Month: December 2022

Wangler, Bjorn published the artcileKit-Like ¹⁸F-Labeling of Proteins: Synthesis of 4-(Di-tert-butyl[¹⁸F]fluorosilyl)benzenethiol (Si[¹⁸F]FA-SH) Labeled Rat Serum Albumin for Blood Pool Imaging with PET, Category: catalysis-chemistry, the publication is Bioconjugate Chemistry (2009), 20(2), 317-321, database is CAplus and MEDLINE.

Radiosyntheses of ¹⁸F-radiopharmaceuticals for positron emission tomog. (PET) normally require an extraordinarily high effort of tech. equipment and specially trained personnel. We recently reported a novel method for the introduction of fluorine-18 into peptides for PET-imaging based on silicon-¹⁸F-chem. (SiFA technique). We herewith introduce the first SiFA-based Kit-like radio-fluorination of a protein (rat serum albumin, RSA) and demonstrate its usefulness for in vivo imaging with ¦ÌPET in normal rats as well as in a rat heterotropic transplanted heart model. As a labeling agent, we prepared 4-(di-tert-butyl[¹⁸F]fluorosilyl)benzenethiol (Si[¹⁸F]FA-SH) by simple isotopic exchange in 40-60% radiochem. yield (RCY) and coupled it directly to a Sulfo-SMCC derivatized RSA in an overall RCY of 12% within 20-30 min. The tech. simple labeling procedure does not require any elaborated purification procedures and is a straightforward example of a successful application of Si-¹⁸F chem. for in vivo imaging with PET.

Bioconjugate Chemistry published new progress about 17351-62-1. 17351-62-1 belongs to catalysis-chemistry, auxiliary class Salt,Amine, name is Tetrabutylammonium hydrogencarbonate, and the molecular formula is C18H28N2O7, Category: catalysis-chemistry.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Surya, S. Sarah published the artcileDegree-based molecular descriptors of certain chemical graphs and drugs of COVID 19, Formula: C24H12, the publication is Eurasian Chemical Communications (2022), 4(1), 113-123, database is CAplus.

Spectral Graph Theory is the interface that connects the graphs and the matrixes associated with them. Chem. is the branch of science which has benefitted the most out of this interaction as the information-theoretic matrixes of the mol. graphs offer immensely useful mol. descriptors. Graph energy and topol. indexes are chem.-initiated directions of research in mathematics. In this paper, we compute the characteristic polynomial of Circum-coronene(n) series of benzenoid graphs, 1 ¡Ü n ¡Ü 3 and few degree-based topol. indexes of Circumpolyacenes(m, n), Circum-pyrene(n) and Circum-trizene(n). Also, the graph invariants namely energy, spectral radius, Wiener index, first Zagreb index, modified first Zagreb index, second Zagreb index and modified second Zagreb index have been computed for few proposed drugs against COVID-19, their extensions and coronoid networks. We have also verified our results using MATLAB programs.

Eurasian Chemical Communications published new progress about 191-07-1. 191-07-1 belongs to catalysis-chemistry, auxiliary class Electronic Materials, name is Coronene, and the molecular formula is C12H20O6, Formula: C24H12.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Zhu, Diya published the artcileAddition reactions and diazomethane capture by the intramolecular P-O-B FLP: tBu₂POBcat, Recommanded Product: Dimesitylphosphine oxide, the publication is Dalton Transactions (2020), 49(3), 901-910, database is CAplus and MEDLINE.

FLPs, R₂POBcat (R = tBu 1, Mes 2), are readily derived from the reactions of the corresponding phosphine oxides, BuLi and ClBcat. Despite the poor Lewis acidity of B, these species react with PhOH, CO₂, CS₂, PhNCO, MesCNO, O₂, 9,10-phenanthrenedione, and diazomethanes to effect FLP addition reactions affording heterocycles. The reaction of 1 with EtO₂CCHN₂ gives the bicyclic product, EtO₂CCHN₂(tBu₂POBcat)₂. High-level DFT calculations reveal that these cyclization processes proceed via 1,1-addition to the terminal N of diazomethane followed by 1,2-B-migration affording the five membered rings. The reaction of the EtO₂CCHN₂ derivative with the 2nd equivalent of FLP 1 is attributed to less steric demands.

