821-10-3Relevant academic research and scientific papers
Generation and Trapping of an Alkatrienylidenecarbene
Stang, Peter J.,Learned, Alan E.
, p. 301 - 302 (1988)
Reaction of ButCH(OMs)CC-CCH (Ms = SO2Me) with ButOK and tetramethylethylene or Et3SiH, in 1,2-dimethoxyethane (glyme) at -62 deg C, results in the respective carbene addition and insertion products.
Facile and selective polynitrations at the 4-pyrazolyl dual backbone: Straightforward access to a series of high-density energetic materials
Domasevitch, Kostiantyn V.,Gospodinov, Ivan,Krautscheid, Harald,Klap?tke, Thomas M.,Stierstorfer, J?rg
supporting information, p. 1305 - 1312 (2019/01/21)
Nitro-functionalized energetic materials are still needed to meet new safety, performance and chemical accessibility demands. The problem of multiple C-nitrations on N-containing heterocycles was resolved successfully for the 4,4′-bipyrazole scaffold. A progression of gradually functionalized 3-nitro-4,4′-bipyrazole (2), 3,3′-dinitro-4,4′-bipyrazole (3), 3,5-dinitro-4,4′-bipyrazole (4), 3,3′,5-trinitro-4,4′-bipyrazole (5) and 3,3′,5,5′-tetranitro-4,4′-bipyrazole (6) was obtained in excellent yields by highly selective direct nitrations of 4,4′-bipyrazole (1). All synthesized polynitro derivatives 3-6 exhibit high decomposition temperatures of above 290 °C. The introduction of three (5) and four nitro groups (6) into the 4,4′-bipyrazole scaffold yields insensitive and thermally stable high explosives with excellent densities and detonation properties. The anhydrous structures of compounds 2-6 were obtained by low-temperature XRD. In addition, the performance of compounds 5 and 6 was investigated with a small scale shock reactivity test.
Selective Cascade Reaction of Bisallenes via Palladium-Catalyzed Aerobic Oxidative Carbocyclization–Borylation and Aldehyde Trapping
Naidu, Veluru Ramesh,Posevins, Daniels,Volla, Chandra M. R.,B?ckvall, Jan-E.
supporting information, p. 1590 - 1594 (2017/02/05)
A cascade reaction, consisting of a palladium-catalyzed regioselective aerobic oxidative carbocyclization–borylation of bisallenes and a final aldehyde trapping, afforded triene alcohols with high diastereoselectivity. The cascade reaction occurs under mild reaction conditions and proceeds via an allylboron intermediate that is trapped by the aldehyde in a stereoselective manner.
Introduction of Peripheral Carboxylates to Decrease the Charge on Tm3+ DOTAM-Alkyl Complexes: Implications for Detection Sensitivity and in Vivo Toxicity of PARACEST MRI Contrast Agents
Suchy, Mojmír,Milne, Mark,Elmehriki, Adam A. H.,McVicar, Nevin,Li, Alex X.,Bartha, Robert,Hudson, Robert H. E.
, p. 6516 - 6532 (2015/09/08)
A series of structurally modified Tm3+ DOTAM-alkyl complexes as potential PARACEST MRI contrast agents has been synthesized with the aim to decrease the overall positive charge associated with these molecules and increase their biocompatibility. Two types of structural modification have been performed, an introduction of terminal carboxylate arms to the alkyl side chains and a conjugation of one of the alkyl side chains with aspartic acid. Detailed evaluation of the magnetic resonance imaging chemical exchange contrast associated with the structurally modified contrast agents has been performed. In contrast to the acutely toxic Tm3+ DOTAM-alkyl complexes, the structurally modified compounds were found to be tolerated well during in vivo MRI studies in mice; however, only the aspartic acid modified chelates produced an amide proton-based PARACEST signal. (Figure Presented).
METHODS OF PRODUCING DICARBONYL COMPOUNDS
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Paragraph 0037, (2015/05/06)
Dicarboxylic acids, such as adipic acid, and diesters, such as adipates, may be produced by hydrogenating alkynes that may be produced from raw materials salvaged from waste stream processes. The carbons of the dicarboxylic acids are provided by alkynes generated from biomass waste and carbon dioxide recovered from waste streams such as exhaust gases.
