- Continuous Flow Synthesis and Purification of Aryldiazomethanes through Hydrazone Fragmentation
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Electron-rich diazo compounds, such as aryldiazomethanes, are powerful reagents for the synthesis of complex structures, but the risks associated with their toxicity and instability often limit their use. Flow chemistry techniques make these issues avoidable, as the hazardous intermediate can be used as it is produced, avoiding accumulation and handling. Unfortunately, the produced stream is often contaminated with other reagents and by-products, making it incompatible with many applications, especially in catalysis. Herein is reported a metal-free continuous flow method for the production of aryldiazomethane solutions in a non-coordinating solvent from easily prepared, bench-stable sulfonylhydrazones. All by-products are removed by an in-line aqueous wash, leaving a clean, base-free diazo stream. Three successful sensitive metal-catalyzed transformations demonstrated the value of the method.
- Lévesque, éric,Laporte, Simon T.,Charette, André B.
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p. 837 - 841
(2017/01/14)
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- Iterative reactions of transient boronic acids enable sequential C-C bond formation
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The ability to form multiple carbon-carbon bonds in a controlled sequence and thus rapidly build molecular complexity in an iterative fashion is an important goal in modern chemical synthesis. In recent times, transition-metal-catalysed coupling reactions
- Battilocchio, Claudio,Feist, Florian,Hafner, Andreas,Simon, Meike,Tran, Duc N.,Allwood, Daniel M.,Blakemore, David C.,Ley, Steven V.
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p. 360 - 367
(2016/04/04)
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- A facile one pot synthesis of substituted pyrazole derivatives
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Diazo compounds derived from aromatic aldehydes were reacted with derivatives of (Z)-2-arylidene-2H-benzofuran- 3-ones to give new highly substituted heterocyclic pyrazoles. The structures of the synthesised compounds were determined on the basis of their
- Haouas, Amel,Hamadi, Naoufel Ben,Nsira, Asma,Msadek, Moncef
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p. 435 - 437
(2013/09/12)
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- Olefin cyclopropanation with aryl diazocompounds upon catalysis by a dirhodium(II) complex
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A dirhodium(II) complex with N-perfluorooctylsulfonylprolinate ligands is found to catalyze the cyclopropanation of olefins with simple aryl diazomethanes. In contrast to previously reported dirhodium(II) catalysts, the present complex works well not only with very electron-rich olefins such as enol ethers, but also with styrenes. Consequently, the present catalyst allows to prepare functionalized diarylcyclopropanes in moderate yields with good diastereoselectivity for the cis product, whereas the enantioselectivity of the reaction appears negligible.
- Verdecchia, Mirella,Tubaro, Cristina,Biffis, Andrea
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experimental part
p. 1136 - 1139
(2011/03/22)
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- New imidazolo-heteroaryl derivatives with antibacterial properties
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The invention relates to Imidazolo-heteroaryl derivatives of formula (I) The compounds inhibit the activity of the Dlta enzyme of Gram-positive bacteria and are useful to treat Gram-positive bacterial infections. Furthermore the application discloses method for assessing the Dlta inhibitory activity of tested molecules and a method for measuring the efficacy of molecules in inhibiting bacteria proliferation in vitro.
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Page/Page column 41-42
(2008/12/08)
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- Mild preparation of cephalosporin allyl and p-methoxybenzyl esters using diazoalkanes
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Vinyl or p-methoxyphenyldiazomethane reacts rapidly with cephalosporins in ether/methylene chloride cosolvent to give the C-9 allyl and p-methoxybenzyl esters, respectively, in good yields, with no isomerization of the double bond to Δ-2.
- Waddell, Sherman T.,Santorelli, Gina M.
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p. 1971 - 1974
(2007/10/03)
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- Advantageous Syntheses of Diazo Compounds by Oxidation of Hydrazones with Lead Tetraacetate in Basic Environments
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Varied sensitive diazo compounds 3 are produced efficiently and safely in 3-6 g quantities by oxidation (eq 1) of hydrazones 1 at -78 deg C with lead tetraacetate (2) in triethylamine/chloroform, N-methylmorpholine/dimethylformamide, tetramethylguanidine (8)/dimethylformamide, and tetramethylguanidine/methylene chloride, respectively, upon use of appropriate workup and handling techniques.New and improved nonhazardous procedures have been developed for preparing and handling hydrazones 1 from aldehydes and ketones in reactions with excess hydrazine.
- Holton, Terrence L.,Shechter, Harold
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p. 4725 - 4729
(2007/10/02)
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- SYNTHESIS OF 2'- OR 3'-O-(4-METHOXYBENZYL)NUCLEOSIDES AND ITS APPLICATION IN THE 3'-TERMINAL NONANUCLEOTIDE SEQUENCE OF ROUS SARCOMA VIRUS 35S RNA SYNTHESIS
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2'- or 3'-O-(4-Methoxybenzyl)nucleoside derivatives were synthesized by treatment of uridine, N4-benzoylcytidine, N6-benzoyladenosine, and N2-benzoylguanosine with 4-methoxyphenyldiazomethane.The separation of 2'- or 3'- i
- Kamaike, Kazuo,Tsuchiya, Hiromichi,Imai, Kazuaki,Takaku, Hiroshi
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p. 4701 - 4712
(2007/10/02)
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