Dalton Transactions published new progress about 23897-16-7. 23897-16-7 belongs to catalysis-chemistry, auxiliary class Aryl phosphine ligand,Mono-phosphine Ligands, name is Dimesitylphosphine oxide, and the molecular formula is C7H11N, Recommanded Product: Dimesitylphosphine oxide.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Wang, Limin published the artcileSynthesis, uptake mechanism characterization and biological evaluation of ¹⁸F labeled fluoroalkyl phenylalanine analogs as potential PET imaging agents, Application of Tetrabutylammonium hydrogencarbonate, the publication is Nuclear Medicine and Biology (2011), 38(1), 53-62, database is CAplus and MEDLINE.

Introduction: Amino acids based tracers represent a promising class of tumor metabolic imaging agents with successful clin. applications. Two new phenylalanine derivatives, p-(2-[¹⁸F]fluoroethyl)-L-phenylalanine (FEP, [¹⁸F]2) and p-(3-[¹⁸F]fluoropropyl)-L-phenylalanine (FPP, [¹⁸F]3) were synthesized and evaluated in comparison to clin. utilized O-(2-[¹⁸F]fluoroethyl)-L-tyrosine (FET, [¹⁸F]1). Methods: FEP ([¹⁸F]2) and FPP ([¹⁸F]3) were successfully synthesized by a rapid and efficient two-step nucleophilic fluorination of tosylate precursors and deprotection reaction. In vitro cell uptake studies were carried out in 9L glioma cells. In vivo studies, 9L tumor xenografts were implanted in Fisher 344 rats. Results: FEP ([¹⁸F]2) and FPP ([¹⁸F]3) could be efficiently labeled within 90 min with good enantiomeric purity (>95%), good yield (11-37%) and high specific activity (21-69 GBq/¦Ìmol). Cell uptake studies showed FEP had higher uptake than FPP as well as reference ligand FET ([¹⁸F]1). Uptake mechanism studies suggested that FEP is a selective substrate for system L and prefers its subtype LAT1. In vivo biodistribution studies demonstrated FEP had specific accumulation in tumor cells and tumor to background ratio reached 1.45 at 60 min. Small animal positron emission tomog. (PET) imaging studies showed FEP was comparable to FET for imaging rats bearing 9L tumor model. FEP had high uptake in 9L tumor compared to surrounding tissue and was quickly excreted through urinary tract. Conclusion: Biol. evaluations indicate that FEP ([¹⁸F]2) is a potential useful tracer for tumor imaging with PET.

Nuclear Medicine and Biology published new progress about 17351-62-1. 17351-62-1 belongs to catalysis-chemistry, auxiliary class Salt,Amine, name is Tetrabutylammonium hydrogencarbonate, and the molecular formula is C8H6ClF3, Application of Tetrabutylammonium hydrogencarbonate.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Li, Yu-Lei published the artcileComparison of different strategies towards the chemical synthesis of long-chain scorpion toxin AaH-II, Recommanded Product: Fmoc-Pro-OH, the publication is Journal of Peptide Science (2022), 28(2), e3365, database is CAplus and MEDLINE.

Long-chain scorpion toxin AaH-II isolated from Androctonus australis Hector can selectively inhibit mammalian voltage-gated sodium ion channel Na_v1.7 responsible for pain sensation. Efficient chem. synthesis of AaH-II and its derivatives is beneficial to the study of the function and mechanism of Na_v1.7 and the development of potential peptide inhibitors. Herein, we compared three different strategies, namely, direct solid-phase peptide synthesis, hydrazide-based two-segment native chem. ligation, and hydrazide-based three-segment native chem. ligation for the synthesis of AaH-II. The hydrazide-based two-segment native chem. ligation affords the target toxin with the optimal efficiency, which provides a practically robust procedure for the preparation of tool mols. derived from AaH-II to study the biol. functions and modulation of Na_v1.7. Our work highlights the importance of selecting suitable segment condensation approach in the chem. synthesis of protein toxins.

Journal of Peptide Science published new progress about 71989-31-6. 71989-31-6 belongs to catalysis-chemistry, auxiliary class Amino acide derivatives,pyrrolidine, name is Fmoc-Pro-OH, and the molecular formula is C20H19NO4, Recommanded Product: Fmoc-Pro-OH.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Liu, Ning published the artcileBulky ¦Á-diimine palladium complexes supported graphene oxide as heterogeneous catalysts for Suzuki-Miyaura reaction, Quality Control of 613-33-2, the publication is Journal of Molecular Structure (2020), 128537, database is CAplus.

To explore high efficiency of the Suzuki-Miyaura reactions, an easily prepared heterogeneous palladium precatalysts bearing sterically bulky ¦Á-diimine I was covalently supported on graphene oxide (GO). The characterization of supported palladium complex was discussed in detail. A simple and efficient protocol for Pd-catalyzed cross coupling was described, which revealed that the bulky ¦Á-diimine ligand is crucial to promote the C_Ar-C_Ar 4-R¹C₆H₄R (R = Ph, thiophen-2-yl, naphthalen-1-yl, etc.; R¹ = H, Me, OMe) transformation. This immobilized system provides a straightforward access to a wide range of aryl bromides RBr with excellent functional groups tolerance.

Journal of Molecular Structure published new progress about 613-33-2. 613-33-2 belongs to catalysis-chemistry, auxiliary class Benzene, name is 4,4′-Dimethyldiphenyl, and the molecular formula is C14H14, Quality Control of 613-33-2.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Liu, Hong-Chuan published the artcileSynthesis and Cytotoxicity Assessment of Novel 7-O- and 14-O-Derivatives of Glaucocalyxin A, Synthetic Route of 104-03-0, the publication is Anti-Cancer Agents in Medicinal Chemistry (2020), 20(10), 1241-1249, database is CAplus and MEDLINE.

Background: Rabdosia japonica has been historically used in China as a popular folk medicine for the treatment of cancer, hepatitis, and gastricism. Glaucocalyxin A (GLA), an ent-kaurene diterpene isolated from Rabdosia japonica, is one of the main active ingredients showing potent inhibitory effects against several types of tumor cells. To the best of our knowledge, studies regarding the structural modification and Structure- Activity Relations (SAR) of this compound have not yet been reported. Objective: The aim of this study was to discover more potent derivatives of GLA and investigate their SAR and cytotoxicity mechanisms. Methods: Novel 7-O- and 14-O-derivatives of GLA were synthesized by condensation of acids or acyl chloride. The anti-tumor activities of these derivatives against various human cancer cell lines were evaluated in vitro by MTT assays. Apoptosis assays of compound 17 (7,14-diacylation product) were performed on A549 and HL-60 cells by flow cytometry and TUNNEL. The acute toxicity of this compound was tested on mice, at the dose of 300mg per kg body weight Results: Seventeen novel 7-O- and 14-O-derivatives of GLA (1-17) were synthesized. These compounds showed potent cytotoxicity against the tested cancer cell lines, and almost all of them were found to be more cytotoxic than GLA and oridonin. Of the synthesized derivatives, compound 17 presented the greatest cytotoxicity, with IC50 values of 0.26¦ÌM and 1.10¦ÌM in HL-60 and CCRF-CEM cells, resp. Furthermore, this compound induced weak apoptosis of A549 cells but showed great potential in stimulating the apoptosis of HL- 60 cells. Acute toxicity assays indicated that compound 17 is relatively safer. Conclusion: The results reported herein indicate that the synthesized GLA derivatives exhibited greater cytotoxicity against leukemia cells than against other types of tumors. In particular, 7,14-diacylation product of GLA was found to be an effective anti-tumor agent. However, the cytotoxicity mechanism of this product in A549 cells is expected to be different than that in other tumor cell lines.

Anti-Cancer Agents in Medicinal Chemistry published new progress about 104-03-0. 104-03-0 belongs to catalysis-chemistry, auxiliary class Nitro Compound,Carboxylic acid,Benzene, name is 4-Nitrophenylacetic acid, and the molecular formula is C8H7NO4, Synthetic Route of 104-03-0.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Xu, Li-Ping published the artcileUnconventional mechanism and selectivity of the Pd-catalyzed C-H bond lactonization in aromatic carboxylic acid, Product Details of C8H8O2, the publication is Nature Communications (2022), 13(1), 315, database is CAplus and MEDLINE.

