Day: January 6, 2023

Can the Formation of Pharmaceutical Cocrystals Be Computationally Predicted? I. Comparison of Lattice Energies was written by Issa, Nizar;Karamertzanis, Panagiotis G.;Welch, Gareth W. A.;Price, Sarah L.. And the article was included in Crystal Growth & Design in 2009.Recommanded Product: 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole This article mentions the following:

A cocrystal is only expected to form if it is thermodynamically more stable than the crystals of its components. To test whether this can be predicted with a current computational methodol., we compare the lattice energies of 12 cocrystals of 4-aminobenzoic acid, 8 of succinic acid and 6 of caffeine, with the sums of the lattice energies of their components. These three mols. were chosen for their potential use in pharmaceutical cocrystals and because they had sufficient determinations of cocrystals and corresponding partner crystal structures in the Cambridge Structural Database. The lattice energies were evaluated using anisotropic intermol. atom-atom potentials, with the electrostatic model and the intramol. energy penalty for changes in specified torsion angles derived from ab initio calculations on the isolated mols. The majority of the cocrystals are calculated to be more stable than their components, but the energy difference is only large in a few of the cases where the partner mol. cannot hydrogen bond to itself. More typically, the cocrystal stabilization is comparable to polymorphic energy differences and some of the specifically identified errors in the computational modeling. The cocrystals will be more stable relative to the observed disordered structures of caffeine and the kinetically preferred polymorph of 4-aminobenzoic acid, highlighting kinetic factors that may be involved in cocrystal formation. Overall, it appears that cocrystal formation should generally be predictable by comparing the relative stability of the most stable cocrystal and its pure components found on the computed crystal energy landscapes, but this is often very demanding of the accuracy of the method used to calculate the crystal energy. In the experiment, the researchers used many compounds, for example, 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole (cas: 15420-02-7Recommanded Product: 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole).

2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole (cas: 15420-02-7) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Recommanded Product: 2,5-Di(pyridin-4-yl)-1,3,4-oxadiazole

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Protonation of carbene-stabilized diphosphorus: complexation of HP₂⁺ was written by Wang, Yuzhong;Hickox, Hunter P.;Xie, Yaoming;Wei, Pingrong;Cui, Dongtao;Walter, Melody R.;Schaefer, Henry F. III;Robinson, Gregory H.. And the article was included in Chemical Communications (Cambridge, United Kingdom).SDS of cas: 628-13-7 This article mentions the following:

Reaction of carbene-stabilized diphosphorus, L:P-P:L (5) (L: = :C{N(2,6-Prⁱ₂C₆H₃)CH}₂) with pyridine hydrochloride yields [L:(H)P-P:L]Cl (6), a salt containing the HP₂⁺ cation-the elusive phosphorus analog of the well known diazonium cation, HN₂⁺. In addition to reporting the synthesis and structure, the nature of (6) was further probed by DFT computations. Interestingly, carbenes may be employed to deprotonate (6), affording the starting material (5). In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7SDS of cas: 628-13-7).

Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. Pyridine has a conjugated system of six π electrons that are delocalized over the ring. The molecule is planar and, thus, follows the Hückel criteria for aromatic systems. Halopyridines are particularly attractive synthetic building blocks in a variety of cross-coupling methods, including the Suzuki-Miyaura cross-coupling reaction.SDS of cas: 628-13-7

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Synthesis of 6-formyl-2-pyridinecarbonitrile was written by Eichinger, K.;Berbalk, H.;Kronberger, H.. And the article was included in Synthesis in 1982.SDS of cas: 1620-76-4 This article mentions the following:

Bromination of 2-cyano-6-methylpyridine with N-bromosuccinimide gave 55% 6-(dibromomethyl)-2-cyanopyridine, which, with AgNO₃, gave 72% 2-cyano-6-formylpyridine, whereas chlorination of 2-cyano-4-methylpyridine with SO₂Cl₂ gave 47% 4-(dichloromethyl)-2-cyanopyridine, which, with AgNO₃, gave 27% 2-(aminocarbonyl)-4-(dichloromethyl)pyridine. In the experiment, the researchers used many compounds, for example, 4-Methylpicolinonitrile (cas: 1620-76-4SDS of cas: 1620-76-4).

4-Methylpicolinonitrile (cas: 1620-76-4) belongs to pyridine derivatives. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Pyridine, its benzo and pyridine-based compounds play diverse roles in organic chemistry. Pyridine-based materials are valued for their optical and physical properties as well as their medical potential. SDS of cas: 1620-76-4

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Use of dipolar species under phase-transfer catalysis. Part 1. 1,3-Dipolar cycloaddition in a two-phase system was written by Alvarez-Builla, Julio;Quintanilla, M. Gloria;Abril, Catalina;Gandasegui, M. Teresa. And the article was included in Journal of Chemical Research, Synopses in 1984.COA of Formula: C7H7ClN2 This article mentions the following:

Eleven indolizines were prepared in 18-82% yield by 1,3-dipolar cycloaddition of pyridinium ylides with RCCCO₂Me (R = MeO₂C, Ph) in a 2-phase system. Addition of MeO₂CCCCO₂Me to N-(methoxycarbonylmethyl)pyridinium chloride and KOH, supported on alumina (1:1) suspended in MeCN, at room temperature for >18 h, followed by dehydrogenation with 5% Pd-C at reflux for 4 h gave 44% indolizine I. Phase-transfer catalysts did not significantly improve the yields. In the experiment, the researchers used many compounds, for example, 1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3COA of Formula: C7H7ClN2).

1-(Cyanomethyl)pyridin-1-ium chloride (cas: 17281-59-3) belongs to pyridine derivatives. Pyridine has a conjugated system of six π electrons that are delocalized over the ring. The molecule is planar and, thus, follows the Hückel criteria for aromatic systems. Pyridine derivatives are also useful as small-molecule α-helix mimetics that inhibit protein-protein interactions, as well as functionally selective GABA ligands.COA of Formula: C7H7ClN2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

The effect of malonic acid on the physico-chemical characterisation of 4-hydroxy pyridine: A new third order NLO single crystal was written by Subha, M.;Anitha, K.;Jauhar, ROMU.. And the article was included in Journal of Molecular Structure in 2019.HPLC of Formula: 626-64-2 This article mentions the following:

The proton transfer complex of 4-hydroxy pyridinium H malonate (4HPMA) single crystal was grown successfully by slow evaporation solution growth technique (SEST) at ambient temperature Cell parameters and crystal structure of 4HPMA were determined by single crystal x-ray diffraction (SCXRD) method. The UV-visible absorption spectrum reveals that 4HPMA grown crystal exhibits 70% optical transparency at 300-850 nm. Photoluminescence study suggests as-grown crystal has violet emission nature. FTIR and Raman spectral anal. were used to identify the presence of various functional groups. ¹H and ¹³C NMR spectral analyses were used to identify the presence of proton and C. Thermal behavior of grown crystal was identified by Thermogravimetric (TGA) and Differential thermogravimetric analyses (DTA). Third-order nonlinear optical studies were evaluated with nonlinear refractive index (n₂), nonlinear absorption coefficient (β) and 3rd-order nonlinear optical susceptibility χ⁽³⁾ of the grown crystal. Hirshfeld surface analyses were used to predict the existence of all intermol. interactions. In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2HPLC of Formula: 626-64-2).

Pyridin-4-ol (cas: 626-64-2) belongs to pyridine derivatives. Pyridine has a dipole moment and a weaker resonant stabilization than benzene (resonance energy 117 kJ·mol−1 in pyridine vs. 150 kJ·mol−1 in benzene). Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.HPLC of Formula: 626-64-2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Determination of the binding situation of pyridine in xylan sulfates by means of detailed NMR studies was written by Gabriel, Lars;Guenther, Wolfgang;Pielenz, Friederike;Heinze, Thomas. And the article was included in Macromolecular Chemistry and Physics in 2020.SDS of cas: 628-13-7 This article mentions the following:

Xylan sulfate is an important drug to treat interstitial cystitis. Production of the drug by sulfation of the polysaccharide with a sulfating agent like chlorosulfuric acid and pyridine-SO₃ complex in pyridine may lead to products containing pyridine-based impurities. Xylan sulfate containing nitrogen is investigated by different NMR measurements in order to clarify the binding situation of pyridine. The detailed NMR studies allow the conclusion that the pyridine-based impurities are covalently bonded to the reducing end group. Furthermore, the NMR spectroscopic investigation indicates that the side reactions occur at shorter polymer chains only. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7SDS of cas: 628-13-7).

Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1.The molecular electric dipole moment is 2.2 debyes. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase and 140.4 kJ·mol−1 in the gas phase. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.SDS of cas: 628-13-7

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Fluorine-Substituted Pyrrolo[2,3-d]Pyrimidine Analogues with Tumor Targeting via Cellular Uptake by Folate Receptor α and the Proton-Coupled Folate Transporter and Inhibition of de Novo Purine Nucleotide Biosynthesis was written by Ravindra, Manasa;Wilson, Mike R.;Tong, Nian;OConnor, Carrie;Karim, Mohammad;Polin, Lisa;Wallace-Povirk, Adrianne;White, Kathryn;Kushner, Juiwanna;Hou, Zhanjun;Matherly, Larry H.;Gangjee, Aleem. And the article was included in Journal of Medicinal Chemistry in 2018.Electric Literature of C6H3BrFNO2 This article mentions the following:

Novel fluorinated 2-amino-4-oxo-6-substituted pyrrolo[2,3-d]pyrimidine analogs were synthesized and tested for selective cellular uptake by folate receptors (FRs) α and β or the proton-coupled folate transporter (PCFT) and for antitumor efficacy. Compounds I (n = 0, 1) and II (n = 0, 1) showed increased in vitro anti-proliferative activities (∼11-fold) over the nonfluorinated analogs toward engineered Chinese hamster ovary and HeLa cells expressing FRs or PCFT. Compounds I (n = 0, 1) and II (n = 0, 1) also inhibited proliferation of IGROV1 and A2780 epithelial ovarian cancer cells; in IGROV1 cells with knockdown of FRα, I (n = 0) and II (n = 0, 1) showed sustained inhibition associated with uptake by PCFT. All compounds inhibited glycinamide ribonucleotide formyltransferase, a key enzyme in the de novo purine biosynthesis pathway. Mol. modeling studies validated in vitro cell-based results. NMR evidence supports the presence of an intramol. fluorine-hydrogen bond. Potent in vivo efficacy of II (n = 1) was established with IGROV1 xenografts in severe compromised immunodeficient mice. In the experiment, the researchers used many compounds, for example, 5-Bromo-3-fluoropicolinic acid (cas: 669066-91-5Electric Literature of C6H3BrFNO2).

5-Bromo-3-fluoropicolinic acid (cas: 669066-91-5) belongs to pyridine derivatives. Pyridine has a conjugated system of six π electrons that are delocalized over the ring. The molecule is planar and, thus, follows the Hückel criteria for aromatic systems. One of the examples of pyridines is the well-known alkaloid lithoprimidine, which is an A3 adenosine receptor antagonist and N,N-dimethylaminopyridine (DMAP) analog, commonly used in organic synthesis.Electric Literature of C6H3BrFNO2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Nickel-catalyzed decyanation of inert carbon-cyano bonds was written by Patra, Tuhin;Agasti, Soumitra;Akanksha;Maiti, Debabrata. And the article was included in Chemical Communications (Cambridge, United Kingdom) in 2013.Category: pyridine-derivatives This article mentions the following:

A nickel catalyzed decyanation of aryl cyanides and aliphatic cyanides with hydrosilane as a hydride source [i.e., 1,1,3,3-tetramethyldisiloxane] has been developed. This method is easy to handle, scalable and can be carried out without a glove box. The method was applied in a cyanide directed functionalization reaction and α-substitution of benzyl cyanide. The synthesis of the target compounds was achieved using as starting materials 1,4-dibutoxy-2,3-naphthalenedicarbonitrile, 6-methoxy-2-naphthalenecarbonitrile, 2-cyanobenzoic acid Et ester, [1,1′-biphenyl]-4-carbonitrile, 4-benzoylbenzonitrile, 6-phenoxy-2-pyridinecarbonitrile, 2-(1H-pyrrol-1-yl)benzonitrile, 2-(1H-indol-1-yl)benzonitrile, 1-(phenylmethyl)-1H-indole-3-carbonitrile, 4-hydroxybenzeneacetonitrile, α-octylbenzeneacetonitrile, dodecanenitrile, benzenepropanenitrile, etc. The decyanation of 1,4-dibutoxy-2,3-naphthalenedicarbonitrile (I) gave 1,4-dibutoxy-2-naphthalenecarbonitrile (II). In the experiment, the researchers used many compounds, for example, 2-Phenoxypyridine (cas: 4783-68-0Category: pyridine-derivatives).

2-Phenoxypyridine (cas: 4783-68-0) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.Category: pyridine-derivatives

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Anchoring a Molecular Iron Catalyst to Solar-Responsive WO₃ Improves the Rate and Selectivity of Photoelectrochemical Water Oxidation was written by Klepser, Benjamin M.;Bartlett, Bart M.. And the article was included in Journal of the American Chemical Society in 2014.Quality Control of (4-Bromopyridin-2-yl)methanol This article mentions the following:

Mol. catalysts help overcome the kinetic limitations of H₂O oxidation and generally result in faster rates for H₂O oxidation than do heterogeneous catalysts. However, mol. catalysts typically function in the dark and therefore require sacrificial oxidants such as Ce⁴⁺ or S₂O₈^2- to provide the driving force for the reaction. In this Communication, covalently anchoring a phosphonate-derivatized complex, Fe(tebppmcn)Cl₂ (1), to WO₃ removes the need for a sacrificial oxidant and increases the rate of photoelectrochem. H₂O oxidation on WO₃ by 60%. The dual-action catalyst, 1-WO₃, also gives rise to increased selectivity for H₂O oxidation in pH 3 Na₂SO₄ (56% on bare WO₃, 79% on 1-WO₃). This approach provides promising alternative routes for solar H₂O oxidation In the experiment, the researchers used many compounds, for example, (4-Bromopyridin-2-yl)methanol (cas: 131747-45-0Quality Control of (4-Bromopyridin-2-yl)methanol).

(4-Bromopyridin-2-yl)methanol (cas: 131747-45-0) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Quality Control of (4-Bromopyridin-2-yl)methanol

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Solvent-dependent oxidations of 5- and 6-azaindoles to trioxopyrrolopyridines and functionalised azaindoles was written by Mahiout, Zahia;Lomberget, Thierry;Goncalves, Sylvie;Barret, Roland. And the article was included in Organic & Biomolecular Chemistry in 2008.Synthetic Route of C6H7NO2 This article mentions the following:

A regioselective synthesis of 4,7-dimethoxy 5- and 6-azaindoles has been achieved, based on the appropriate choice of ortho-directing or ortho-repulsing groups in the formylation of a pyridine ring. Studies on the regioselectivity of the formylation step and on the preparation of azidoacrylate intermediates are described in this paper. The reactivity of the 5- and 6-azaindole structures towards BBr₃-mediated selective monodemethylation and oxidative demethylation reactions were also investigated. The regioselectivity of the deprotection was confirmed using a chem. approach. Oxidation reactions were then carried out on either dimethoxy- or hydroxymethoxyazaindoles, in different solvents, using [bis(trifluoroacetoxy)iodo]benzene. In acetonitrile-water, trioxopyrrolopyridines, e.g., I, were obtained, whereas the formation of functionalised azaindoles, e.g., II, were observed in acetonitrile-methanol. The tautomeric structure of the trioxopyrrolopyridines was proved by X-ray diffraction anal. In the experiment, the researchers used many compounds, for example, 5-Hydroxy-2-methoxylpyridine (cas: 51834-97-0Synthetic Route of C6H7NO2).

5-Hydroxy-2-methoxylpyridine (cas: 51834-97-0) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Synthetic Route of C6H7NO2

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem