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1.
B. A. Arbuzov N. N. Zobova F. B. Balabanova M. F. Tarasova 《Russian Chemical Bulletin》1972,21(10):2257-2258
Conclusions Trichloroacetyl isocyanate reacts with the n-butyl, isoamyl, and phenyl vinyl sulfides on the type of 1, 4-cycloaddition with the formation of 3, 1-oxazin-6-one derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2324–2325, October, 1972. 相似文献
2.
Conclusions Trichloroacetyl isocyanate reacts with trichloroacetonitrile on the type of 22-cycloaddition with the formation of 1-trichloroacetyl-2-trichloromethyl-1,3-diaza-2-cyclobuten-4-one.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimichesckaya, No. 10, pp. 2325–2326, October, 1972. 相似文献
3.
Conclusions Trifluoroacetyl isocyanate reacts with Schiff bases on the type of 2 + 4-cycloaddition to give substituted 4-oxo-1, 3,5-oxadiazines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.1, pp.202–204, January, 1976. 相似文献
4.
Dihydropyran reacts easily with the α, β-unsaturated carbonyl system of heterocyclic rings (pyrazoles or isoxazoles) in accordance with a 1,4-cycloaddition. 相似文献
5.
Karl Seckinger 《Helvetica chimica acta》1973,56(2):776-794
The addition of methyl isocyanate to N,N-dimethyl-N′-arylformamidines 4d – 4r leads to the perhydro-s-triazine-diones 5d – 5o and to the s-triazinylureas 10a – 10k . The mechanism of formation is discussed. The addition of the arylisocyanates 18a – 18p to the N,N,N′-trialkylformamidines 9 and 27a – 27i furnishes the expected 1,4-cycloaddition products 26 and 27 in good yields. The N,N-di-isopropyl-N′-alkylformamidines 27j – 271 , however, do not undergo 1,4-dipolar cycloadditions and react with the arylisocyanate 18b to yield the alkyl isocyanates 31a – 31c and N,N-diisopropyl-N′-(p-chlorphenyl)-formamidine 32 exclusively. 相似文献
6.
B. A. Arbuzov N. N. Zobova F. B. Balabanova M. F. Tarasova 《Russian Chemical Bulletin》1973,22(2):440-441
Conclusions Trichoroacetyl isocyanate under the influence of quinoline forms ditrichloroacetylcarbodiimide, which adds to the C=N bond of quinoline on the type of a 2+4-cycloaddition. Benzoyl isocyanate under the influence of quinoline forms the dimer.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.2, pp.456–458, February, 1973. 相似文献
7.
Ethyl vinylether reacts with 3-oxindolideneacetophenones. In addition to some 2,3-dihydropyran[2,3-b]indoles, obtained by 1,4-cycloaddition, previously unknown 3-(3-oxindolyl)dihydrofurans whose origin may involve a dipolar intermediate were isolated. Rationalization of the mechanism is proposed and the approach in terms of frontier orbitals is discussed. 相似文献
8.
1,3,2,4‐Dithiadiphosphetane‐2,4‐disulfide 1 reacts with substituted 2‐amino‐1,4‐naphthoquinons 2a–d to give 4,5,4′,5′‐benzodiphenoquinone‐bis‐1,3,2‐thiazaphospholine‐2‐sulfide derivatives of type 3. Compatible analytical and spectroscopic results were obtained for all the new compounds. A mechanism is proposed to explain the formation of compounds 3. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 488–491, 1999 相似文献
9.
1,4-Dilithio-1,3-dienes or zirconacyclopentadienes reacted with oxalyl chloride in the presence of CuCl in a 1,1-cycloaddition manner to give cyclopentadienone derivatives in high yields along with the elimination of CO. 相似文献
10.
Treatment of amides 1a,b with thionyl chloride followed by reaction with triethylamine gave 1,4-dihydro[1]benzopyrano[4,3-b]pyrrole derivatives ( 4a,b ) arising from intramolecular 1,3-cycloaddition of intermediate nitrile ylides ( 3a,b ). 相似文献
11.
