- A simple synthesis of salicylamide and 2,5-diphenylpyrazine
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The compound I (C7H7NO2, salicylamide) and the compound II (C16H12N2, 2,5-diphenylpyrazine) were both obtained as the by-product of the onepot synthesis of oxazolinyl zinc complexes from the reaction of 2-hydroxybenzonitrile and 3-(N-ethyl-N-phenyl)-propanenitrile with D-phenylalaninol, which was catalyzed by 235 and 83.1 mol% zinc dichloride. Their structures were determined by X-ray diffraction, IR ,and elemental analysis.
- Mei, Luo,Bing, Yan
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Read Online
- PHOSPHINE FREE COBALT BASED CATALYST, PROCESS FOR PREPARATION AND USE THEREOF
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The present invention discloses a phosphine free cobalt based catalyst of formula (I) and a process for preparation thereof. The present invention further discloses a process for the synthesis of aromatic heterocyclic compounds of formula (II) and pyrazine derivative using the phosphine free cobalt based catalyst of formula (I).
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Paragraph 0069; 0158-0159
(2020/12/29)
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- Streamlined Routes to Phenacyl Azides and 2,5-Diarylpyrazines Enabled by Deep Eutectic Solvents
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A Deep Eutectic Solvent like choline chloride/glycerol (1:2 mol mol–1) proved to be an effective, sustainable reaction medium to easily synthesize both phenacyl azides and symmetrical 2,5-diarylpyrazines of interest in pharmacology and in coordination chemistry. Notable features of our report include: (i) nucleophilic substitution reactions of α-halo carbonyl compounds to the corresponding phenacyl azides compatible with the eutectic mixture, (ii) the reduction of phenacyl azides to α-amino carbonyl compounds, which undergo spontaneous dimerisation/cyclisation/aromatisation in the same eutectic mixture to provide valuable pyrazines. Telescoped, one-pot, two-steps stoichiometric/catalytic processes have also been successfully developed to furnish 2,5-diarylpyrazines in up to 95 % yield.
- Vitale, Paola,Cicco, Luciana,Messa, Francesco,Perna, Filippo Maria,Salomone, Antonio,Capriati, Vito
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p. 5557 - 5562
(2019/08/21)
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- Acceptorless Dehydrogenative Coupling Using Ammonia: Direct Synthesis of N-Heteroaromatics from Diols Catalyzed by Ruthenium
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The synthesis of N-heteroaromatic compounds via an acceptorless dehydrogenative coupling process involving direct use of ammonia as the nitrogen source was explored. We report the synthesis of pyrazine derivatives from 1,2-diols and the synthesis of N-substituted pyrroles by a multicomponent dehydrogenative coupling of 1,4-diols and primary alcohols with ammonia. The acridine-based Ru-pincer complex 1 is an effective catalyst for these transformations, in which the acridine backbone is converted to an anionic dearomatized PNP-pincer ligand framework.
- Daw, Prosenjit,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 11931 - 11934
(2018/09/27)
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- Synthesis of Pyrazines and Quinoxalines via Acceptorless Dehydrogenative Coupling Routes Catalyzed by Manganese Pincer Complexes
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Base-metal catalyzed dehydrogenative self-coupling of 2-amino alcohols to selectively form functionalized 2,5-substituted pyrazine derivatives is presented. Also, 2-substituted quinoxaline derivatives are synthesized by dehydrogenative coupling of 1,2-diaminobenzene and 1,2-diols. In both cases, water and hydrogen gas are formed as the sole byproducts. The reactions are catalyzed by acridine-based pincer complexes of earth-abundant manganese.
- Daw, Prosenjit,Kumar, Amit,Espinosa-Jalapa, Noel Angel,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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p. 7734 - 7741
(2018/08/03)
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- Direct Assembly of 4-Substituted Quinolines with Vinyl Azides as a Dual Synthon via C=C and C-N Bond Cleavage
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An unprecedented Zn-promoted selective cleavage of vinyl azides for the synthesis of 4-substituted quinolines is developed. In this conversion, vinyl azides function as a dual synthon via C=C and C-N bond cleavage with two C=C bonds and one C=N bond formation in a one-step manner. The reaction is appreciated for its readily accessible substrates, high step economy, mild conditions, and use of air as the sole oxidant.
- Cen, Jinghe,Li, Jianxiao,Zhang, Yu,Zhu, Zhongzhi,Yang, Shaorong,Jiang, Huanfeng
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p. 4434 - 4438
(2018/08/07)
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- Cobalt-catalyzed acceptorless dehydrogenative coupling of aminoalcohols with alcohols: Direct access to pyrrole, pyridine and pyrazine derivatives
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Here, the first example is reported of a new, molecularly defined SNS-cobalt(ii) catalyst for the acceptorless dehydrogenative coupling (ADC) of unprotected amino alcohols with secondary alcohols leading to pyrrole and pyridine derivatives.
- Midya, Siba P.,Landge, Vinod G.,Sahoo, Manoj K.,Rana, Jagannath,Balaraman, Ekambaram
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supporting information
p. 90 - 93
(2017/12/27)
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- The reaction of α-halocarbonyl compounds with (NH4)OH, (NH4)So4 or NH4CI solution under microwave-irradiation
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Reaction of α-halo ketone (a-bromo ketone) under microwave, irradiation gives the pyrazine and quinoxaline derivative in good yields. This reaction affords a clean and convenient synthetic method for pyrazine and quinoxaline derivatives.
- Utsukihara, Takamitsu,Koshimura, Masahiro,Kitsuta, Kazunori,Sato, Akinori,Matsushita, Masatoshi,Takahashi, T. Tomoyoshi,Horiuchi, C. Akira
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p. 1495 - 1502
(2017/11/10)
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- Synthesizing method of 2,5-diphenyl pyrazine
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A synthesizing method of a 2,5-diphenyl pyrazine having a chemical formula as below, comprises: refluxing 2.6845g of 1-(cyanoacetyl) pyrrolidine and 4.3788g of D-phenylglycinol in a chlorobenzene solution with the presence of 1.2583g of cupric acetate as a catalyst for 60-70 hours without water and oxygen, wherein the dosage of cupric acetate if 31.1mol% of the dosage of raw material 1-(cyanoacetyl) pyrrolidine; removing chlorobenzene after the reaction is complete, adding water, stirring for dissolving, then extracting by chloroform, drying and desolventizing the extract phase, then separating by silica gel chromatographic column, eluting by petroleum ether/chloromethane (volume ratio 9:1), collecting the first component, and removing the eluent, thereby obtaining the target product 2,5-diphenyl pyrazine.
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Paragraph 0008
(2016/12/01)
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- Diversity in Gold-Catalyzed Formal Cycloadditions of Ynamides with Azidoalkenes or 2H-Azirines: [3+2] versus [4+3] Cycloadditions
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Gold-catalyzed cycloadditions of ynamides with azidoalkenes or 2H-azirines give [3+2] or [4+3] formal cycloadducts of three classes. Cycloadditions of ynamides with 2H-azirine species afford pyrrole products with two regioselectivities when the Cb-substituted 2H-azirine is replaced from an alkyl (or hydrogen) with an ester group. For ynamides substituted with an electron-rich phenyl group, their reactions with azidoalkenes proceed through novel [4+3] cycloadditions to deliver 1H-benzo[d]azepine products instead.
- Pawar, Samir Kundlik,Sahani, Rajkumar Lalji,Liu, Rai-Shung
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p. 10843 - 10850
(2015/07/20)
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- Gold-catalyzed reactions of propargylic esters with vinylazides for the synthesis of Z- or E-configured buta-1,3-dien-2-yl esters
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Gold-catalyzed synthesis of buta-1,3-dien-2-yl esters by the reaction of propargyl esters with vinylazides is described; the reaction mechanism is postulated to involve a vinyl attack of vinylazides at alkenyl gold carbenes.
- Wagh, Sachin Bhausaheb,Liu, Rai-Shung
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p. 15462 - 15464
(2015/10/20)
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- Domino reactions of 2H-azirines with acylketenes from furan-2,3-diones: Competition between the formation of ortho-fused and bridged heterocyclic systems
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3-Aryl-2H-azirines react with acylketenes, generated by thermolysis of 5-arylfuran-2,3-diones, to give bridged 5,7-dioxa-1-azabicyclo[ 4.4.1]undeca-3,8-diene-2,10-diones and/or ortho-fused 6,6a,12,12a- tetrahydrobis[1,3]oxazino[3,2-a:3′,2′-d]pyrazine-4,10
- Khlebnikov, Alexander F.,Novikov, Mikhail S.,Pakalnis, Viktoriia V.,Iakovenko, Roman O.,Yufit, Dmitry S.
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p. 784 - 793
(2014/05/06)
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- Highly luminescent dinuclear platinum(II) complexes incorporating bis-cyclometallating pyrazine-based ligands: A versatile approach to efficient red phosphors
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A series of luminescent dinuclear platinum(II) complexes incorporating diphenylpyrazine-based bridging ligands (LnH2) has been prepared. Both 2,5-diphenylpyrazine (L2H2) and 2,3-diphenylpyrazine (L3H2) are able to undergo cyclometalation of the two phenyl rings, with each metal ion binding to the two nitrogen atoms of the central heterocycle, giving, after treatment with the anion of dipivaloyl methane (dpm), complexes of formula {Pt(dpm)} 2Ln. These compounds are isomers of the analogous complex of 4,6-diphenylpyrimidine (L1H2). Related complexes of dibenzo(f,h)quinoxaline (L4H2), 2,3-diphenyl-quinoxaline (L5H2), and dibenzo[3,2-a:2′,3′-c]phenazine (L6H2) have also been prepared, allowing the effects of strapping together the phenyl rings (L4H2 and L 6H2) and/or extension of the conjugation from pyrazine to quinoxaline (L5H2 and L6H2) to be investigated. In all cases, the corresponding mononuclear complexes, Pt(dpm)LnH, have been isolated too. All 12 complexes are phosphorescent in solution at ambient temperature. Emission spectra of the dinuclear complexes are consistently red shifted compared to their mononuclear analogues, as are the lowest energy absorption bands. Electrochemical data and TD-DFT calculations suggest that this effect arises primarily from stabilization of the LUMO. Introduction of the second metal ion also has the effect of substantially increasing the molar absorptivity and, in most cases, the radiative rate constants. Meanwhile, extension of conjugation in the heterocycle of L5H2 and L6H2 and planarization of the aromatic system favored by interannular bond formation in L 4H2 and L6H2 leads to further red shifts of the absorption and emission spectra to wavelengths that are unusually long for cyclometalated platinum(II) complexes. The results may offer a versatile design strategy for tuning and optimizing the optical properties of d-block metal complexes for contemporary applications.
- Culham, Stacey,Lanoe, Pierre-Henri,Whittle, Victoria L.,Durrant, Marcus C.,Williams, J. A. Gareth,Kozhevnikov, Valery N.
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p. 10992 - 11003
(2013/10/22)
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- Highly efficient synthesis of 2,5-disubstituted pyrazines from (Z)-β-haloenol acetates
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A highly efficient synthesis of a wide range of 2,5-disubstituted pyrazines from (Z)-β-haloenol acetates is described. The reactions are conducted under convenient conditions and provide products with excellent regioselectivity in moderate to excellent yields with a broad substrate scope, including a variety of aromatic and aliphatic haloenol acetates.
- Chen, Zhengwang,Ye, Dongnai,Xu, Guohai,Ye, Min,Liu, Liangxian
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supporting information
p. 6699 - 6702
(2013/10/01)
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- Ambivalent role of metal chlorides in ring opening reactions of 2H-azirines: Synthesis of imidazoles, pyrroles and pyrrolinones
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2H-Azirines were found to react with imines, enaminones and enaminoesters in the presence of metal salts. Imidazoles, pyrroles and new pyrrolinones derivatives are isolated in good overall yields. The role of metal salts was investigated as they can act as Lewis acids or electron donors. Mechanisms are proposed suggesting that imidazoles arise from addition of azirine to imines via radical or ionic mechanism; pyrroles and pyrrolinones are obtained from azirines with enamino derivatives when the salt acts as a Lewis acid. In the latter case the properties of the metallic compound influence the reaction regioselectivity.
- Auricchio, Sergio,Truscello, Ada M.,Lauria, Mirvana,Meille, Stefano V.
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experimental part
p. 7441 - 7449
(2012/09/22)
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- Synthesis of peptides and pyrazines from β-amino alcohols through extrusion of h2 catalyzed by ruthenium pincer complexes: Ligand-controlled selectivity
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Your choice: The choice of the Ru-pincer-complex catalyst determines if peptides or pyrazines are formed from β-amino alcohols. Use of PNN complex 1 leads to linear poly(alanine) or to cyclic dipeptides, depending on the R group (see scheme). With the PNP
- Gnanaprakasam, Boopathy,Balaraman, Ekambaram,Ben-David, Yehoshoa,Milstein, David
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supporting information; experimental part
p. 12240 - 12244
(2012/01/30)
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- Selenation/thionation of α-amino acids: Formation and x-ray structures of diselenopiperazine and dithiopiperazine and related compounds
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N-Phenylglycine reacts with an equivalent of 2,4-bis(phenyl)-1,3- diselenadiphosphetane 2,4-diselenide (Woollins' reagent, WR to generate as the major product 1,4-diphenylpiperazine-2,5-diselenone and as the minor product 1,4-diphenyl-5-selenoxopiperazin-
- Hua, Guoxiong,Fuller, Amy L.,Buehl, Michael,Slawin, Alexandra M. Z.,Woollins, J. Derek
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experimental part
p. 3067 - 3073
(2011/06/28)
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- A novel synthesis of 2,5-diphenylpyrazine
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The compound C16H12N2 (2,5- diphenylpyrazine) was obtained as the by-product of synthesizing 5H-Imidazol[2,3-b]isoquinoline-1-ethanol-5-one, 1,2,3, 10b-tetrahydro-, β(S)-phenyl-3(S)-phenyl-(compound 2), and its structure was determined by X-ray diffraction. The crystal is monoclinic, P2(1)/c, a = 13.466(5) A, α = 90.00°, b = 5.758(2) A, β = 93.049(9)°, c = 7.713(3) A, γ = 90.00°, V = 597.2(4) A3, Z = 2, Dcalc. = 1.292 mg/m3; the final R factor is R1 = 0.0592, 771 for reflections with I0 > 2σ(I0). Springer Science+Business Media B.V. 2010.
- Luo, Mei,Pang, Wen Min,Yin, Hao,Hu, Ke Liang
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experimental part
p. 491 - 494
(2011/11/05)
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- New highlights in the synthesis and reactivity of 1,4-dihydropyrazine derivatives
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In the course of our investigations on the synthesis of original nitrogen heterocyclic derivatives, we were interested in the synthesis and study of original 1,4-dihydropyrazine rings. To this aim the desired bisvinylphosphate derivative was prepared from N-Boc piperazine-2,5-dione and then was engaged in palladium catalyzed reactions (reduction, Suzuki and Stille cross-coupling reactions). The 1,4-dihydropyrazine and the corresponding 2,5-disubstituted derivatives were obtained in fair to good yields and were then functionalized under anionic conditions. Aromatization into 1,4-pyrazines was investigated in a second stage.
