- Imidazopyrazinone compound as well as preparation method and application thereof
-
The invention provides an imidazopyrazinone compound as well as a preparation method and application thereof. The imidazopyrazinone compound structure has the structure shown I, and R. 1 Is phenyl. R2 In the benzyl group, and the compound has at least one D substituent, the D substituent is at R. 1 And/or R2 . The compound has excellent luminescence performance, can be used as a substrate of NanoLuc luminescent system, and is applied to detection and drug detection of luciferase.
- -
-
-
- Selective C-H Allylic Oxygenation of Cycloalkenes and Terpenoids Photosensitized by [Cu(Xantphos)(neoc)]BF4
-
We present herein for the first time the use of the [Cu(Xantphos)(neoc)]BF4 as a photocatalyst for the selective C-H allylic oxygenation of cycloalkenes into the corresponding allylic hydroperoxides or alcohols in the presence of molecular oxygen. The proposed methodology affords the products at good yields and has also been applied successfully to several bioactive terpenoids, such as geraniol, linalool, β-citronellol, and phytol. A mechanistic study involving also kinetic isotope effects (KIEs) supports the proposed singlet oxygen-mediated reaction. On the basis of the high chemoselectivity and yields and the fast and clean reaction processes observed, the present catalytic system, [Cu(Xantphos)(neoc)]BF4, has also been applied to the synthesis, at a laboratory scale, of the cis-Rose oxide, a well-known perfumery ingredient used in rose and geranium perfumes.
- Kallitsakis, Michael G.,Gioftsidou, Dimitra K.,Tzani, Marina A.,Angaridis, Panagiotis A.,Terzidis, Michael A.,Lykakis, Ioannis N.
-
p. 13503 - 13513
(2021/09/13)
-
- Iron-Catalyzed Amination of Strong Aliphatic C(sp3)-H Bonds
-
A concept for intramolecular denitrogenative C(sp3)-H amination of 1,2,3,4-tetrazoles bearing unactivated primary, secondary, and tertiary C-H bonds is discovered. This catalytic amination follows an unprecedented metalloradical activation mechanism. The utility of the method is showcased with the short synthesis of a bioactive molecule. Moreover, an initial effort has been embarked on for the enantioselective C(sp3)-H amination through the catalyst design. Collectively, this study underlines the development of C(sp3)-H bond functionalization chemistry that should find wide application in the context of drug discovery and natural product synthesis.
- Das, Sandip Kumar,Roy, Satyajit,Khatua, Hillol,Chattopadhyay, Buddhadeb
-
p. 16211 - 16217
(2020/10/26)
-
- Rhodium-Catalyzed Intramolecular C-H Bond Activation with Triazoles: Preparation of Stereodefined Pyrrolidines and Other Related Cyclic Compounds
-
On treatment of triazoles having an N-sulfonyl-protected benzylamine moiety with [Rh2(C7H15CO2)4], intramolecular C-H bond insertion takes place at the benzylic position to give cis-N-sulfonyl-2-aryl-3-[(sulfonylimino)methyl]pyrrolidines in good yields and with highly stereoselectivities. Analogously, the similar treatment of triazoles having an ether or even an alkyl moiety affords 2-alkyl- or 2-aryl-3-[(sulfonylimino)methyl]tetrahydrofurans or a 2-alkyl-3-[(sulfonylimino)methyl]cyclopentane in good yields. Three is a magic number: On treatment of triazoles with [Rh2(C7H15CO2)4], the rhodium catalyst plays three roles, denitrogenation, C-H bond activation, and stereoselective cyclization, providing a new method for heterocycle synthesis. Intramolecular C-H bond insertion takes place at the benzylic position to give pyrrolidines and related heterocycles in good yields.
- Senoo, Masato,Furukawa, Ayana,Hata, Takeshi,Urabe, Hirokazu
-
p. 890 - 895
(2016/01/16)
-
- Mechanistic analysis of oxidative C-H cleavages using inter- and intramolecular kinetic isotope effects
-
A series of monodeuterated benzylic and allylic ethers were subjected to oxidative carbon-hydrogen bond cleavage to determine the impact of structural variation on intramolecular kinetic isotope effects in DDQ-mediated cyclization reactions. These values
- Jung, Hyung Hoon,Floreancig, Paul E.
