [trimethiodide, red, m. 192° (decomposition)]; 1 g. IV and 1.1 g. phenanthrenequinone in 10 mL. AcOH, refluxed 1.5 h., give 7-bromophenanthro[9′,10′,2,3]-5-azaquinoxaline, golden, m. 222°. 3-Nitro-2,6-diaminopyridine (1.5 g.), 4 g. Fe, 10 mL. EtOH, 5 mL. H₂O, and 0.5 mL. concentrated HCl, refluxed 10 min., 2 g. Bz₂ in EtOH added, and the mixture refluxed an addnl. hr., give 26% 6-amino-2,3-diphenyl-5-azaquinoxaline, light yellow, m. 273°; Ac derivative, m. 268-9°. V (1.4 g.) and 2 mL. 100% H₂O₂ in 6 mL. AcOH, heated 1 h. at 70°, give 73% of the mono-N-oxide, m. 286° (decomposition); the 2,3-di-Me derivative of III did not react with H₂O₂ and the product from the 2,3-di-Ph derivative could not be purified. I (700 mg.) and 1 mL. 98% HCO₂H, refluxed 1 h., give 52% 4-azabenzimidazole, m. 153-4°. 5-Bromo-2,3-diacetamidopyridine, heated about 2 min. at 315°, gives 50% 6-bromo-2-methyl-4-azabenzimidazole, m. 299°. I (1.1 g.) and 600 mg. CO(NH₂)₂, heated 30 min. at 130-40°, give 2-hydroxy-4-azabenzimidazole (VI), m. 274°. IV (900 mg.) and 300 mg. CO(NH₂)₂, heated 45 min. at 160-70°, give the 6-Br derivative of VI, with 0.5 mol. AcOH, m. above 300°. I (1 g.) and 800 mg. CS₂ in 20 mL. EtOH, refluxed 5 h., give 58% 4-azabenzimidazole-2-thiol (VII), cream, m. above 300°; 6-Br derivative of VII, light yellow, m. above 300°, results from IV and CS₂ or CS(NH₂)₂. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Application In Synthesis of Pyrido[2,3-b]pyrazine).

Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine derivatives have antitumor, antibiotic, anticonvulsant, antituberculous and diuretic effects as well as kinase, enzymatic and potent tubulin and FtsZ polymerization inhibitory activities. Substituted pyrazines have been found as subunits of multiple synthetically constructed therapeutic agents, as well as several natural products.Application In Synthesis of Pyrido[2,3-b]pyrazine

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Discovery of New Monocarbonyl Ligustrazine-Curcumin Hybrids for Intervention of Drug-Sensitive and Drug-Resistant Lung Cancer was written by Ai, Yong;Zhu, Bin;Ren, Caiping;Kang, Fenghua;Li, Jinlong;Huang, Zhangjian;Lai, Yisheng;Peng, Sixun;Ding, Ke;Tian, Jide;Zhang, Yihua. And the article was included in Journal of Medicinal Chemistry in 2016.Computed Properties of C8H12N2O This article mentions the following:

The elevation of oxidative stress preferentially in cancer cells by inhibiting thioredoxin reductase (TrxR) and/or enhancing reactive oxygen species (ROS) production has emerged as an effective strategy for selectively targeting cancer cells. In this study, we designed and synthesized 21 ligustrazine-curcumin hybrids (10a-u). Biol. evaluation indicated that the most active compound 10d significantly inhibited the proliferation of drug-sensitive (A549, SPC-A-1, LTEP-G-2) and drug-resistant (A549/DDP) lung cancer cells but had little effect on nontumor lung epithelial-like cells (HBE). Furthermore, 10d suppressed the TrxR/Trx system and promoted intracellular ROS accumulation and cancer cell apoptosis. Addnl., 10d inhibited the NF-κB, AKT, and ERK signaling, P-gp-mediated efflux of rhodamine 123, P-gp ATPase activity, and P-gp expression in A549/DDP cells. Finally, 10d repressed the growth of implanted human drug-resistant lung cancer in mice. Together, 10d acts a novel TrxR inhibitor and may be a promising candidate for intervention of lung cancer. In the experiment, the researchers used many compounds, for example, (3,5,6-Trimethylpyrazin-2-yl)methanol (cas: 75907-74-3Computed Properties of C8H12N2O).

(3,5,6-Trimethylpyrazin-2-yl)methanol (cas: 75907-74-3) belongs to pyrazine derivatives. Pyrazines are volatile compounds that are used in the cosmetic, food, flavor, and fragrance industries. Pyrazine-based skeletons were incorporated into agents targeting a range of ailments. Many derivatives were synthesized and evaluated as potential cancer treatments.Computed Properties of C8H12N2O

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Syntheses and structure-activity relationship (SAR) studies of 2,5-diazabicyclo[2.2.1]heptanes as novel α7 neuronal nicotinic receptor (NNR) ligands was written by Li, Tao;Bunnelle, William H.;Ryther, Keith B.;Anderson, David J.;Malysz, John;Helfrich, Rosalind;Gronlien, Jens H.;Hakerud, Monika;Peters, Dan;Schrimpf, Michael R.;Gopalakrishnan, Murali;Ji, Jianguo. And the article was included in Bioorganic & Medicinal Chemistry Letters in 2010.Safety of 2-Bromo-5-chloropyrazine This article mentions the following:

Biaryl substituted 2,5-diazabicyclo[2.2.1]heptanes have been synthesized and tested for their affinity toward α7 neuronal nicotinic receptors (NNRs). SAR studies established that 5-N-Me substituent, heteroaryl linker and the nature of terminal aryl group are critical for the ligand to achieve potent α7 NNR agonist activity. In the experiment, the researchers used many compounds, for example, 2-Bromo-5-chloropyrazine (cas: 912773-21-8Safety of 2-Bromo-5-chloropyrazine).

2-Bromo-5-chloropyrazine (cas: 912773-21-8) belongs to pyrazine derivatives. Pyrazinesare six-membered aromatic heterocyclic organic compounds with two nitrogen atoms at 1,4-positions. Pyrazine is a weaker base (pKb = 13.4) than pyridine (pKb = 8.8), pyrimidine (pKb = 12.7). Pyrazines are chemical compounds (technically called “methoxypyrazines”) found in grape skin and stems that are responsible for many “green” flavors in wine. Levels of pyrazines are dependent on viticultural practices, climate, and grape variety.Safety of 2-Bromo-5-chloropyrazine

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem