A Systematic Study on the Synthesis of n‐Butyl Substituted 8‐Aminoquinolines

A systematic study on the synthesis of 8‐aminoquinoline derivatives with an n‐butyl group at each alternate position of the quinoline ring was carried out. Skraup Reaction and its Doebner–von Miller variation were used to obtain most of the quinoline ring except for the 2‐butyl‐8‐aminoquinolines and 4‐butyl‐8‐aminoquinolines where the commercially available methylquinoline derivatives were used as precursors. The structures of the synthesized compounds were characterized by FTIR, ¹H‐NMR, COSY, ¹³C‐NMR and HRMS spectra.     

Synthesis,characterization, and structural investigations of 1‐amino‐3‐substituted‐1,2,3‐triazolium salts,and a new route to 1‐substituted‐1,2,3‐triazoles

Quarternary salts based upon 3‐alkyl substituted 1‐amino‐1,2,3‐triazolium cations (alkyl = methyl, ethyl, nypropyl, 2‐propenyl, and n‐butyl) have been synthesized and characterized by vibrational spectra, multinuclear NMR, elemental analysis, and DSC studies. Subsequent diazotization of these salts results in the exclusive formation of 1‐alkyl‐1,2,3‐triazoles. Single crystal X‐ray studies were carried out for 1‐amino‐3‐methyl‐1,2,3‐triazolium iodide, 1‐amino‐3‐ethyl‐1,2,3‐triazolium bromide, 1‐amino‐3‐n‐propyl‐1,2,3‐triazolium bromide, and 1‐amino‐3‐n‐butyl‐1,2,3‐triazolium bromide as well as the starting heterocycle, 1‐amino‐1,2,3‐triazole, and all of the structures are discussed.     

Rate constants for the reactions of OH radicals and Cl atoms with Di‐n‐Propyl ether and Di‐n‐Butyl ether and their deuterated analogs

Using relative rate methods, rate constants for the gas‐phase reactions of OH radicals and Cl atoms with di‐n‐propyl ether, di‐n‐propyl ether‐d₁₄, di‐n‐butyl ether and di‐n‐butyl ether‐d₁₈ have been measured at 296 ± 2 K and atmospheric pressure of air. The rate constants obtained (in cm³ molecule⁻¹ s⁻¹ units) were: OH radical reactions, di‐n‐propyl ether, (2.18 ± 0.17) × 10⁻¹¹; di‐n‐propyl ether‐d₁₄, (1.13 ± 0.06) × 10⁻¹¹; di‐n‐butyl ether, (3.30 ± 0.25) × 10⁻¹¹; and di‐n‐butyl ether‐d₁₈, (1.49 ± 0.12) × 10⁻¹¹; Cl atom reactions, di‐n‐propyl ether, (3.83 ± 0.05) × 10⁻¹⁰; di‐n‐propyl ether‐d₁₄, (2.84 ± 0.31) × 10⁻¹⁰; di‐n‐butyl ether, (5.15 ± 0.05) × 10⁻¹⁰; and di‐n‐butyl ether‐d₁₈, (4.03 ± 0.06) × 10⁻¹⁰. The rate constants for the di‐n‐propyl ether and di‐n‐butyl ether reactions are in agreement with literature data, and the deuterium isotope effects are consistent with H‐atom abstraction being the rate‐determining steps for both the OH radical and Cl atom reactions. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 425–431, 1999     

Synthesis,Spectroscopic Characterization,DFT Calculations,and Dynamic Behavior of Mononuclear Macrocyclic Diorganotin(IV) Bis‐Dithiocarbamate Complexes

Nine mononuclear diorganotin(IV) dithiocarbamate complexes 1 – 9 with 19‐, 20‐ and 21‐membered macrocyclic structures were synthesized from dimethyl, di‐n‐butyl, and diphenyltin(IV) dichloride and three bis‐dithiocarbamate ligands derived from secondary bis‐amines having aromatic spacer groups. All compounds were characterized by elemental analysis, mass spectrometry, and spectroscopic methods (IR and ¹H, ¹³C, and ¹¹⁹Sn NMR). Additionally, quantum chemical DFT calculations were performed for the dimethyltin(IV) derivatives in order to model the molecular structures. For one compound series the NMR spectra showed a concentration‐dependent behavior in solution, which was analyzed in detail and permitted to postulate the existence of an equilibrium with the corresponding [2+2] macrocycles.     

13C NMR and electron spin resonance analyses of the radical polymerization of diisopropyl itaconate

Radical polymerizations of dialkyl itaconates were performed in benzene at 50 °C. The ¹³C NMR spectra of the obtained polymers indicated that intramolecular chain‐transfer reaction had taken place more frequently in the polymerizations of itaconates with bulkier ester groups as follows: isopropyl (i‐Pr) > n‐butyl (n‐Bu) ≈ ethyl (Et) > methyl (Me). In addition to the ¹³C NMR analysis, an electron spin resonance (ESR) analysis was conducted for polymerizations of diisopropyl itaconate, the ESR spectra of which consisted of two kinds of resonances due to the radicals with different conformations. It was assumed that the difference in conformation was attributable to the stereosequences near the propagating chain end because the relative intensity ratios of the resonances varied with the magnitude of the intramolecular chain‐transfer reaction, which was accompanied by a decrease in the syndiotacticity of the obtained poly(diisopropyl itaconate)s. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4513–4522, 2002     

Unusual Pathway Taken in the Reaction of Bis(alkynyl)diisopropylaminoboranes with B(C6F5)3

The bis(alkynyl)diisopropyl‐aminoboranes 7 were prepared by treatment of iPr₂NBCl₂ with two molar equivalents of 1‐pentynyl lithium or lithium phenylacetylenide, respectively. Their reaction with one molar equivalent of B(C₆F₅)₃ resulted in the formation of the 1,1‐carboboration products 8 that were subsequently stabilized by adduct formation ( 9 ) with tert‐butyl isocyanide. Thermolysis of 8a (R=nPr) proceeded with hydride transfer from a N‐isopropyl substituent to the distal carbon atom of the remaining pentynyl unit at boron to give the zwitterionic five‐membered heterocyclic product 10a in good yield. The analogous product 10b (R=Ph) was obtained upon photolysis of 8b . The compounds 7b , 9b , 10a , and 10b were characterized by X‐ray crystal structure analysis.     

Catalyst Activity and Selectivity in the Isomerising Alkoxycarbonylation of Methyl Oleate

The synthesis of unsymmetrical diphosphine ligands ( 3 a – g ) with an o‐tolyl backbone and tert‐butyl, adamantyl, cyclohexyl and isopropyl substituents on the phosphorus moiety is described (1,2‐(CH₂PR₂)(PR′₂)C₆H₄; 3 a : R=tBu, R′=tBu, 3 b : R=tBu, R′=Cy, 3 c : R=tBu, R′=iPr, 3 d : R=Ad, R′=tBu, 3 e : R=Ad, R′=Cy, 3 f : R=Cy, R′=Cy, 3 g : R=Ad, R′=Ad). The corresponding diphosphine–Pd^II ditriflate complexes [(P^P)Pd(OTf)₂] ( 5 a – g ) were prepared and structurally characterised by X‐ray crystallography. These new complexes were studied as catalyst precursors in the isomerising methoxycarbonylation of methyl oleate, and were found to convert methyl oleate into the corresponding linear α,ω‐diester ( L ) with 70–80 % selectivity. The products of this catalytic reaction with the known [{1,2‐(tBu₂PCH₂)₂C₆H₄}Pd(OTf)₂] complex ( 5 h ) were fully analysed, and revealed the formation of the linear α,ω‐diester ( L , 89.0 %), the methyl‐branched diester B1 (4.3 %), the ethyl‐branched diester B2 (1.0 %), the propyl‐branched diester B3 (0.6 %) and all diesters from butyl‐ to hexadecyl‐branched diesters B4 – B16 (overall 4.8 %) at 90 °C and 20 bar CO. The productivity of the catalytic conversion of methyl oleate with complexes 5 a – g varied with the steric bulk of the alkyl substituent on the phosphorus. Ligands with more bulky groups, like tert ‐ butyl or adamantyl (e.g., 5 a , 5 d , 5 g ), were more productive systems. The formation of the catalytically active hydride species [(P^P)Pd(H)(MeOH)]⁺ ( 6‐MeOH ) was investigated and observed directly for complexes 5 a – e and 5 g , respectively. These hydride species were isolated as the corresponding triphenylphosphine complexes ( 6‐PPh₃ ) and fully characterised, including by X‐ray crystallography. The catalytic productivity of 6 a‐PPh₃ was virtually identical to that of 5 a , thereby confirming the efficient hydride formation of 5 a under catalytic conditions.     

