Month: November 2022

Munday, Elizabeth S. published the artcileIsothiourea-Catalyzed Atropselective Acylation of Biaryl Phenols via Sequential Desymmetrization/Kinetic Resolution, Application of 1-Bromo-4-fluoro-2-methylbenzene, the main research area is biaryldiol monoester enantioselective preparation; imidazolobenzothiazole pyrimidobenzothiazole catalyst enantioselective acylation biaryldiol; isothiourea catalyst enantioselective acylation biaryldiol; mechanism tandem acylation kinetic resolution biaryldiol pyrimidobenzothiazole catalyst; transition state structure free energy enantioselective acylation biaryldiol; atropisomers; desymmetrization; isothiourea; kinetic resolution; organocatalysis.

Nonracemic biaryldiol monoesters such as I were prepared by desymmetrization of racemic biaryldiols with isobutyric anhydride and diisopropylethylamine in CH2Cl2 in the presence of nonracemic imidazo- or pyrimidobenzothiazoles. The optimal catalyst depended on the substitution pattern of the biaryldiol. The kinetics of the reaction were determined to understand the enantioselectivity of the acylation; the observed enantioselectivity is a result of an enantioselective desymmetrization coupled to a chiroablative kinetic resolution The free energies and structures of potential transition states were determined using DFT calculations to understand the factors leading to high enantiocontrol; maintenance of substrate planarity to maximize a 1,5-S···O interaction within the key acyl ammonium intermediate is the major determinant of acylation selectivity and thus product enantioselectivity.

Angewandte Chemie, International Edition published new progress about Acylation catalysts (stereoselective). 452-63-1 belongs to class bromides-buliding-blocks, name is 1-Bromo-4-fluoro-2-methylbenzene, and the molecular formula is C7H6BrF, Application of 1-Bromo-4-fluoro-2-methylbenzene.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Crescenzi, Manuela published the artcileIon association and reactivity of the alkali metal salts of alkanoic acids in dipolar aprotic solvents, Recommanded Product: 15-Bromopentadecanoic acid, the main research area is ion association lactonization kinetics; carboxylic acid lactonization alkali metal ion.

The effect of added alkali metal perchlorates on the rate of lactonization of ω-bromoalkanoate ions was investigated in 99% DMSO (4-membered ring formation) and in DMF (4- and 16-membered ring formation). In all cases, the effect of the added metal salts is rate depressing, as a result of the lower reactivity of metal ion-associated species relative to the free ions. Ion-pairing association constants were determined, but the reactivity of ion pairs was so low as to elude direct measurement in most cases. Evidence was also obtained for the formation of ion triplets with Li+ in DMF. The relevance of the present results in connection with the cesium effect is briefly discussed.

Journal of Physical Organic Chemistry published new progress about Alkali metal ions Role: PRP (Properties). 56523-59-2 belongs to class bromides-buliding-blocks, name is 15-Bromopentadecanoic acid, and the molecular formula is C15H29BrO2, Recommanded Product: 15-Bromopentadecanoic acid.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Shintani, Ryo published the artcileA new entry of nucleophiles in rhodium-catalyzed asymmetric 1,4-addition reactions: addition of organozinc reagents for the synthesis of 2-aryl-4-piperidones, Formula: C7H6BrF, the main research area is pyridinone arylzinc chloride conjugate addition; arylpiperidone asym preparation; rhodium conjugate addition catalyst.

A rhodium-catalyzed asym. 1,4-addition reaction has been applied to the synthesis of 2-aryl-4-piperidones, e.g., I. While other conventional nucleophiles failed, organozinc reagents have been successfully utilized for the construction of these useful compounds in very good yield and enantiomeric excess.

Journal of the American Chemical Society published new progress about Conjugate addition reaction, stereoselective. 452-63-1 belongs to class bromides-buliding-blocks, name is 1-Bromo-4-fluoro-2-methylbenzene, and the molecular formula is C7H6BrF, Formula: C7H6BrF.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Hossain, Muhammad Saddam published the artcileEffects of Self-Assembly on the Photogeneration of Radical Cations in Halogenated Triphenylamines, Recommanded Product: 4-(Bromomethyl)-N,N-diphenylaniline, the main research area is self Assembly photogeneration radical cation halogenated triphenylamines; crstal structure urea tethered TPA derivatives.

