Day: December 1, 2022

Pelchowicz, Zvi published the artcileSubstituted tryptamines and their derivatives, HPLC of Formula: 102236-19-1, the publication is Journal of the Chemical Society (1960), 4699-701, database is CAplus.

o-MeC₆H₄NH₂ (21.3 g.), 54 ml. concentrated HCl, and 236 ml. H₂O diazotized with 15 g. NaNO₂, 10% aqueous Na₂CO₃ added at 0° to bring the pH to 5-6, the whole filtered, added to 34 g. Et 2-oxopiperidine-3-carboxylate (I), 400 ml. H₂O, and 12 g. KOH (kept 24 hrs. at room temperature before use), the pH adjusted to 34 with AcOH, and the whole kept 48 hrs. at 0° gave 35 g. 3-(o-tolyl)hydrazone of 2,3-dioxopiperidine (II), m. 140.0-40.5° (aqueous alc.). 3-(p-Tolyl)hydrazone of 2,3-dioxopiperidine (III) was similarly obtained, 81%, m. 209-9.5°. Crude II (45 g.), 200 ml. AcOH, and 100 ml. concentrated HCl refluxed 1 hr., cooled, and diluted with H₂O gave 28.8 g. 1,2,3,4-tetrahydro-8-methyl-1-oxo-β-carboline (IV), m. 228.5-29° (aqueous alc.); III similarly gave 83% 6-Me analog of IV, m. 187.5-8.5° (aqueous alc.). III (28 g.), 260 ml. alc., and 260 ml. 4N aqueous KOH refluxed 1 hr., concentrated to half volume, diluted with 250 ml. H₂O, and neutralized with AcOH gave 24 g. 7-methyltryptamine-2-carboxylic acid (V), m. 278-81°; the 5-Me analog (VI) of V was obtained similarly, 83%, m. 267-7.5° (decomposition). V (10.5 g.) and 400 ml. 5% HCl refluxed until CO₂ evolution ceased, the whole cooled, and neutralized with NaOH gave 7.2 g. 7-methyltryptamine (VII), purified by sublimation, m. 130-1°; 5-methyltryptamine, obtained in 76% yield from VI, m. 99-9.5° (Et₂O-petr. ether). Diazotized 5,2-FMeC₆H₃NH₂ and I as above gave 72% 5-F derivative (VIII) of II, m. 204.5-5.0°, and VIII was used as above to obtain 73% 5-F derivative of IV, m. 204.5-5.0° (aqueous alc.), 80% 4-F derivative of V, m. 273° (decomposition) (H₂O), and 4-F derivative of VII, m. 141-2° (after sublimation). VIII (5 g.), 100 ml. 10% aqueous AcH, 16 ml. 2N H₂SO₄, and 100 ml. H₂O heated 0.33 hr. at 110°, cooled, and treated with excess alkali gave 4.9 g. 6-fluoro-1,2,3,4-tetrahydroharmaline, m. 201-2° (by sublimation) (L.D.₅₀ 600 mg./kg. in mice). VIII (5.74 g.), 1 g. NaHCO₃, and 25 ml. Ac₂O refluxed 0.25 hr., poured into H₂O, the whole treated with excess Na₂CO₃, and extracted with Et₂O gave 5.5 g. N^α-Ac derivative (IX), m. 127.5-8.0° (Et₂O-petr. ether). To 5 g. IX in 200 ml. hot xylene was added in small portions 50 g. P₂O₅; the whole refluxed 2 hrs., the solid filtered off and added in small portions to 500 ml. 5% HCl, the whole heated at 80°, filtered, the filtrate cooled, treated with excess alkali and extracted with Et₂O gave 6-fluoro-3,4-dihydroharmaline, m. 206-7° (aqueous alc.).

Journal of the Chemical Society published new progress about 102236-19-1. 102236-19-1 belongs to pyridine-derivatives, auxiliary class Pyridine,Chloride, name is 5-(tert-Butyl)-2-chloropyridine, and the molecular formula is C9H12ClN, HPLC of Formula: 102236-19-1.