- Chaignaud, Mathilde,Gillaizeau, Isabelle,Ouhamou, Nouara,Coudert, Gérard
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p. 8059 - 8066
(2008/12/20)
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- The study of cyclization of N-acylphenacyl anthranilates with ammonium salts under various conditions
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N-Acylphenacyl anthranilates were heated with ammonium salts in organic acid or NMP, and formation of various heterocyclic compounds was observed. Reaction results are strongly influenced by reaction conditions. The most interesting are imidazole derivati
- Hradil, Pavel,Grepl, Martin,Hlavac, Jan,Lycka, Antonin
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p. 269 - 280
(2008/02/09)
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- Microwave-assisted synthesis of α-hydroxy ketone and α-diketone and pyrazine derivatives from α-halo and α,α′-dibromo ketone
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A novel reaction of α-halo ketone (α-bromo and α-chloro ketone) with irradiation under microwave gave the corresponding α-hydroxyketone and pyrazine derivative in good yields. In the case of α,α′-dibromo ketone, α-diketone was obtained. This reaction affords a new, clean and convenient synthetic method for α-hydroxyketone, α-diketone, α-chloro ketone and pyrazine derivative.
- Utsukihara, Takamitsu,Nakamura, Hiroaki,Watanabe, Masashige,Akira Horiuchi
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p. 9359 - 9364
(2008/01/27)
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- Radical chain reactions of α-azido ketones with tributyltin hydride: Reduction vs nitrogen insertion and 1,2-hydrogen shift in the intermediate N-stannylaminyl radicals
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The radical chain reactions of a variety of acyclic and cyclic α-azido ketones with tributyltin hydride have been investigated. The derived N-(tributylstannyl)aminyl radicals normally undergo H-abstraction reaction yielding corresponding amines, and thence symmetrical pyrazines by subsequent self-condensation, in competition with 1,2-H-migration from the α-carbon to nitrogen leading to α-imino ketone decomposition products with loss of the chain-carrying tributyltin radical. The noteworthy occurrence of a quite uncommon radical 1,2-hydrogen-atom shift is considered to be largely due to consequent formation of a highly stable, captodative carbon-centred radical. In contrast with our previous N-stannylaminyl radicals produced from α-azido-β-keto esters, the present aminyl congeners give poor amounts (or even none) of nitrogen-inserted amides/lactams, which are envisaged to arise from intramolecular three-membered cyclisation onto the ketone moiety followed by β-scission of the resultant alkoxyl radical. It is inferred that adequate stabilisation of the eventual ring-opened carbon radical be a major factor for the successful outcome of the regiospecific nitrogen insertion process. Evidence is also presented that chemoselective attack of tris(trimethylsilyl)silyl radical to the ketone oxygen of an α-azido ketone gives rise to deazidation as a likely consequence of β-elimination of azidyl radical by the ensuing α-silyloxyalkyl radical. X-Ray crystal structure analyses of the bromo ketone 5a, the azido ketone 5b, the caprolactam 22, and the pyrazine 26 have been performed.
- Benati, Luisa,Leardini, Rino,Minozzi, Matteo,Nanni, Daniele,Spagnolo, Piero,Strazzari, Samantha,Zanardi, Giuseppe,Calestani, Gianluca
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p. 3485 - 3492
(2007/10/03)
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- New cleavage of the azirine ring by single electron transfer: The synthesis of 2H-imidazoles, pyridazines and pyrrolines
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Here we report the first example of the dimerisation of azirines to 2H-imidazoles or 3,5-disubstituted pyridazines from a reaction promoted by FeCl2. An azirine complex with a radical structure is proposed as an intermediate. Cyclopropyl ketones and pyrrolines are isolated when the reaction is carried out in the presence of styrenes.
