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1.
Sergey A. Popov Nikita V. Chukanov Galina V. Romanenko Tatjana V. Rybalova Yuri V. Gatilov Vladimir A. Reznikov 《Journal of heterocyclic chemistry》2006,43(2):277-291
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Mamoru Koketsu Hiromune Ando Tomomi Sasaki Hideharu Ishihara 《Journal of heterocyclic chemistry》2007,44(1):231-232
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Jan M. Bakke Hanna S. H. Gautun Harald Svensen 《Journal of heterocyclic chemistry》2003,40(4):585-591
A new synthetic route to 6‐substituted‐imidazo[4,5‐c]pyridin‐2‐ons from 4‐aminopyridine has been investigated. 4‐Aminopyridine protected as alkyl carbamates were nitrated with dinitrogen pentoxide to the corresponding methyl, i‐propyl and t‐butyl 3‐nitropyridin‐4‐yl carbamates ( 5a‐c ) in 51‐63 % yields. Attempts to substitute these in the 6‐position by the ONSH and the VNS techniques succeeded with butyl‐amine and the t‐butyl carbamate 9 . From the methyl or t‐butyl 3‐nitropyridin‐4‐yl carbamates 5a, 5c 1,3‐dihydro‐2H‐imidazo[4,5‐c]pyridin‐2‐one ( 1 ) was formed in 73 and 39 % yields, respectively. t‐Butyl 6‐N‐butylamin‐3‐aminopyridin‐4‐yl carbamate ( 6 ) gave 6‐butylamino‐1,3‐dihydro‐2H‐imidazo[4,5‐c]‐pyridin‐2‐one (7) in 53 % yield. 相似文献
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Mikhail Yu. Ovchinnikov Tagir A. Yangirov Alexander N. Lobov Rimma M. Sultanova Sergey L. Khursan 《国际化学动力学杂志》2013,45(8):499-507
1,3‐Dipolar cycloaddition of methyl diazoacetate to methyl acrylate was investigated by kinetic 1Н NMR spectroscopy. It was established that the mechanism of the process includes parallel formation of trans‐ and cis‐dimethyl‐4,5‐dihydro‐3H‐pyrazol‐3,5‐dicarboxylates as a result of [3 + 2]‐cycloaddition of methyl diazoacetate to methyl acrylate; the corresponding rate constants were denoted k1t and k1c. The reaction rate of the isomerization of 3Н‐pyrazolines to 4,5‐dihydro‐1H‐pyrazol‐3,5‐dicarboxylate (3Н → 1Н‐pyrazoline rearrangement) was found to be sensitive to both the methyl acrylate (k2t, k2c) and 1Н‐pyrazoline concentrations (k3t, k3c). Kinetic analysis showed that the proposed scheme is valid for various reagent concentrations. The numerical solution of the system of differential equations corresponded to the reaction scheme and was used to determine the complete set of reaction rate constants (k (× 105 M–1·s–1), 298 K; solvent, benzene‐d6): k1t = 2.3 ± 0.3, k1c = 1.6 ± 0.2, k2t = 1.1 ± 0.3, k2c = 1.8 ± 0.5, k3t = 1.2 ± 0.4, k3c = 2.2 ± 0.7. 相似文献
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Péter Csomós Lajos Fodor Antal Csámpai Pál Sohár 《Journal of heterocyclic chemistry》2011,48(5):1079-1084
We report a convenient approach for the synthesis of a new ring system: 4,5‐dihydro‐1,3‐thiazino[5,4‐b]indoles. The procedure involves the use of Lawesson's reagent in the presence of silica to achieve the one‐step ring‐closure reactions of 2‐benzoylamino‐3‐hydroxymethylindole intermediates to furnish 4,5‐dihydro‐2‐aryl‐1,3‐thiazino[5,4‐b]indoles. 2‐Phenylimino‐1,3‐thiazino[5,4‐b]indoles were obtained via the corresponding 3‐phenylthiourea‐2‐carboxylic acid ester derivatives by chemoselective reduction of the ester group, followed by ring closure under acidic conditions. The structures of the novel products were elucidated by IR, 1H‐NMR, and 13C‐NMR spectroscopy, including 2D‐HMQC, 2D‐HMBC, and DEPT measurements. J. Heterocyclic Chem., (2011). 相似文献
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The reaction of prop‐1‐ene‐1,3‐sultone 1 with a variety of nitrile oxides 3 afforded novel [3+2] cycloaddition products 4 in good yield. The cycloaddition reaction achieved excellent regioselectivity. 相似文献
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Said Kitane Amina Taimi Abdelmejid Bahloul Abdelfatah Sebban Mohamed Berrada Jean‐Pierre Joly 《Journal of heterocyclic chemistry》2000,37(6):1641-1645