Imidazolium‐based poly(ionic liquid)s with poly(ethylene oxide) main chains: Effects of spacer and tail structures on ionic conductivity

Ten types of cationic glycidyl triazole polymers (GTPs) are prepared from combinations of five alkyl‐imidazolium units (methyl‐, ethyl‐, n‐propyl‐, iso‐propyl‐, and n‐butyl‐imidazoliums) and two spacers [di‐ and tri(ethylene glycol)s]. Since these poly(ionic liquid)s are prepared from the same sample of glycidyl azide polymer by postfunctionalization method, they have the same degree of polymerization. Therefore, the structure–property relationship can be discussed without influence of molecular weight difference. The samples are characterized by NMR, differential scanning calorimetry, and thermogravimetric analysis. The ionic conductivity data are obtained by impedance measurements. The GTPs with the tri(ethylene glycol) spacer and ethyl‐ and n‐butyl‐imidazolium units afford the highest anhydrous conductivity of 1.5 × 10^?5 S cm^?1 at 30 °C. Based on electrode polarization (EP) analysis, we calculate the conducting ion (carrier) concentration and mobility. We discuss the effect of the spacer and N‐alkyl tail structures on the ionic conductivity using the data obtained by EP analysis and X‐ray diffraction. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2896–2906     

Synthesis and Some Reactions of New N-[Aryl(Benzyl,Cyclohexyl, Propyl)sulfonyl]-4-azatricyclo[5.2.1.02,6]dec-8-enes

A synthesis was accomplished of 4-azatricyclo[5.2.1.02,6]dec-8-ene by aminolysis of bicyclo[2.2.1]hept-2-ene-endo,endo-5,6-dicarboxylic acid anhydride followed by transformation of amidoacid into imide that was subsequently reduced by lithium aluminum hydride. The reaction of the key tricyclic amine with sulfonyl chlorides afforded N-[aryl(benzyl, cyclohexyl, propyl)sulfonyl]-4-azatricyclo[5.2.1.02,6]dec-8-enes.The sulfonamides were subjected to epoxidation with perphthalic acid. By reaction of sulfonamides with p-nitrophenyl azide triazolines were obtained. The structure of compounds synthesized was confirmed by IR, ^1Hand ¹³ NMR spectra.     

In situ Fourier transform near infrared spectroscopy monitoring of copper mediated living radical polymerization

In situ Fourier transform near infrared (FTNIR) spectroscopy was successfully used to monitor monomer conversion during copper mediated living radical polymerization with N‐(n‐propyl)‐2‐pyridylmethanimine as a ligand. The conversion of vinyl protons in methacrylic monomers (methyl methacrylate, butyl methacrylate, and N‐hydroxysuccinimide methacrylate) to methylene protons in the polymer was monitored with an inert fiber‐optic probe. The monitoring of a poly(butyl methacrylate‐b‐methyl methacrylate‐b‐butyl methacrylate) triblock copolymer has also been reported with difunctional poly(methyl methacrylate) as a macroinitiator. In all cases FTNIR results correlated excellently with those obtained by ¹H NMR. On‐line near infrared (NIR) measurement was found to be more accurate because it provided many more data points and avoided sampling during the polymerization reaction. It also allowed the determination of kinetic parameters with, for example, the calculation of an apparent first‐order rate constant. All the results suggest that FTNIR spectroscopy is a valuable tool to assess kinetic data. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4933–4940, 2004     

Single‐drop microextraction followed by in‐syringe derivatization and GC‐MS detection for the determination of parabens in water and cosmetic products

A single‐drop microextraction (SDME) method followed by in‐syringe derivatization and GC‐MS determination has been developed for analysis of five parabens, including methyl, ethyl, isopropyl, n‐propyl and n‐butyl paraben in water samples and cosmetic products. N,O‐Bis(trimethylsilyl)acetamide (BSA) was used as derivatization reagent. Derivatization reaction was performed inside the syringe barrel using 0.4 μL of BSA. Parameters that affect the derivatization yield such as temperature and time of the reaction were studied. In addition, experimental SDME parameters such as selection of organic solvent, addition of salt, extraction time and extraction temperature were investigated and optimized. The RSD of the method for aqueous samples varied from 8.1 to 13%. The LODs ranged from 0.001 (n‐butyl paraben) to 0.015 (methyl paraben) μg/L, and the enrichment factors were between 23 and 150.     

Manganese‐σ‐Borane Complexes from Dihaloboranes

The hydride complex K[(η⁵‐C₅H₅)Mn(CO)₂H] reacted with a range of dihalo(organyl)boranes X₂BR (X = Cl, Br; R = tBu,Mes, Ferrocenyl) to give the corresponding borane complexes[(η⁵‐C₅H₅)Mn(CO)₂(HB(X)R)]., The presence of a hydride in bridging position between manganese and boron was deduced from ¹¹B decoupled ¹H NMR spectra. Additionally, the structure of the tert‐butyl borane complex was confirmed by single‐crystal X‐ray diffraction.     

Rate constants for the gas‐phase reactions of Cl atoms with a series of ethers

The laser photolysis–resonance fluorescence technique has been used to determine the absolute rate coefficient for the Cl atom reaction with a series of ethers, at room temperature (298 ± 2) K and in the pressure range 15–60 Torr. The rate coefficients obtained (in units of cm³ molecule⁻¹ s⁻¹) are dimethyl ether (1.3 ± 0.2) × 10⁻¹⁰, diethyl ether (2.5 ± 0.3) × 10⁻¹⁰, di‐n‐propyl ether (3.6 ± 0.4) × 10⁻¹⁰, di‐n‐butyl ether (4.5 ± 0.5) × 10⁻¹⁰, di‐isopropyl ether (1.6 ± 0.2) × 10⁻¹⁰, methyl tert‐butyl ether (1.4 ± 0.2) × 10⁻¹⁰, and ethyl tert‐butyl ether (1.5 ± 0.2) × 10⁻¹⁰. The results are discussed in terms of structure–reactivity relationship. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 105–110, 2000     

Phosphinoyl and Thiophosphinoylcarbodithioates: Synthesis,Molecular Structure,and Application as New Efficient Mediators for RAFT Polymerization

New phosphinoyl and thiophosphinoylcarbodithioates were synthesized in a one‐pot reaction from the corresponding phosphinochalcogenides. Compounds of this new generation of thiocarbonylthio derivatives have been fully characterized by IR as well as ¹H, ³¹P, and ¹³C NMR spectroscopy and by mass spectrometry. Their solid‐state structures reveal that they are isostructural but crystallize in different space groups. These new compounds are highly efficient reversible chain‐transfer agents for the reversible addition‐fragmentation chain transfer (RAFT) polymerization of styrene (St) and n‐butyl acrylate (nBA), with controlled number‐average molecular weights (M_n) and narrow dispersity values (Ð<1.3). The controlled character of the polymerization was further exemplified by MALDI‐TOF mass spectrometry and the synthesis of PSt‐P(nBA) diblock copolymers.     

Synthesis and characterization of chiral poly(alkyl isocyanates) by coordination polymerization using a chiral half‐titanocene complex

A new chiral half‐titanocene complex, [CpTiCl₂(O‐(S)?2‐Bu)], is synthesized and characterized by ¹H and ¹³C NMR spectroscopy. This complex is employed for the coordination polymerization of n‐butyl and n‐hexyl‐ isocyanate leading to chiral polymers, as revealed by their CD spectra. Only the left‐handed helix is produced, due to the chiral (S)?2‐butoxy group, which is bound to the polymer chain end. The polymerization of 3‐(triethoxysilyl)propyl isocyanate produces less soluble polymers. On the other hand, phenyl isocyanate reacts slowly with the complex leading quantitatively and selectively to triphenyl isocyanurate. 2‐Ethylhexyl isocyanate is slowly and selectively cyclotrimerized in the presence of the half‐titanocene complex. However, a statistical copolymer of 2‐ethylhexyl isocyanate and hexyl isocyanate is produced. The reaction of benzyl isocyanate with the complex leads to a mixture of low molecular weight polymer and cyclotrimer. The polymers are characterized using SEC, NMR, and CD spectroscopy and their thermal properties are investigated by TGA/DSC analysis. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2141–2151     

Improving the Ring‐opening Polymerization of l‐Lactide Using n‐Butyl Lithium with Various Bidentate Ligands

A series of bidentate ligands were examined to improve the catalytic activity of l ‐lactide (LA) polymerization by using n‐butyl lithium and BnOH. For LA polymerization, n‐butyl lithium with tetraisopropyl methylenebis(phosphonate) (L⁸ ) showed the greatest catalytic activity but with poor controllability of the polymer molecular weight. The polydispersity indices (PDIs) could be improved without BnOH addition, but Mn _GPC was much different from the Mn _Cal . ¹H NMR spectra confirmed that the cyclized PLA was obtained, thus implying that active chain‐end mechanisms were operative in LA polymerization.     

Synthesis and Structure of a Series of New Molybdenum(VI) Complexes with the Esters of 2‐Mercaptonicotinic Acid

The novel dioxomolybdenum(VI) complexes with methyl ( 1 ), ethyl ( 2 ), n‐propyl ( 3 ), i‐propyl ( 4 ), n‐butyl ( 5 ) and cyclohexyl ( 6 ) ester of 2‐mercaptonicotinic acid have been prepared in the reactions of MoO₂Cl₂ and MoO₂(acac)₂ (acac = 2,4‐pentandionate) with mercaptonicotinic acid in corresponding alcohol. The esterification reaction was catalyzed by Mo^V originated from the reduction of Mo^VI with mercaptonicotinic ‐SH group with simultaneous formation of S–S bond resulting from the condensation of two 2‐mercaptonicotinic molecules. The presence of Mo^V was proved by ESR spectra. The molecular and crystal structures of 1 , 2 , 3 and 4 as well as of the by‐products 1,1′‐dithio‐2,2′‐n‐butylnicotinoate ( 7 ) and tetramethylammonium hexachloromolybdate(V) ( 8 ) have been determined by a X‐ray single crystal diffraction. The complexes 1 – 4 contain MoO₂²⁺ core with octahedral coordination of each molybdenum atom complexed by two 2‐mercaptonicotinato N and S donor atoms.     

Synthesis,characterization and catalytic activity in Suzuki–Miyaura coupling of palladacycle complexes with n‐butyl‐substituted N‐heterocyclic carbene ligands

A series of monomeric palladacycle complexes bearing n‐butyl‐substituted N‐heterocyclic carbenes, namely [Pd(NHC)X(dmba)] (dmba: dimethylbenzylamine and [Pd(NHC)X(ppy)]; NHC: 1‐n‐butyl‐3‐substituted benzylimidazol‐2‐ylidene; ppy: 2‐phenylpyridine), were prepared either by transmetallation from the corresponding silver carbene complexes or by the reaction of the corresponding acetate‐bridged palladacycle dimer with N‐heterocyclic carbene ligands in high yields. The palladium(II) complexes were characterized using elemental analyses, APCI‐MS, ¹H NMR and ¹³C NMR spectroscopies. These complexes are efficient in the Suzuki–Miyaura coupling reaction between phenylboronic acid and aryl bromides.     

Reactions of tris(dimethylsilyl)methane and polymers containing si—h groups with various hydroxy compounds under aerobic and mild conditions

Tris(dimethylsilyl)methane, (HMe₂Si)CH, reacts with n‐propyl, iso‐propyl, n‐butyl, s‐butyl, iso‐butyl, n‐pentyl, s‐pentyl, n‐hexyl alcohol, and phenol in the presence of chloroplatinic acid (H₂PtCl₆ċ6H₂O) in air to give products (ROMe₂Si)₃CH (where R is n‐propyl, iso‐propyl, n‐butyl, s‐butyl, iso‐butyl, n‐pentyl, s‐pentyl, n‐hexyl, phenyl). Similar reactions with benzyl alcohol and acetic acid lead to the unexpected products, (PhCH₂)₂O and HC(Me₂SiOSiMe₂)₃CH, respectively. The compound (n‐BuOMe₂Si)₃CSiMe₂H was made from (n‐BuOMe₂Si)₃CH by treatment with lithium diisopropylamide, followed by quenching with HMe₂SiCl. The homopolymer poly{(4‐chloromethyl)styrene} and copolymers with styrene (in 1:1 and 1:3 mol ratio) were synthesized by free radical polymerization, and (HMe₂Si)₃C groups were linked to them by nucleophilic substitution reactions between (HMe₂Si)₃CLi and the chloromethyl groups of the polymer side chains. The resulting functional polymers containing Si—H bonds reacted with various alcohols in the presence of chloroplatinic acid under heterogeneous conditions. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:365–376, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20440     

Synthesis and Characterization of Base‐catalyzed Phenyl Modified PDMS/PHMS Copolymers

A series of phenyl modified polydimethylsiloxane (PDMS) / polyhydrogenmethylsiloxane (PHMS) random copolymers containing both internal Si‐H and terminal SiH₂ and T (MeSiO_3/2) units was synthesized in one step through n‐BuLi‐catalyzed ring‐opening polymerization of cyclic comonomers and characterized by GPC, IR and ¹H and ²⁹Si NMR. Sequential microstructures of these copolymers were determined by ²⁹Si‐NMR spectroscopy. Epoxy‐modified polysiloxanes were prepared and used as comparable standards for the assignment of the NMR spectra. A hydride‐transfer mechanism has been proposed to account for the formation of terminal Si‐H and T group. Detailed sequential analyses and chemical shifts of ²⁹Si‐NMR for various siloxane units are reported for the first time.