- Crystallization Does It All: An Alternative Strategy for Stereoselective Aza-Henry Reaction
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An efficient and experimentally straightforward method for the stereoselective synthesis of a variety of β-nitro-α-amino carboxylic acids via aza-Henry (nitro-Mannich) reaction of aldimines is disclosed, yielding either anti- or a rarely reported syn-configuration. The reaction operates directly on free glyoxylic acid and generates imine species in situ. Crystallization-controlled diastereoselectivity enables isolation of the target compounds in high enantio- and diastereomeric purities by a simple filtration.
- Mar?eková, Michaela,Ger?a, Peter,?oral, Michal,Moncol, Ján,Berke?, Du?an,Kolarovi?, Andrej,Jakubec, Pavol
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supporting information
p. 4580 - 4584
(2019/06/17)
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- Synthesis of 1-Palmitoyl-2-((E)-9- and (E)-10-nitrooleoyl)- sn -glycero-3-phosphatidylcholines
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Extensive investigation of nitrated phospholipids in connection with various biologically important processes requires reliable access to suitable material. A selective chemical synthesis introducing a defined nitrofatty acid at the sn -2 position of a 2-lyso sn -glycero-3-phosphatidylcholine was developed. Given that the nitroalkene moiety of both reactant nitrofatty acid derivative and the product esters is characterised by particular sensitivity to nucleophile addition and, depending on the intermediate, subsequent olefin isomerisation and retro-Henry-type reaction, a reliable two-step ester formation was introduced. The activation of the nitrofatty acid succeeded after reaction with trichlorobenzoyl chloride, and the mixed anhydride could be isolated via extractive work-up. Subsequent reaction with 1-palmitoyl-2-lyso- sn -glycero-3-phosphatidylcholine enabled the sn -2 esterification to be achieved with high yield by using a minimum of reagents, avoiding the formation of side products and facilitating final isolation and purification.
- Dietz, Ulrich,Frank, Andrea,Lehr, Alexander,Münch, Winfried,Nubbemeyer, Udo
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p. 3295 - 3304
(2019/08/28)
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- Modular Regiospecific Synthesis of Nitrated Fatty Acids
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Endogenous nitrated fatty acids are an important class of signaling molecules. Herein a modular route for the efficient and regiospecific preparation of nitrooleic acids as well as various analogues is described. The approach is based on a simple set of alkyl halides as common building blocks and a Henry reaction/Burgess dehydration sequence for the formation of the key nitroalkene moiety.
- Hock, Katharina J.,Grimmer, Jennifer,G?bel, Dominik,Gasaya, George Gichogo T.,Roos, Jessica,Maucher, Isabelle V.,Kühn, Benjamin,Fettel, Jasmin,Maier, Thorsten J.,Manolikakes, Georg
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p. 615 - 636
(2017/01/25)
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- Continuous-flow synthesis using a column reactor packed with heterogeneous catalysts: A convenient production of nitroolefins by using amino-functionalized silicagel
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A continuous-flow synthesis of β-nitroolefins by using heterogeneous base catalysts has been developed. Although the use of an excess amount of nitro-donor such as nitromethane is required in conventional methods, nearly equimolar amounts of nitro-donors and carbonyl compounds are sufficient for high-yielding production of nitroolefins. Catalysts for this flow protocol are inexpensive and abundant, and high durability and high productivity were also realized by using an appropriate second support.
- Ishitani, Haruro,Furiya, Yuichi,Kobayashi, Shū
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supporting information
p. 6229 - 6232
(2017/09/30)
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- S-benzyl isothiouronium chloride as a recoverable organocatalyst for the reduction of conjugated nitroalkenes with Hantzsch ester
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The reduction of conjugated nitroalkenes into nitroalkanes with Hantzsch ester using S-benzyl isothiouronium chloride as a recoverable organocatalyst was successfully accomplished with high yield and excellent chemoselectivity.
- Nguyen, Quynh Pham Bao,Kim, Jae Nyoung,Kim, Taek Hyeon
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supporting information; experimental part
p. 6513 - 6516
(2012/08/28)
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- Synthesis of nitrolipids. All four possible diastereomers of nitrooleic acids: (E)- and (Z)-, 9- and 10-nitro-octadec-9-enoic acids
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Unsaturated fatty acids are nitrated endogenously to produce nitrated lipids. Recent studies have shown that these nitrated lipids have high chemical reactivity and profound biological implications. We report an efficient, scalable synthesis which is regiospecific and stereoselective for all possible isomers of nitrated oleic acid: (E)- and (Z)-, 9- and 10-octadec-9-enoic acids.
- Woodcock, Steven R.,Marwitz, Adam J. V.,Bruno, Paulo,Branchaud, Bruce P.
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p. 3931 - 3934
(2007/10/03)
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- Regio- and stereospecific syntheses and nitric oxide donor properties of (E)-9- and (E)-10-nitrooctadec-9-enoic acids
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Nitrated fatty acids act as endogenous peroxisome proliferator-activated receptor γ (PPARγ) ligands and nitric oxide (NO) donors. We describe the first specific preparation of the two regioisomers of nitrooleic acid, (E)-9-nitrooctadec-9-enoic acid (1) an
- Gorczynski, Michael J.,Huang, Jinming,King, S. Bruce
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p. 2305 - 2308
(2007/10/03)
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- SYNTHESIS OF LOW-MOLECULAR NITROPARAFFINS IN IONIC MELTS
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It was shown that pure low-molecular nitroparaffins can be synthesized by the reaction between alkyl sodium sulfates and nitrite ion in ionic melts.The yield of the product is temperature controlled.Because of the ambident nature of nitrite ion, the main side product is alkyl nitrite, subsequent decomposition of which results in formation of a series of organic oxygen-containing compounds.The formal kinetics of the alkylation of nitrite ion by alkyl sodium sulfates was found to be described by the first-order equation.
- Belobrzhetskaya, M. K.,Laskin, B. M.,Malin, A. S.
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p. 105 - 108
(2007/10/02)
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- Viologen-mediated Reductive Desulfonylation of α-Nitro Sulfones by Sodium Dithionite
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Reductive desulfonylation of α-nitro sulfones to give the corresponding nitro compounds was carried out conveniently with sodium dithionite, by using octylviologen as an electron-transfer catalyst in organic solvent-water two-phase systems.Sulfones which do not have an α-nitro group are not desulfonylated.A reaction scheme involving a nitroalkyl radical has been proposed.
- Park, Kwanghee Koh,Lee, Chul Woo,Choi, Sook Young
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p. 601 - 604
(2007/10/02)
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- A Highly Chemoselective Reduction of Conjugated Nitro Olefins with Hantzsch Ester in the Presence of Silica Gel
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An effective system to reduce conjugated nitro olefins into the corresponding nitroalkanes is described.The system composed Hantzsch ester (HEH) and silica gel in benzene exerts high yield and excellent chemoselectivity under almost neutral conditions.Facile applications of the system to the syntheses of natural products are also described.
- FUJI, Masayuki
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p. 4029 - 4036
(2007/10/02)
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- REDUCTION OF NITRO ALKENES BY A MODEL OF NAD(P)H
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Carbon-carbon double bonds in α,β-unsaturated nitro compounds are reduced smoothly into the corresponding nitro alkanes by a model of NAD(P)H in benzene in the presence of silica gel.Other functional groups are inert under the reaction conditions.
- Nakamura, Kaoru,Fujii, Masayuki,Oka, Shinzaburo,Ohno, Atsuyoshi
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p. 523 - 526
(2007/10/02)
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