- Dipolar HCP materials as alternatives to DMF solvent for azide-based synthesis
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Hypercrosslinked polymers HCP-DMF and HCP-DMF-SO3H containing abundant and flexible DMF moieties were designed and synthesized. Benefitting from the solvation microenvironment provided by the pseudo-DMF moities, the polar HCPs manifested outstanding performances in the conversions of NaN3 to benzylic azides and 1,2,3-triazoles in EtOH (95%), respectively, avoiding the use of risky DMF and improving the separation processes of the products.
- Bai, Rongxian,Gao, Feng,Gu, Yanlong,Li, Minghao
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supporting information
p. 7499 - 7505
(2021/10/12)
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- A Deprotonation Approach to the Unprecedented Amino-Trimethylenemethane Chemistry: Regio-, Diastereo-, and Enantioselective Synthesis of Complex Amino Cycles
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The first realization of the amino-trimethylenemethane chemistry is reported using a deprotonation strategy to simplify the synthesis of the amino-trimethylenemethane donor in two steps from commercial and inexpensive materials. A broad scope of cycloaddition acceptors (seven different classes) participated in the chemistry, chemo-, regio-, diastereo-, and enantioselectively generating various types of highly valuable complex amino cycles. Multiple derivatization reactions that further elaborated the initial amino cycles were performed without isolation of the crude product. Ultimately, we applied the amino-trimethylenemethane chemistry to synthesize a potential pharmaceutical in 8 linear steps and 7.5 % overall yield, which previously was achieved in 18 linear steps and 0.6 % overall yield.
- Trost, Barry M.,Wang, Youliang
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supporting information
p. 11025 - 11029
(2018/07/30)
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- Catalyst- and Substituent-Controlled Switching of Chemoselectivity for the Enantioselective Synthesis of Fully Substituted Cyclobutane Derivatives via 2 + 2 Annulation of Vinylogous Ketone Enolates and Nitroalkene
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The first regioselective, diastereoselective, and enantioselective organocatalyzed Michael-Michael cascade of vinylogous ketone enolates and nitroalkenes for the construction of fully substituted cyclobutanes is achieved by the deployment of the appropriate chiral squaramide catalyst and the pertinent substituent on the substrate. The domino reaction provided cyclobutanes with four contiguous stereocenters, including a quaternary center in good yields with diastereomeric ratio of >20:1 and with enantioselectivities of mostly up to 98% enantiomeric excess (ee). The structures and the absolute configurations of the adducts were confirmed by single-crystal X-ray crystallographic analyses of the appropriate products.
- Akula, Pavan Sudheer,Hong, Bor-Cherng,Lee, Gene-Hsiang
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supporting information
p. 7835 - 7839
(2019/01/04)
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- Synthesis, antiproliferative and pro-apoptotic effects of nitrostyrenes and related compounds in Burkitt’s lymphoma
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Background: Cancers of the lymphatic cells (lymphomas) account for approximately 12% of malignant diseases worldwide. The nitrostyrene scaffold is identified as a lead target structure for the development of particularly effective compounds targeting Burkitt’s lymphoma (BL). Objectives: The aims of the curent study were to synthesise a panel of nitrostyrene compounds and to evaluate their activity in Burkitt’s lymphoma (BL). Methods: A panel of structurally varied compounds were designed and synthesised using Henry Knoevenagel condensation reactions. Single crystal X-Ray analysis confirmed the E configuration for six examples of these novel structures. A number of nitrostyrene-related compounds were also investigated including 1,3-bis(aryl)-2-nitropropenes together with heterocyclic scaffolds containing the nitrovinyl pharmacophore such as 3-nitro-2-phenyl-2H-chromenes. The antiproliferative activities of the compounds were evaluated using the BL cell lines EBV- MUTU-1 and EBV+ DG-75 (chemoresistant) to establish preliminary structure-activity relationships. Results: Lead compounds with optimized nitrostyrene scaffolds and 3-nitro-2-phenyl-2Hchromene structures were successfully established with typical IC50 values of 0.45 μM and 0.47 μM in MUTU-1 cells and 1.41 μM and 1.92 μM, respectively, in DG-75 cells. The mechanism of cell death was identified as apoptotic and the lead compound was found to elicit comparable apoptotic effects to Taxol in Burkitt’s lymphoma cell lines MUTU-1 and DG-75. Conclusion: This class of pharmaceutically active compounds with potential for the treatment of Burkitt’s lymphoma suggest a potential role for nitrostyrene based agents in chemotherapy.
- Byrne, Andrew J.,Bright, Sandra A.,Fayne, Darren,McKeown, James P.,McCabe, Thomas,Twamley, Brendan,Williams, Clive,Meegan, Mary J.
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p. 181 - 199
(2018/03/13)
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- Electronic effect of substituents on anilines favors 1,4-addition to: Trans -β-nitrostyrenes: Access to N -substituted 3-arylindoles and 3-arylindoles
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A simple and an efficient method for the regioselective synthesis of N-alkyl/aryl/H 3-arylindole derivatives from N-substituted anilines and trans-β-nitrostyrenes has been described using 10 mol% of bismuth(iii) triflate as a catalyst in acetonitrile at 80 °C. The present protocol profits from the formation of new C-C and C-N bonds, broad substrate scope and moderate to good yields.
- Gattu, Radhakrishna,Bhattacharjee, Suchandra,Mahato, Karuna,Khan, Abu T.
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supporting information
p. 3760 - 3770
(2018/05/30)
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- Inhibition of LDL oxidation and inflammasome assembly by nitroaliphatic derivatives. Potential use as anti-inflammatory and anti-atherogenic agents
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We have previously shown the antioxidant and anti-inflammatory properties of several para-substituted arylnitroalkenes. Since oxidative stress and inflammation are key processes that drive the initiation and progression of atherosclerosis, in the present work the antioxidant, anti-inflammatory and anti-atherogenic properties of an extended library of aryl-nitroaliphatic derivatives, including several newly designed nitroalkanes, was explored. The antioxidant capacity of the nitroaliphatic compounds, measured using the oxygen radical absorbance capacity assay (ORAC) showed that the p-methylthiophenyl-derivatives were about three times more effective than Trolox to prevent fluorescein oxidation, independently of the presence or the absence of the double bond next to the nitro group. The peroxyl radical scavenger capacity of the p-dimethylaminophenyl-derivatives was even higher, being the reduced form of these compounds even more active. In fact, while the antioxidant capacity of 1-dimethylamino-4-(2-nitro-1Z-ethenyl)benzene and 1-dimethylamino-4-(2-nitro-1Z-propenyl)benzene was 4.2 ± 0.1 and 5.4 ± 0.1 Trolox Eq/mol, respectively; ORAC values obtained with the ethyl and the propyl derivatives were 10 ± 1 and 13 ± 2 Trolox Eq/mol, respectively. The p-dimethylamino-derivatives, especially the nitroalkanes, were also able to prevent LDL oxidation mediated by peroxyl radicals. Oxygen consumption due to the oxidation of fatty acids was delayed in the presence of the dimethylamino substituted compounds, only the alkanes interrupted the chain of lipid oxidations decreasing the rate of oxygen consumption. Although the formation of foam cells in the presence of oxidized-LDL (oxLDL) remained unaffected, the molecules containing the dimethylamino moiety were able to decrease the expression of IL-1β in LPS/INF-γ challenged macrophages.
- Cataldo, Nicolás,Musetti, Bruno,Celano, Laura,Carabio, Claudio,Cassina, Adriana,Cerecetto, Hugo,González, Mercedes,Thomson, Leonor
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p. 178 - 186
(2018/10/15)
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- Catalytic asymmetric Tamura cycloadditions involving nitroalkenes
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The first examples of asymmetric Tamura cycloaddition reactions involving singly activated alkenes are reported. Homophthalic anhydride reacts with α-methyl nitrosytrenes in the presence of an alkaloid-based catalyst to generate fused bicyclic aromatic ketone products with three new stereocentres (which are susceptible to subsequent equilibration) in 12-99% ee. An unusual equilibration process which occurs in methanolic medium in the absence of a recognisable base via proton transfer at the α-carbon of an ester was investigated experimentally and computationally.
- Manoni, Francesco,Farid, Umar,Trujillo, Cristina,Connon, Stephen J.
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p. 1463 - 1474
(2017/02/15)
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- In order to iodide is one pot synthesis nitryl source α, β - unsaturated nitro olefin derivatives (by machine translation)
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The present invention discloses a one-pot synthesis nitryl source iodide is α, β - unsaturated nitro olefin derivatives, vinyl compounds containing four aryl ferrous (III), iodide and tertiary-butyl hydrogen peroxide in acetonitrile solution system a pot of reaction, generating α, β - unsaturated nitro olefin derivatives; the method to achieve the under mild reaction conditions, high yield with high stereo selectivity of the E synthesis of α, β - unsaturated nitro olefin. (by machine translation)
- -
-
Paragraph 0122-0125; 0135-0137
(2017/09/01)
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- Α, β - unsaturated nitro olefin derivative synthesis method (by machine translation)
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The invention discloses a α, β - unsaturated nitro olefin derivative synthesis method, vinyl compounds containing four aryl ferrous (III), ammonium halide and tertiary-butyl hydrogen peroxide in the system of the one-pot reaction, generating α, β - unsaturated nitro olefin derivatives; the method to achieve the under mild reaction conditions, high yield with high stereo selectivity of the E synthesis of α, β - unsaturated nitro olefin. (by machine translation)
- -
-
Paragraph 0027; 0034; 0124; 0126; 0136; 0137; 0138
(2017/09/05)
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- Insights into the diastereoselective control in the sulfa-Michael addition of thiols to nitroalkenes: Stereoelectronic effect in the cyclic chelated transition state
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The diastereoselective control in the sulfa-Michael addition of nitroalkenes and lithium thiolates followed by protonation was investigated. Lithium thiolates first added to nitroalkenes to afford cyclic lithium-chelated nitronates. The subsequent kinetic protonation of nitronates was proved to be the stereochemical determinant through the chelate-controlled six-membered half-chair transition state bearing two approximately 1,2-diaxial substituents due to stereoelectronic effect control. The stereoelectronic effect in the cyclic chelated transition state was probed and verified by tuning the steric bulkiness of the corresponding substituents. The reaction involving 1-nitrocyclohexene provided perfect support for the proposed diastereoselective control model. The current investigation provided not only comprehensive insights into the diastereoselective control in the sulfa-Michael addition of nitroalkenes and thiolates, but also an important role of the stereoelectronic effect in certain organic reactions involving cyclic chelate transition states.