The search for more effective and highly selective C-H bond oxidation of accessible hydrocarbons and biomols. is a greatly attractive research mission. The elucidating of mechanism and controlling factors will, undoubtedly, help to broaden scope of these synthetic protocols, and enable discovery of more efficient, environmentally benign, and highly practical new C-H oxidation reactions. Here, we reveal the stepwise intramol. S_N2 nucleophilic substitution mechanism with the rate-limiting C-O bond formation step for the Pd(II)-catalyzed C(sp³)-H lactonization in aromatic 2,6-dimethylbenzoic acid. We show that for this reaction, the direct C-O reductive elimination from both Pd(II) and Pd(IV) (oxidized by O₂ oxidant) intermediates is unfavorable. Critical factors controlling the outcome of this reaction are the presence of the ¦Ç³-(¦Ð-benzylic)-Pd and K+-O(carboxylic) interactions. The controlling factors of the benzylic vs ortho site-selectivity of this reaction are the: (a) difference in the strains of the generated lactone rings; (b) difference in the strengths of the ¦Ç³-(¦Ð-benzylic)-Pd and ¦Ç²-(¦Ð-phenyl)-Pd interactions, and (c) more pronounced electrostatic interaction between the nucleophilic oxygen and K⁺ cation in the ortho-C-H activation transition state. The presented data indicate the utmost importance of base, substrate, and ligand in the selective C(sp³)-H bond lactonization in the presence of C(sp²)-H.

Nature Communications published new progress about 118-90-1. 118-90-1 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Natural product, name is 2-Methylbenzoic acid, and the molecular formula is C20H12N2O2, Product Details of C8H8O2.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

McMurtry, Brandon M. published the artcileContinuous Nucleation and Size Dependent Growth Kinetics of Indium Phosphide Nanocrystals, Recommanded Product: N1,N2-Dibenzylethane-1,2-diamine, the publication is Chemistry of Materials (2020), 32(10), 4358-4368, database is CAplus.

Aminophosphines derived from N,N’-disubstituted ethylenediamines (R-N(H)CH₂CH₂N(H)-R; R = ortho-tolyl, Ph, benzyl, iso-Pr, and n-octyl) were used to adjust the kinetics of InP nanocrystal formation by more than 1 order of magnitude. UV-visible absorption and ³¹P NMR measurements demonstrate that the rate of nanocrystal formation is limited by the precursor reactivity. At low temperature (180¡ãC), crystal nucleation is concurrent with growth throughout the reaction, rather than occurring in a burst at early times. The low temperature produces a narrow range of small sizes (d = 4.2-4.9 nm) regardless of the precursor used. Higher temperatures (up to 270¡ãC) promote growth to larger sizes (d ¡Ü 7.8 nm), shorten the nucleation period, and create conditions where the final size is controlled by the precursor conversion reactivity. The temperature dependence is proposed to arise from growth kinetics that slow as the nanocrystal size increases, a novel surface attachment limited size distribution-focusing mechanism. Such a mechanism supports a narrow size distribution without separating the nucleation and growth phases.

Chemistry of Materials published new progress about 140-28-3. 140-28-3 belongs to catalysis-chemistry, auxiliary class Benzenes, name is N1,N2-Dibenzylethane-1,2-diamine, and the molecular formula is C16H20N2, Recommanded Product: N1,N2-Dibenzylethane-1,2-diamine.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Zhou, Hua published the artcileThe research to the condition of catalytic degradation of borofluoric acid diazonium salt, Application of Bis(4-fluorophenyl)methane, the publication is Shandong Huagong (2009), 38(1), 18-20, database is CAplus.

The influencing factors of the the catalytic degradation of borofluoric acid diazonium salt were discussed, which was the key step to synthesize 4,4′- difluorobenzophenone. It was found that with iron powder as catalyst and adding dry diazonium salt to toluene whose volume was triple-weight of diazonium salt, the reaction could be occurred smoothly; and with those conditions the yield of the reaction could be up to 85% and the purity could be 94% (with GC detection).

Shandong Huagong published new progress about 457-68-1. 457-68-1 belongs to catalysis-chemistry, auxiliary class Fluoride,Benzene, name is Bis(4-fluorophenyl)methane, and the molecular formula is C23H20BN, Application of Bis(4-fluorophenyl)methane.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia