Pyrazines

Are molecular 5,8-π-extended quinoxaline derivatives good chromophores for photoluminescence applications? was written by Mancilha, Fabiana S.;Da Silveira Neto, Brenno A.;Lopes, Aline S.;Moreira, Paulo F. Jr.;Quina, Frank H.;Goncalves, Reinaldo S.;Dupont, Jairton. And the article was included in European Journal of Organic Chemistry in 2006.Recommanded Product: 5,8-Dibromoquinoxaline This article mentions the following:

The synthesis of a new series of photoluminescent compounds, namely 5,8-diarylquinoxalines (aryl = Ph, 4-FC₆H₄,4-MeOC₆H₄, $-NCC₆H₄), was achieved by a direct Suzuki cross-coupling reaction using a NCP-pincer palladacycle. The electrochem. and photophys. properties of these compounds were also investigated. Four new 4,8-diaryl-2,1,3-benzothiadiazoles were also synthesized in order to enable a comparison between the two types of nitrogen-containing π-extended heterocycles. The substitution of a hydrogen atom at the 4-position of the aryl group attached to the quinoxaline or benzothiadiazole base by either electron-donating or -withdrawing groups results in an increase in the bandgap energy (from 2.21 to 2.52 eV) of π-extended 5,8-quinoxaline derivatives and a decrease in the bandgap energy (from 2.65 to 2.40 eV) of π-extended 2,1,3-benzothiadiazoles. Moreover, π-extension at the 5- and 8-positions of the quinoxaline core is not essential for the photoluminescence of these compounds and 4,7-π-extended 2,1,3-benzothiadiazoles are far better candidates for luminescence applications than are the quinoxaline derivatives In the experiment, the researchers used many compounds, for example, 5,8-Dibromoquinoxaline (cas: 148231-12-3Recommanded Product: 5,8-Dibromoquinoxaline).

5,8-Dibromoquinoxaline (cas: 148231-12-3) 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.Recommanded Product: 5,8-Dibromoquinoxaline

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Donor-Acceptor Polymers for Electrochemical Supercapacitors: Synthesis, Testing, and Theory was written by DiCarmine, Paul M.;Schon, Tyler B.;McCormick, Theresa M.;Klein, Philipp P.;Seferos, Dwight S.. And the article was included in Journal of Physical Chemistry C in 2014.Application of 148231-12-3 This article mentions the following:

Donor-acceptor polymers can store both a pos. and neg. charge allowing them to function as both the pos. and neg. charge storage material in a supercapacitor device, however few were explored for this application. Here, the synthesis is described of several donor-acceptor polymers and their electrodeposited polymer electrodes. Differing mol. structures are used to examine the effect of electron acceptor concentration and show that device stability can be improved significantly by increasing the acceptor concentration Further, the computational insight is provided into the important chem. requirements for achieving even higher performance supercapacitors based on donor-acceptor conjugated polymers. Supercapacitor devices with specific energy and specific power as high as 11 Wh kg^-1 (at 0.5 A g^-1) and 20 kW kg^-1 (at 50 A g^-1 with an energy of 3.6 Wh kg^-1) are reported, which are some of the highest values achieved to date. In the experiment, the researchers used many compounds, for example, 5,8-Dibromoquinoxaline (cas: 148231-12-3Application of 148231-12-3).

5,8-Dibromoquinoxaline (cas: 148231-12-3) belongs to pyrazine derivatives. Pyrazine is a symmetrical molecule with point group D2h. Pyrazine is less basic than pyridine, pyridazine and pyrimidine. Pyrazine heterocycles and their benzo derivatives possess many interesting properties, including chemical reactivity profiles, and have diverse applications in total synthesis, medicine, chemical biology, materials, dyes, and imaging.Application of 148231-12-3

