Month: October 2022

In 2017,Spaulding, Andrew; Takrouri, Khuloud; Mahalingam, Pornachandran; Cleary, Dillon C.; Cooper, Harold D.; Zucchi, Paola; Tear, Westley; Koleva, Bilyana; Beuning, Penny J.; Hirsch, Elizabeth B.; Aggen, James B. published 《Compound design guidelines for evading the efflux and permeation barriers of Escherichia coli with the oxazolidinone class of antibacterials: Test case for a general approach to improving whole cell Gram-negative activity》.Bioorganic & Medicinal Chemistry Letters published the findings.Application In Synthesis of 6-Bromopyridin-3-amine The information in the text is summarized as follows:

Previously the authors reported the results from an effort to improve Gram-neg. antibacterial activity in the oxazolidinone class of antibiotics via a systematic medicinal chem. campaign focused entirely on C-ring modifications. In that series the authors set about testing if the efflux and permeation barriers intrinsic to the outer membrane of Escherichia coli could be rationally overcome by designing analogs to reside in specific property limits associated with Gram-neg. activity: (i) low MW (<400), (ii) high polarity (clogD7.4 <1), and (iii) zwitterionic character at pH 7.4. Indeed, the authors observed that only analogs residing within these limits were able to overcome these barriers. Herein the authors report the results from a parallel effort where the authors explored structural changes throughout all three rings in the scaffold for the same purpose. Compounds were tested against a diagnostic MIC panel of Escherichia coli and Staphylococcus aureus strains to determine the impact of combining structural modifications in overcoming the OM barriers and in bridging the potency gap between the species. The results demonstrated that distributing the charge-carrying moieties across two rings was also beneficial for avoidance of the outer membrane barriers. Importantly, anal. of the structure-permeation relationship (SPR) obtained from this and the prior study indicated that in addition to MW, polarity, and zwitterionic character, having ≤4 rotatable bonds is also associated with evasion of the OM barriers. These combined results provide the medicinal chemist with a framework and strategy for overcoming the OM barriers in GNB in antibacterial drug discovery efforts. The experimental part of the paper was very detailed, including the reaction process of 6-Bromopyridin-3-amine(cas: 13534-97-9Application In Synthesis of 6-Bromopyridin-3-amine)

6-Bromopyridin-3-amine(cas: 13534-97-9) belongs to anime. Left-handed and right-handed forms (mirror-image configurations, known as optical isomers or enantiomers) are possible when all the substituents on the central nitrogen atom are different (i.e., the nitrogen is chiral). With amines, there is extremely rapid inversion in which the two configurations are interconverted.Application In Synthesis of 6-Bromopyridin-3-amine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

In 2019,Angewandte Chemie, International Edition included an article by Koniarczyk, J. Luke; Greenwood, Jacob W.; Alegre-Requena, Juan V.; Paton, Robert S.; McNally, Andrew. SDS of cas: 100-48-1. The article was titled 《A Pyridine-Pyridine Cross-Coupling Reaction via Dearomatized Radical Intermediates》. The information in the text is summarized as follows:

A pyridine-pyridine coupling reaction has been developed between pyridyl phosphonium salts and cyanopyridines using B2pin2 as an electron-transfer reagent. Complete regio- and cross-selectivity are observed when forming a range of valuable 2,4′-bipyridines. Phosphonium salts were found to be the only viable radical precursors in this process, and mechanistic studies indicate that the process does not proceed through a Minisci-type coupling involving a pyridyl radical. Instead, a radical-radical coupling process between a boryl phosphonium pyridyl radical and a boryl-stabilized cyanopyridine radical explains the C-C bond-forming step. In the experiment, the researchers used many compounds, for example, 4-Cyanopyridine(cas: 100-48-1SDS of cas: 100-48-1)

4-Cyanopyridine(cas: 100-48-1) belongs to pyridine. Pyridine’s structure is isoelectronic with that of benzene, but its properties are quite different. Pyridine is completely miscible with water, whereas benzene is only slightly soluble. Like all hydrocarbons, benzene is neutral (in the acid–base sense), but because of its nitrogen atom, pyridine is a weak base.SDS of cas: 100-48-1

