Month: November 2022

Bertuzzi, Giulio published the artcileOrganocatalytic Enantioselective Construction of Conformationally Stable C(sp²)-C(sp³) Atropisomers, COA of Formula: C8H8O2, the publication is Journal of the American Chemical Society (2022), 144(2), 1056-1065, database is CAplus and MEDLINE.

Nonbiaryl atropisomers are mols. defined by a stereogenic axis featuring at least one nonarene moiety. Among these, scaffolds bearing a conformationally stable C(sp²)-C(sp³) stereogenic axis have been observed in natural compounds; however, their enantioselective synthesis remains almost completely unexplored. Herein we disclose a new class of chiral C(sp²)-C(sp³) atropisomers obtained with high levels of stereoselectivity (up to 99% ee) by means of an organocatalytic asym. methodol. Multiple mol. motifs could be embedded in this class of C(sp²)-C(sp³) atropisomers, showing a broad and general protocol. Exptl. data provide strong evidence of the conformational stability of the C(sp²)-C(sp³) stereogenic axis (up to t_1/2²⁵?^¡ãC >1000 y) in the obtained compounds and show kinetic control over this rare stereogenic element. This, coupled with d. functional theory calculations, suggests that the observed stereoselectivity arises from a Curtin-Hammett scenario establishing an equilibrium of intermediates. Furthermore, the exptl. investigation led to evidence of the operating principle of central-to-axial chirality conversions.

Journal of the American Chemical Society 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 C8H8O2, COA of Formula: C8H8O2.

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

Singhania, Vani published the artcileLipase-catalyzed esterification in water enabled by nanomicelles. Applications to 1-pot multi-step sequences, Recommanded Product: 3-Benzoylpropionicacid, the publication is Chemical Science (2022), 13(5), 1440-1445, database is CAplus and MEDLINE.

Esterification in an aqueous micellar medium is catalyzed by a com. available lipase in the absence of any co-factors. The presence of only 2 wt% designer surfactant, TPGS-750-M, assisted in a 100% selective enzymic process in which only primary alcs. participated (in a 1:1 ratio with carboxylic acid). An unexpected finding was also disclosed where the simple additive, PhCF₃ (1 equivalent vs. substrate), appeared to significantly extend the scope of usable acid/alc. combinations. Taken together, several chemo- and bio-catalyzed 1-pot, multi-step reactions was performed in water.

Chemical Science published new progress about 2051-95-8. 2051-95-8 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Ketone, name is 3-Benzoylpropionicacid, and the molecular formula is C10H16O2, Recommanded Product: 3-Benzoylpropionicacid.

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

Gomez, Antonio Bermejo published the artcileEfficient DBU accelerated synthesis of ¹⁸F-labelled trifluoroacetamides, Safety of Tetrabutylammonium hydrogencarbonate, the publication is Chemical Communications (Cambridge, United Kingdom) (2016), 52(97), 13963-13966, database is CAplus and MEDLINE.

Nucleophilic ¹⁸F-fluorination of bromodifluoromethyl derivatives was performed using [¹⁸F]Bu₄NF in the presence of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). This novel procedure provided a diverse set of [¹⁸F]trifluoroacetamides in good to excellent radiochem. conversions. A mechanism where DBU acts as organomediator in this transformation is proposed.

Chemical Communications (Cambridge, United Kingdom) 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 C17H37NO3, Safety of Tetrabutylammonium hydrogencarbonate.

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

Page, Claire G. published the artcileQuaternary Charge-Transfer Complex Enables Photoenzymatic Intermolecular Hydroalkylation of Olefins, Recommanded Product: 3-Benzoylpropionicacid, the publication is Journal of the American Chemical Society (2021), 143(1), 97-102, database is CAplus and MEDLINE.