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

Martinez, Kristina published the artcilePhotophysics of Ru(II) complexes with hydroxylated diimine ligands: Photoinduced electron/proton transfer to anthraquinone, Name: 2-Pyridinylboronic acid, the publication is Polyhedron (2021), 115376, database is CAplus.

This manuscript reports the reaction of the ³MLCT excited states of two luminescent chromophores, [(bpy)₂Ru(OHbpy)]²⁺ and [(bpy)₂Ru(OMebpy)]²⁺ (bpy = 2,2â€?bipyridine, OHbpy = 4-hydroxy-2,2â€?bipyridine, OMebpy = 4-methoxy-2,2â€?bipyridine), with anthraquinone (AQ). A series of luminescence, electrochem., spectrophotometric and transient absorption studies were done in order to determine free energies for the potential reaction paths between the photoexcited complexes and AQ. For the OMebpy complex, only excited state electron transfer (ET*) from the ³MLCT state of the complex to AQ was possible. However, for the OHbpy complex, the excited state could react with AQ via a variety of pathways including excited state electron transfer, ET*, excited state proton transfer (PT*) and excited state proton coupled electron transfer (PCET*). The thermodn. anal. revealed that, for the OHbpy complex PT* was very endergonic and not a viable reaction pathway, however both ET* and PCET* could occur. Luminescence quenching studies revealed that both the OHbpy and the OMebpy excited complexes reacted with AQ (k_q âˆ?10⁹ M^-1s^-1 for both). Transient absorption anal. showed that, for the OMebpy complex, no photoproducts escaped the encounter complex associated with the quenching reaction. The result is consistent with strong electrostatic association of the 3+/1- encounter complex. For the OHbpy complex transient absorption results clearly show the formation of PCET* products from the encounter complex. The result represents one of a small number of examples of excited states of chromophores reacting via proton coupled electron transfer within an encounter complex.

Polyhedron 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 C5H6BNO2, Name: 2-Pyridinylboronic acid.

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

Yao, Xin published the artcileSurfactants Accelerate Crystallization of Amorphous Nifedipine by Similar Enhancement of Nucleation and Growth Independent of Hydrophilic-Lipophilic Balance, Computed Properties of 21829-25-4, the publication is Molecular Pharmaceutics (2022), 19(7), 2343-2350, database is CAplus and MEDLINE.

Amorphous formulations, increasingly employed to deliver poorly soluble drugs, generally contain surfactants to improve wetting and dissolution These surfactants are often liquids and can potentially increase the mobility of the drug and reduce its stability, but little is known about this effect. Here we investigate the effect of four common nonionic surfactants (Tween 80, Span 80, Triton X-100, and Poloxamer 407) on the crystallization of amorphous nifedipine (NIF). We find that the surfactants significantly enhance the rates of crystal nucleation and growth even at low concentrations, by up to 2 orders of magnitude at 10 wt %. The surfactants tested show similar enhancement effects independent of their structural details and hydrophilic-lipophilic balance (HLB), suggesting that surfactant adsorption at solid/liquid interfaces does not play a major role in crystal nucleation and growth. Importantly, the surfactants accelerate crystal nucleation and growth by a similar factor. This result mirrors the previous finding that a polymer dopant in a mol. glass-former causes similar slowdown of nucleation and growth. These results indicate that nucleation and growth in a deeply supercooled liquid are both mobility-limited, and a dopant mainly functions as a mobility modifier (enhancer or suppressor depending on the dopant). The common surfactants tested are all mobility enhancers and destabilize the amorphous drug, and this neg. effect must be managed using stabilizers such as polymers. The effect of surfactants on nucleation can be predicted from the effect on crystal growth and the crystallization kinetics of the pure system, using the same principle previously established for drug-polymer systems. We show how the independently measured nucleation and growth rates enable predictions of the overall crystallization rates.

Molecular Pharmaceutics 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 C9H7NO2, Computed Properties of 21829-25-4.

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

Rayder, Thomas M. published the artcileEngineering Second Sphere Interactions in a Host-Guest Multicomponent Catalyst System for the Hydrogenation of Carbon Dioxide to Methanol, Product Details of C23H43NP2, the publication is Journal of the American Chemical Society (2021), 143(3), 1630-1640, database is CAplus and MEDLINE.

Many enzymes utilize interactions extending beyond the primary coordination sphere to enhance catalyst activity and/or selectivity. Such interactions could improve the efficacy of synthetic catalyst systems, but the supramol. assemblies employed by biol. to incorporate second sphere interactions are challenging to replicate in synthetic catalysts. Herein, a strategy is reported for efficiently manipulating outer-sphere influence on catalyst reactivity by modulating host-guest interactions between a noncovalently encapsulated transition-metal-based catalyst guest and a metal-organic framework (MOF) host. This composite consists of a ruthenium PNP pincer complex encapsulated in the MOF UiO-66 that is used in tandem with the zirconium oxide nodes of UiO-66 and a ruthenium PNN pincer complex to hydrogenate carbon dioxide to methanol. Due to the method used to incorporate the complexes in UiO-66, structure-activity relationships could be efficiently determined using a variety of functionalized UiO-66-X hosts. These investigations uncovered the beneficial effects of the ammonium functional group (i.e., UiO-66-NH₃⁺). Mechanistic experiments revealed that the ammonium functionality improved efficiency in the hydrogenation of carbon dioxide to formic acid, the first step in the cascade. Isotope effects and structure-activity relationships suggested that the primary role of the ammonium functionality is to serve as a general Bronsted acid. Importantly, the cooperative influence from the host was effective only with the functional group in close proximity to the encapsulated catalyst. Reactions carried out in the presence of mol. sieves to remove water highlighted the beneficial effects of the ammonium functional group in UiO-66-NH₃⁺ and resulted in a 4-fold increase in activity. As a result of the modular nature of the catalyst system, the highest reported turnover number (TON) (19 000) and turnover frequency (TOF) (9100 h^-1) for the hydrogenation of carbon dioxide to methanol are obtained. Moreover, the reaction was readily recyclable, leading to a cumulative TON of 100 000 after 10 reaction cycles.

Journal of the American Chemical Society published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C23H43NP2, Product Details of C23H43NP2.

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

Prechtl, Martin H. G. published the artcileSynthesis and characterisation of nonclassical ruthenium hydride complexes containing chelating bidentate and tridentate phosphine ligands, Product Details of C23H43NP2, the publication is Chemistry – A European Journal (2007), 13(5), 1539-1546, database is CAplus and MEDLINE.

The synthesis and characterization of nonclassical Ru hydride complexes containing bidentate diphosphine and tridentate PCP (1,3-bis(di-tert-butylphosphinomethyl)benzene) and PNP (1,6-bis(di-tert-butylphosphinomethyl)pyridine) pincer-type ligands are described. The mononuclear and dinuclear Ru complexes presented were synthesized in moderate to high yields by the direct hydrogenation route (1-pot synthesis) or in a two-step procedure. In both cases [Ru(cod)(metallyl)₂] served as a readily available precursor. The influences of the coordination geometry and the ligand framework on the structure, binding, and chem. properties of the M-H₂ fragments were studied by x-ray crystal structure anal., spectroscopic methods, and reactivity towards N₂, D₂, and deuterated solvents.

Chemistry – A European Journal published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C23H43NP2, Product Details of C23H43NP2.

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

Feller, Moran published the artcileCO₂ activation by metal-ligand-cooperation mediated by iridium pincer complexes, Formula: C23H43NP2, the publication is Journal of Coordination Chemistry (2018), 71(11-13), 1679-1689, database is CAplus.

Herein we report the reversible activation of CO₂ by the dearomatized complex [(^tBuPNP*)Ir(COE)] and by the aromatized complex [(^tBuPNP)Ir(C₆H₅)] via metal-ligand cooperation (MLC) (^tBuPN = 2,6-bis-(di-tert-butylphosphinomethyl)pyridine; ^tBuPNP* = deprotonated PNP; COE = cyclooctadiene). The [1,3]-addition of CO₂ to both complexes is reversible at ambient temperature While the dearomatized complex reacts readily at ambient temperature with CO₂ in THF or benzene, the aromatized complex reacts with CO₂ upon heating in benzene at 80 °C or at ambient temperature in THF. The novel aromatized complex [(^tBuPNP)IrCl] does not react with CO₂. Based on the reactivity patterns of these complexes with CO₂, we suggest that CO₂ activation via MLC takes place only via the dearomatized species, and that in the case of [(^tBuPNP)Ir(C₆H₅)], THF plays a role as a polar solvent in facilitating formation of the dearomatized hydrido Ph complex intermediate.