Petro P Onys'ko Olena A SuvalovaYuliya V Rassukana Tetyana I ChudakovaAnatolii D Sinitsa 《Tetrahedron letters》2003,44(9):1855-1857
The reaction of alkyl trifluoro(organylsulfonylimino)propionates with phosphites occurs with NC transfer of the RSO2 group and leads to sulfonyl-substituted trifluoroalanine derivatives. The novel rearrangement is interpreted as cheletropic 1,4-cycloaddition of the phosphite and subsequent 1,2-shift of the sulfonyl group in the intermediate cyclic phosphorane. 相似文献
12.
《Tetrahedron》2019,75(34):130461
A protocol of [3 + 3]-cycloaddition was proposed for the synthesis of 2H-1,4-thiazin-3(4H)-ones and thiomorpholine-3,5-diones from α-chlorohydroxamates and 1,4-dithiane-2,5-diol. This direct and practical method provides a novel and rapid approach for the synthesis of thiomorpholin-3-one derivatives under mild condition with moderate to good yield and wide functional group tolerance. 相似文献
13.
F. I. Zubkov V. P. Zaitsev A. A. Orlova A. S. Peregudov N. M. Mikhailova A. V. Varlamov 《Russian Journal of Organic Chemistry》2007,43(8):1202-1208
Dimethyl acetylenedicarboxylate reacts with 4-substituted and 3,4-fused 2-furyl-1,2,3,4-tetrahydroquinoline derivatives at the furan fragment according to the [4 + 2]-cycloaddition pattern. The reaction is not stereoselective, and it yields two diastereoisomeric 7-oxabicyclo[2.2.1]hepta-2,5-dienes whose structure was determined by X-ray analysis and NMR spectroscopy. 相似文献
14.
N. A. Keiko T. A. Kuznetsova L. I. Larina Yu. A. Chuvashev T. A. Klepikova L. V. Sherstyannikova 《Russian Journal of Organic Chemistry》2006,42(10):1421-1425
Conditions were found for the preparation of 2-ethoxyprop-2-enal dimethylhydrazone by reaction of 2-ethoxypropenal with N,N-dimethylhydrazine. 2-Ethoxyprop-2-enal dimethylhydrazone reacted with methyl vinyl ketone and methyl acrylate according to the [4 + 2]-cycloaddition pattern with regioselective formation of substituted tetrahydropyridines. The major product in the reaction of 2-ethoxyprop-2-enal dimethylhydrazone with 1,4-benzoquinone was 5-hydroxy-1-benzofuran-2-carbaldehyde dimethylhydrazone formed as a result of [3 + 2]-cycloaddition; a small amount of the corresponding [4 + 2]-cycloaddition product was also obtained. Some spontaneous transformations of the primary cycloaddition products were revealed. 相似文献
15.
Yu. V. Kharitonov E. E. Shul’ts M. M. Shakirov G. A. Tolstikov 《Russian Journal of Organic Chemistry》2008,44(4):516-523
16-(Benzylaminomethyl)lambertianic acid methyl ester reacts with 2-methylprop-2-enoyl chloride to give unsaturated amide which readily undergoes intramolecular [4 + 2]-cycloaddition with formation of terpenoid derivatives of 10-oxa-3-azatricyclo[5.2.1.01,5]decenone. Acetylation of lambertianic acid methyl ester with acetic anhydride occurs preferentially at the 2-position of the furan ring and is accompanied by migration of the exocyclic double bond. Reductive amination of 16-acetyl-15,16-epoxylabda-8(9),13,14-triene and subsequent reaction of the resulting amine with 2-methylprop-2-enoyl chloride give intramolecular cyclization products in high yield without isolation of intermediate furfurylacryloyl derivative. Reactions of methyl 16-(benzylaminomethyl)-15,16-epoxylabda-8(9),13,14- and -8(17),13,14-trien-18-oates with maleic anhydride lead to the formation of the corresponding 10-oxa-3-azatricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid derivatives as mixtures of diastereoisomers. 相似文献
16.
The synthesis of variously substituted pyridazines by 1,4-cycloaddition of cyclic enol ethers, esters, and some electron-rich acetylenes is described. Extension of the scheme to include some imino-ethers as dienophiles resulted in the synthesis of 1,2,4-triazine derivatives. 相似文献
17.