- Wang, Jiandong,Li, Pingfan,Yang, Zhanhui,Chen, Ning,Xu, Jiaxi
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p. 370 - 378
(2015/12/31)
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- K2S2O8-mediated nitration of alkenes with NaNO2 and 2,2,6,6-tetramethylpiperidine-1-oxyl: Stereoselective synthesis of (E)-nitroalkenes
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A transition-metal-free nitration of alkenes with NaNO2 in the presence of K2S2O8 and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) is developed. The transformation exhibits a broad substrate scope and good functional group tolerance, thus providing a new and expedient protocol for stereoselective synthesis of (E)-nitroalkenes with moderate to good yields. Moreover, the nitration processes of (E)- and (Z)-stilbene are also studied: even though the proportion of substrates is different, the E/Z ratio of the products is basically the same. Based upon experimental observations, a possible reaction mechanism is proposed.
- Zhao, An,Jiang, Qing,Jia, Jing,Xu, Bin,Liu, Yufeng,Zhang, Mingzhong,Liu, Qiang,Luo, Weiping,Guo, Cancheng
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supporting information
p. 80 - 84
(2015/12/23)
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- Nitration-Oximization of Styrene Derivatives with tert-Butyl Nitrite: Synthesis of α-Nitrooximes
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A highly efficient method for direct nitration-oximization of styrene derivatives using tert-butyl nitrite (t-BuONO) in DMSO was developed. The present method offers a convenient and practical approach for the synthesis of α-nitrooximes in moderate to high yields. The salient features entail mild reaction conditions, metal-free reagent, environmentally benign solvent and simple experimental procedure.
- Chumnanvej, Napasawan,Katrun, Praewpan,Pohmakotr, Manat,Reutrakul, Vichai,Soorukram, Darunee,Kuhakarn, Chutima
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p. 830 - 838
(2016/09/03)
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- Cathodic hydrodimerization of nitroolefins
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Nitroalkenes are easily accessible in high variety by condensation of aldehydes with aliphatic nitroalkanes. They belong to the group of activated alkenes that can be hydrodimerized by cathodic reduction. There are many olefins with different electron withdrawing groups used for cathodic hydrodimerization, but not much is known about the behaviour of the nitro group. Synthetic applications of this group could profit from the easy access to nitroolefins in large variety, the C-C bond formation with the introduction of two nitro groups in a 1,4-distance and the conversions of the nitro group by reduction to oximes and amines, the conversion into aldehydes and ketones via the Nef reaction and base catalyzed condensations at the acidic CH bond. Eight 1-aryl-2-nitro-1-propenes have been electrolyzed in an undivided electrolysis cell to afford 2,5-dinitro-3,4-diaryl hexanes in high yield. The 4-methoxy-, 4-trifluoromethyl-, 2-chloro- and 2,6-difluorophenyl group and furthermore the 2-furyl and 2-pyrrolyl group have been applied. The reaction is chemoselective as only the double bond but not the nitro group undergoes reaction, is regioselective as a β,β-coupling with regard to the nitro group and forms preferentially two out of six possible diastereomers as major products.
- Wessling, Michael,Sch?fer, Hans J.
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supporting information
p. 1163 - 1174
(2015/08/18)
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- Enantioselective hydrogenation of α,β-disubstituted nitroalkenes
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The first highly chemo- and enantioselective hydrogenation of α,β-disubstituted nitroalkenes was accomplished with rhodium/JosiPhos-J2 as a catalyst, with the yield and enantioselectivity of up to 95% and 94%, respectively. The α-chiral nitroalkanes will provide an entry to valuable chiral amphetamines which are otherwise not so easily accessed. This journal is the Partner Organisations 2014.
- Li, Shengkun,Huang, Kexuan,Zhang, Xumu
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supporting information
p. 8878 - 8881
(2014/08/05)
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- Arylnitroalkenes as scavengers of macrophage-generated oxidants
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Oxygen and nitrogen derived molecules mediated oxidation and nitration have been involved in several pathological conditions. Conversely, nitric oxide and hydrogen peroxide are important signalization intermediates, whose concentrations are tightly regula
- Celano, Laura,Carabio, Claudio,Frache, Renata,Cataldo, Nicolás,Cerecetto, Hugo,González, Mercedes,Thomson, Leonor
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- Oxone/KI-Mediated Nitration of Alkenes and Alkynes: Synthesis of Nitro- and β-Iodonitro-Substituted Alkenes
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Oxone (2KHSO5·KHSO4·K2SO4) was used to promote the nitration of alkenes and alkynes with sodium nitrite (NaNO2) and potassium iodide (KI). This stable, easy-to-handle, and environmentally benign oxidant was used under mild conditions (room temperature) and provided short reaction times. Styrene derivatives that did not contain electron-donating groups afforded the corresponding nitro alkenes in moderate to good yields, whereas aliphatic alkenes and electron-deficient alkenes were not good substrates. Under similar reaction conditions, aryl alkynes yielded β-iodonitro alkenes. Oxone (2KHSO5·KHSO4·K2SO4) was used to promote the reactions of alkenes and alkynes with sodium nitrite (NaNO2) and potassium iodide (KI) to afford the corresponding nitro and β-iodonitro-substituted alkenes, respectively, in moderate to good yields.
- Hlekhlai, Sornsiri,Samakkanad, Natthapol,Sawangphon, Tassaporn,Pohmakotr, Manat,Reutrakul, Vichai,Soorukram, Darunee,Jaipetch, Thaworn,Kuhakarn, Chutima
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p. 7433 - 7442
(2016/02/19)
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- Convenient synthesis of α-nitrooximes mediated by OXONE
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A novel OXONE mediated direct difunctionalization of alkenes with NaNO2 in aqueous acetonitrile for the synthesis of α-nitrooximes was developed. The α-nitrooximes were readily prepared in moderate to high yields at room temperature under mild reaction conditions. The present protocol offers an easy and environmentally benign approach to access various α-nitrooximes derived from styrene derivatives.
- Chumnanvej, Napasawan,Samakkanad, Natthapol,Pohmakotr, Manat,Reutrakul, Vichai,Jaipetch, Thaworn,Soorukram, Darunee,Kuhakarn, Chutima
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p. 59726 - 59732
(2015/02/19)
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- Selective conversion of nitroalcohols to nitroolefins over sulfonic acid functionalized mesoporous SBA-15 material
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Highly ordered 2D-hexagonal mesoporous SBA-15 has been synthesized by using triblock copolymer as template and its surface has been functionalized by 3-propylsulfonic acid group via post-synthetic grafting with 3-mercaptopropyltrimethoxy silane. A variety of α,β-substituted nitroalcohols are converted to their corresponding nitroolefins under mild reaction conditions using this 3-propylsulfonic acid-functionalized SBA-15 material. Nitroalcohols with open-chain, cyclic, and heterocyclic substituents at the α-position are smoothly converted into their corresponding nitroolefins in high yields over this solid acid catalyst. Propylsulfonic acid functionalized SBA-15 materials are found to be more efficient catalysts than microporous zeolites under similar reaction conditions.
- Sasidharan, Manickam,Bhaumik, Asim
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-
- One-pot solid phase synthesis of (E)-nitroalkenes
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An efficient one-pot protocol for the synthesis of (E)-nitroalkenes by reaction of aldehydes and nitroalkanes in the presence of polymer-bound triphenylphosphine, iodine and imidazole is described. Although the reaction works with similar efficiency with triphenylphosphine and its polymer-bound version, easy removal of the unwanted polymer-bound triphenylphosphine oxide and its recovery as triphenylphosphine provide the edge for practical application of the method.
- Rokhum, Lalthazuala,Bez, Ghanashyam
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p. 5500 - 5504
(2013/09/23)
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- A predictably selective nitration of olefin with Fe(NO3) 3 and TEMPO
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Ferric nitrate with catalytic TEMPO has been identified as a useful reagent for regio- and stereoselective nitration of a wide variety of aromatic, aliphatic, and heteroaromatic olefins. This reaction provided nitroolefins in preparatively useful yields with excellent E-selectivity. Due to its mild nature and operational simplicity, the present protocol is expected to find application in synthetic setup.
- Naveen, Togati,Maity, Soham,Sharma, Upendra,Maiti, Debabrata
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p. 5949 - 5954
(2013/07/26)
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- Synthesis of nitroalkenes involving a cooperative catalytic action of iron(III) and piperidine: A one-pot synthetic strategy to 3-alkylindoles, 2H-chromenes and N-arylpyrrole
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An efficient and simple strategy has been developed to synthesize various substituted nitroalkenes involving a cooperative catalytic system of FeCl 3 and piperidine. This dual catalytic protocol simultaneously activates both electrophile and nucleophile and works under mild reaction conditions so that many sensitive functional groups were tolerated. Moreover, this cooperative catalytic reaction is also suitable for various one-pot reactions involving nitroalkenes such as, 2H-chromenes, N-arylpyrrole and Michael reaction with indole. Notably, this method is low-cost, efficient and environmentally friendly. Copyright
- Jalal, Swapnadeep,Sarkar, Soumen,Bera, Krishnendu,Maiti, Sukhendu,Jana, Umasish
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supporting information
p. 4823 - 4828
(2013/08/23)
-
- Design of phosphorus ligands with deep chiral pockets: Practical Synthesis of chiral β-arylamines by asymmetric hydrogenation
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WingPhos, a C2-symmetric bisphosphorus ligand with a deep and well-defined chiral pocket was developed. It has shown high efficiency in the rhodium-catalyzed asymmetric hydrogenation of (E)-β-aryl-N-acetyl enamides, cyclic β-aryl enamides, and heterocyclic β-aryl enamides. A series of chiral β-arylisopropylamines, 2-aminotetralines, and 3-aminochromans can be synthesized with excellent ee values (nbd=3,5-norbornadiene; TON=turnover number). Copyright
- Liu, Guodu,Liu, Xiangqian,Cai, Zhihua,Jiao, Guangjun,Xu, Guangqing,Tang, Wenjun
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supporting information
p. 4235 - 4238
(2013/05/08)
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- Synthesis of (E)-nitroolefins via decarboxylative nitration using t-butylnitrite (t-BuONO) and TEMPO
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Nitroolefins are usually synthesized using the Henry reaction. Here we report an alternative metal-free decarboxylative nitration protocol for the preparation of the nitroolefins from α,β-unsaturated carboxylic acids using t-butylnitrite (t-BuONO) and TEMPO. α,β-Unsaturated carboxylic acids bearing β-aromatic and β-heteroaromatic substituents gave (E)-nitroolefins exclusively under mild conditions. A radical based pathway has been proposed for this decarboxylative nitration reaction. The Royal Society of Chemistry 2013.
