N,N-Dimethylpicramide–methoxide ion interactions: 1:1 and 2:1 σ-complex formation

1980 ◽  
Vol 58 (16) ◽  
pp. 1609-1614 ◽  
Author(s):  
Erwin Buncel ◽  
Masashi Hamaguchi ◽  
Albert R. Norris
Keyword(s):  
Complex Formation ◽  
Reaction Conditions ◽  
Ion Interactions ◽  
Methanol Solutions ◽  
Methoxide Ion ◽  
First Time

The interactions of N,N-dimethylpicramide (DMP) with methoxide ion in dimethylsulfoxide–methanol media have been investigated spectrophotometrically at 25.0 °C. Both the 1:1 and 2:1 σ-complexes of DMP and methoxide ion have been observed under the various reaction conditions employed. However, dimethylsulfoxide has been found to preferentially stabilize the 1:1 σ-complex relative to the 2:1 σ-complex. As a consequence, at low base concentrations in dimethylsulfoxide–methanol solutions rich in dimethylsulfoxide (i.e. 95/5, v/v, DMSO/MeOH), the 1:1 σ-complex can be formed in the absence of any 2:1 σ-complex. This observation has been used to obtain, for the first time, values of the absorption maxima and molar absorptivities at the absorption maxima of both the 1:1 and 2:1 σ-complexes.

N-Methylpicramide–methoxide ion interactions: proton abstraction versus σ-complex formation

1980 ◽  
Vol 58 (16) ◽  
pp. 1615-1620 ◽  
Author(s):  
Erwin Buncel ◽  
Masashi Hamaguchi ◽  
Albert R. Norris
Keyword(s):  
Complex Formation ◽  
Hydrogen Ion ◽  
Proton Abstraction ◽  
Ring Carbon ◽  
Bearing Ring ◽  
Ion Interactions ◽  
Methoxide Ion ◽  
First Time ◽  
Conjugate Base ◽  
Sole Product

The interactions of N-methylpicramide (NMP) with methoxide ion in dimethylsulfoxide–methanol media and with 1,4-diazabicyclooctane in dimethylsulfoxide have been investigated spectrophotometrically at 25.0 °C. Dimethylsulfoxide has been found to stabilize the conjugate base of NMP, formed via loss of hydrogen ion from the methylamino group, with respect to the anionic σ-complex generated via addition of methoxide ion to a ring carbon position. As a result, methanol–dimethylsulfoxide solutions rich in dimethylsulfoxide (i.e., 95/5, v/v, DMSO/MeOH) contain the conjugate base of NMP as the sole product of the 1:1 interaction of NMP and methoxide ion. At mole ratios of methoxide ion to NMP > 1 a second interaction results, yielding a dianion formed via addition of methoxide ion to one of the H-bearing ring carbon atoms of the conjugate base. Values of absorption maxima and molar absorptivities at the absorption maxima for the conjugate base of NMP and the dianion are reported here for the first time.

Formation and Trapping of the Thermodynamically Unfavoured Inverted-Hemicucurbit[6]uril

2019 ◽  
Author(s):  
Elena Prigorchenko ◽  
Sandra Kaabel ◽  
Triin Narva ◽  
Anastassia Baškir ◽  
Maria Fomitšenko ◽  
...  
Keyword(s):  
Complex Formation ◽  
Combinatorial Chemistry ◽  
Trifluoroacetic Acid ◽  
Chloride Anion ◽  
Binding Affinities ◽  
Dynamic Covalent Chemistry ◽  
Reaction Selectivity ◽  
Low Concentration ◽  
Dynamic Combinatorial Chemistry ◽  
First Time

Amplification of a thermodynamically unfavoured macrocyclic product through the directed shift of the equilibrium between dynamic covalent chemistry library members is difficult to achieve. We show for the first time that during condensation of formaldehyde and <i>cis</i>-<i>N,N'</i>-cyclohexa-1,2-diylurea formation of <i>inverted-cis</i>-cyclohexanohemicucurbit[6]uril (<i>i-cis</i>-cycHC[6]) can be induced at the expense of thermodynamically favoured <i>cis</i>-cyclohexanohemicucurbit[6]uril (<i>cis</i>-cycHC[6]). The formation of <i>i-cis-</i>cycHC[6] is enhanced in low concentration of the templating chloride anion and suppressed in excess of this template. We found that reaction selectivity is governed by the solution-based template-aided dynamic combinatorial chemistry and continuous removal of the formed cycHC[6] macrocycles from the equilibrating solution by precipitation. Notably, the <i>i-cis</i>-cycHC[6] was isolated with 33% yield. Different binding affinities of three diastereomeric <i>i-cis</i>-, <i>cis</i>-cycHC[6] and their chiral isomer (<i>R,R</i>)-cycHC[6] for trifluoroacetic acid demonstrate the influence of macrocycle geometry on complex formation.

scholarly journals A Sustainable Improvement of ω-Bromoalkylphosphonates Synthesis to Access Novel KuQuinones

Organics ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 107-117
Author(s):  
Mattia Forchetta ◽  
Valeria Conte ◽  
Giulia Fiorani ◽  
Pierluca Galloni ◽  
Federica Sabuzi
Keyword(s):  
Metal Oxides ◽  
Phosphonic Acid ◽  
Organic Molecules ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Phosphonic Acids ◽  
Sustainable Improvement ◽  
Phosphonate Esters ◽  
First Time ◽  
Complex Organic

Owing to the attractiveness of organic phosphonic acids and esters in the pharmacological field and in the functionalization of conductive metal-oxides, the research of effective synthetic protocols is pivotal. Among the others, ω-bromoalkylphosphonates are gaining particular attention because they are useful building blocks for the tailored functionalization of complex organic molecules. Hence, in this work, the optimization of Michaelis–Arbuzov reaction conditions for ω-bromoalkylphosphonates has been performed, to improve process sustainability while maintaining good yields. Synthesized ω-bromoalkylphosphonates have been successfully adopted for the synthesis of new KuQuinone phosphonate esters and, by hydrolysis, phosphonic acid KuQuinone derivatives have been obtained for the first time. Considering the high affinity with metal-oxides, KuQuinones bearing phosphonic acid terminal groups are promising candidates for biomedical and photo(electro)chemical applications.

Sulfonyl Radical Triggered Selective Iodosulfonylation and Bicycli-zations of 1,6-Dienes

2021 ◽  
Author(s):  
Shi-Ping Wu ◽  
Dong-Kai Wang ◽  
Qing-Qing Kang ◽  
Guo-Ping Ge ◽  
Hongxing Zheng ◽  
...  
Keyword(s):  
Functional Group ◽  
High Selectivity ◽  
Reaction Conditions ◽  
First Time

A novel sulfonyl radical triggered selective iodosulfonylation and bicyclizations of 1,6-dienes has been described for the first time. High selectivity and efficiency, mild reaction conditions, excellent functional group compatibility, and...

scholarly journals New opportunities in the stereoselective dearomatization of indoles

2016 ◽  
Vol 88 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Elisabetta Manoni ◽  
Assunta De Nisi ◽  
Marco Bandini
Keyword(s):  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
High Yields ◽  
First Time ◽  
Tailored Design ◽  
Bronsted Acid Catalysis

AbstractThe regio- and stereoselective dearomatization of indoles is realized for the first time by combining readily available indolyl precursors and electron-rich allenes, namely allenamides and aryloxyallenes. Inter- as well as intramolecular condensations were realized under gold and Brønsted acid catalysis providing a range of densely functionalized indoline and indolenine cores in high yields and excellent stereochemical outcome. Chemodivergent reaction profiles (Micheal-type addition vs. [2+2]-cycloaddition) were realized by a tailored design of both reaction conditions and functionalization of the reaction partners.

scholarly journals SYNTHESIS OF AN AZIDE–THIOL LINKER FOR HETEROGENEOUS POLYMER FUNCTIONALIZATION VIA THE “CLICK” REACTION

2018 ◽  
Vol 55 (1B) ◽  
pp. 152
Author(s):  
Thuy Thu Truong
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Click Reaction ◽  
Proton Nuclear Magnetic Resonance ◽  
Reaction Yield ◽  
Reaction Conditions ◽  
Click Reactions ◽  
Heterogeneous Polymer ◽  
Ft Ir ◽  
First Time ◽  
Layer Chromatography

In this study, the synthesis of a telechelic linker bearing both azide and thiol functional groups was described. The reaction conditions were investigated to optimize the reaction yield. The product was analyzed using thin layer chromatography (TLC) and proton nuclear magnetic resonance (1H NMR). The employment of the obtained azide–thiol linker in heterogeneous polymer “click” functionalization was demonstrated for the first time, which was monitored by an online FT–IR method. The obtained telechelic azide–thiol linker is envisioned to be useful chemical tools to link macromolecular chains via orthogonal click reactions.

scholarly journals Efficient N-formylation of primary aromatic amines using novel solid acid magnetic nanocatalyst

RSC Advances ◽  
2020 ◽  
Vol 10 (67) ◽  
pp. 41229-41236
Author(s):  
Jitendra Kumar Yadav ◽  
Priyanka Yadav ◽  
Satish K. Awasthi ◽  
Alka Agarwal
Keyword(s):  
Magnetic Nanoparticles ◽  
Aromatic Amines ◽  
Sulfonic Acid ◽  
Solid Acid ◽  
Recyclable Catalyst ◽  
Primary Amines ◽  
Magnetic Nanocatalyst ◽  
Reaction Conditions ◽  
Primary Aromatic Amines ◽  
First Time

Sulfonic acid functionalized over biguanidine fabricated silica-coated heterogeneous magnetic nanoparticles (NP@SO3H) have been synthesized, well characterized and explored for the first time, as an efficient and recyclable catalyst for N-formylation of primary amines under mild reaction conditions.

Deep eutectic solvent-catalyzed Meyer–Schuster rearrangement of propargylic alcohols under mild and bench reaction conditions

2020 ◽  
Vol 56 (96) ◽  
pp. 15165-15168
Author(s):  
Nicolás Ríos-Lombardía ◽  
Luciana Cicco ◽  
Kota Yamamoto ◽  
José A. Hernández-Fernández ◽  
Francisco Morís ◽  
...  
Keyword(s):  
Room Temperature ◽  
Deep Eutectic Solvent ◽  
Reaction Times ◽  
Reaction Conditions ◽  
Propargylic Alcohols ◽  
First Time

Faster, milder, greener…better! The Meyer–Schuster rearrangement is disclosed for the first time in a deep eutectic solvent, namely FeCl3·6H2O/glycerol (3 : 1), enabling the reaction at room temperature, under air and with short reaction times.

A practical chlorination of tert-butyl esters with PCl3 generating acid chlorides

2020 ◽  
Vol 44 (5-6) ◽  
pp. 301-304
Author(s):  
Xiaofang Wu ◽  
Lei Zhou ◽  
Ruoqi Yang ◽  
Fengzhe Guo ◽  
Zi-Long Tang ◽  
...  
Keyword(s):  
Aromatic Acid ◽  
Aliphatic Acid ◽  
Acid Chlorides ◽  
Alkyl Esters ◽  
Reaction Conditions ◽  
Simple Reaction ◽  
Tert Butyl ◽  
Butyl Esters ◽  
Plausible Mechanism ◽  
First Time

For the first time, using PCl3, a range of tert-butyl esters is chlorinated successfully, allowing access of both aromatic acid chlorides and aliphatic acid chlorides in good yields. The method features simple reaction conditions and wide substrate scope. Various tert-butyl esters including aryl esters, alkenyl esters, and alkyl esters were tolerated well in the reaction. A plausible mechanism is proposed.

scholarly journals The investigations of bioactive copper(II) complexes with reduced low-molar dextran

2008 ◽  
Vol 22 (2-3) ◽  
pp. 177-185 ◽  
Author(s):  
Milorad Cakić ◽  
Žarko Mitić ◽  
Goran S. Nikolić ◽  
Ljubomir Ilić ◽  
Goran M. Nikolić
Keyword(s):  
Fourier Transform ◽  
Complex Formation ◽  
Room Temperature ◽  
Molar Mass ◽  
Reaction Conditions ◽  
Average Molar Mass ◽  
Square Planar ◽  
Physicochemical Methods ◽  
Fourier Transform Ir ◽  
Aqueous Complexes

The optimization of the reaction conditions (pH,T,t) to obtain stable copper(II) ion complexes with dextran derivatives were investigated in this paper. A complete synthesis of stable aqueous complexes can be realized with reduced low-molar polysaccharides, at an average molar mass 5000 g mol–1and pH 7.5–8. Fourier-transform IR spectra of polysaccharide dextran and its compounds with copper(II) ion, recorded at room temperature, were analyzed in order to obtain the information about the structure and the conformation of these polymer compounds. The ESR parameters of the spectra indicate the square-planar coordination of Cu(II) ion with four O atoms. Copper(II) complex formation with dextran and its derivatives were analyzed by physicochemical methods. Synthesized complexes of Cu(II) ion with reduced low-molar dextran in comparison with commercial preparations showed the considerably lower acute toxicity (LD501705).

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