- Auricchio, Sergio,Grassi, Simona,Malpezzi, Luciana,Sartori, Attilio Sarzi,Truscello, Ada M.
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p. 1183 - 1187
(2007/10/03)
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- Ladderlike oligomers; Intramolecular hydrogen bonding, push - pull character, and electron affinity
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Symmetrical 2,5-bis(2-aminophenyl)pyrazines have been synthesized by application of the Stille coupling strategy. These cotrimers feature three important properties, namely strong intramolecular hydrogen bonding, push-pull character, and high electron aff
- Pieterse, Koen,Vekemans, Jef A.J.M.,Kooijman, Huub,Spek, Anthony L.,Meijer
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p. 4597 - 4603
(2007/10/03)
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- Phototransformations of C-benzoylaziridines. Dipolarophilic trapping of photogenerated azomethine ylides
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The phototransformations of a few 2,3-diaroylaziridines and 2-aryl-3-aroylaziridines have been studied by steady-state photolysis and product analysis.The formation of various photoproducts could be substantiated by ring opening via C-C bond cleavage (leading to azomethine ylides), intramolecular hydrogen abstraction, and C-N bond cleavage.Isolation of stereospecific 3-pyrrolidine derivatives from the photoreaction of benzoylaziridines in the presence of DMAD confirms our previous results concerning the azomethine ylides as major transient intermediates, produced under laser pulse photoexcitation.Dimethyl 1-cyclohexyl-2-benzoylpyrrole-3,4-dicarboxylate (25), one of the photoadducts derived from the reaction of 1a and 1b with DMAD undergoes a novel and unusual photoarrangement to give dimethyl 2-(1-benzoylcyclohexyl)pyrrole-3,4-dicarboxylate (27), the structure of which was confirmed through X-ray crystallographic analysis.
- Ramaian, D.,Muneer, M.,Gopidas, K. R.,Das, P. K.,Rath, N. P.,George, M. V.
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p. 4240 - 4246
(2007/10/03)
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- Cycloaddition of chlorosulfonyl isocyanate to 2H-azirines: Formation of [2+2+2] cycloadducts
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Chlorosulfonyl isocyanate (CSI) reacts with 2H-azirines 1a-c at -78°C to form [2+2+2] cycloadducts 3a-c and 4a-c. The tricyclic aziridine derivatives 4a-c undergo CSI extrusion reactions and subsequent oxidation to the corresponding pyrazines 5a-c. Structural identifications of 3a-c and 4a-c are based on ir, nmr and mass spectral data.
- Daniel,Dhar
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p. 1649 - 1655
(2007/10/02)
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- THE FORMATION OF PYRAZINES FROM N-β-KETOIMINOTRIPHENYLPHOSPHORANES; IMINOPHOSPHORANE-MEDIATED SYNTHESES OF 2,2,4,4-TETRAPHENYL-N,N'-BIS(2-PENTANE-3-ON)-CYCLOBUTANE-1,3-DIIMINE; 1,3,4-OXADIAZOLES; 2-AMINO-3,5-DIHYDROIMIDAZOL-4-ONES; AND 2-DIPHENYLMETHYL-1,5-DIHYDROIMIDAZOL-4-ONE
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The aza-Wittig reaction has been applied to the synthesis of the unstable N-β-keto ketenimine (18), which dimerize spontaneously, forming the very sterically hindered 2,2,4,4-tetraphenyl-N,N'-bis (2-pentane-3-on)-cyclobutane-1,3-diimine (21).Iminophosphoranes (33) and (38) are used for the preparation of some novel 1,5 and 3,5-dihydroimidazol-4-ones (36), (41a-b), (42).N-acylamino iminotriphenylphosphoranes (2a-d) are applied for the syntheses of a series of 1,3,4-oxadiazoles (32).The mechanism of the decomposition of the unstable N-β-keto iminotriphenylphosphoranes (1) into pyrazines and triphenylphosphine oxide has been investigated.Key words: Iminophosphoranes; β-keto carbodiimides; N-β-keto ketenimines; heterocycles.