- Manna, Srimanta,Jana, Sandipan,Saboo, Tapish,Maji, Arun,Maiti, Debabrata
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supporting information
p. 5286 - 5288
(2013/06/27)
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- Efficient and stereoselective nitration of mono- and disubstituted olefins with AgNO2 and TEMPO
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Nitroolefin is a common and versatile reagent. Its synthesis from olefin is generally limited by the formation of mixture of cis and trans compounds. Here we report that silver nitrite (AgNO2) along with TEMPO can promote the regio- and stereoselective nitration of a broad range of olefins. This work discloses a new and efficient approach wherein starting from olefin, nitroalkane radical formation and subsequent transformations lead to the desired nitroolefin in a stereoselective manner.
- Maity, Soham,Manna, Srimanta,Rana, Sujoy,Naveen, Togati,Mallick, Arijit,Maiti, Debabrata
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supporting information
p. 3355 - 3358
(2013/04/10)
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- Highly enantioselective reduction of β,β-disubstituted aromatic nitroalkenes catalyzed by Clostridium sporogenes
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(Chemical Equation Presented) This is the first report of the use of Clostridium sporogenes extracts for enantioselective reduction of C=C double bonds of β,β-disubstituted (1) and α,β-disubstituted nitroalkenes (3). Crude enzyme preparations reduced aryl derivatives 1a-e and 1h, in 35-86% yield with ≥97% ee. Reduction of (E)- and (Z)-isomers of 1c gave the same enantiomer of 2c (≥99% ee). In contrast, α,β- disubstituted nitroalkene 3a was a poor substrate, yielding (S)-4a in low yield (10-20%), and the ee (30-70% ee) depended on NADH concentration. An efficient synthesis of a library of nitroalkenes 1 is described.
- Fryszkowska, Anna,Fisher, Karl,Gardiner, John M.,Stephens, Gill M.
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p. 4295 - 4298
(2008/12/20)
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- An efficient synthesis of (E)-nitroalkenes catalyzed by recoverable diamino-functionalized mesostructured polymers
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A clean, efficient, and simple method has been developed for synthesis of (E)-nitroalkenes using FDU-ED as an efficient catalyst. The reactions proceeded with moderate to high yields (60-96%) under mild conditions. The catalyst FDU-ED is recyclable and can be reused more than seven times without significant loss of activity and selectivity.
- Yan, Shaoyu,Gao, Yuan,Xing, Rong,Shen, Yali,Liu, Yueming,Wu, Peng,Wu, Haihong
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p. 6294 - 6299
(2008/09/21)
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- Solvent-free nucleophilic addition of N-alkylhydroxylamines to substituted nitroolefins: Formation of nitrones by a tandem process
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Nucleophilic addition of 1-methyl-2-arylethylhydroxylamine to substituted β-nitrostyrene under solvent-free conditions has led to unexpected nitrones via a tandem process involving 1,4-addition and elimination. Copyright Taylor & Francis Group, LLC.
- Amutha, Chinnadurai,Muthusubramanian, Shanmugam
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p. 328 - 337
(2008/04/01)
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- Selective nitroaldol condensations over heterogeneous catalysts in the presence of supercritical carbon dioxide
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(Chemical Equation Presented) At 40-60°C, in the presence of heterogeneous catalysts based on Al2O3, supercritical carbon dioxide not only acts as a good solvent for the reaction of aromatic and aliphatic aldehydes with 1-nitroalkanes but, most importantly, it also allows the selectivity to be tuned between the competitive formation of β-nitroalcohols and nitroalkenes (from the Henry reaction and the nitroaldol condensation, respectively). In particular, when the pressure (and the density) of the supercritical phase is enhanced from 80 to 140 bar, the nitroalkene's selectivity increases, on average, from ~60 to >90%. Experiments show that, in the same pressure range, a steep increase of the concentration profiles of reactant aldehydes takes place. By contrast, under solvent-free conditions, the reaction usually proceeds with a higher conversion, but nitroalkanols are the major products.
- Ballini, Roberto,Noe, Marco,Perosa, Alvise,Selva, Maurizio
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supporting information; experimental part
p. 8520 - 8528
(2009/04/05)
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- Evaluation of nitroalkenes as nitric oxide donors
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Chemiluminescence experiments demonstrate that simple nitroalkenes release low levels of nitric oxide. UV and EPR measurements suggest but cannot confirm direct NO release from nitroalkenes. Given the biological activity of nitrated unsaturated fatty acids, these results suggest the possible metabolic conversion of nitroalkenes to NO.
- Gorczynski, Michael J.,Huang, Jinming,Lee, Heather,King, S. Bruce
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p. 2013 - 2017
(2008/02/05)
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- A convenient procedure for the synthesis of 3-substituted 5,6-dihydro-4H-1,2-oxazines from nitroethane
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A novel and efficient four-step procedure for the synthesis of C-3-functionalised 5,6-dihydro-4H-1,2-oxazines from nitroethane is described. It includes preparation of 3-methyl-substituted six-membered cyclic nitronates, 3-(bromomethyl)-substituted 5,6-dihydro-4H-1,2-oxazines as intermediates, and nucleophilic substitution of bromine. Total yields of the target C-3-functionalised oxazines are 15-30% from nitroethane. Georg Thieme Verlag Stuttgart.
- Sukhorukov, Alexey Yu.,Klenov, Michael S.,Ivashkin, Pavel E.,Lesiv, Alexey V.,Khomutova, Yulya A.,Ioffe, Sema L.
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- Determination of the synthetic origin of methamphetamine samples by 2H NMR spectroscopy
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Samples of methamphetamine, prepared according to the most common synthetic pathways, were submitted to natural-abundance 2H NMR spectroscopy. The deuterium content at the various sites of the molecule was found to depend on its synthetic history. The technique provides a chemical fingerprint of methamphetamine samples and can give hints to trace back the starting materials and the synthetic procedures.
- Armellin, Silvia,Brenna, Elisabetta,Frigoli, Samuele,Fronza, Giovanni,Fuganti, Claudio,Mussida, Daniele
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p. 3113 - 3117
(2008/02/09)
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- Catalytic activity of aminopropyl xerogels in the selective synthesis of (E)-nitrostyrenes from nitroalkanes and aromatic aldehydes
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Various aminopropyl-functionalized silicas (APS) were prepared by the sol-gel technique using different tetraethyl orthosilicate/ aminopropyltriethoxysilane (TEOS/ATS) ratios and tested as base catalysts for the nitroaldol reaction. The solids were fully characterized. It was proved that the amount of organic component strongly influences the composition and textural properties of the hybrid organic-inorganic materials. In particular, when ATS was increased to more than 40%, pore volume collapse was observed and a significant decrease in interaction with benzaldehyde reagent was revealed by FT-IR. Catalytic activity in the nitroaldol reaction was correlated with chemical composition and textural properties, suggesting that the catalyst efficiency depends on accessibility to the catalytic sites. In all cases, (E)-nitrostyrene was selectively obtained.
- Sartori,Bigi,Maggi,Sartorio,Macquarrie,Lenarda,Storaro,Coluccia,Martra
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p. 410 - 418
(2007/10/03)
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- A novel asymmetric reduction of nitroolefin 2-nitro-1phenyl-1-propene by using BINAP-ruthenium(II) complexes
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The ruthenium BINAP complex, [Ru(OAc)2{(S)-BINAP}], can catalyse the hydrogenation of 2-nitro-1-phenyl-1-propene (1) to give optically active 2-nitro-1-phenylpropane (2) in moderate enantiomeric excess.
- Li, Yanjun,Izumi, Taeko
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p. 128 - 129
(2007/10/03)
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- Low-valent Ruthenium Induced Simultaneous Reduction of Nitro Group and C-C Double Bond in Nitroolefin 1-Phenyl-2-nitropropene-1-
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The reduction of 1-phenyl-2-nitropropene-1 (1) on using ruthenium complexes was studied in detail in order to correlate this method with those previously recorded in the literature for the hydrogenation of nitroolefins. A variety of products was isolated by varying the reaction temperature and solvent. Among them was 1-phenyl-2-propylamine (4), completely reduced from the selective both double bond and nitro group. 1-Phenyl-2-propanol (5) was observed due to reduction of phenylacetone at 125 deg C in the presence of ruthenium catalyst. When reaction temperature was lower than 125 deg C, by employing RuCl2(PPh3)3 complex, 1-phenyl-2-nitropropane (2) and phenylacetone (3) were obtained, respectively. Ru-BINAP complexes were attempted to produce chiral amine from starting material 1-phenyl-2-nitropropene-1 (1).
- Li, Yanjun,Izumi, Taeko
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p. 505 - 508
(2007/10/03)
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- Diastereoselective access to 3-nitro-4-vinylidenetetrahydrofurans and 3-nitro-4-vinylidenetetrahydropyrans and their conversion into 3,6-dihydro-1,2-oxazines by reverse cope elimination of hydroxylamine precursors
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A new approach to the synthesis of unsaturated nitro-allenyltetrahydrofurans 3 and -tetrahydropyrans 5 has been developed, involving oxa-Michael addition/SN2′ substitution of propargyl and homopropargyl alcohol derivatives 2a and 4h on nitroalkenes1a-g. Complete allylic 1,3-strain control during the cyclization accounts for the observed diastereoselectivity. Reduction of nitro compounds 3 and 5 with SmI2 provided new α-allenylhydroxylamines 7 and 8, which were easily isomerized into 3,6-dihydro-1,2-oxazines 9 and 10 by reverse Cope elimination. Wiley-VCH Verlag GmbH, 2001.
- Dumez, Estelle,Faure, Robert,Dulcere, Jean-Pierre
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p. 2577 - 2588
(2007/10/03)
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- Supported organic catalysts: Synthesis of (E)-nitrostyrenes from nitroalkanes and aromatic aldehydes over propylamine supported on MCM-41 silica as a reusable catalyst
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MCM-41-supported propylamine showed high catalytic efficiency in the nitroaldol condensation between nitroalkanes and aromatic aldehydes.
- Demicheli, Giuseppina,Maggi, Raimondo,Mazzacani, Alessandro,Righi, Paolo,Sartori, Giovanni,Bigi, Franca
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p. 2401 - 2403
(2007/10/03)
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- Asymmetric reduction of nitroalkenes with baker's yeast
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Various α,β-disubstituted and trisubstituted nitroalkenes were chemoselectively reduced with baker's yeast to the corresponding nitroalkanes. Stereoselectivities of the reduction of α,β-disubstituted nitroalkenes were modest to low, and e.e.s up to 52% were obtained. Trisubstituted nitroalkenes could be reduced to the corresponding nitroalkanes with excellent enantioselectivities, moderate diastereoselectivities and in good yield.
- Kawai, Yasushi,Inaba, Yoshikazu,Tokitoh, Norihiro
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p. 309 - 318
(2007/10/03)
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- A modified Horner-Wadsworth-Emmons reaction for the synthesis of nitroalkenes
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A range of trisubstituted nitroalkenes are available from the reaction of an α-nitrophosphonate anion and an aldehyde in tetrahydrofuran under reflux.
- Franklin
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p. 1154 - 1156
(2007/10/03)
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- Morpholine adsorbed on silica gel: A novel and mild basic catalyst for the synthesis of α,β-unsaturated nitroalkenes
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Syntheses of α,β-unsaturated nitroalkenes have been carried out under mild condition using morpholine adsorbed on silica gel as a novel catalyst.
- Bandgar, Babasaheb P.,Uppalla, Lav S.,Sadavarte, Vaibhav S.
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p. 949 - 952
(2007/10/03)
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- Zeolite as base catalyst: Nitroaldolic condensation
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The use of heterogeneous catalysts in producing petrochemicals and fine chemicals is one of the most successful lines in catalysis research. They may replace dangerous, corrosive, or toxic catalysts in some cases. The use of zeolites as main catalysts in petrochemical cracking reactions and in oil processing is a case of specific importance. The activity and selectivity of alkaline Y and X zeolites in promoting the nitroaldolic condensation of aromatic aldehydes with nitroalkanes affording nitroalkenes were studied. The reaction was promoted by the intrinsic basicity of the zeolites that increased with increases in both the aluminum content in the framework and the radius of the counter cation. The zeolite cages were microreactors, the walls of which were the basic sites whose number and strength could be controlled by choosing the chemical composition. The activity of substituted benzaldehyde revealed the influence of electronic effects. Steric factors played a critical role regarding the nitroalkanes; the combined effect of shape selectivity and basicity had to be considered in the heterogeneous nitroaldolic condensation.
- Ballini, Roberto,Bigi, Franca,Gogni, Elena,Maggi, Raimondo,Sartori, Giovanni
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p. 348 - 353
(2007/10/03)
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- Clean five-step synthesis of an array of 1,2,3,4-tetra-substituted pyrroles using polymer-supported reagents
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Polymer-supported reagents and other solid sequestering agents may be used to generate an array of 1,2,3,4-tetra-substituted pyrrole derivatives without any chromatographic purification step.
- Caldarelli, Marina,Habermann, Joerg,Ley, Steven V.
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p. 107 - 110
(2007/10/03)
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- Mechanism of the yeast mediated reduction of nitrostyrenes in light petroleum
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The yeast mediated reduction of a range of α- and β-deutero substituted nitrostyrenes has been conducted in light petroleum in the presence of a small amount of water or D2O. NMR analysis of the products from these reactions has allowed the determination of the mechanism of this yeast reduction reaction. The results indicate that initially, a reversible non-stereoselective protonation occurs at the β-centre, followed by stereoselective addition of hydride at the α-position.
- McAnda, Anita F.,Roberts, Kade D.,Smallridge, Andrew J.,Ten, Abilio,Trewhella, Maurie A.
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p. 501 - 504
(2007/10/03)
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- Synthesis of (E)-nitro olefins by isomerisation of (Z)-nitro olefins with polymer-supported triphenylphosphine
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We have found that (Z)-nitro olefins or mixtures of (E)- and (Z)-compounds can be converted to the pure (E)-isomers by treatment with catalytic amounts of triethylamine or polymer-bound triphenylphosphine, respectively.
- Stanetty, Peter,Kremslehner, Manfred
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p. 811 - 812
(2007/10/03)
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- Selective Conversion of Nitroalcohols into Nitroolefins over Zeolite under Heterogeneous Conditions
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Various zeolites catalyse the formation of aliphatic, aromatic and heteroaromatic nitroolefins from the corresponding nitroalcohols with high selectivity and yield at optimum reaction temperature.
- Anbazhagan,Kumaran,Sasidharan
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p. 336 - 337
(2007/10/03)
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- Synthesis of Phenylpyrrolylpyrroles. Part III
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Several ethyl 3-[(3-aryl-4-methyl)-2(1H)-pyrrolyl]-4-methyl-1H-pyrrole-2-carboxylates have been synthesized using two successive ethyl isocyanide addition-cyclizations to the appropriate nitropropene derivatives.
- Dumoulin,Rault,Robba
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- Microwave-Assisted Henry Reaction: Solventless Synthesis of Conjugated Nitroalkenes
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In a solventless system and under microwave irradiation, nitroalkanes react with arylaldehydes in the presence of a catalytic amount of ammonium acetate to afford, in one step, conjugated nitroalkenes without the isolation of intermediary β-nitro alcohols. - Key Words: Arylaldehydes; Nitroalkanes; Ammonium acetate; Conjugated nitroalkenes; Henry reaction; Microwave irradiation
- Varma, Rajender S.,Dahiya, Rajender,Kumar, Sudhir
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p. 5131 - 5134
(2007/10/03)
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- The yeast-mediated reduction of nitrostyrenes in organic solvent systems
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A range of nitrostyrenes have been reduced with dried baker's yeast in an organic solvent system. It was found that the reduction proceeded smoothly to give the corresponding nitroalkanes in good yield and with higher efficiency than the corresponding aqueous reaction system. No evidence for reduction of the nitro group was observed. In the case of β-methyl nitrostyrenes, racemic mixtures were formed, and it was shown that this is not due to racemization of the product.
- Bak, Radoslaw R.,McAnda, Anita F.,Smallridge, Andrew J.,Trewhella, Maurie A.
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p. 1257 - 1260
(2007/10/03)
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- REACTIONS DES METHYLAZIDE ET PHENYLAZIDE AVEC QUELQUES ALCYNES ET OLEFINES α-NITREES. SYNTHESE REGIOSPECIFIQUE DES 1,2,3 TRIAZOLES
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The reactions of alkynes and α-nitro-olefines with methylazide and phenylazide was studied.In contrast to known reactions with alkynes which are non-regioselective, methylazide and phenylazide react regiospecifically with α-nitro-olefines and give only one type of triazole after elimination of HNO2.These reactions are very useful synthetic approaches to 1,2,3 triazoles.
- Piet, J. C.,Hetet, G. Le,Cailleux, P.,Benhaoua, H.,Carrie, R.
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- Mechanism of Debromination of 1-Aryl-1,2-dibromo-2-nitropropanes Promoted by Secondary Amines in Acetonitrile
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Debromination reactions of erythro-dl-1-aryl-1,2-dibromo-2-nitropropanes with secondary amines in MeCN have been investigated kinetically.Reactions of erythro-dl-1-aryl-1,2-dibromo-2-nitropropanes with secondary amines in MeCN are stereospecific, producing (E)-1-aryl-2-nitropropenes quantitatively.The rate equation for the reaction is kobs = k2 + k32, indicating that the reactions proceed by both uncatalyzed and base-catalyzed pathways.The Hammett ?, Broensted β, ΔH(excit.), and ΔS(excit.) values for the k2 and k3 processes are 1.22 +/- 0.04 and 1.20 +/- 0.02, 0.77 +/- 0.05 and 1.05 +/- 0.13, 5.6 +/- 0.3 and 1.7 +/- 0.1 kcal/mol, and -49.1 +/- 4.5 and -60.7 +/- 204 eu, respectively.For dehalogenation reactions from vicinal dibromo and bromochloro compounds, the element effect of the leaving group kBr/kCl = 7.8 and 25 have been determined for the k2 and k3 processes.From these results, the mechanism and the trasition-state character of these reactions are assessed.
- Cho, Bong Rae,Lee, Sup Joo,Kim, Yong Kwan
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p. 2072 - 2076
(2007/10/02)
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- Electrochemical Debromination of 1-Aryl-1,2-dibromo-2-nitropropanes in Dimethyl Sulfoxide
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Electrochemical debromination reactions of erythro-dl-1-aryl-1,2-dibromo-2-nitropropanes 1a-d at a platinum electrode have been investigated by cyclic voltammetry in 0.10 M LiClO4/DMSO.The reactions produced (E)-1-aryl-2-nitropropenes 2a-d in high yields.The cyclic voltammograms were irreversible and the reduction current decrease as the number of cycles increased.The peak potential for the reductions waves are in the range of -0.51 to -0.56 V (vs Ag/Ag(1+)) and show no clear trend with different aryl substituent.The current density increased as the concentration of the substrate increased.The slopes of the plots of log(I/A) vs log are close to unity, indicating unimolecular processes.For all reactions, the Tafel slopes are in the range of 115-125 mV.The logarithm of the ratio iX/iH at -0.16 V did not correlate with the Hammett substituent constants.From these results, the mechanism of these reactions is assessed.
- Cho, Bong Rae,Cho, Eun Jeong,Lee, Seung Jae,Chae, Won Seok
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p. 2077 - 2081
(2007/10/02)
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