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

In 2019,Journal of the American Chemical Society included an article by Lundrigan, Travis; Welsh, Erin N.; Hynes, Toren; Tien, Chieh-Hung; Adams, Matt R.; Roy, Kayelani R.; Robertson, Katherine N.; Speed, Alexander W. H.. SDS of cas: 53939-30-3. The article was titled 《Enantioselective Imine Reduction Catalyzed by Phosphenium Ions》. The information in the text is summarized as follows:

The first use of phosphenium cations in asym. catalysis is reported. A diazaphosphenium triflate, prepared in two or three steps on a multigram scale from com. available materials, catalyzes the hydroboration or hydrosilylation of cyclic imines with enantiomeric ratios of up to 97:3. Catalyst loadings are as low as 0.2 mol %. Twenty-two aryl/heteroaryl pyrrolidines and piperidines were prepared using this method. Imines containing functional groups such as thiophenes or pyridyl rings that can challenge transition-metal catalysts were reduced employing these systems. In the experimental materials used by the author, we found 5-Bromo-2-chloropyridine(cas: 53939-30-3SDS of cas: 53939-30-3)

5-Bromo-2-chloropyridine(cas: 53939-30-3) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. SDS of cas: 53939-30-3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

The author of 《Catalytic enantioselective pyridine N-oxidation》 were Hsieh, Sheng-Ying; Tang, Yu; Crotti, Simone; Stone, Elizabeth A.; Miller, Scott J.. And the article was published in Journal of the American Chemical Society in 2019. COA of Formula: C5H3BrClN The author mentioned the following in the article:

The catalytic, enantioselective N-oxidation of substituted pyridines is described. The approach is predicated on a biomol.-inspired catalytic cycle wherein high levels of asym. induction are provided by aspartic-acid-containing peptides as the aspartyl side chain shuttles between free acid and peracid forms. Desymmetrizations of bis(pyridine) substrates bearing a remote pro-stereogenic center substituted with a group capable of hydrogen bonding to the catalyst are demonstrated. Our approach presents a new entry into chiral pyridine frameworks in a heterocycle-rich mol. environment. Representative functionalizations of the enantioenriched pyridine N-oxides further document the utility of this approach. Demonstration of the asym. N-oxidation in two venerable drug-like scaffolds, Loratadine and Varenicline, show the likely generality of the method for highly variable and distinct chiral environments, while also revealing that the approach is applicable to both pyridines and 1,4-pyrazines. In the experiment, the researchers used many compounds, for example, 5-Bromo-2-chloropyridine(cas: 53939-30-3COA of Formula: C5H3BrClN)

5-Bromo-2-chloropyridine(cas: 53939-30-3) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. COA of Formula: C5H3BrClN

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

The author of 《Fast Oxygen Reduction Catalyzed by a Copper(II) Tris(2-pyridylmethyl)amine Complex through a Stepwise Mechanism》 were Langerman, Michiel; Hetterscheid, Dennis G. H.. And the article was published in Angewandte Chemie, International Edition in 2019. Formula: C12H13N3 The author mentioned the following in the article:

Catalytic pathways for the reduction of dioxygen can either give H2O or peroxide as the reaction product. The electrocatalytic reduction of O2 by the pyridylalkylamine Cu complex [Cu(tmpa)(L)]2+ in a neutral aqueous solution follows a stepwise 4 e-/4 H+ pathway, in which H2O2 is formed as a detectable intermediate and subsequently reduced to H2O in two sep. catalytic reactions. These homogeneous catalytic reactions are 1st order in catalyst. Coordination of O2 to CuI is the rate-determining step in the formation of the peroxide intermediate. Also, electrochem. studies of the reaction kinetics revealed a high turnover frequency of 1.5 × 105 s-1, the highest reported for any mol. Cu catalyst. The experimental part of the paper was very detailed, including the reaction process of Bis(pyridin-2-ylmethyl)amine(cas: 1539-42-0Formula: C12H13N3)

Bis(pyridin-2-ylmethyl)amine(cas: 1539-42-0) is a secondary amine with two picolyl substituents. As a tridentate ligand this compound provides three nitrogen donors that affords good selectivity for Zn2+ over biologically relevant metals such as Na+, K+, Mg2+ and Ca2+, and leaves coordination sites free for anion binding. Formula: C12H13N3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

The author of 《Palladium-Catalyzed Regioselective C-H Iodination of Unactivated Alkenes》 were Schreib, Benedikt S.; Carreira, Erick M.. And the article was published in Journal of the American Chemical Society in 2019. Quality Control of Picolinic acid The author mentioned the following in the article:

A palladium-catalyzed C-H iodination of unactivated alkenes is reported. A picolinamide directing group enables the regioselective functionalization of a wide array of olefins to furnish iodination products as single stereoisomers. Mechanistic studies suggest the reversible formation of a six-membered alkenyl palladacycle intermediate through a turnover-limiting C-H activation. In the part of experimental materials, we found many familiar compounds, such as Picolinic acid(cas: 98-98-6Quality Control of Picolinic acid)

Picolinic acid(cas: 98-98-6) is used as a chelate for alkaline earth metals. Used to prepare picolinato ligated transition metal complexes. In synthetic organic chemistry, has been used as a substrate in the Mitsunobu reaction and in the Hammick reaction.Quality Control of Picolinic acid

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

《Substituted 4-phenylthiazoles: Development of potent and selective A1, A3 and dual A1/A3 adenosine receptor antagonists》 was published in European Journal of Medicinal Chemistry in 2020. These research results belong to Abdelrahman, Aliaa; Yerande, Swapnil G.; Namasivayam, Vigneshwaran; Klapschinski, Tim A.; Alnouri, Mohamad Wessam; El-Tayeb, Ali; Mueller, Christa E.. Category: pyridine-derivatives The article mentions the following:

Adenosine acts as a powerful signaling mol. via four distinct G protein-coupled receptors, designated A1, A2A, A2B and A3 adenosine receptors (ARs). A2A and A2B ARs are Gs-coupled, while A1 and A3 ARs inhibit cAMP production via Gi proteins. Antagonists for A1 and A3 ARs may be useful for the treatment of (neuro)inflammatory diseases including acute kidney injury and kidney failure, pulmonary diseases, and Alzheimer’s disease. In the present study, we optimized the versatile 2-amino-4-phenylthiazole scaffold by introducing substituents at N2 and C5 to obtain A1 and A3 AR antagonists including dual-target compounds Selective A1 antagonists with (sub)nanomolar potency were produced, e.g. 11 and 13. These compounds showed species differences being significantly more potent at the rat as compared to the human A1 AR, and were characterized as inverse agonists. Several potent and selective A3 AR antagonists, e.g. 7, 8, 17 and 22 (Ki values of 5-9 nM at the human A3 AR) were prepared, which were much less potent at the rat orthologue. Moreover, dual A1/A3 antagonists (10, 18) were developed showing Ki values between 8 and 42 nM. Docking and mol. dynamic simulation studies using the crystal structure of the A1 AR and a homol. model of the A3 AR were performed to rationalize the observed structure-activity relationships. The experimental part of the paper was very detailed, including the reaction process of 2-(Bromomethyl)pyridine hydrobromide(cas: 31106-82-8Category: pyridine-derivatives)

2-(Bromomethyl)pyridine hydrobromide(cas: 31106-82-8) belongs to pyridine. Pyridine is widely used in the precursor to agrochemicals and pharmaceuticals. Also, it is used as an important reagent and organic solvent.Category: pyridine-derivatives

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

《The effects of chromium picolinate on glucose and lipid metabolism in running rats》 was published in Journal of Trace Elements in Medicine and Biology in 2020. These research results belong to Pala, Ragip; Sari, Mehmet Akif; Erten, Fusun; Er, Besir; Tuzcu, Mehmet; Orhan, Cemal; Deeh, Patrick Brice Defo; Sahin, Nurhan; Cinar, Vedat; Komorowski, James R.; Sahin, Kazim. COA of Formula: C6H5NO2 The article mentions the following:

We aimed to elucidate the effects of CrPic on glucose and lipid metabolism and the expression of glucose transporters in exercised rats. Forty-two male Wistar rats (8-wk-old) were distributed into six groups (n = 7) as follows: Control, CrPic, Chronic Exercise (CEx), CEx + CrPic, Acute Exercise (AEx), and AEx + CrPic. CrPic was supplemented at 400μg elemental Cr/kg of diet for 6 wk. In the AEx groups, animals were run on the treadmill at 30 m/min until exhaustion. CEx significantly lowered blood glucose (BG), total cholesterol (TC) and triglyceride (TG) levels, but elevated insulin concentration (IC), compared with control (P < 0.05). CEx significantly decreased the level of malondialdehyde (MDA) in the serum, liver, and muscle while AEx elevated it (P < 0.001 for all). CrPic also significantly reduced serum, liver, and muscle MDA levels (P < 0.001). Both AEx and CEx increased the expression of liver glucose transporter 2 (GLUT-2) and muscle GLUT-4 with the highest level in CEx rats (P < 0.05). Moreover, CrPic supplementation significantly elevated GLUT-2 and GLUT-4 expressions in the liver and muscle of sedentary and exercise-treated rats (P < 0.05). CrPic improves various metabolic parameters and reduces oxidative stress in CEx and AEx rats by decreasing BG, TC, TG, MDA levels in serum and elevating GLUT-2 and GLUT-4 expression in the liver and muscle samples. The efficacy of CrPic was more pronounced in CEx rats. In the experimental materials used by the author, we found Picolinic acid(cas: 98-98-6COA of Formula: C6H5NO2)

Picolinic acid(cas: 98-98-6) is used in the preparation of 2-Aminodihydro[1,3]thiazines as BACE 2 inhibitors and their preparation and use in the treatment of diabetes.COA of Formula: C6H5NO2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

《Highly Diastereoselective Functionalization of Piperidines by Photoredox-Catalyzed α-Amino C-H Arylation and Epimerization》 was published in Journal of the American Chemical Society in 2020. These research results belong to Walker, Morgan M.; Koronkiewicz, Brian; Chen, Shuming; Houk, K. N.; Mayer, James M.; Ellman, Jonathan A.. Synthetic Route of C33H24IrN3 The article mentions the following:

We report a photoredox catalyzed α-amino C-H arylation reaction of highly substituted piperidine derivatives with electron deficient cyano(hetero)arenes. The scope and limitations of the reaction were explored, with piperidines bearing multiple substitution patterns providing the arylated products in good yields and with high diastereoselectivity. In order to probe the mechanism of the overall transformation, optical and fluorescent spectroscopic methods were used. By employing flash-quench transient absorption spectroscopy, we were able to observe electron transfer processes associated with radical formation beyond the initial excited state Ir(ppy)3 oxidation Following the rapid and unselective C-H arylation reaction, a slower epimerization occurs to provide the high diastereomer ratio observed for a majority of the products. Several stereoisomerically pure products were re-subjected to the reaction conditions, each of which converged to the exptl. observed diastereomer ratios. The observed distribution of diastereomers corresponds to a thermodn. ratio of isomers based upon their calculated relative energies using d. functional theory (DFT). Safety: NaCN is a reaction byproduct. The results came from multiple reactions, including the reaction of fac-Tris(2-phenylpyridine)iridium(cas: 94928-86-6Synthetic Route of C33H24IrN3)

fac-Tris(2-phenylpyridine)iridium(cas: 94928-86-6) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. Synthetic Route of C33H24IrN3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

《The synthesis of a hexameric expanded hemiporphyrazine》 was written by Schrage, Briana R.; Chanawanno, Kullapa; Crandall, Laura A.; Ziegler, Christopher J.. Computed Properties of C5H7N3 And the article was included in Journal of Porphyrins and Phthalocyanines in 2020. The article conveys some information:

In this report the synthesis and characterization of a new hexameric expanded hemiporphyrazine which refer to as hexahemiporphyrazine were presented. The synthesis incorporated bis(6-amino-2-pyridyl)amine as a starting material, which could be produced from 2,6-diaminopyridine using melt reaction conditions. Bis(6-amino-2-pyridyl)amine can adopt three different conformations, two of which are observed in the free base and protonated form, and the third in the backbone of hexahemiporphyrazine. Reaction of bis(6-amino-2-pyridyl)amine and diiminoisoindoline in the presence of a catalytic amount of BF3 produces the hexihemiporphyrazine macrocycle, which was characterized spectroscopically and by X-ray crystallog. Structure elucidation reveals two inverted pyridine rings in a configuration reminiscent of that seen in hexaphyrin, however hexahemiporphyrazine lacks cross conjugation across the macrocycle. After reading the article, we found that the author used 2,6-Diaminopyridine(cas: 141-86-6Computed Properties of C5H7N3)

2,6-Diaminopyridine(cas: 141-86-6) belongs to pyridine. Pyridine and its simple derivatives are stable and relatively unreactive liquids, with strong penetrating odours that are unpleasant.Computed Properties of C5H7N3

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem