Presence Of Aliphatic Amines Research Articles

An Acid-Controlled Method for the Regioselective Functionalization of Anilines over Aliphatic Amines.

Regioselective transformations at similar functional groups are of paramount importance in organic synthesis. Traditional strategies towards regioselective functionalization include serial protection/deprotection and sequential synthesis. Modern organic synthesis emphasizes pathway efficiency and protecting group free routes with a goal of exploiting inherent differences in reactivity. This study reports a method for the regioselective functionalization of anilines over aliphatic amines. Utilizing classic conditions for the Baeyer-Mills reaction, anilines were shown to react preferentially in the presence of aliphatic amines. Subsequently, this principle of reactivity was extended to other electrophiles and conditions.

Diversity and Oriented Synthesis of Clopidogrel Drug Derivatives

An efficient synthetic route has been developed for the synthesis of new clopidogrel drug derivatives. Key step of this method is to replacement of mesyl protected alcohol group with various aliphatic amines in presence of base. Various clopidogrel drug derivatives have been prepared in good yields. All the new compounds were confirmed by spectral studies and mass analysis. The main advantage of the new synthetic route has low cost and is fit for industrial applications.

2,4,7‐Triaminofluorenone as a Multi‐Analyte Colorimetric Sensor of Fluoride, Acetone Vapor, and Other Harmful Compounds

Abstract2,4,7‐Triaminofluorenone, a fluorenone derived multi‐analyte colorimetric chemosensor, has been synthesized via an extremely cost‐effective synthetic pathway. The sensor molecule can detect various analytes such as fluoride ion, acetone vapor, and picric acid. The violet solution of the sensor molecule becomes deep blue in the presence of fluoride ion. It can detect fluoride down to 120 ppb level. The compound in the solid state shows vapochromism only in the presence of acetone. The grey colored solid coating of the sensor molecule becomes blue in the presence of acetone vapor. This property was utilized to sense acetone vapor. Color Grab, an android based app, was utilized to detect acetone in real time down to 10 ppm level. Apart from that, the same sensor molecule was also tested for sensing different electron deficient nitro aromatic compounds due to its electron rich framework. The sensor was found to detect picric acid selectively. The sensor compound also shows acid‐base induced color change. The violet solution of the sensor molecule becomes brown in the presence of carboxylic as well as mineral acid. This reaction is reversible. Hence, the brown solution becomes violet again in the presence of aliphatic amines as well as ammonia. Utilizing this property, a method has been described to detect two widely used highly volatile chemicals HCl and NH3 in different industries.

Fast and Slow Release of Catalytically Active Species in Metal/NHC Systems Induced by Aliphatic Amines

The behavior of ubiquitously used nickel, palladium, and platinum complexes containing N-heterocyclic carbene ligands was studied in solution in the presence of aliphatic amines. Transformation of M(NHC)X2L complexes readily occurred according to the following reactions: (i) release of the NHC ligand in the form of azolium salt and formation of metal clusters or nanoparticles and (ii) isomerization of mono-NHC complexes M(NHC)X2L to bis-NHC derivatives M(NHC)2X2. Facile cleavage of the M–NHC bond was observed and provided the possibility for fast release of catalytically active NHC-free metal species. Bis-NHC metal complexes M(NHC)2X2 were found to be significantly more stable and represented a molecular reservoir of catalytically active species. Slow decomposition of the bis-NHC complexes by removal of the NHC ligands (also in the form of azolium salts) occurred, generating metal clusters or nanoparticles. The observed combination of dual fast- and slow-release channels is an intrinsic latent opportunity...

Augmentation of Corrosion Inhibition Property of Thiourea by Aliphatic Amines in Presence of Aggressive Cl- ions and Acidic SO2 Environment

Augmentation of Corrosion Inhibition Property of Thiourea by Aliphatic Amines in Presence of Aggressive Cl- ions and Acidic SO2 Environment

Mono- and double carbonylation of iodobenzene in the presence of reusable supported palladium catalysts

AbstractVarious silica-supported palladium catalysts were prepared and tested in the carbonylation of aryl iodides in the presence of aliphatic amines and aniline. In the former reaction, the main products are the α-ketoamides, whereas monocarbonylation is favoured with aniline. Small modification of the support, of the palladium precursor, or of the conditions of immobilisation were found to affect considerably the outcome of the reactions and recyclability of the catalysts. Under optimum conditions, the phosphine-free palladium catalysts can be reused six to ten times without considerable loss of activity. By the proper selection of the solvent, the leaching of palladium into the reaction mixtures can be reduced considerably.

Syn–anti conformation switching of a bis-porphyrin derivative at the air–water interface and in the solid state as an effective tool for chemical sensing

A Langmuir film of bis(zinc octaethylporphyrin) (ZnPP) was characterised at the air–water interface and its syn–anti conformation switching induced upon addition of aromatic amines was studied by infrared and UV–vis reflection spectroscopic methods. The highly specific interaction of ZnPP with aromatic amines was maintained even after the floating film was transferred onto solid supports by the Langmuir–Schaefer (LS) technique, enabling us to selectively sense aromatic amines at concentrations as low as 20 ppb. Furthermore, LS ZnPP active layer selectivity was evaluated in the presence of aliphatic amines.

Efficient catalytic systems based on paramagnetic closo-ruthenacarboranes for the controlled synthesis of polymers

Novel catalytic systems were proposed for controlled radical polymerization of vinyl monomers. These systems are based on the paramagnetic (17-electron) closo-complex, namely, 3,3-(dppb)-3-Cl-closo-3,1,2-RuC2B9H11 (1, dppb is 1,4-bis(diphenylphosphino)butane) and its mono(P-phenylene)- and di(P,P-ortho-phenylene)cycloboronated derivatives, namely, (R = H, n = 10 (2); R = Me, n = 8 (3)) and (4). With the polymerization of methyl methacrylate as an example, the effect of the steric hindrances in complexes 1–4 on the synthesis and molecular-weight characteristics of the resulting polymers was analyzed. In the presence of aliphatic amines, the polymerization rate increases substantially and the catalyst concentration can be lowered without losing control of the process. The structure of 17-electron complex 3 in the solid state and its paramagnetic nature were confirmed by X-ray diffraction and ESR spectroscopy.

ChemInform Abstract: A Method for the Selective Protection of Aromatic Amines in the Presence of Aliphatic Amines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Method for the Selective Protection of Aromatic Amines in the Presence of Aliphatic Amines

A simple and efficient procedure has been developed for the regioselectiveprotection of aromatic amines in the presence of aliphatic amines.The method is general for the preparation of mono- N-Boc,- N-Cbz, - N-Fmocor - N-Alloc aromatic amines in high yieldwithout affecting the aliphatic amines. This approach is applicableto substituted (aminoalkyl)aniline compounds with different functionalitiesand was employed to supply gram quantities of the protected anilineproduct.

Isomerization and rearrangement of (E)‐ and (Z)‐phenylhydrazones of 3‐benzoyl‐5‐phenyl‐1,2,4‐oxadiazole: evidence for a ‘new’ type of acid‐catalysis by copper(II) salts in mononuclear rearrangement of heterocycles

AbstractA kinetic investigation in methanol of the title reaction has evidenced the occurrence of two processes: the 1‐E $ \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} $ 1‐Z isomerization and the rearrangement of the (Z)‐isomer into the relevant 4‐benzoylamino‐2,5‐diphenyl‐1,2,3‐triazole (1‐ Z → T). The latter reaction is in line with the ability of the (Z)‐phenylhydrazones of 3‐benzoyl‐1,2,4‐oxadiazoles to undergo the so called mononuclear rearrangement of heterocycles (MRH). The occurrence of both the examined reactions is dependent on a Lewis‐acid‐catalysis. The obtained results have shown the possibility of a ‘new’ type of acid‐catalysis (bifunctional catalysis by Lewis salts) in the MRH. This catalysis operates through a completely different mechanism with respect to the one recently observed, and deeply investigated, in the presence of protic acids for the (Z)‐phenylhydrazone of 5‐amino‐3‐benzoyl‐1,2,4‐oxadiazole, in both dioxane/water and toluene, for which the catalytic process was dependent on the protonation of N(4) ring‐nitrogen of the 1,2,4‐oxadiazole. As a matter of fact, the copper salts seem able to interact with the >CNNHC6H5 moiety, yielding adducts which, in some cases, are prone to both isomerize and rearrange. Therefore, a similar behaviour in some manner parallel to that already observed in benzene in the presence of aliphatic amines (base‐catalysis) has been evidenced. Copyright © 2008 John Wiley & Sons, Ltd.

Photochemistry of the Phototoxic Drug Lomefloxacin: Paths Observed in the Presence of Amines or NaOH and from the Methyl Ester

AbstractThe photochemistry of the fluoroquinolone drug lomefloxacin has been examined in aqueous solution in the presence of aliphatic amines (0.01 and 0.2 M) as well as 0.01 M NaOH; a fairly efficient decomposition (Φ = 0.2 to 0.4) takes place. Under the above conditions the product distribution is the same and differs from that previously observed in neutral and acidic aqueous solution. Five products have been characterized, all of them resulting from reductive elimination of the fluorine in the 8‐position and some alteration of the piperazine side‐chain. All of the products are rationalized as resulting from the heterolytic cleavage of the C8−F bond in triplet lomefloxacin to give the corresponding triplet aryl cation. Due to the multiplicity, the C8 site has a carbene rather than a localized cation character. Under these conditions — the amino group in the 4′‐position is free — the main process is formal hydride transfer from the 3′‐position and the minor one attack of the 4′‐amino group at the C6−F bond. In accordance with this rationalization, the methyl ester of lomefloxacin exhibits a closely analogous photochemistry under neutral conditions. The cationic intermediate may be involved in the observed phototoxicity of the drug, via an oxygen‐independent path. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Photochemistry of (E)-1-(9-anthryl)-2-(4-nitrophenyl)ethene in the presence of aliphatic amines: H-bonding and charge-transfer effects.