The 1,3‐dipolar cycloaddition of arylnitriloxides on 1,2‐dihydroisoquinoline derivatives led to new 3‐aryl, 3a‐8,9,9a‐tetrahydro[5,4‐c]‐isoxazoloisoquinoline adducts. The regioselectivity of the cycloaddition reactions is discussed on the basis of 1H and 13C NMR data. 相似文献
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Twelve novel compounds were synthesized by the [3+2] 1,3‐dipolar cycloaddition reaction of 5,6‐dehydronorcantharidin derivatives of substituted aromatic amines with nitrile oxides. The structure and the configuration of all compounds were confirmed by 1H NMR, IR, MS, 1H‐1HCOSY, and NOESY spectral data. Their anti‐tumor activities are under way. 相似文献
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V. Padmavathi K. Venugopal Reddy A. Balaiah T. V. Ramana Reddy D. Bhaskar Reddy 《Heteroatom Chemistry》2002,13(7):677-682
Sulfonyl bis pyrazolines and isoxazolines were prepared by 1,3‐dipolar cycloaddition of nitrile imines and nitrile oxides to E,E‐bis(styryl) sulfones. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:677–682, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10087 相似文献
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Pedro C. Vasquez Derrick C. Bennett Kishia K. Towns G. Davon Kennedy A. L. Baumstark 《Heteroatom Chemistry》2000,11(4):299-302
A kinetics study of the thermolysis of a series of hexasubstituted‐4,5‐dihydro‐3H‐pyrazoles (pyrazolines 1a: 3,3,4,4‐tetramethyl‐5‐phenyl‐5‐acetoxy; 1b: cis‐3,5‐diphenyl‐3,3,4‐trimethyl‐5‐acetoxy; 1c: cis‐3,5‐diphenyl‐3,4,4‐trimethyl‐5‐methoxy; 1d: 3,3,5‐triphenyl‐4,4‐dimethyl‐5‐acetoxy), which produced the corresponding hexasubstituted cyclopropanes 2a–d in quantitative yields was carried out. The first order rate constants (k1) for thermal decomposition and activation parameters were determined. The relative reactivity series was found to be 1d >> 1b ∼ 1c > 1a. The activation parameters for thermolysis were found to be: for 1a ΔH‡ = 39.8 kcal/mol, ΔS‡ = 14 eu, k150° = 6.8 × 10−5 s−1; for 1b ΔH‡ = 33.5 kcal/mol, ΔS ‡ = 0.2 eu, k150° = 1.7 × 10−4s−1; for 1c ΔH‡ = 32.7 kcal/mol, ΔS‡ = −1.8 eu, k150° = 1.2 × 10−4s−1; for 1d ΔH‡ = 30.1 kcal/mol, ΔS‡ = −1.6 eu, k150° = 8.8 × 10−3s−1. The effect of variation of C3 substituents on the activation parameters for thermolysis paralleled the trend reported for acyclic analogs. The results are consistent with the formation of a (singlet) 1,3‐diradical intermediate with subsequent closure to yield the cyclopropanes. The mechanism of diradical formation appears to involve N2‐C3 bond cleavage as the rate determining step rather than simultaneous two bond scission. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:299–302, 2000 相似文献
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Juzo Nakayama Ayako Kaneko Yoshiaki Sugihara Akihiko Ishii Akihiro Oishi Isao Shibuya 《Heteroatom Chemistry》2000,11(6):434-440
It was shown that dimethyl 2‐thiono‐1,3‐dithiole‐4,5‐dicarboxylate ( 2 ) and dimethyl acetylenedicarboxylate (DMAD) undergo a 1,3‐dipolar cycloaddition to produce a short‐lived ylide intermediate ( 3 ). The 1,3‐dipolar cycloaddition took place even at room temperature, although sluggishly, but took place much more rapidly under application of a high pressure of 500 MPa. The 1,3‐dipolar cycloaddition is reversible and the ylide 3 immediately splits into 2 and DMAD. When the reaction of 2 with DMAD was carried out at room temperature without solvent, a spiro‐1,3‐dithiole ( 11 ) was formed in 11% yield, whereas the reaction at 150°C provided a thiophene derivative ( 13 ) in 41% yield. It was found that 11 undergoes a thermal rearrangement to 13 . Results of attempted chemical trapping of the ylide 3 are also reported. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:434–440, 2000 相似文献
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Ganesabaskaran Sivaprasad Radhakrishnan Sridhar Paramasivan T. Perumal 《Journal of heterocyclic chemistry》2006,43(2):389-394
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Bogdan A. Demydchuk Vladimir S. Brovarets Alexander N. Vasilenko Boris S. Drach 《Heteroatom Chemistry》2008,19(7):677-681
Based on readily available chloralamides, a preparative method for the synthesis of hitherto unknown 2,5‐diaryl‐3a,6a‐dihydro[1,3]thiazolo[4,5‐d][1,3]thiazoles with the Lawesson reagent has been elaborated. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:677–681, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20493 相似文献
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Zilong Tang Weiwen Chen Zhonghua Zhu Hanwen Liu 《Journal of heterocyclic chemistry》2011,48(2):255-260
A series of novel 2,3‐diaryl‐3,4‐dihydro‐2H‐1,3‐benzoxazines have been prepared in high yields from o‐arylaminomethylphenols and aromatic aldehydes in the presence of SnCl4 for the first time, and their fungicidal activities were investigated too. Some of the products showed good fungicidal activities against Rhizoctonia solani justified by 100% activity of compound 1b. J. Heterocyclic Chem., (2010) 相似文献
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Alexey M. Starosotnikov Maxim A. Bastrakov Sergey Yu. Pechenkin Margarita A. Leontieva Vadim V. Kachala Svyatoslav A. Shevelev 《Journal of heterocyclic chemistry》2011,48(4):824-828
The 1,3‐dipolar cycloaddition of unstabilized N‐methyl azomethine ylide to mononitro benzazoles was studied. Depending on the nature of substituents and annelated azoles, the reaction affords previously unknown isoindole fused heterocyclic systems. The reactivity of the cycloadducts was examined. J. Heterocyclic Chem., (2011). 相似文献
18.
A series of new 4,6‐diaryl‐4,5‐dihydro‐3‐hydroxy‐2H‐indazoles 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k were synthesized by the cyclization of ethyl 2‐oxo‐4,6‐diarylcyclohex‐3‐ene carboxylates 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k . The compounds were characterized by IR, 1H NMR, 13C NMR, 2D NMR, and elemental analysis. The synthesized compounds were evaluated for in vitro antibacterial and antifungal activities against Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Candida albicans, Aspergillus niger, Aspergillus flavus, and Rhizopus sp. Most of the compounds exhibited good activity against the tested organisms. J. Heterocyclic Chem.,, (2012). 相似文献
19.
Norbert Kuhn Ahmed Abu‐Rayyan Carla Piludu Manfred Steimann 《Heteroatom Chemistry》2005,16(5):316-319
2,3‐Dihydro‐1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene 1 (Carb, R1 = iPr, R2 = Me) reacts with TeI4 to give the carbene adduct CarbTeI2 ( 3 ). The crystal structure of 3 consists of T‐shaped monomeric fragments linked by weak Te. I interactions to form infinite helical chains. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:316–319, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20090 相似文献
20.
This article reports a new one‐pot method for polymer preparation, which involves double click chemistry. In one pot, two click reactions take place sequentially by adding the reactants step by step. The first click reaction is to produce the monomer for the second click reaction for polymerization. The click polymerization differs from the general click polymerization with the reaction of diazides and dialkynes. Nitrile oxides, produced in situ by the first click reaction of the formation of aldoxime, instead azides, avoiding the poisonousness and explosiveness of azides and being much safer and easy to operate. And 3,5‐disubstitute polyisoxazoles are produced by the copper(I)‐catalyzed the 1,3‐dipolar cycloaddition of nitrile oxides with alkynes in high yields by our one‐pot method. The resulting polyisoxazoles agree well with the structural assignment obtained by the 1H NMR and IR analyses, with high molecular weights, narrow molecular weight distribution (Mw/Mn < 1.2) and high regioregularity. The poor solubility of these polymers is found to be caused by their crystallization. Improvement of solubility is achieved by modifying the structures of alkyne monomers. All the polymers are thermally stable, losing little of their weights when heated to ~350 °C. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献