Chalcogenation of 1,4-dichlorobut-2-yne with organic dichalcogenides in the system hydrazine hydrate–KOH
Levanova,Vakhrina,Grabel’nykh,Rozentsveig,Russavskaya,Albanov,Klyba,Korchevin
, p. 2083 - 2089 (2016/10/03)
A reaction of organic dichalcogenides R2Y2 (R = Ph, Bn, Pr; Y = S, Se) with 1,4-dichlorobut-2-yne in the system hydrazine hydrate–KOH leads to four principal products: 1,4-bis(organylchalcogenyl)but-2-ynes, 1-organylchalcogenylbut-1-en-3-ynes, 4-organylchalcogenylbut-1-en-3-ynes, and 3(5)-methylpyrazole. The selectivity of the formation of individual products is determined by the ratio of the substrates used and the reaction temperature. A plausible mechanism of chalcogenation considered in the work agrees with the effect of the nature of chalcogene atoms and organic substituents R on stability of intermediates and products. The stabilization of carbanions by α chalcogene-containing groups corresponds to the following order: PhS > PhSe > BnS > BnSe > PrS.
Synthesis of functionalized lipids, and their use for a tunable hydrophobization of nucleosides and nucleic acids
Korneev, Sergei,Rosemeyer, Helmut
, p. 201 - 216 (2013/03/28)
Two series of functionalized single and double side-chained lipid molecules (Schemes 1 and 2) were prepared. The compounds carry either terminal COOH, OH, or halogen substituents. Moreover, the double side-chained lipid 18 carries an internal alkyne functionality. The latter compound was used to hydrophobize thymidine at N(3) by base-catalyzed alkylation. Additionally, fully protected thymidine, 32, was N(3)-alkylated with the double side-chained alcohol 9 applying Mitsunobu reaction conditions. Copyright
Cyclopropyl building blocks for organic synthesis, 131. Palladium-catalyzed bicyclization with carbonyl insertion of alkenyl-tethered propargyl carbonates towards a scalable synthesis of various 2-(bicyclo[3.1.0]hex-1-yl)acrylates
Bagutski, Viktor,Moszner, Norbert,Zeuner, Frank,Fischer, Urs Karl,De Meijere, Armin
, p. 2133 - 2147 (2007/10/03)
The Pd-catalyzed 5-exo-trig-3-exo-trig cascade cyclization of 1,6-enynes with a propargyl carbonate terminus offers the shortest synthetic route to variously substituted 2-(bicyclo[3.1.0]hex-1-yl)acrylates, a novel class of prospective monomers for low-shrinkage polymers. To apply this reaction to large-scale preparations of the said bicyclic acrylates, a flexible Pd catalyst system with tunable reactivity has been developed. The dependence of the product and diastereomer distribution on both the reaction conditions, including the type of palladium catalyst used, and on the nature of the substrate has been investigated. A variety of methyl 2-(bicyclo[3.1.0]hex-1-yl)acrylates and parent carboxylic acids as well as some of their derivatives of potential interest towards a technical application were prepared on a multigram scale. A general large-scale synthesis of the cyclization precursors bearing one or two carbonyl groups in the tether is also disclosed.
Ketyl-allene cyclizations promoted by samarium(II) iodide
Molander, Gary A.,Cormier, Elizabeth Pollina
, p. 2622 - 2626 (2007/10/03)
(Chemical Equation Presented) Samarium(II) iodide has proven to be an effective reagent for intramolecular reductive coupling Sreactions. Previous investigations of intramolecular ketyl-olefin coupling reactions provided carbocycles in excellent yield and good diastereoselectivity. This method has been extended to ketyl cyclizations with allenes. Substrates leading to both carbocycles and heterocycles in a selective manner are explored.
Synthesis of the Alkaloid Homaline in (+/-) and Natural (S,S)-(-) Forms, using Amination and Transamidative Ring Expansion in Liquid Ammonia
Crombie, Leslie,Haigh, David,Jones, Raymond C. F.,Mat-Zin, Ab. Rasid
, p. 2047 - 2054 (2007/10/02)
Synthesis of the alkaloid homaline in (+/-) and natural (S,S)-(-) forms is reported.Linking of 2-azacyclooctanone units either directly or successively using 1,4-dihalogenobutanes or 1,4-dihalogenobut-2-ynes is examined. (+/-)-5-Methyl-4-phenyl-1,5-diazacyclooctan-2-one is first made by a 2,2'-dithiodipyridine/triphenylphosphine-mediated cyclisation, and then by amination and transamidative ring expansion from N-(3-chloropropyl)-4-phenylazetidin-2-one in liquid ammonia, followed by N-methylation.Coupling through a 1,4-dihalogenobutane of either the N-methylated azalactam, or the unmethylated azalactam followed by methylation, gave homaline in (+/-) and meso forms. (R)-(-)-Phenylglycine was converted via (S)-β-phenyl-β-alanine into an (S)-β-lactam which was then alkylated with 1-bromo-3-chloropropane, and aminated and ring expanded in liquid ammonia.Coupling of the homochiral azalactam (2 mol) so formed with 1,4-dibromobutane, followed by N-methylation, gave (S,S)-(-)-homaline identical with the natural material.
