Xn:Harmful;
90-12-0Relevant articles and documents
Radiation-induced C-C Bond Cleavage in 1,2-Diarylethanes as Model compounds of Coal. Part 1.- Pulse and Steady-state Radiolysis of 1,2-Di(1-naphthyl)ethane
Haenel, Matthias W.,Richter, Udo-Burckhard,Solar, Sonja,Getoff, Nikola
, p. 311 - 319 (1990)
1,2-Di(1-naphthyl)ethane (1,2-DNE) has been used to study the radiation-induced C-C bond cleavage of the ethane linkage.Pulse radiolysis was applied both in the absence and presence of NaAlH4 and NaAlH2(OR)2 used as scavengers for solvent cations.In the presence of the sodium aluminium hydrides the radical anions of 1,2-DNE are stabilized by the metal cation, resulting in the formation of radical anion/sodium cation pairs (Na+, 1,2-DNE.-), these species have a rather long lifetime (τ>2 ms) in DME as well as in THF, and show three absorption bands at 330, 370 and 750 nm.In THF ε370=14000 dm3 mol-1 cm-1 and ε750=5000 dm3 mol-1 cm-1 were established.Cleavage of the ethano bridge of 1,2-DNE was achieved by means of steady-state as well as multi-pulse radiolysis in the presence of alkali-metal aluminium hydrides.The efficiency of this process was studied by using NaAlH4, NaAlH2(OR)2, NaAlH2Et2, NaAlEt4 and LiAlH4 in THF as well as in DME.The most efficient C-C bond cleavage results from the successive attack of two sodium cation/electron ion pairs (Na+, e-) forming the unstable dianions (2 Na+, 1,2-DNE2-).These decompose under scission of the ethano bridge, producing naphthylmethyl carbanionic fragments C10H7CH2-Na+ which supposedly form aluminate salts, e.g.C10H7CH2AlH3-Na+, with AlH3 generated in the scavenging processes.From these aluminate salts 1-methylnaphthalene is obtained through hydrolysis.
Vibronic Absorption Spectra of Naphthalene and Substituted Naphthalene Cations in Solid Argon
Andrews, Lester,Kelsall, Benuel J.,Blankenship, Terry A.
, p. 2916 - 2926 (1982)
Naphthalene and methyl- and halonaphthalene cations have been produced by one- and two-photon matrix photoionization techniques and trapped in solid argon for absorption spectroscopic study.Five transitions in the visible and ultraviolet regions have been assigned to the radical cations.The argon matrix absorption spectra are in agreement with photoelectron and photodissociation spectra, absorption spectra of the ions in Freon glasses, and simple HMO calculations.Substituent effects were observed for the origins of the five transitions.The repeating vibronic intervals in the red N+ transitions due to the C(9)-C(10) stretching fundamentals for this group of substituted naphthalene cations are 40 - 50 cm-1 above the Raman fundamentals for the molecules whereas the vibronic intervals due to ring deformation modes are up to 30 cm-1 below the appropriate Raman fundamentals, and vibronic intervals in the sharp UV band are 30 - 45 cm-1 below Raman fundamentals, which correlate with HMO ? bond orders.
Preparation method of naphthalene ring C marked α .
-
, (2021/10/05)
The invention discloses C labeled α - naphthalene acetic acid preparation method and belongs to the field of radioisotope C labeled compounds. C-labeled α - naphthylacetic acid preparation method, C radioisotope labeling is introduced on a naphthalene ring structure α -naphthol acid, C labeling site is in α-position. The method has the advantages that the reaction raw materials are easily available, the synthesis steps are high in yield, the total yield is more 60%, C marker isotopes are less in use amount, and waste is generated. The marker site α-position on the naphthalene ring is less likely to be metabolized compared to C-labeled branched acetic acid, and the synthesized C-labeled compound provides a better study of α -naphthoic acid in the environment.
Synthesis of renewable alkylated naphthalenes with benzaldehyde and angelica lactone
Cong, Yu,Li, Guangyi,Li, Ning,Wang, Aiqin,Wang, Ran,Wang, Xiaodong,Xu, Jilei,Zhang, Tao
supporting information, p. 5474 - 5480 (2021/08/16)
Herein, we report a new route for the synthesis of renewable alkylated naphthalenes (ANs) with benzaldehyde and angelica lactone, two platform compounds that can be derived from lignocellulose.
Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
supporting information, p. 9029 - 9039 (2021/06/28)
Chemoselective deoxygenation of carbonyls and alcohols using hydrogen by heterogeneous base-metal catalysts is crucial for the sustainable production of fine chemicals and biofuels. We report an aluminum metal-organic framework (DUT-5) node support cobalt(II) hydride, which is a highly chemoselective and recyclable heterogeneous catalyst for deoxygenation of a range of aromatic and aliphatic ketones, aldehydes, and primary and secondary alcohols, including biomass-derived substrates under 1 bar H2. The single-site cobalt catalyst (DUT-5-CoH) was easily prepared by postsynthetic metalation of the secondary building units (SBUs) of DUT-5 with CoCl2 followed by the reaction of NaEt3BH. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of CoII and AlIII centers in DUT-5-CoH and DUT-5-Co after catalysis. The coordination environment of the cobalt center of DUT-5-Co before and after catalysis was established by extended X-ray fine structure spectroscopy (EXAFS) and density functional theory. The kinetic and computational data suggest reversible carbonyl coordination to cobalt preceding the turnover-limiting step, which involves 1,2-insertion of the coordinated carbonyl into the cobalt-hydride bond. The unique coordination environment of the cobalt ion ligated by oxo-nodes within the porous framework and the rate independency on the pressure of H2 allow the deoxygenation reactions chemoselectively under ambient hydrogen pressure.
A New Protocol for Catalytic Reduction of Alkyl Chlorides Using an Iridium/Bis(benzimidazol-2′-yl)pyridine Catalyst and Triethylsilane
Fukuyama, Takahide,Hamada, Yuki,Ryu, Ilhyong
, p. 3404 - 3408 (2021/07/14)
The reduction of alkyl chlorides using triethylsilane is investigated. Primary, secondary, tertiary, and benzylic C-Cl bonds are effectively converted into C-H bonds using an [IrCl(cod)] 2/2,6-bis(benzimidazol-2′-yl)pyridine catalyst system. This catalyst system is quite simple since the tridentate N-ligand can be easily prepared in one step from commercially available reagents.
Cobalt?NHC Catalyzed C(sp2)?C(sp3) and C(sp2)?C(sp2) Kumada Cross-Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents
Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
, p. 202 - 206 (2020/12/01)
The first cobalt-catalyzed cross-coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF3 and NHCs (NHC=N-heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C?O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp2)?C(sp3) cross-coupling of C?O electrophiles, circumventing isomerization and β-hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C?O cross-coupling sets the stage for a sequential cross-coupling by exploiting the orthogonal selectivity of the catalytic system.
A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
Feng, Boya,Yang, Yudong,You, Jingsong
, p. 6031 - 6035 (2020/07/10)
Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
Iron-Catalyzed Direct Julia-Type Olefination of Alcohols
Landge, Vinod G.,Babu, Reshma,Yadav, Vinita,Subaramanian, Murugan,Gupta, Virendrakumar,Balaraman, Ekambaram
, p. 9876 - 9886 (2020/09/03)
Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance (amino, nitro, halo, alkoxy, thiomethoxy, and S- A nd N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.
C-F activation for C(sp2)-C(sp3) cross-coupling by a secondary phosphine oxide (SPO)-nickel complex
Müller, Valentin,Ghorai, Debasish,Capdevila, Lorena,Messinis, Antonis M.,Ribas, Xavi,Ackermann, Lutz
supporting information, p. 7034 - 7040 (2020/09/15)
A secondary phosphine oxide (SPO)-nickel catalyst allowed the activation of otherwise inert C-F bonds of unactivated arenes in terms of challenging couplings with primary and secondary alkyl Grignard reagents. The C-F activation is characterized by mild reaction conditions and high levels of branched selectivity. Electron-rich and electron-deficient arenes were suitable electrophiles for this transformation. In addition, this strategy also proved suitable to heterocycles and for the activation of C-O bonds under slightly modified conditions.