- Froeyen, Paul
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p. 283 - 293
(2007/10/02)
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- Nonacarbonyldiiron or Pentacarbonyliron Induced Decomposition of Organic Azides and an Azirine. Novel Reduction and Carbonyl Insertion of the Complexed Nitrene Intermediate in Protic Solvents
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The thermal reactions of or the photochemical reactions of with organic azides and an azirine in protic media have been investigated.The thermal reaction of azidobenzene (1) with in methanol under mild conditions gave aniline and methyl phenylcarbamate, along with N,N'-diphenylurea, while in the presence of water, 1 afforded aniline and N,N'-diphenylurea, in good combined yield.Similarly, the thermal reaction of α-azidostyrene (4) with in methanol gave methyl 1-phenylvinylcarbamate and acetophenone which could be derived from the corresponding enamine, while in the presence of water, 4 gave only acetophenone in good yield.The photoirradiation of with 1 or 4 also gave results similar to the -induced reaction.However, the thermal reaction of 3-phenyl-2H-azirine (5) with in methanol gave 2,5-diphenylpyrazine in low yield, in addition to acetophenone and methyl 1-phenylvinylcarbamate, although 5 afforded only acetophenone in the presence of water.The reaction pathways for the formation of the products are discussed on the basis of the formation of a complexed nitrene intermediate, reduction of which induces amine or enamine and carbonyl insertion to yield an organic isocyanate in protic media.
- Nitta, Makoto,Kobayashi, Tomoshige
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p. 1035 - 1039
(2007/10/02)
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- NOVEL TYPES OF TRANSFORMATIONS OF α-AZIDOSTYRENE DERIVATIVES AND 3-ARYL-2H-AZIRINES IN THE PRESENCE OF HEXACARBONYLMOLYBDENUM
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The reaction of α-azidostyrene derivatives with hexacarbonylmolybdenum was found to give 2,5-diarylpyrroles and acetophenone derivatives via a complexed 1-arylvinylnitrene intermediate, while that of 3-aryl-2H-azirines gave 2,4-diarylpyrroles in addition to acetophenone derivatives and 2,5-diarylpyrazines.
- Nitta, Makoto,Kobayashi, Tomoshige
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p. 1715 - 1718
(2007/10/02)
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- RECYCLIZATION REACTIONS. RECYCLIZATIONS OF 3-ACYLMETHYL-2,4-THIAZOLIDINEDIONES BY THE ACTION OF NUCLEOPHILES
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Four directions were established and investigated in the recyclization of 3-acylmethyl-2,4-thiazolidinediones with the participation of the side chain at the cyclic nitrogen atom and the formation of substituted 2-imidazolones or 2-oxazolones (under the influence of ammonia or hydroxides respectively), 2,5-diarylpyrazines (under the influence of methylamine), 6-monosubstituted or 2,6-disubstituted 4,5-dihydro-1,2,4-triazin-3-ones, and 5-substituted 1-amino-2-imidazolones (under the influence of hydrazine and phenylhydrazine).The directions of recyclization with hydrazines are determined by the stereochemical configuration of the intermediate hydrazones; the E-hydrazones of 3-acylmethyl-2,4-thiazolidenediones are converted into 4,5-dihydro-1,2,4-triazin-3-ones, while the Z izomers are converted into 1-amino-2-imidazolones.
- Shvaika, O. P.,Korotkikh, N. I.,Chervinskii, A. Yu.,Artemov, V. N.
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p. 1533 - 1543
(2007/10/02)
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- Photo-induced decarbonylation of β-styryl isocyanates
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Irradiation of a β-styryl isocyanate released the elements of carbon monoxide and gave products formally derived from rearrangement and dimerization of the residue.
- Mikol,Boyer
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p. 439 - 439
(2007/10/04)
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