-
experimental part
p. 10830 - 10836
(2010/02/28)
-
- An unprecedented rearrangement in collision-induced mass spectrometric fragmentation of protonated benzylamines
-
The collision-induced dissociation (CID) mass spectra of several protonated benzylamines are described and mechanistically rationalized. Under collision-induced decomposition conditions, protonated dibenzylamine, for example, loses ammonia, thereby forming an ion of m/z 181. Deuterium labeling experiments confirmed that the additional proton transferred to the nitrogen atom during this loss of ammonia comes from the ortho positions of the phenyl rings and not from the benzylic methylene groups. A mechanism based on an initial elongation of a C-N bond at the charge center that eventually cleaves the C-N bond to form an ion/neutral complex of benzyl cation and benzylamine is proposed to rationalize the results. The complex then proceeds to dissociate in several different ways: (1) a direct dissociation to yield a benzyl cation observed at m/z 91; (2) an electrophilic attack by the benzyl cation within the complex on the phenyl ring of the benzylamine to remove a pair of electrons from the aromatic sextet to form an arenium ion, which either donates a ring proton (or deuteron when present) to the amino group forming a protonated amine, which undergoes a charge-driven heterolytic cleavage to eliminate ammonia (or benzylamine) forming a benzylbenzyl cation observed at m/z 181, or undergoes a charge-driven heterolytic cleavage to eliminate diphenylmethane and an immonium ion; and (3) a hydride abstraction from a methylene group of the neutral benzylamine to the benzylic cation to eliminate toluene and form a substituted immonium ion. Corresponding benzylamine and dibenzylamine losses observed in the spectra of protonated tribenzylamine and tetrabenzyl ammonium ion, respectively, indicate that the postulated mechanism can be widely applied. The postulated mechanisms enabled proper prediction of mass spectral fragments expected from protonated butenafine, an antifungal drug. Copyright
- Bialecki, Jason,Ruzicka, Josef,Attygalle, Athula B.
-
p. 1195 - 1204
(2007/10/03)
-
- Preparation of ortho-Aryl-benzaldehyde Derivatives via Free-Radical ipso-Substitution of an Amidomethyl Group
-
Preparation of 2-biarylcarbaldehydes using an intramolecular free-radical ipso-substitution is described. The two aryl moieties to be coupled are pre-associated using a glycolamide derivative. An unusual amidomethyl leaving group was successfully employed in this process.
- Giraud, Luc,Lacote, Emmanuel,Renaud, Philippe
-
p. 2148 - 2156
(2007/10/03)
-
- The remarkable electron impact mass spectrum of (2-benzyl-1,3-xylylene)-15- crown-4: Expulsion of triethylene glycol by double hydrogen transfer
-
During our investigations of the synthesis of magnesium-containing crown ethers, the mass spectral characterisation of a precursor, (2-benzyl-1,3- xylylene)-15-crown-4 (C21H26O4), leads to a surprising result: its electron
- Gruter, Gert-Jan M.,Van Baar, Ben L. M.,Gerrits, Tom J.,Akkerman, Otto S.,Bickelhaupt, Friedrich,Barkow, Anja,Kuck, Dietmar
-
p. 925 - 932
(2007/10/03)
-
- Selective sp3 C-H bond activation of alkylaromatics promoted by platinum complexes
-
Facile sp3 C-H bond activation of toluene, p-xylene and mesitylene, was photochemically promoted by trans-Pt(CH2CMe2Et)Br(PPh3)2 leading to trans-Pt(CH2Ar)Br(PPh3)2 quantitatively, while regioselective sp3 C-H bond cleavage at the benzylic position of ethylbenzene and cumene readily took place to yield styrene and α-methylstyrene, respectively.A possible reaction mechanism involving radical process is discussed on the basis of isotope and radical-trap experiments. Key words: Platinum; Benzyl; Bond activation; Radical; Photochemistry
- Miyashita, Akira,Hotta, Masatoshi,Saida, Yoshiko
-
p. 353 - 358
(2007/10/02)
-
- Mechanistic aspects of the reaction of anionic iron(0)-olefin complexes with organic halides. detection and characterization of paramagnetic organometallic intermediates
-
The scope and the mechanism of the reactions of [CpFe(COD)][Li(TMEDA) (Cp = C5H5-; COD = 1,5-cyclooctadiene; TMEDA = Me2NCH2CH2NMe2), 1, with a number of organic monohalides and geminal dih
- Hill, Dale H.,Parvez, Masood A.,Sen, Ayusman
-
p. 2889 - 2901
(2007/10/02)
-
- Generation and IR spectroscopic study of benzyl radical
-
The benzyl radical C6H5CH2 has been obtained by gas phase pyrolysis of two different precursors, benzyl bromide and dibenzyl, and studied in an argon matrix at 12 K by IR spectroscopy.Similarly, the deuterosubstituted benzyl radicals, C6H5CD2 and C6D5CH2,
- Baskir, E. G.,Maltsev, A. K.,Korolev, V. A.,Khabashesku, V. N.,Nefedov, O. M.
-
p. 1438 - 1440
(2007/10/02)
-
- Primary and Secondary Kinetic Deuterium Isotope Effects and Transition-State Structures for Benzylic Chlorination and Bromination of Toluene
-
As a chemical model for benzylic hydroxylations effected by cytochrome P-450 enzymes, the chlorination of PhCH3, PhCH2D, PhCHD2, and PhCD3 in a two-phase system of hypochlorite/CH2Cl2 with a phase-transfer catalyst has been investigated.On the basis of th
- Hanzlik, Robert P.,Schaefer, Angela R.,Moon, Joseph B.,Judson, Charles M.
-
p. 4926 - 4930
(2007/10/02)
-
- Intramolecular Kinetic Deuterium Isotope Effects on Microsomal Hydroxylation and Chemical Chlorination of Toluene-α-d1 and Toluene-α,α-d2
-
Deuterated toluenes PhCH2D and PhCHD2 were synthesized and subjected separately to microsomal hydroxylation in vitro.Mass spectral analysis of the resulting benzyl alcohols indicated substatial excess retention of deuterium, a consequence of the combined
- Hanzlik, Robert P.,Hogberg, Kerstin,Moon, Joseph B.,Judson, Charles M.
-
p. 7164 - 7167
(2007/10/02)
-
- MECHANISMS OF FREE-RADICAL REACTIONS. XIII. MECHANISM AND SELECTIVITY OF THE FREE-RADICAL HALOGENATION OF ALKYL AROMATIC HYDROCARBONS WITH FLUOROALKYL SUBSTITUENTS
-
The free-radical chlorination and bromination of 1-fluoro-2-arylethanes and 1,1,1-trifluoro-2-arylethanes was studied by the method of competing reactions.In all cases a good correalation between log krel and the Brown ?+ constants was observed.The variation of the selectivity in the transition from one reaction series to the other indicates that two independent factors which determine the reactivity (the change in the dissociation energy of the C-H bond and the polar effect of the substituents) have a simultaneous effect.
- Dneprovskii, A. S.,Eliseenkov, E. V.,Mil'tsov, S. A.
-
p. 317 - 324
(2007/10/02)
-
- Skeletal Rearrangements on Chemical Ionization of Dibenzyl Ether and Derivatives
-
Protonated molecular ions of dibenzyl ether, formed by chemical ionization using hydrogen and isobutane as reagent gases, undergo skeletal rearrangements to lose water and formaldehyde, both in the ion source and the flight path.The rearrangements have been elucidated by deuterium labelling and chemical substitution.The water lost contains the reagent proton and an aromatic hydrogen atom, and the aromatic hydrogen atoms have been shown to be mobile prior to the reaction.It is proposed that the skeletal rearrangement for water loss is initiated by protonation on the other oxygen atom, followed by benzyl migration.The formaldehyde loss contains benzylic hydrogen atoms exclusively, and it is proposed that the skeletal rearrangement is preceded by hydrogen rearrangement of an oxygen protonated molecular ion to a ring protonated molecular ion.Daughter ion structures are supported by comparisons of their collision induced dissociation spectra with those of isomeric ions prepared by alternative routes.
- Kingston, Eric E.,Shannon, James S.,Diakiw, Vladimir,Lacey, Michael J.
-
p. 428 - 440
(2007/10/02)
-
- VEREINFACHUNG DER 1H- UND 13C-NMR-SPEKTREN VON BENZYLETHER-BLOCKIERTEN SACCHARIDEN. EINE LEISTUNGSFAEHIGE SYNTHESE VON BROMMETHYL-d2-BENZOL
-
An efficient synthesis of bromomethyl-d2-benzene as reagent for protection of hydroxyl groups and its benefit in (1)H- and (13)C-NMR-spectroscopical analysis of benzylether blocked saccharides is described.
- Paulsen, Hans,Roeben, Wolfgang,Heiker, Fred R.
-
p. 3679 - 3680
(2007/10/02)
-
- Azetidines. 5. Reaction of 1,1,3,3-Tetramethyl- and 1-Benzyl-1,3,3-trimethylazetidinium Ions with Butyllithium and Phenyllithium. Deuterium Labeling as a Mechanistic Probe
-
The reactions of 1,1,3,3-tetramethylazetidinium iodide (1) and 1-benzyl-1,3,3-trimethylazetidinium bromide (7) with butyllithium and with phenyllithium were studied in ether.The products from the reaction of 1 with butyllithium were 1,3,3-trimethylpyrrolidine (2), 3,3-dimethyl-4-(methylamino)-1-butene (3), 1-(dimethylamino)-2,2-dimethylheptane (4), neopentylpyrrolidine (5), and 1-(dimethylamino)-2,2-dimethylcyclopropane (6).With phenyllithium, 1 gave 2 and 1-(dimethylamino)-2,2-dimethyl-3-phenylpropane (11).With butyllithium, 7 gave 2-phenyl-1,4,4-trimethylpyrrolidine (8), 1-benzyl-3,3-dimethylpyrrolidine (9), and 1-neopentyl-2-phenylpyrrolidine (10).The reaction of phenyllithium with 7 gave only 8 and 9.Mechanistic information was obtained by labeling 1 with deuterium in three different ways: N-methyl-d3, 2,2-d2, and N-methyl-d3-2,2-d2.A primary kinetic isotope effect of 9.4 was found for the formation of 2 from 1-N-methyl-d3.When 2 was formed from 1-2,2-d2, a secondary kinetic isotope effect of 1.17 was measured.The formation of 4 from 1-2,2-d2 was accompanied by a primary kinetic isotope effect of 4.7, suggesting a carbene intermediate.Ylide carbanions involving decomposition to a carbene carbanion in the formation of 3 and an azomethine ylide in the formation of 5 and 9 are probable intermediates.It is postulated that the azomethine ylides react with ethylene formed from the reaction of butyllithium with the solvent ether by means of a concerted (4 + 2) cycloaddition reaction.A primary kinetic isotope effect of 20 was found for the formation of pentylbenzene from dibenzyldimethylammonium bromide and butyllithium.
- Wills, Max T.,Wills, Irene E.,Dollen, Lawrence Von,Butler, Barry L.,Porter, John,Anderson, Arthur G.
-
p. 2489 - 2498
(2007/10/02)
-
- α-Deuterium Isotope Effects in Benzyl Halides. 2. Reaction of Nucleophiles with Substituted Benzyl Bromides. Evidence for a Change in Transition-State Structure with Electron-Donating Substituents
-
Rates and α-D isotope effects have been determined for the following substrates and nucleophiles: p-methoxybenzyl bromide (Et3N, SCN-, N3-, OH-, S2O32-) benzyl bromide (Et3N, SCN-, N3-, OH-, S2O32-), and p-nitrobenzyl bromide (Et3N, SCN-, N3-, S2O32-).In nearly all cases the second-order rate constant for each nucleophile goes though a minimum for the unsubstituted compound while the α-D isotope increases monotonically in the sequence p-NO2>p-H>p-OCH3.These results are consistent with an increasing "looseness" of the SN2 transition state as the substituent on the aromatic ring becomes more electron donating.
- Vitullo, V.P.,Grabowski, J.,Sridharan, S.
-
p. 6463 - 6465
(2007/10/02)
-
- REARRANGEMENTS OF THE CARBANIONS DERIVED FROM ALLYL BENZYL THIOETHER
-
The metalation of allyl benzyl thioether involves the benzylic or the allylic hydrogens.The benzylic carbanion undergoes a rapid sigmatropic shift whereas the allylic carbanion gives rise to various rearrangements, among them migration of the allylic unit to the para position with allylic inversion.The temperature dependence of the ratio of products arising from the benzylic carbanion vs those from the allylic carbanion shows that the allylic-to-benzylic carbanion transformation occurs only under special conditions: (a) with slow addition of the base; (b) with thioether in excess relative to the base, and (c) on raising the temperature of the reaction medium from -78 deg C to -15 deg C.In the last instance, the proton transfer is intramolecular as shown with labeled thioethers.The extent of the different rearrangements depends on the temperature and solvent.A choise of mechanism cannot be made at this time for the para migration 5-->9a.A leaving group effect on the reaction regioselectivity of the carbanion from allyl methyl thioether with benzyl halides has been noticed.The presence of dibenzyl indicates that, in addition to SN2 reactions, some electron transfer process is occuring.
- Biellmann, J. F.,Ducep, J. B.,Schirlin, D.
-
p. 1249 - 1260
(2007/10/02)
-