Intermol. C-C bond-forming reactions are underdeveloped transformations in the field of biocatalysis. Here we report a photoenzymic intermol. hydroalkylation of olefins catalyzed by flavin-dependent ‘ene’-reductases. Radical initiation occurs via photoexcitation of a rare high-order enzyme-templated charge-transfer complex that forms between an alkene, ¦Á-chloroamide, and flavin hydroquinone. This unique mechanism ensures that radical formation only occurs when both substrates are present within the protein active site. This active site can control the radical terminating hydrogen atom transfer, enabling the synthesis of enantioenriched ¦Ã-stereogenic amides. This work highlights the potential for photoenzymic catalysis to enable new biocatalytic transformations via previously unknown electron transfer mechanisms.

Journal of the American Chemical Society published new progress about 2051-95-8. 2051-95-8 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Ketone, name is 3-Benzoylpropionicacid, and the molecular formula is C10H10O3, Recommanded Product: 3-Benzoylpropionicacid.

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

Abraham, Raymond J. published the artcileThe use of MM/QM calculations of ¹³C and ¹⁵N chemical shifts in the conformational analysis of alkyl substituted anilines, Product Details of C14H23N, the publication is Magnetic Resonance in Chemistry (2020), 58(6), 520-531, database is CAplus and MEDLINE.

The calculation of the ¹³C and ¹⁵N NMR chem. shifts by a combined mol. mechanics (Pcmodel 9.1/MMFF94) and ab initio GIAO B3LYP/DFT, 6-31 + G(d) procedure is used to investigate the conformations of a variety of alkyl substituted anilines. The ¹³C shifts are obtained from the GIAO isotropic shielding (Ciso) with sep. references for sp³ and sp² carbons (¦Äc = ¦Äref – Ciso). The ¹⁵N shifts are obtained similarly from the GIAO isotropic shielding (Niso) with reference to the ¹⁵N chem. shift of aniline. Comparison of the observed and calculated shifts provides information on the mol. conformations. Aniline and the 2,6-dialkylanilines exist with a rapidly inverting sym. pyramidal nitrogen atom. The 2-alkylanilines have similar conformations with the NH₂ group tilted away from the 2-alkyl substituent. The N,N-dialkylanilines show more varied conformations. N,N-dimethylaniline has a similar structure to aniline, but N-Et, N-methylaniline, N,N-diethylaniline, and N,N-diisopropylaniline are conformationally mobile with two rapidly interconverting conformers. In contrast, the anilines substituted at C₂ and the nitrogen atom exist as one conformer where the steric interaction between the C₂ substituent and the N substituent determines the conformation. In 2-methyl-N-methylaniline, the nitrogen atom is pyramidal as usual with the N-Me opposite to the 2-Me, but in 2-methyl-N,N-dimethyl aniline, the NMe₂ group is now almost orthogonal to the Ph plane. This is also the case with 2-methyl-N,N-diethylaniline and 2,6-diisopropyl-N,N-dimethylaniline. The comparison of the observed and calculated ¹⁵N chem. shifts confirms the above findings, in particular the pyramidal conformation of aniline and the above observations with respect to the conformations of the N,N-dialkylanilines.

Magnetic Resonance in Chemistry published new progress about 2909-77-5. 2909-77-5 belongs to catalysis-chemistry, auxiliary class Amine,Benzene, name is 2,6-Diisopropyl-N,N-dimethylaniline, and the molecular formula is C14H23N, Product Details of C14H23N.

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

Alauddin, Mian M. published the artcileSynthesis of [¹⁸F]-labeled 2′-deoxy-2′-fluoro-5-methyl-1-¦Â-D-arabinofuranosyluracil ([¹⁸F]-FMAU), Safety of Tetrabutylammonium hydrogencarbonate, the publication is Journal of Labelled Compounds & Radiopharmaceuticals (2002), 45(7), 583-590, database is CAplus.

Synthesis of 2′-deoxy-2′-[¹⁸F]fluoro-5-methyl-1-¦Â-D- arabinofuranosyluracil ([¹⁸F]-FMAU) is reported. 2-Deoxy-2-[¹⁸F]fluoro-1,3,5-tri-O-benzoyl-¦Á-D-arabinofuranose was prepared by the reaction of the resp. triflate with tetrabutylammonium[¹⁸F]fluoride. The fluorosugar was converted to its 1-bromo-derivative and coupled with protected thymine. The crude product mixture was hydrolyzed in base and purified by HPLC to obtain the radiolabeled FMAU (I). The radiochem. yield of I was 20-30% decay corrected (d.c.) in four steps with an average of 25% in four runs. Radiochem. purity was >99% and average specific activity was 2300 mCi/¦Ìmol at the end of synthesis (EOS). The synthesis time was 3.5-4.0h from the end of bombardment (EOB).

Journal of Labelled Compounds & Radiopharmaceuticals 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 C17H37NO3, Safety of Tetrabutylammonium hydrogencarbonate.

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

Passarella, Daniele published the artcileA Convenient Synthesis of ¦¤^7,8-Morphinan-6-one and Its Direct Oxidation to 14-Hydroxy-¦¤^7,8-morphinan-6-one, Formula: C15H14O3, the publication is Bioorganic & Medicinal Chemistry Letters (2002), 12(15), 1981-1983, database is CAplus and MEDLINE.

Synthesis of ¦¤^7,8-morphinan-6-one I (R₂ = bond) by Grewe cyclization of quinolinecarboxaldehyde derivative II and bromoketalization reaction of I (R = H) as crucial steps is described. Introduction of a hydroxyl group at 14-position is demonstrated by direct oxidation with MnO₂ in the presence of silica gel.

Bioorganic & Medicinal Chemistry Letters published new progress about 1860-58-8. 1860-58-8 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Ether, name is 2-(3-(Benzyloxy)phenyl)acetic acid, and the molecular formula is C15H14O3, Formula: C15H14O3.

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

Thakur, Punam published the artcileComplexation studies of Cm(III), Am(III), and Eu(III) with linear and cyclic carboxylates and polyaminocarboxylates, Application In Synthesis of 5411-14-3, the publication is Journal of Coordination Chemistry (2011), 64(18), 3214-3236, database is CAplus.

Solvent extraction and potentiometric titration methods were used to measure the stability constants of Cm(III), Am(III), and Eu(III) with both linear and cyclic carboxylates and polyaminocarboxylates in an ionic strength of 0.1 mol L^-1 (NaClO₄). Luminescence lifetime measurements of Cm(III) and Eu(III) were used to study the change in hydration upon complexation over a range of concentrations and pH values. Aromatic carboxylates, phthalate (1,2 benzene dicarboxylates, PHA), trimesate (1,3,5 benzene tricarboxylates, TSA), pyromellitate (1,2,4,5 tetracarboxylates, PMA), hemimellitate (1,2,3 benzene tricarboxylates, HMA), and trimellitate (1,2,4 benzene tricarboxylates, TMA) form only 1:1 complexes, while both 1:1 and 1:2 complexes were observed with PHA. Their complexation strength follows the order: PHA approx. TSA > TMA > PMA > HMA. Carboxylate ligands with adjacent carboxylate groups are bidentate and replace two H₂O mols. upon complexation, while TSA displaces 1.5 H₂O mols. of hydration upon complexation. Only 1:1 complexes were observed with the macrocyclic dicarboxylates 1,7-diaza-4,10,13-trioxacyclopentadecane-N,N’-diacetate (K21DA) and 1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N’-diacetate (K22DA); both 1:1 and 1:2 complexes were observed with methyleneiminodiacetate (MIDA), hydroxyethyleneiminodiacetate (HIDA), benzene-1,2-bis(oxyacetate) (BDODA), and ethylenediaminediacetate (EDDA), while three complexes (1:1, 1:2, and 1:3) were observed with pyridine 2,6 dicarboxylates (DPA) and chelidamate (CA). The complexes of M-MIDA are tridentate, while that of M-HIDA is tetradentate in both 1:1 and 1:2 complexes. The M-BDODA and M-EDDA complexes are tetradentate in the 1:1 and bidentate in the 1:2 complexes. The complexes of M-K22DA are octadentate with one H₂O mol. of hydration, while that of K21DA is heptadentate with two H₂O mols. of hydration. Simple polyaminocarboxylate 1,2 diaminopropanetetraacetate (PDTA) and ethylenediamine N,N’-diacetic-N,N’-dipropionate (ENDADP) like ethylenediaminetetraacetate (EDTA) form only 1 : 1 complexes and their complexes are hexadentate. Polyaminocarboxylates with addnl. functional groups in the ligand backbone, e.g., ethylenebis(oxyethylenenitrilo)tetraacetate (EGTA), and 1,6 diaminohexanetetraacetate (HDTA) or with addnl. number of groups in the carboxylate arms diethylenetriamine pentaacetato-monoamide (DTPA-MA), diethylenetriamine pentaacetato-bis-methoxyethylamide (DTPA-BMEA), and diethylenetriamine pentaacetato-bis glucosaamide (DTPA-BGAM) are octadentate with one H₂O mol. of hydration, except N-Me MS-325 which is heptadentate with two H₂O mols. of hydration and HDTA which is probably dimeric with three H₂O mols. of hydration. Macrocyclic tetraaminocarboxylate, 1,4,7,10-tetraazacyclododecanetetraacetate (DOTA) forms only 1:1 complex which is octadentate with one H₂O mol. of hydration. The functionalization of these carboxylates and polycarboxylates affect the complexation ability toward metal cations. The results, in conjunction with previous results on the Eu(III) complexes, provide insight into the relation between ligand steric requirement and the hydration state of the Cm(III) and Eu(III) complexes in solution The data are discussed in terms of ionic radii of the metal cations, cavity size, basicity, and ligand steric effects upon complexation.

Journal of Coordination Chemistry published new progress about 5411-14-3. 5411-14-3 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Ether, name is 2,2-(1,2-Phenylenebis(oxy))diacetic acid, and the molecular formula is C4H3Cl2N3, Application In Synthesis of 5411-14-3.

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

Veronesi, Stefano published the artcileMorphology and electronic properties of incipient soot by scanning tunneling microscopy and spectroscopy, Application of Coronene, the publication is Combustion and Flame, database is CAplus.

Soot nucleation is one of the most complex and debated steps of the soot formation process in combustion. In this work, we used scanning tunneling microscopy (STM) and spectroscopy (STS) to probe morphol. and electronic properties of incipient soot particles formed right behind the flame front of a lightly sooting laminar premixed flame of ethylene and air. Particles were thermophoretically sampled on an atomically flat gold film on a mica substrate. High-resolution STM images of incipient soot particles were obtained for the first time showing the morphol. of sub-5 nm incipient soot particles. High-resolution single-particle spectroscopic properties were measured confirming the semiconductor behavior of incipient soot particles with an electronic band gap ranging from 1.5 to 2 eV, consistent with earlier optical and spectroscopic observations.

Combustion and Flame 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 C20H40O2, Application of Coronene.

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

Schilling, M. L. published the artcileAcrylate Oligomer-Based Photopolymers for Optical Storage Applications, SDS of cas: 2909-77-5, the publication is Chemistry of Materials (1999), 11(2), 247-254, database is CAplus.

Photopolymers are attractive candidates for high-d. holog. data storage because of their high sensitivity and refractive index contrast. The authors incorporated several high-index organic monomers into high optical quality acrylate oligomer-based formulations. Using reactivity ratio, reaction kinetics, and component refractive indexes as guidelines, a 6-fold increase in ¦¤n has been achieved compared to an initial all-acrylate formulation. Samples prepared from these formulations have been used to write and read >200 high-quality holograms in a given volume of material. This is the first time a photopolymeric medium has successfully been used to multiplex this number of holograms. Using these resins, a protocol for the evaluation of photopolymers as holog. media has been developed.

Chemistry of Materials published new progress about 2909-77-5. 2909-77-5 belongs to catalysis-chemistry, auxiliary class Amine,Benzene, name is 2,6-Diisopropyl-N,N-dimethylaniline, and the molecular formula is C14H23N, SDS of cas: 2909-77-5.

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