Journal of Coordination Chemistry published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C23H43NP2, Formula: C23H43NP2.

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

Feller, Moran published the artcileCationic, Neutral, and Anionic PNP Pd^II and Pt^II Complexes: Dearomatization by Deprotonation and Double-Deprotonation of Pincer Systems, Synthetic Route of 338800-13-8, the publication is Inorganic Chemistry (2010), 49(4), 1615-1625, database is CAplus and MEDLINE.

Cationic, neutral, and anionic Pd^II and Pt^II PNP (PNP = 2,6-bis(di-tert-butylphosphinomethyl)pyridine) complexes were synthesized. The neutral, dearomatized complexes [(PNP^*)MX] (PNP^* = deprotonated PNP; M = Pd, Pt; X = Cl, Me) were prepared by deprotonation of the PNP methylene group of the corresponding cationic complexes [(PNP)MX][Cl] with 1 equiv of base (KN(SiMe₃)₂ or ^tBuOK), while the anionic complexes [(PNP^**)MX]^–Y⁺ (PNP^** = double-deprotonated PNP; Y = Li, K) were prepared by deprotonation of the two methylene groups of the corresponding cationic complexes with either 2 equiv of KN(SiMe₃)₂ or an excess of MeLi. While the reaction of [(PNP)PtCl][Cl] with an excess of MeLi led only to the anionic complex without chloride substitution, reaction of [(PNP)PdCl][Cl] with an excess of MeLi led to the methylated anionic complex [(PNP^**)PdMe]^–Li⁺. NMR studies, x-ray structures, and d. functional theory (DFT) calculations reveal that the neutral complexes have a broken aromatic system with alternating single and double bonds, and the deprotonated arm is bound to the ring by an exocyclic C:C double bond. The anionic complexes are best described as a π system comprising the ring carbons conjugated with the exocyclic double bonds of the deprotonated arms. The neutral complexes are reversibly protonated to their cationic analogs by H₂O or MeOH. The thermodn. parameters ΔH, ΔS, and ΔG for the reversible protonation of the neutral complexes by MeOH were obtained.

Inorganic Chemistry published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C23H43NP2, Synthetic Route of 338800-13-8.

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

Feller, Moran published the artcileMononuclear Rh(II) PNP-Type Complexes. Structure and Reactivity, Product Details of C23H43NP2, the publication is Inorganic Chemistry (2007), 46(25), 10479-10490, database is CAplus and MEDLINE.

The Rh(II) mononuclear complexes [(PNP^tBu)RhCl][BF₄] (2), [(PNP^tBu)Rh(OC(O)CF₃)] (4), and [(PNP^t-Bu)Rh(acetone)][BF₄]₂ (6), where PNP^tBu = 2,6-bis(di-tert-butylphosphinomethyl)pyridine, were synthesized by oxidation of the corresponding Rh(I) analogs with silver salts. However, treatment of (PNP^tBu)RhCl with AgOC(O)CF₃ led only to chloride abstraction, with no oxidation 2 And 6 were characterized by x-ray diffraction, EPR, cyclic voltammetry, and dipole moment measurements. 2 And 6 react with NO gas to give diamagnetic [(PNP^tBu)Rh(NO)Cl][BF₄] (7) and [(PNP^tBu)Rh(NO)(acetone)][BF₄]₂ (8), resp. 6 Is reduced to Rh(I) in the presence of phosphines, CO, or isonitriles to give the Rh(I) complexes [(PNP^tBu)Rh(PR₃)][BF₄] (11, 12) (R = t, Ph), [(PNP^tBu)Rh(CO)][BF₄] (13) and [(PNP^tBu)Rh(L)][BF₄] (15, 16) (L = tert-Bu isonitrile or 2,6-dimethylphenyl isonitrile), resp. However, 2 disproportionates to Rh(I) and Rh(III) complexes in the presence of acetonitrile, or CO. 2 Is also reduced by triethylphosphine and water to Rh(I) complexes [(PNP^tBu)RhCI] (1) and [(PNP^tBu)Rh(PEt₃)][BF₄] (11). When triphenylphosphine and water were used, the reduced Rh(I) complex reacts with a proton, which is formed in the redox reaction to give a Rh(III) complex with a coordinated BF₄, [(PNP^tBu)Rh(Cl)(H)(BF₄)] (9).