Polysubstituted aliphatic and aromatic amines and alcohols quench the fluorescence of (E)-1-(9-anthryl)-2-(4-nitrophenyl)ethene (NA). The quenching occurs without modification of the NA emission characteristics, follows a Stern-Volmer (SV) relationship and correlates with the decrease of the photoisomerization and intersystem crossing (ISC) yields. The dependence of the quenching rate constants (k(q)) on the ionization potentials suggests a charge-transfer interaction for the amines. The dependence of the k(q) values on alcohol acidity indicates the intervention of H-bonding phenomena. The interaction of primary aliphatic amines and NA in low-polarity solvents results in a broadening and a quenching of the NA emission. The quenching does not follow the SV relationship, has no effect on the E --> Z photoisomerization nor on the population of the triplet state, and increases the yield of the photobleaching reaction, especially in more polar solvents (chlorobenzene). This peculiar behaviour of primary aliphatic amines is attributed to H-bonded complexes in both the ground and the lowest excited singlet state.

1,1-Bis(ethylsulfanyl)perfluorobut-1-ene as Starting Material for the Synthesis of Substituted 2-Trifluoromethylfurans and -pyrroles

In a two-step sequence (condensation with acetone enolate/acid hydrolysis), 1,1-bis(ethylsulfanyl)perfluorobut-1-ene was converted into the corresponding S-ethyl 4-oxo-2-pentafluoroethylpentanethioate. This thioester proved to be a versatile intermediate, leading, in the presence of aliphatic amine, to substituted 2-trifluoromethylfurans and/or -pyrroles. The selectivity of these heterocyclisations depends on the reaction conditions and on the basicity/nucleophilicity balance of the amine. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

RETRO ABRAMOV VS. REARRANGEMENT PATH COMPETITION IN HYDROXYPHOSPHONATE DECOMPOSITION

1-hydoxyphosphonates in the presence of aliphatic amine undergo two competitive processes: retro Abramov reaction and intramolecular hydroxyphosphonate-phosphate rearrangement. Both reaction rates and their ratio strongly depend on the nature of the substituent on a alpha carbon atom. Kinetic experiments indicate that two reactions proceed via common transition state.

Modification of catechol polymer redox properties during electropolymerization in the presence of aliphatic amines

The reactions of electrogenerated 1,2-quinoid derivatives with electroinactive ethylene diamine and its various N-methyl derivatives was investigated. This reaction led to the formation of a range of polymer films that retained redox activity when polymerized on carbon based electrodes and whose properties could be substantially modified through variations in the amine structure and the polymerization conditions employed. Possible mechanisms were investigated by electrochemical and NMR spectroscopic methods and the applicability of the technique for utilization in sensor construction is assessed.

Photoreduction of resazurin in the presence of aliphatic amines

Photophysical and photochemical properties of the dye resazurin were measured. The quantum yields of fluorescence and triplet formation were determined to be 0.10±0.01 and 0.2, respectively. The lifetimes of the singlet and triplet states are 1.2 ns and 30 μs. In the presence of aliphatic amines, resazurin is readily photoreduced to resorufin. This reaction proceeds through the triplet state and is inhibited by the presence of oxygen.

ON THE REVERSIBILITY OF HYDROXYPHOSPHONATE FORMATION IN THE KABACHNIK-FIELDS REACTION

Abstract The reversibility of hydroxyphosphonate synthesis in the Kabachnik-Fields synthesis was studied. It was found that in all studies cases which included aliphatic and aromatic aldehydes or ketones the hydroxyphosphonates decompose to the starting ketone and dialkyl phosphite in the presence of aliphatic amines as determined by 1H-, 13C-, 31P-NMR.

Photochemical reactions of α,β-unsaturated γ,δ-epoxy ketones and nitriles in the presence of amine

Direct irradiation (λ 254 nm) of the α,β-unsaturated γ,δ-epoxy ketone (1) and nitrile (2) in acetonitrile in the presence of aliphatic amines gave the divinyl ethers (5) and (11), respectively, as the main products, whose formation was shown to depend on solvent polarity and ionization potential of amines. On the other hand, when compounds (1) and (2) were irradiated in various alcohols in the presence of an amine they afforded the corresponding ketals (14)–(19) and (21) in 85–21% yield. Photochemical reactions of ketone (3) and nitrile (4) in methanol, were also studied.

ChemInform Abstract: Photochemical Reaction of 1‐Alkyl‐4,6‐diaryl‐2(1H)‐pyrimidinones in the Presence of Amines.

AbstractIrradiation of the pyrimidinones (I) in the presence of aliphatic amines, e.g. (II), give C‐C adducts such as (III) and small amounts of the reduced dihydropyrimidinones (IV), while irradiation of (I) in the presence of aromatic amines such as (V) yields the 1:1 adducts, e.g. (VI), exclusively.