Matxain JM Ristilä M Strid A Eriksson LA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(16):4636-4642
Singlet oxygen is known to cause oxidative stress in cells, leading to severe damage (e.g., lipid peroxidation, membrane degradation, mutagenic alterations to DNA, protein misfunctionality). Recently, pyridoxine has been discovered to be capable of quenching singlet oxygen, however, the mechanism of this reaction remains essentially unknown. In this work, we have investigated four sets of reactions: 1) 1,3-addition to a double bond connected to a hydrogen-carrying group, resulting in the formation of allylic hydroperoxides; 2) [pi2+pi2] 1,2-cycloaddition to an isolated double bond, resulting in the formation of 1,2-peroxides; 3) 1,4-cycloaddition to a system containing at least two conjugated double bonds, resulting in the formation of the so-called 1,4-peroxides; 4) 1,4-addition to phenols and naphthols with the formation of hydroperoxide ketones. Thermodynamically, reaction 4 and the 6(9), 3(8), and 5(8) cases of reaction 1 are the most exergonic ones, with energies ranging from -16 to -18 kcal mol(-1). Furthermore, reaction 4 shows the lowest barrier through the reaction path, and is predicted to be the preferred mechanism for the pyridoxine + singlet-oxygen reaction, which is in agreement with previous experimental results. 相似文献
18.
The chemoselectivity in the reaction of 2‐diazo‐3‐oxo‐3‐phenylpropanal ( 1 ) with aldehydes and ketones in the presence of Et3N was investigated. The results indicate that 1 reacts with aromatic aldehydes with weak electron‐donating substituents and cyclic ketones under formation of 6‐phenyl‐4H‐1,3‐dioxin‐4‐one derivatives. However, it reacts with aromatic aldehydes with electron‐withdrawing substituents to yield 1,3‐diaryl‐3‐hydroxypropan‐1‐ones, accompanied by chalcone derivatives in some cases. It did not react with linear ketones, aliphatic aldehydes, and aromatic aldehydes with strong electron‐donating substituents. A mechanism for the formation of 1,3‐diaryl‐3‐hydroxypropan‐1‐ones and chalcone derivatives is proposed. We also tried to react 1 with other unsaturated compounds, including various olefins and nitriles, and cumulated unsaturated compounds, such as N,N′‐dialkylcarbodiimines, phenyl isocyanate, isothiocyanate, and CS2. Only with N,N′‐dialkylcarbodiimines, the expected cycloaddition took place. 相似文献
19.
In the presence of aqueous trialkylammonium hydrogen carbonate, the Staudinger reaction leads to the intermediate formation of the corresponding isocyanate, which, in turn, reacts further with a nucleophilic reagent also present in the mixture and results in carbamoylation with good yield. On the basis of this reaction a practical carbamoylation procedure was devised and a comparative study on suitability of different solvents and phosphorus (III) derivatives for carbamoylation reaction was conducted. The versatility of the method was demonstrated by examples with different classes of nucleophilic compounds that included the aminomethyl resin and natural compounds that display poor solubility in organic solvents. 相似文献
20.
The reaction of p-methoxystyrene and TCNE is studied in 50% CHCl3–50% CCl4 (v/v) at 25°C at high pressures up to 1000 bar by following the disappearance of the absorbance at 600 nm due to the EDA complex. By using the mixed solvent, equations required for the high-pressure kinetics are simplified. The volume of activation is ?42 to ?46 cm3/mol for the 1,4-cycloaddition and ?55 cm3/mol for the 1,2-cycloaddition. The activation volume for the 1,4-cycloreversion is assumed to be ?8 to ?12 cm3/mol based on a previous study on a similar system. The rate of the cycloreversion process is affected by solvent polarity. The rate of the 1,2-cycloaddition is influenced by solvent more significantly than that of the 1,4-cycloaddition. It is concluded that the transition state is polar in both cycloadditions and that its zwitterionic character is much stronger in the 1,2-cycloaddition. 相似文献