We investigate the effect of assembly on charge transfer, charge recombination, and the persistence of radical cations in halogen-substituted triphenylamine (TPA) dimers. A series of urea-tethered TPA derivatives, R-NH-CO-NH-R (R = X-p-C6H4-N(Ph)-p-C6H4-CH2-, X = H, Cl, Br, and I)(1X) are compared, which have one Ph group modified at the para position with a halogen. Ureas direct the assembly of these derivatives while halogen substituents influence the packing of the TPA units. These modifications affect the generation and persistence of TPA radical cations as monitored by ESR (EPR) spectroscopy. The formation and degradation pathways of the radical cations in solution and gas phase were probed by ion-mobility spectrometry mass spectrometry. In contrast, supramol. assembly enhanced the stability of these materials as well as the persistence of their photogenerated radical cations, which appear to undergo charge recombination without degradation Greater quantities of these radical cations are observed for the bromo and non-halogenated derivatives (1Br, 1H). Time-dependent d. functional theory (TD-DFT) calculations on single mols. and hydrogen-bonded dimers suggest the stability of TPA radical cations largely depends on initial photoinduced charge separation and electronic coupling between assembled TPA dimers. The latter was found to be about 7 times stronger in 1I than in 1Br dimers, which may explain faster charge recombination and shorter lifetimes of 1I radicals. Transient absorption (TA) spectroscopy and TD-DFT were able to identify the charged species for 1Br along with the kinetic traces and measured lifetime of ~80 ns. Fluorescence quenching studies are consistent with initial charge separation and subsequent charge transfer event between nearby TPAs. Future exploration will focus on the mobility and application of these TPA assemblies as hole transport materials.

Journal of Physical Chemistry C published new progress about Charge separation (photoinduced, electron hole pair). 183994-94-7 belongs to class bromides-buliding-blocks, name is 4-(Bromomethyl)-N,N-diphenylaniline, and the molecular formula is C19H16BrN, Recommanded Product: 4-(Bromomethyl)-N,N-diphenylaniline.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Chu, John C. K. published the artcileZn-Catalyzed Enantio- and Diastereoselective Formal [4 + 2] Cycloaddition Involving Two Electron-Deficient Partners: Asymmetric Synthesis of Piperidines from 1-Azadienes and Nitro-Alkenes, Formula: C8H7BrO3, the main research area is zinc catalyst stereoselective formal cycloaddition azadiene nitroalkene kinetics; stereoselective preparation piperidine.

We report a catalytic asym. synthesis of piperidines, e.g. I, through [4 + 2] cycloaddition of 1-azadienes and nitro-alkenes. The reaction uses earth abundant Zn as catalyst and is highly diastereo- and regioselective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to be particularly impactful, due to limiting the undesired coordination of 1-azadiene to the Lewis acid and thus allowing the reaction to be carried out at lower temperature A series of secondary kinetic isotope effect studies using a range of ligands implicates a stepwise mechanism for the transformation, involving an initial Michael-type addition of the imine to the nitro-alkene followed by a cyclization event. The stepwise mechanism obviates the electronic requirement inherent to a concerted mechanism, explaining the successful cycloaddition between two electron-deficient partners.

Journal of the American Chemical Society published new progress about [4+2] Cycloaddition reaction (formal stereoselective). 74317-85-4 belongs to class bromides-buliding-blocks, name is 2-Bromo-4-methoxybenzoic acid, and the molecular formula is C8H7BrO3, Formula: C8H7BrO3.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Tsarev, A. A. published the artcileTitanium and zirconium complexes with η5:η1-4-(alkyl/arylamino)(dimethyl)silylindene ligands as catalysts for ethene polymerization, Safety of 7-Bromo-2-methyl-1H-indene, the main research area is titanium zirconium complex catalyst polyethylene polymerization.

First members of a novel family of constrained geometry complexes of titanium and zirconium containing a short bridge between the amide and inden-4-yl fragments were obtained. When activated with methylaluminoxane, these complexes can be used as highly active catalysts for ethene polymerization producing high-mol.-weight polymers.

Russian Chemical Bulletin published new progress about Aluminoxanes, Me Role: CAT (Catalyst Use), USES (Uses). 880652-93-7 belongs to class bromides-buliding-blocks, name is 7-Bromo-2-methyl-1H-indene, and the molecular formula is C10H9Br, Safety of 7-Bromo-2-methyl-1H-indene.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Lindsay, Karl B. published the artcileFormal Total Synthesis of the Potent Renin Inhibitor Aliskiren: Application of a SmI2-Promoted Acyl-like Radical Coupling, Category: bromides-buliding-blocks, the main research area is renin inhibitor aliskiren total synthesis; samarium diiodide radical addition phenylalanine thioester acrylate.

A formal total synthesis of the potent renin inhibitor aliskiren is disclosed exploiting an alternative coupling strategy recently developed by the authors for the preparation of the hydroxyethylene isostere-based class of protease inhibitors. The 4-pyridyl thioester derivative of amino acid, CbzNHCH(CH2Ph)COS-Pyr (Pyr = 4-pyridyl), representing the C5-C9 fragment of the aliskiren carbon skeleton underwent a carbon chain extension via a SmI2-promoted radical addition to Bu acrylate. Introduction of the C3-iso-Pr group with the correct relative configuration was accomplished via stereoselective reduction of the obtained ketone with concomitant lactonization, followed by an aldol reaction with acetone. Further functional group and protecting group manipulation culminated in a formal total synthesis of aliskiren in 10 steps from the corresponding fully protected non-natural amino acid.

Journal of Organic Chemistry published new progress about Alkenes Role: RCT (Reactant), RACT (Reactant or Reagent). 172900-69-5 belongs to class bromides-buliding-blocks, name is 2-(3-Methoxypropoxy)-4-((R)-2-(bromomethyl)-3-methylbutyl)-1-methoxybenzene, and the molecular formula is C17H27BrO3, Category: bromides-buliding-blocks.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Zhang, Yun published the artcileChiral Phosphoric Acid Catalyzed Asymmetric Ugi Reaction by Dynamic Kinetic Resolution of the Primary Multicomponent Adduct, Related Products of bromides-buliding-blocks, the main research area is chiral phosphoric acid catalyzed asym Ugi dynamic kinetic resolution; enantioselective synthesis aryloxoisoindolinecarboxamide; formylbenzoic acid aniline isonitrile asym Ugi reaction; asymmetric synthesis; kinetic resolution; multicomponent reaction; organocatalysis; reaction mechanisms.

Reaction of isonitriles with 3-(arylamino)isobenzofuran-1(3H)-ones in the presence of a catalytic amount of an octahydro (R)-binol-derived chiral phosphoric acid afforded 3-oxo-2-arylisoindoline-1-carboxamides in high yields with good to high enantioselectivities [e.g., I + tert-BuNC → II (93% yield, 87% ee)]. An enantioselective Ugi four-center three-component reaction of 2-formylbenzoic acids, anilines, and isonitriles was subsequently developed for the synthesis of the same heterocycle. Mechanistic studies indicate that the enantioselectivity results from the dynamic kinetic resolution of the primary Ugi adduct, rather than from the C-C bond-forming process. The resulting heterocycle products are of significant medicinal importance.

Angewandte Chemie, International Edition published new progress about Anilines Role: RCT (Reactant), RACT (Reactant or Reagent). 74317-85-4 belongs to class bromides-buliding-blocks, name is 2-Bromo-4-methoxybenzoic acid, and the molecular formula is C8H7BrO3, Related Products of bromides-buliding-blocks.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Yu, Lin published the artcileFe3O4 nanoparticle-supported copper(I): magnetically recoverable and reusable catalyst for the synthesis of quinazolinones and bicyclic pyrimidinones, Category: bromides-buliding-blocks, the main research area is quinazolinone bicyclic pyrimidinone preparation; amidine halobenzoic acid bromocycloalkenecarboxylic acid cyclocondensation; ferrous ferric oxide nanoparticle supported copper catalyst.

A highly efficient, easily recoverable and reusable Fe3O4 magnetic nanoparticle-supported Cu(I) catalyst has been developed for the synthesis of quinazolinones I(R1 = H, 6-F, 7-MeO, 8-Me, 7-NO2, R2 = Me, Ph, cyclopropyl)and bicyclic pyrimidinones II(R = Me, Ph, cyclopropyl). In the presence of supported Cu(I) catalyst (10 mol%), amidines reacted with substituted 2-halobenzoic acids and 2-bromocycloalk-1-enecarboxylic acids to generate the corresponding N-heterocycle products in good to excellent yields at room temperature in DMF. In addition, the supported Cu(I) catalyst could be recovered at least 10 times without significant loss of its catalytic activity.

Applied Organometallic Chemistry published new progress about Amidines Role: RCT (Reactant), RACT (Reactant or Reagent). 74317-85-4 belongs to class bromides-buliding-blocks, name is 2-Bromo-4-methoxybenzoic acid, and the molecular formula is C8H7BrO3, Category: bromides-buliding-blocks.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Cristau, Henri-Jean published the artcileSynthesis of diphosphine dioxides for extraction of actinides using supported liquid membranes technology, COA of Formula: C6H12Br2O, the main research area is diphosphine dioxide preparation extraction actinide; organophosphorus extractant diphosphine dioxide preparation; radioactive liquid waste treatment organophosphorus extractant; plutonium extraction diphosphine dioxide; neptunium extraction diphosphine dioxide; supported liquid membrane actinide extraction organophosphorus.

A recurrent method for synthesis of diphosphine dioxides to be used for extraction of actinides from acidic aqueous solution is described. Selective phosphonium salt formation and cleavage permits the stepwise introduction of different bridges between the P atoms as well as various chains on them. The influence of the structural parameters on liquid-liquid extraction properties of Pu, Np, and Am was studied. Pu and Np can be efficiently removed from radioactive contaminated liquid wastes, using the supported liquid membranes technol. with the more lipophilic organophosphorus extractants, e.g., I.

Heteroatom Chemistry published new progress about Actinides Role: REM (Removal or Disposal), PROC (Process). 58929-72-9 belongs to class bromides-buliding-blocks, name is 1-Bromo-3-(3-bromopropoxy)propane, and the molecular formula is C6H12Br2O, COA of Formula: C6H12Br2O.

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary