scholarly journals An Easy Synthesis of Monofluorinated Derivatives of Pyrroles from β-Fluoro-β-Nitrostyrenes

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3515
Author(s):  
Alexander S. Aldoshin ◽  
Andrey A. Tabolin ◽  
Sema L. Ioffe ◽  
Valentine G. Nenajdenko
Keyword(s):  
Nitrous Acid ◽  
Substituent Effect ◽  
Activation Parameters ◽  
Conjugate Addition ◽  
Solvent Free ◽  
Quantitative Yield ◽  
Direct Reaction ◽  
Solvent Free Conditions ◽  
Kinetics Of ◽  
Derivatives Of

The catalyst-free conjugate addition of pyrroles to β-Fluoro-β-nitrostyrenes was investigated. The reaction was found to proceed under solvent-free conditions to form 2-(2-Fluoro-2-nitro-1-arylethyl)-1H-pyrroles. The effectiveness of this approach was demonstrated through the preparation of a series of the target products in a quantitative yield. The kinetics of a conjugate addition of pyrrole was studied in detail to reveal the substituent effect and activation parameters of the reaction. The subsequent base-induced elimination of nitrous acid afforded a series of novel 2-(2-Fluoro-1-arylvinyl)-1H-pyrroles prepared in up to an 85% isolated yield. The two-step sequence herein proposed is an indispensable alternative to a direct reaction with elusive and unstable 1-Fluoroacetylenes.

scholarly journals Tandem Fries Reaction–Conjugate Addition under Microwave Irradiation in Dry Media; One-pot Synthesis of Flavanones

1999 ◽  
Vol 23 (9) ◽  
pp. 574-575
Author(s):  
Firouz Matloubi Moghaddam ◽  
Mohammad Ghaffarzadeh ◽  
Seyed Hossein Abdi-Oskoui
Keyword(s):  
Microwave Irradiation ◽  
Silica Gel ◽  
Conjugate Addition ◽  
Solvent Free ◽  
Naphthalene Derivatives ◽  
One Pot ◽  
Fries Rearrangement ◽  
One Pot Synthesis ◽  
Solvent Free Conditions ◽  
Fries Reaction

An AICl3–ZnCl2 mixture supported on silica gel is found to be an efficient medium for the Fries rearrangement of acyloxybenzene or naphthalene derivatives in solvent-free conditions under microwave irradiation.

scholarly journals Solvent-free synthesis of symmetric methylene diesters via direct reaction of aromatic carboxylates with 1,n-dihaloalkanes

RSC Advances ◽  
2021 ◽  
Vol 11 (46) ◽  
pp. 28711-28715
Author(s):  
Lin Bai ◽  
Shenglong Ding ◽  
Xiaofang Ma
Keyword(s):  
Solvent Free ◽  
Direct Reaction ◽  
Highly Efficient ◽  
Solvent Free Conditions ◽  
Aromatic Carboxylates ◽  
Solvent Free Synthesis

This work provides a highly efficient and feasible strategy for the synthesis of symmetric methylene diesters, involving the direct diesterification of various carboxylates with 1,n-dihaloalkanes under solvent-free conditions.

Solvent-free synthesis of novel vanillidene derivatives of Meldrum's acid: biological evaluation, DNA and BSA binding study

RSC Advances ◽  
2016 ◽  
Vol 6 (45) ◽  
pp. 39452-39459 ◽  
Author(s):  
Nenad Janković ◽  
Jovana Muškinja ◽  
Zoran Ratković ◽  
Zorica Bugarčić ◽  
Branislav Ranković ◽  
...  
Keyword(s):  
Biological Evaluation ◽  
Solvent Free ◽  
Binding Study ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
Bsa Binding ◽  
Solvent Free Conditions ◽  
Derivatives Of ◽  
Solvent Free Synthesis

A series of novel O-alkyl vanillidene derivatives containing Meldrum's acid scaffold under solvent-free conditions were synthesized.

A mild and efficient chemoselective N-benzyloxycarbonylation of amines using TBAB as a catalyst under solvent-free conditions

2009 ◽  
Vol 87 (2) ◽  
pp. 393-396 ◽  
Author(s):  
Kothamasu Suresh Babu ◽  
Vidadala Rama Subba Rao ◽  
Ravu Ranga Rao ◽  
Sakhamuri Sivaram Babu ◽  
Janaswami Madhusudana Rao
Keyword(s):  
Efficient Method ◽  
Aromatic Amines ◽  
Solvent Free ◽  
Solvent Free Conditions ◽  
Derivatives Of

We describe a mild and efficient method for the chemoselective N-benzyloxycarbonylation of amines by treatment of amines and aminoesters with benzyloxycarbonyl chloride (Cbz-Cl) in the presence of TBAB under solvent-free conditions in excellent yields. The method is general for the preparation of a wide variety of N-Cbz derivatives of aliphatic, aromatic amines, and aminoesters.

The Reaction of Amino Acids and Proteins with Diazonium Compounds. I. A Spectrophotometric Study of Azo-Derivatives of Histidine and Tyrosine.

1952 ◽  
Vol 5 (4) ◽  
pp. 736 ◽  
Author(s):  
HG Higgins ◽  
D Fraser
Keyword(s):  
Amino Acids ◽  
Nitrous Acid ◽  
Spectrophotometric Study ◽  
Maximum Absorption ◽  
Direct Reaction ◽  
Quantitative Investigation ◽  
Conjugated Systems ◽  
Azo Derivatives ◽  
Derivatives Of ◽  
Yellow Compound

The coupling in alkaline solution of free histidine and tyrosine with p-diazobenzene-sulphonic acid has been studied as a basis for quantitative investigation of the behaviour of proteins in the presence of diazonium compounds. Both mono- and bisazo- derivatives may be formed with each amino acid, the wavelengths of maximum absorption being 380 and 490 mμ respectively for histidine and 325 and 480 mμ respectively for tyrosine ; the wavelength displacements on accepting a second diazonium group are comparable to effects reported for similarly conjugated systems. When appropriate corrections are made for other absorbing components, the extinctions at 490 mμ and the initial histidine concentrations up to the (bis) equivalent of diazonium compound conform to Beer's law, showing that bis(azobenzenesu1phonic acid)histidine is formed exclusively under these conditions. At higher histidine concentrations mono(azobenzenesulphonic acid)histidine is formed in increasing proportions. Even at low initial tyrosine concentrations both mono- and bis(azobenzenesulphonic acid)-tyrosine are formed, although mono-coupling is again favoured more as the concentration increases. No direct reaction between histidine and the nitrous acid used in the formation of the diazonium compound could be detected spectrophotometrically, but diazotization of tyrosine appears to reduce the propensity for bis-coupling to some extent. If urea is incorporated in the system to destroy excess nitrous acid, a yellow compound having maximum absorption at 430 mμ is formed between p-diazo-benzenesulphonic acid and the urea.

scholarly journals Mukaiyama-Michael vinylogous additions to nitroalkenes under solvent-free conditions

2012 ◽  
Vol 10 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Arrigo Scettri ◽  
Rosaria Villano ◽  
Patrizia Manzo ◽  
Maria Acocella
Keyword(s):  
Good Yield ◽  
Conjugate Addition ◽  
Solvent Free ◽  
Silyl Ether ◽  
Bronsted Acids ◽  
Solvent Free Conditions

AbstractThe first Mukaiyama-Michael vinylogous reaction of a dioxinone-derived silyl ether to nitroalkenes is reported. The conjugate addition is performed in absence of any catalyst under solvent-free conditions, proceeding with satisfactory efficiency with variously substituted nitroalkenes.Moreover, the first organocatalyzed Mukaiyama-Michael vinylogous reaction of trimethylsilyloxyfuran to nitroalkenes is described.The reaction is promoted by Brønsted acids under solvent-free conditions, taking place in moderate to good yield with variously substituted nitroalkenes..

scholarly journals Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

2021 ◽  
Vol 17 ◽  
pp. 2642-2649
Author(s):  
Akhil K Dubey ◽  
Raghunath Chowdhury
Keyword(s):  
Temperature Control ◽  
Carbonyl Compounds ◽  
Room Temperature ◽  
Conjugate Addition ◽  
High Reactivity ◽  
Solvent Free ◽  
Reaction Conditions ◽  
Silyl Group ◽  
Solvent Free Conditions ◽  
Solvent Free Synthesis

An enantioselective 1,4-conjugate addition of nitromethane to β-silyl α,β-unsaturated carbonyl compounds catalyzed by bifunctional squaramide catalysts has been developed. This methodology offers both enantiomers of β-silyl nitroalkanes in good to excellent yields (up to 92%) and enantioselectivities (up to 97.5% ee) under solvent-free conditions at room temperature. Control experiments reveal that the presence of a β-silyl group in the enones is crucial for high reactivity under the optimized reaction conditions.

scholarly journals Radical Formation in Sugar-Derived Acetals under Solvent-Free Conditions

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5897
Author(s):  
Aleksandra A. Wróblewska ◽  
H. Y. Vincent Ching ◽  
Jurrie Noordijk ◽  
Stefaan M. A. De Wildeman ◽  
Katrien V. Bernaerts
Keyword(s):  
Hydrogen Abstraction ◽  
Solvent Free ◽  
Paramagnetic Resonance ◽  
Cyclic Acetals ◽  
Radical Degradation ◽  
Solvent Free Conditions ◽  
Amide Exchange ◽  
Methylene Unit ◽  
Electron Paramagnetic ◽  
Derivatives Of

The degradation of acetal derivatives of the diethylester of galactarate (GalX) was investigated by electron paramagnetic resonance (EPR) spectroscopy in the context of solvent-free, high-temperature reactions like polycondensations. It was demonstrated that less substituted cyclic acetals are prone to undergo radical degradation at higher temperatures as a result of hydrogen abstraction. The EPR observations were supported by the synthesis of GalX based polyamides via ester-amide exchange-type polycondensations in solvent-free conditions at high temperatures in the presence and in the absence of radical inhibitors. The radical degradation can be offset by the addition of a radical inhibitor. The radical is probably formed on the methylene unit between the oxygen atoms and subsequently undergoes a rearrangement.

Sign in / Sign up

Export Citation Format

Share Document