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1.
Gerhard Maas Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(44):8186-8195
Diazo compounds (R1R2C?N2) are known as versatile and useful substrates for an array of chemical transformations and, therefore, diazo chemistry is still far from losing anything of its long‐standing fascination. In addition to many studies on the subsequent chemistry of the diazo group, the inventory of methods for the preparation of diazo compounds is continuously supplemented by new methods and novel variations of established procedures. Several of these synthetic approaches take into account the lability and remarkable chemical reactivity of certain classes of diazo compounds, and environmentally more benign procedures also continue to be developed. 相似文献
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Konstantin A. Popov Alexander M. Polozov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Diazo esters (la,b) react with trialkyl phosphates (2a–c) in the presence of BF3.OEt2 to give the corresponding phosphates (3a–e) in 42–58 % yields. The competed intra/intermolecular protonation in the reaction of la with dimethyl hydrogen phosphite leads to phosphonate. 4,and phosphite 5. 相似文献
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A. M. Simonov S. N. Kolodyazhnaya L. N. Podladchikova 《Chemistry of Heterocyclic Compounds》1974,10(5):596-599
Stable primary N-nitrosamines of the benzimidazole series were obtained by the action of sodium amide and isoamyl nitrite on 1-substituted 2-aminobenzimidazoles and subsequent acidification of the resulting benzimidazole-2-diazotates. The effect of the acidity of the solution on the activity of the benzimidazole-2-diazonium salts formed from the nitrosamines was traced.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 689–692, May. 1974. 相似文献
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S. N. Kolodyazhnaya A. M. Simonov L. N. Podladchikova 《Chemistry of Heterocyclic Compounds》1975,11(6):726-730
2-(N-Nitrosamino)benzimidazoles in aqueous solutions or in organic solvents are spontaneously converted to 1,3-di(2-benzimidazolyl)triazenes. Other methods for the synthesis of triazenes of the benzimidazole series and their properties are examined. 相似文献
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Transition metal catalyzed decomposition of diazo compounds and consequent transformations constitute various synthetic useful reactions in the past decades. The catalytic addition of diazo compounds to olefins generally provides cyclopropanes in high yield. However the reaction of electron-rich enamines with diazo compounds gave variable results. Wenkert et al. reported the reaction of enamines with ethyl diazoacetae (EDA) in the presence of cuprous chloride or silver oxide unexpectedly gave… 相似文献
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《Liquid crystals》2000,27(11):1473-1479
Nine series of liquid crystals containing an electron-donating group at one end of a conjugated system and an electron-withdrawing group at the other end have been synthesized. The electron-donating group is 4-n-alkylpiperazine and the electron-withdrawing group is the nitro group; and the conjugated system is diphenyldiazene with zero, one or two substituents on the phenyl ring not containing the nitro group. The substituents are-F,-Cl, and-CH3. Most of the compounds synthesized are nematogenic and exhibit rather broad liquid crystalline ranges. The effects of the lateral substituents on the optical absorption and phase transition temperatures are correlated with their nature and position of substitution. Dielectric anisotropy and birefringence measurements were made using mixtures containing 10 wt % of synthesized liquid crystals dissolved in commercial mixture E7. 相似文献
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Nine series of liquid crystals containing an electron-donating group at one end of a conjugated system and an electron-withdrawing group at the other end have been synthesized. The electron-donating group is 4-n-alkylpiperazine and the electron-withdrawing group is the nitro group; and the conjugated system is diphenyldiazene with zero, one or two substituents on the phenyl ring not containing the nitro group. The substituents are-F,-Cl, and-CH3. Most of the compounds synthesized are nematogenic and exhibit rather broad liquid crystalline ranges. The effects of the lateral substituents on the optical absorption and phase transition temperatures are correlated with their nature and position of substitution. Dielectric anisotropy and birefringence measurements were made using mixtures containing 10 wt % of synthesized liquid crystals dissolved in commercial mixture E7. 相似文献
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Diazo Strategy for the Synthesis of Pyridazines: Pivotal Impact of the Configuration of the Diazo Precursor on the Process
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Prof. Dr. Valerij A. Nikolaev Dr. David Cantillo Prof. Dr. C. Oliver Kappe Dr. Jury J. Medvedev Prof. Dr. G. K. Surya. Prakash Dr. Murat B. Supurgibekov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):174-184
Phosphazenes of vinyldiazocarbonyl compounds having cis stereochemistry of the functional groups on the vinyl bond readily produce pyridazines by a diaza‐Wittig process, whereas their counterparts with trans configuration remain intact under similar reaction conditions. Upon UV irradiation trans‐phosphazenes furnish pyridazines through a tandem trans‐to‐cis isomerization followed by intramolecular cyclization. At elevated temperatures trans‐(triphenyl)phosphazenes dissociate to give the initial vinyldiazo compounds, which produce pyrazoles in high yields. The first theoretical study on the mechanism of the diaza‐Wittig process by DFT calculations at the M06‐2X/6‐31G(d) level of theory suggest that for the cis‐phosphazenes a rapid tandem [2+2] cycloaddition/cycloelimination process with low energy barriers is preferred over trans isomers. 相似文献
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Progress in the transition‐metal‐catalyzed or ‐free fluoroalkylation of diazo compounds with different types of fluoroalkyl (Rfn) transfer reagents is summarized in this review. Special attention is focused on the straightforward trifluoromethylation, gem‐difluoroolefination, trifluoromethoxylation, fluoroalkylthiolation, and trifluoromethylselenolation of diazo substrates. The mechanistic insights and the application of some of the products are also discussed in this article. We believe that this review will inspire both young and experienced chemists to further study the direct fluoroalkylation of diazo compounds as an efficient and convenient way to build complex fluorine‐containing molecules. 相似文献
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Zsuzsa M. Jászay Truong Son Pham Katalin Gönczi Imre Petneházy László Tőke 《合成通讯》2013,43(11):1574-1579
A simple and efficient solid/liquid phase-transfer catalytic diazo transfer reaction for the synthesis of diazocarbonyl, diazophosphonyl, and diazophosphinyl compounds is reported. 相似文献
14.
The [Rh2(OAc)4]-catalyzed addition of methyl diazoacetate to N-benzylideneaniline ( 1a ) afforded the imine cis- 2 in 35% yield. Under catalysis by chiral RhII catalysts, however, only racemic 1a was produced, and the yield was low. In the presence of dimethyl maleate, aziridine formation was suppressed, and an intermediate ylide 6 was trapped as cycloadduct 7 . No aziridines were obtained, however, from 1b, 1c , and 3 . The iminium salt 8 reacted with (trimethylsilyl)diazomethane in the absence of [Rh2(OAc)4] via dipolar cycloaddition followed by extrusion of N2 to 10 . 相似文献
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Justus Reitz Patrick W. Antoni Dr. Julian J. Holstein Jun.-Prof. Dr. Max M. Hansmann 《Angewandte Chemie (International ed. in English)》2023,62(19):e202301486
Recently, stable diazoalkenes have received significant attention as a new substance class in organic chemistry. While their previous synthetic access was exclusively limited to the activation of nitrous oxide, we here establish a much more general synthetic approach utilizing a Regitz-type diazo transfer with azides. Importantly, this approach is also applicable to weakly polarized olefins such as 2-pyridine olefins. The new pyridine diazoalkenes are not accessible by the activation of nitrous oxide, allowing for a considerable extension of the scope of this only recently accessed functional group. The new diazoalkene class has properties distinct from the previously reported classes, such as photochemically triggered loss of dinitrogen affording cumulenes and not C−H insertion products. Pyridine-derived diazoalkenes represent the so far least polarized stable diazoalkene class reported. 相似文献
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YAN Ming HU Wen-Hao Groneberg Luisa S. Doyle Michael P. 《有机化学》2003,23(Z1):233-233
Transition metal-catalyzed decomposition of diazo compounds and subsequent transformations constitute vast synthetically useful reactions. Recently the catalytic approaches to ylide generation and reaction leading to heterocycle compounds from diazo compounds have achieved remarkable successes. 相似文献
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Andrea Vasella Christian Witzig Jose-Luis Chiara Manuel Martin-Lomas 《Helvetica chimica acta》1991,74(8):2073-2077
Diazo transfer from trifluoromethanesulfonyl azide (TfN3) to 2-amino-2-deoxy-glycoses constitutes a high-yielding, simple procedure for the preparation of partially protected or unprotected 2-azido-2-deoxy-aldoses. Thus, the D -allosamine derivative 2 gave 93% of 3 , while diazo transfer to D -glucosamine, D -mannosamine, and D -galactosamine, followed by acetylation, yielded the azides 5 , 7 , and 9 in yields of 74–91, 65, and 70%, respectively. 相似文献
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Olga Bakulina Anna Inyutina Dmitry Darin Mikhail Krasavin 《Molecules (Basel, Switzerland)》2021,26(21)
This review summarizes recent developments in multicomponent reactions of diazo compounds. The role of diazo reagent and the type of interaction between components was analyzed to structure the discussion. In contrast to previous reviews on related topics mostly focused on metal catalyzed transformations, a substantial amount of organocatalytic or catalyst-free methodologies is covered in this work. 相似文献
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M. Regitz 《Angewandte Chemie (International ed. in English)》1967,6(9):733-749
When an arenesulfonyl azide, particularly p-toluenesulfonyl azide, reacts, in the presence of a base, with a compound containing an active methylene group, the two hydrogen atoms of the active methylene group are replaced by a diazo group to form a diazo compound and an arenesulfonamide. The method may be used for the synthesis of the diazo derivatives of cyclopentadienes, cyclohexadienes, 1,3-dicarbonyl, 1,3-disulfonyl, and 1,3-ketosulfonyl compounds, ketones, carbonic acid esters, and β-iminoketones. Secondary reactions can lead to azo compounds and heterocycles such as 1,2,3-triazoles, 1,2,3-thiadiazoles, and pyrazolin-4-ones. Azidinium salts react in the same way, but in this case an acidic reaction medium is necessary, a fact that is sometimes advantageous. 相似文献