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

Two-component gel of a D-π-A-π-D carbazole donor and a fullerene acceptor was written by Xue, Pengchong;Xu, Qiuxia;Gong, Peng;Qian, Chong;Zhang, Zhenqi;Jia, Junhui;Zhao, Xin;Lu, Ran;Ren, Aimin;Zhang, Tierui. And the article was included in RSC Advances in 2013.Electric Literature of C8H4Br2N2 This article mentions the following:

A D-π-A-π-D carbazole derivative (PCQ) with a quinoxaline moiety was designed and synthesized. Its photophys. properties in solution were studied. Moreover, PCQ was found to be a highly efficient gelator toward various apolar and polar organic solvents with the critical gelation concentrations (CGCs) as low as 0.06 wt/vol%. Spectral studies and mol. dynamic stimulation revealed that the intermol. H-bonds and π-π stacking interactions might be responsible for guiding the self-assembly processes and the gel formation. Interestingly, PCQ could construct two-component gel with fullerene derivative driven by intermol. hydrogen bonds. Moreover, the two-component gel film could generate photocurrent under light irradiation, indicating photo-induced electron transfer from the PCQ aggregate to the fullerene derivative In the experiment, the researchers used many compounds, for example, 5,8-Dibromoquinoxaline (cas: 148231-12-3Electric Literature of C8H4Br2N2).

5,8-Dibromoquinoxaline (cas: 148231-12-3) 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.Electric Literature of C8H4Br2N2

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

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

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

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

A Kinome-Wide Selective Radiolabeled TrkB/C Inhibitor for in Vitro and in Vivo Neuroimaging: Synthesis, Preclinical Evaluation, and First-in-Human was written by Bernard-Gauthier, Vadim;Bailey, Justin J.;Mossine, Andrew V.;Lindner, Simon;Vomacka, Lena;Aliaga, Arturo;Shao, Xia;Quesada, Carole A.;Sherman, Phillip;Mahringer, Anne;Kostikov, Alexey;Grand’Maison, Marilyn;Rosa-Neto, Pedro;Soucy, Jean-Paul;Thiel, Alexander;Kaplan, David R.;Fricker, Gert;Wangler, Bjorn;Bartenstein, Peter;Schirrmacher, Ralf;Scott, Peter J. H.. And the article was included in Journal of Medicinal Chemistry in 2017.Formula: C9H8ClN3O2 This article mentions the following:

The proto-oncogenes NTRK1/2/3 encode the tropomyosin receptor kinases TrkA/B/C which play pivotal roles in neurobiol. and cancer. We describe herein the discovery of [¹¹C]-(R)-3 ([¹¹C]-(R)-IPMICF16), a first-in-class positron emission tomog. (PET) TrkB/C-targeting radiolabeled kinase inhibitor lead. Relying on extensive human kinome vetting, we show that (R)-3 is the most potent and most selective TrkB/C inhibitor characterized to date. It is demonstrated that [¹¹C]-(R)-3 readily crosses the blood-brain barrier (BBB) in rodents and selectively binds to TrkB/C receptors in vivo, as evidenced by entrectinib blocking studies. Substantial TrkB/C-specific binding in human brain tissue is observed in vitro, with specific reduction in the hippocampus of Alzheimer’s disease (AD) vs. healthy brains. We addnl. provide preliminary translational data regarding the brain disposition of [¹¹C]-(R)-3 in primates including first-in-human assessment. These results illustrate for the first time the use of a kinome-wide selective radioactive chem. probe for endogenous kinase PET neuroimaging in human. In the experiment, the researchers used many compounds, for example, Ethyl 6-chloroimidazo[1,2-b]pyridazine-3-carboxylate (cas: 1150566-27-0Formula: C9H8ClN3O2).

Ethyl 6-chloroimidazo[1,2-b]pyridazine-3-carboxylate (cas: 1150566-27-0) 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 and a variety of alkylpyrazines are flavor and aroma compounds found in baked and roasted goods. Tetramethylpyrazine (also known as ligustrazine) is reported to scavenge superoxide anion and decrease nitric oxide production in human Granulocytes.Formula: C9H8ClN3O2

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