Synthèse d'isoxazoles substitués en α de l'azote par une chaine alkyle ou alcényle

1990 ◽  
Vol 68 (8) ◽  
pp. 1271-1276 ◽  
Author(s):  
Jean-Claude Cherton ◽  
Marc Lanson ◽  
Daïf Ladjama ◽  
Yvette Guichon ◽  
Jean-Jacques Basselier
Keyword(s):  
Vinyl Acetate ◽  
Nitrile Oxide ◽  
Side Chain ◽  
Dipolar Cycloaddition ◽  
Side Chains ◽  
Alkyl Side Chain ◽  
Magnesium Compounds ◽  
Convenient Route ◽  
General Method ◽  
Convenient Access

Several syntheses of special isoxazoles bearing a long alkyl or alkenyl side chain in the α position of the nitrogen are presented. A very convenient route in the case of an alkyl side chain is the classical 1,3-dipolar cycloaddition of a nitrile-oxide to a vinyl acetate. Although it is a rather long approach, the reaction of hydroxylamine with enone-epoxides represents a new and unequivocal method compatible with alkenyl side chains. The isomerisation of the easily synthesized isoxazoles bearing such substitutents α to the oxygen, by the reaction of their isoxazolium salts with hydroxylamine, is a fast and general method. Another very convenient access to "α-N substituted" isoxazoles is the coupling of magnesium compounds with 3-bromomethyl 5-methyl isoxazole. Keywords: isoxazoles, substitution in the α position of nitrogen.

n-Alkylresorcinol Occurrence in Mercurialis perennis L. (Euphorbiaceae)

2010 ◽  
Vol 65 (3-4) ◽  
pp. 174-179 ◽  
Author(s):  
Peter Lorenz ◽  
Matthias Knödler ◽  
Julia Bertrams ◽  
Melanie Berger ◽  
Ulrich Meyer ◽  
...  
Keyword(s):  
Side Chain ◽  
Side Chains ◽  
Alkyl Side Chain ◽  
Alkyl Side Chains ◽  
Chain Lengths ◽  
New View

Investigation of the dichloromethane extracts from herbal and root parts of Mercurialis perennis L. afforded a mixture of 11 homologous n-alkylresorcinols (ARs) with saturated odd-numbered alkyl side chains (C15:0-C27:0). In addition to three predominant ARs (C19:0, C21:0 and C23:0), a number of minor ARs were identified by use of LC-MS/MS and GC-MS techniques. Among the compounds detected, four uncommon ARs with evennumbered alkyl side chain lengths were also determined. The overall AR concentration in herbal parts was 7 to 9 times higher compared to that of the roots. The results presented may open a new view on the phytochemistry and pharmacognosy of M. perennis and other members of the Euphorbiaceae family.

Trifluoroacetylation of unsymmetrical ketone acetals. A convenient route to obtain alkyl side chain trifluoromethylated heterocycles

1999 ◽  
Vol 99 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Helio G Bonacorso ◽  
Marcos A.P Martins ◽  
Sandra R.T Bittencourt ◽  
Rogério V Lourega ◽  
Nilo Zanatta ◽  
...  
Keyword(s):  
Side Chain ◽  
Alkyl Side Chain ◽  
Convenient Route

Impact of the alkyl side chain position on the photovoltaic properties of solution-processable organic molecule donor materials

2016 ◽  
Vol 4 (30) ◽  
pp. 11747-11753 ◽  
Author(s):  
J. Zhang ◽  
X. W. Zhu ◽  
C. He ◽  
H. J. Bin ◽  
L. W. Xue ◽  
...  
Keyword(s):  
Organic Molecule ◽  
Side Chain ◽  
Side Chains ◽  
Alkyl Side Chain ◽  
Photovoltaic Properties ◽  
Alkyl Side Chains ◽  
Solution Processable ◽  
New Compounds

Two new compounds with alkyl side chains at different positions have a similar structure, but exhibit different photovoltaic properties.

Synthèse d'isoxazoles substitués en α de l'oxygène et d'isoxazoles substitués en α de l'azote et de l'oxygène par des chaînes alkyle ou alcényle

1991 ◽  
Vol 69 (4) ◽  
pp. 625-631 ◽  
Author(s):  
Jean-Claude Cherton ◽  
M. Lanson ◽  
D. Ladjama ◽  
N. Lefebvre ◽  
Z. Vossough ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Key Words ◽  
Dipolar Cycloaddition ◽  
Side Chains ◽  
Alternative Route ◽  
Methyl Group ◽  
Additional Step ◽  
Alkenyl Chain ◽  
Convenient Route

Two series of isoxazoles substituted by long alkyl or alkenyl chains in the α position with respect to the oxygen atom or in the α position with respect to the two heteroatoms have been synthesized. Starting from 3,5-dimethylisoxazole, the regioselective metalation/alkylation on the α-O methyl group was a very convenient route to a large variety of "α-O substituted isoxazoles". When applied to α-O methylated isoxazoles bearing an α-N alkenyl chain the same method provides an original unequivocal approach to 3,5-dialkenyl isoxazoles. An alternative route to these compounds, despite the formation of di-isoxazoline as by-product and an additional step corresponding to the oxidation of the intermediate isoxazoline, is the 1,3-dipolar cycloaddition, by using terminal dienes as dipolarophiles with alkenyl dipoles. Nevertheless, the cycloaddition between monoalkylated alcynes and alkylated dipoles remains the most straightforward synthesis of 3,5-dialkyl isoxazoles. Key words: isoxazoles, alkenyl side chains, metalation–alkylation, regioselectivity.

The New Synthesis of Organic Light-Emitting Material BHBT Monomer by Stille Coupling

2012 ◽  
Vol 602-604 ◽  
pp. 1261-1264
Author(s):  
Xiao Xiao Zhuang ◽  
Xiao Long Lei ◽  
Xiao Xia Sun
Keyword(s):  
Side Chain ◽  
Side Chains ◽  
Alkyl Side Chain ◽  
Stille Coupling ◽  
Light Emitting ◽  
Good Solubility ◽  
Organic Light ◽  
New Synthesis ◽  
High Yields

Heterocyclic monomer based on 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over three steps from readily available starting materials. The alkyl side chain in the 4-position of both thiophene rings gives the material mononer a good solubility.

ChemInform Abstract: Trifluoroacetylation of Unsymmetrical Ketone Acetals. A Convenient Route to Obtain Alkyl Side Chain Trifluoromethylated Heterocycles.

ChemInform ◽  
2010 ◽  
Vol 31 (9) ◽  
pp. no-no
Author(s):  
Helio G. Bonacorso ◽  
Marcos A. P. Martins ◽  
Sandra R. T. Bittencourt ◽  
Rogerio V. Lourega ◽  
Nilo Zanatta ◽  
...  
Keyword(s):  
Side Chain ◽  
Alkyl Side Chain ◽  
Convenient Route

scholarly journals Aqueous Self-assembly of Peptide-Diketopyrrolopyrrole Conjugates with Variation of N-alkyl Side Chain and π-Core Lengths

2021 ◽  
Author(s):  
Sayak Subhra Panda ◽  
John D. Tovar
Keyword(s):  
Chain Length ◽  
Self Assembly ◽  
Photophysical Properties ◽  
Side Chain ◽  
Side Chains ◽  
Alkyl Side Chain ◽  
Organic Electronic ◽  
Side Chain Length ◽  
Alkyl Side Chains ◽  
Electronic Groups

Peptidic sequences when conjugated to π-electronic groups form self-assembled networks of π-electron pathways. These materials hold promise for bio-interfacing charge transporting applications because of their aqueous processability and compatibility. In this work, we incorporated diketopyrrolopyrrole (DPP), a well-established π-core for organic electronic applications, within the peptidic sequence. We embedded different numbers of thiophene rings (2 and 3) on both sides of the DPP to alter the length of the π-cores. We also varied the length of the N-alkyl side chains (methyl, butyl, hexyl) attached to the DPP core. These variations allowed us to explicitly study the effect of π-core and N-alkyl side-chain length on photophysical properties and morphology of the resulting nanomaterials. All of these molecules formed H-type aggregates in the assembled state. Longer π-cores have relatively red-shifted absorption maxima whereas the N-alkyl variation did not present significant photophysical changes.