Inorganic Chemistry published new progress about 338800-13-8. 338800-13-8 belongs to pyridine-derivatives, auxiliary class Bis-phosphine Ligands, name is 2,6-Bis((di-tert-butylphosphino)methyl)pyridine, and the molecular formula is C23H43NP2, Product Details of C23H43NP2.

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

Quddus, M. A. published the artcileExtraction of zinc by pyridine 2-carboxaldehyde 2-pyridylhydrazone (PAPHY) in chloroform, SDS of cas: 2215-33-0, the publication is Journal of Inorganic and Nuclear Chemistry (1971), 33(7), 2001-7, database is CAplus.

The distribution of Zn between aqueous solutions and pyridine 2-carboxaldehyde 2-pyridylhydrazone (PAPHY) in CHCl3 has been studied as a function of the pH of the aqueous phase and the concentration of PAPHY. Stability and acid dissociation constants of the complex ions have been determined as well as the partition coefficients of the ligand and its extractable Zn complex. An equation has been proposed to represent the extraction equilibrium and its essential correctness verified.

Journal of Inorganic and Nuclear Chemistry published new progress about 2215-33-0. 2215-33-0 belongs to pyridine-derivatives, auxiliary class Pyridine,Amine, name is 2-((2-(Pyridin-2-yl)hydrazono)methyl)pyridine, and the molecular formula is C11H10N4, SDS of cas: 2215-33-0.

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

Oliveira, Isabel B. published the artcileAcute toxicity of tralopyril, capsaicin and triphenylborane pyridine to marine invertebrates, Safety of Triphenyl(pyridin-1-ium-1-yl)borate, the publication is Ecotoxicology (2014), 23(7), 1336-1344, database is CAplus and MEDLINE.

A need for environmentally acceptable alternative antifouling (AF) biocides has arisen through restrictions in the use of many common biocides in the European Union through the Biocidal Product Regulation (Regulation EU Number 528/2012). Three such alternatives are triphenylborane pyridine (TPBP), tralopyril and capsaicin. This study aims at extending the available information on the toxicity of these three emerging AF biocides to key marine invertebrates. Here we investigate the toxicity of tralopyril and capsaicin to the early life stages of the mussel Mytilus galloprovincialis and the sea urchin Paracentrotus lividus and also of tralopyril, capsaicin and TPBP to the early life stages of the copepod Tisbe battagliai. The EC₅₀ that causes abnormal development of mussel’s D-veliger larvae and impairs the growth of sea urchin pluteus larvae are resp. 3.1 and 3.0 μg/L for tralopyril and 3,868 and 5,248 μg/L for capsaicin. Regarding the copepod T. battagliai, the LC₅₀ was 0.9 μg/L for tralopyril, 1,252 μg/L for capsaicin and 14 μg/L for TPBP. The results obtained for the three substances are compared to a reference AF biocide, tributyltin (TBT), and their ecol. risk evaluated. These compounds pose a lower environmental risk than TBT but still, our results suggest that tralopyril and TPBP may represent a considerable threat to the ecosystems.

Ecotoxicology published new progress about 971-66-4. 971-66-4 belongs to pyridine-derivatives, auxiliary class Pyridine,Benzene, name is Triphenyl(pyridin-1-ium-1-yl)borate, and the molecular formula is C23H20BN, Safety of Triphenyl(pyridin-1-ium-1-yl)borate.

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