Influence of Flexible Side-Chains on the Breathing Phase Transition of Pillared Layer MOFs: A Force Field Investigation

2020 ◽  
Author(s):  
Julian Keupp ◽  
Johannes P. Dürholt ◽  
Rochus Schmid
Keyword(s):  
First Principles ◽  
Good Accuracy ◽  
Field Investigation ◽  
Square Lattice ◽  
Side Chain ◽  
Second Step ◽  
Side Chains ◽  
Dynamics Simulations ◽  
Complex Phenomena ◽  
Closed Pore

The prototypical pillared layer MOFs, formed by a square lattice of paddle-<br>wheel units and connected by dinitrogen pillars, can undergo a breathing phase<br>transition by a “wine-rack” type motion of the square lattice. We studied this not<br>yet fully understood behavior using an accurate first principles parameterized force<br>field (MOF-FF) for larger nanocrystallites on the example of Zn 2 (bdc) 2 (dabco) [bdc:<br>benzenedicarboxylate, dabco: (1,4-diazabicyclo[2.2.2]octane)] and found clear indi-<br>cations for an interface between a closed and an open pore phase traveling through<br>the system during the phase transformation [Adv. Theory Simul. 2019, 2, 11]. In<br>conventional simulations in small supercells this mechanism is prevented by periodic<br>boundary conditions (PBC), enforcing a synchronous transformation of the entire<br>crystal. Here, we extend this investigation to pillared layer MOFs with flexible<br>side-chains, attached to the linker. Such functionalized (fu-)MOFs are experimen-<br>tally known to have different properties with the side-chains acting as fixed guest<br>molecules. First, in order to extend the parameterization for such flexible groups,<br>1a new parametrization strategy for MOF-FF had to be developed, using a multi-<br>structure force based fit method. The resulting parametrization for a library of<br>fu-MOFs is then validated with respect to a set of reference systems and shows very<br>good accuracy. In the second step, a series of fu-MOFs with increasing side-chain<br>length is studied with respect to the influence of the side-chains on the breathing<br>behavior. For small supercells in PBC a systematic trend of the closed pore volume<br>with the chain length is observed. However, for a nanocrystallite model a distinct<br>interface between a closed and an open pore phase is visible only for the short chain<br>length, whereas for longer chains the interface broadens and a nearly concerted trans-<br>formation is observed. Only by molecular dynamics simulations using accurate force<br>fields such complex phenomena can be studied on a molecular level.

π-Facial Selectivity in 1,3-Dipolar Cycloaddition Reactions of α-Methylidene-γ-lactone Substituted by 4-Methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl Group in γ-Position

2002 ◽  
Vol 67 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Petr Melša ◽  
Ctibor Mazal
Keyword(s):  
Double Bond ◽  
Carboxylic Acid ◽  
Nitrile Oxide ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Enantiomerically Pure ◽  
Nitrile Imine ◽  
Facial Selectivity ◽  
Excellent Selectivity

Diastereoselectivity of 1,3-dipolar cycloaddition reactions of benzyl azide, diazomethane, a nitrile oxide and a nitrile imine to α-methylidene-γ-lactone dipolarophile was effectively controlled by a bulky γ-substituent, 4-methyl-2,6,7-trioxabicyclo[2.2.2]octan-1-yl in γ-position of the dipolarophile. The dipoles added from the less hindered face of the double bond with an excellent selectivity. Enantiomerically pure dipolarophile was prepared from the easily available (S)-5-oxotetrahydrohydrofuran-2-carboxylic acid.

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