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The density, viscosity and sound velocity of the binary liquid mixtures of P-methyl acetophenone with cyclohexylamine, cyclohexanol, and cyclohexane are measured over the complete composition range at temperatures of 303.15–313.15 K and at atmospheric pressure of 0.1 M. Excess molar volume, excess isentropic compressibility and viscosity deviation are calculated from the experimental measurements. The sign and magnitude of the derived parameters reveal the nature and type of interactions between the constituent molecules in the binary mixtures. Thermodynamic properties for this work reveal association interactions between dissimilar molecules in the binary systems P-methyl acetophenone + cyclohexylamine and P-methyl acetophenone + cyclohexanol systems, whereas dispersion forces cause the opposite trend in the other binary system P-methyl acetophenone + cyclohexane. [ABSTRACT FROM AUTHOR]

In this work, we investigated the reaction of cyclamate with hypochlorous acid (HOCl) in simulated gastric juice. The reaction products were detected by high-performance liquid chromatography diode array detection (HPLC-DAD) and ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). We also explored the changes in product concentration as a function of reaction time, cyclamate and HOCl concentrations. Cyclamate reacted with hypochlorous acid instantly in the simulated gastric fluid. N, N-dichlorcyclohexylamine and cyclohexylamine were both detected when the HOCl concentration was at millimole. Cyclohexylamine can only be found when HOCl concentration was at micromole. N, N-dichlorcyclohexylamine and cyclohexylamine concentrations both increased when cyclamate concentration increased under the millimole level of HOCl. As an important reactive oxygen species, hypochlorous acid (HClO) is produced in various physiological processes. The abnormal rise of the HClO level is associated with many inflammatory diseases. Chronic gastritis associated with Helicobacter pylori is a multistep, progressive, life-long inflammation. So, chronic gastritis infected with H. pylori may cause cyclamate metabolizing into cyclohexylamine in vivo. [ABSTRACT FROM AUTHOR]

Antioxidants play a role in the transformation of free radicals into more stable chemical structures. Work on phenolic antioxidants has accelerated in recent years. Curcumin is a natural phenolic with antioxidant properties. In this study, a salt-supported homogenous liquid-phase microextraction method was used for preconcentration and spectrophotometric determination of curcumin for the first time. The curcumin was transferred into the organic phase using cyclohexylamine as the extraction solvent at pH values between 2.0 and 7.0 and determined by spectrophotometry. The results showed that the performance of the method for curcumin was unaffected by pH. The pH of the sample solution, the mass of salt, and the volume of the solvent were optimized, and the influence of the matrix types was investigated. The limits of detection and quantification were 1.44 and 4.80 µg L−1 for curcumin. The developed method was employed for the analysis of food samples. [ABSTRACT FROM AUTHOR]

We scrutinise the adsorption of cyclohexylamine (CHA) on pure and Cu-doped BN-nanotube (Cu@BN-NT) through density functional theory calculations. CHA had a weak interaction with the pristine BN-NT, making BN-NT not suitable to be used as a sensor. However, there was a substantial rise in the reactivity and sensitivity of the BN-NT after replacing the B with metal Cu, based on the standard Gibbs free energy of formation. There is a reduction in the energy gap of the HOMO–LUMO of Cu@BN-NT from 2.28 to 1.42 eV (∼ −37.7%) when CHA was adsorbed, which substantially increased the electrical conductivity. Hence, converting the substantial change in the electrical conductivity into an electronic signal was possible, which demonstrated that the Cu@BN-NT was an encouraging sensor to detect CHA. The computed recovery time for the Cu@BN-NT was 26.8 s, which is short. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of 1-isopropyl-4-isothiocyanato-4-methylcyclohex-1-ene has been developed with p-menth-3-en-1-amine as raw material. Next, a number of p-menth-3-en-1-amine thiourea derivatives (4a–f) have been obtained from the reactions between 1-isopropyl-4-isothiocyanato-4-methylcyclohex-1-ene and cyclohexylamine or the reactions between p-menth-3-en-1-amine and different isothiocyanates. Then, the herbicidal activities of these compounds were evaluated. The result indicated that some of these newly synthesised compounds displayed remarkable herbicidal activities against annual ryegrass. In addition, the derivative containing cyclohexane ring (4a) displayed much higher herbicidal activity against annual ryegrass than the derivatives containing benzene ring. [ABSTRACT FROM AUTHOR]

In the conventional method of synthesis by using cyclohexylamine (CA) as template produces in the pore range of 0–3 nm. To enlarge the pore size which is suitable for biodiesel synthesis, the modified synthesis method is adopted by using CA as a template. In this novel method, pore size is enlarged to 7 nm. Cyclohexylamine was applied as a template for AlPO4 and AlSiO4 molecular sieves synthesis. In AlSiO4 synthesis, tetraethyl orthosilicate hydrolyzed to produce ethyl carbocation which is used for ethylation of CA in the presence of aluminum chloride. This ethylated CA size is large enough to produce a large pore size (7 nm). In AlPO4 two types of pore are produced with a pore size of 3 and 7 nm. The 3 nm are created by CA and 7 nm by the binding of CA with phosphoric acid. The synthesized materials are analyzed by physicochemical characterization. AlPO4 has a neutral framework, but the synthesized AlPO4 has acidity which is evidence for the CA binding with phosphoric acid. The synthesis of a promising catalyst (AlPO4-7 and AlSiO4-7) with an enlarged pore that can be effectively applied for the production of biodiesel from waste cooking oil (WCO) at room temperature. The acidity of the synthesized AlPO4 and AlSiO4 are 0.168 and 0.548 mmol/g. These catalysts are active at room temperature due to higher acidity. So the reaction takes place faster and it will reduce the reaction time. It is observed that AlSiO4 produces 90% biodiesel and AlPO4 produces 72% biodiesel with a shorter reaction time. This result reveals that 7 nm pores are suitable for biodiesel production. The diethyl ether selectivity of AlPO4 and AlSiO4 is 24% and 4%, respectively. This is due to the 3 nm pore size created by CA in AlPO4 and it favors diethyl ether synthesis. [ABSTRACT FROM AUTHOR]

A new series of benzochromene, benzochromenopyrimidine, and benzotriazolopyrimdine derivatives 3-10 were prepared via reaction of ethyl formimidate 2 with primary amines such as sulfanilamide, cyclohexylamine, 3-aminopyridine, 4-aminoantipyrine in addition to its reactions with different acid hydrazides. Compound 5 was further allowed to react with different C-electrophiles by classical and phase transfer catalysis conditions to get novel chromenotriazolopyrimidine derivatives. Screening of the antitumor activity in some of the newly synthesized compounds was tested in vitro against a panel of two human tumor cell lines namely HepG2 and HCT-116 cell lines. Compounds 4, 7, 8, 10, and 20 showed remarkable broad-spectrum antitumor activity. [ABSTRACT FROM AUTHOR]

Heat-induced homogeneous liquid-liquid microextraction method (HIH-LLME) has been proposed for separation/enrichment of trace levels of erythrosine in drug, cosmetic and food samples prior to its UV-Vis spectrophotometric determination. Cyclohexylamine was utilised as extraction phase to produce two different phases. It dissolves in water at low temperatures and decreases its solubility in water when heated. Thus, the heated sample forms a two-phase system in NaCl medium and erythrosine was extracted into cyclohexylamine phase. Analytical parameters such as volume of cyclohexylamine, amount of NaCl, pH, effect of matrix ions and temperature have been optimised. Optimum pH has been set at pH 5. The proposed (HIH-LLME) method exhibits a limit of detection (LOD) of 0.006 μg mL−1 and a limit of quantification (LOQ) of 0.021 μg mL−1. A pre-concentration factor was obtained as 37.5 and the relative standard deviation was 2.9%. This method is environmentally sensitive due to the usage of very little organic solvent and at the same time, it is simple and fast and it has a low cost and short extraction period. Cyclohexylamine solvent showed a high affinity and good accessibility for erythrosine. [ABSTRACT FROM AUTHOR]

Synthetic methods for random copolymers of N-vinylpyrrolidone and 6-crotonoyl aminohexanoic acid (6-CAHA) were developed. These carboxyl-containing water-soluble copolymers are the promising drug carriers. The technique for purification of polymers of this type from admixed comonomer (hydrophobic 6-CAHA) was proposed. Molecular masses, sizes, and molecular mass distributions were determined by HPLC, optical and hydrodynamic methods. [ABSTRACT FROM AUTHOR]

A facile synthesis of 3,5-disubstituted 1,2,4-oxadiazole derivatives under focused microwave irradiation (FMWI) is reported. Arylamidoximes 1a-i and dicyclohexylcarbodiimide (DCC) were carried out in DMF under FMWI to obtain 1,2,4-oxadiazoles 2a-i in 61-81% yields. All compounds exhibited antiproliferative activities in vitro against three human cancer cell lines HCT-116, PC-3, and SNB-19. [ABSTRACT FROM AUTHOR]

A cyclohexane-trans-1,2-diimine capped conjugate of 1,3-calix[4]arene (L) has been synthesized and characterized using different analytical and spectral techniques. L has been shown to be sensitive toward Al3+ by exhibiting ~45-fold enhancement in its emission intensity at 445 nm upon complexation. All the other 15 metal ions showed almost no or minimal change in the fluorescence intensity of the L supporting that none of those 15 ions is sensed by L. The complexation between L and Al3+ has been further confirmed by absorption spectroscopy, isothermal titration calorimetry and ESI MS. The isotopic peak pattern of the ESI MS peak clearly confirmed the presence of aluminum in the 1:1 complex formed. The need for the flexible cap moiety for bringing selectivity to Al3+ was proven by comparing the titration studies with the corresponding control molecules. The sensing of Al3+ by L in the solid powder was demonstrated by fluorescence microscopy. The supramolecular behavior of L changes from simple spherical type morphology in L to an aggregated micro pots and fibers upon Al3+ binding. The DFT computational study yielded a distorted tetrahedral complex of the dianionic receptor resulting in AlN2O2 core. [ABSTRACT FROM AUTHOR]

Two dinuclear copper(II) complexes, [LCu(μ-Cl)Cl]2(DMF) (1) and [LCu(μ-Br)Br]2(2), with the bidentate ligandN-(pyridin-2-ylmethyl)cyclohexanamine, L, were synthesized and characterized by physicochemical and spectroscopic (IR, UV–vis) data. The crystal structural analysis of1shows that both copper(II) ions are in a distorted square pyramidal N2Cl3environment with the apical position of the copper(II) being occupied by the bridging chloride anion which is equatorial to the other copper ion, forming a dimeric copper(II) complex. The chromotropic properties of both complexes, including solvato-, thermo-, and halochromism, were investigated. The complexes show reversible thermochromism in solution which is irreversible in the solid state. It was found that the solvatochromism is due to structural change followed by solvation of the vacant sites of the complexes. Their halochromic properties were studied in pH range of 1–11 by visible absorption spectroscopy. The color changes from blue to green and to colorless are due to deprotonation and protonation of the ligands. [ABSTRACT FROM PUBLISHER]

(1R,2R)-N1-2-amyl-1,2-diaminocyclohexane, which has an amyl substituent as compared with 1,2-diaminocyclohexane, was used as the carrier group to construct three platinum(II) complexes. MTT assay revealed that the complexes showed decent cytotoxicity against all of the four tested tumor cell lines with the IC50values ranging from 1.08 to 253.36 μM. Particularly, the IC50values of2against A549 and HCT-116 reached 3.32 and 1.08 μM, respectively, which were much lower than those of cisplatin and oxaliplatin. Flow cytometry demonstrated that2inhibited HepG2 cells proliferation and caused cytotoxicity by inducing apoptosis and arresting cells in the G2 phase. Furthermore, agarose gel electrophoresis showed that2had the ability to interact with DNA in a manner different from cisplatin and oxaliplatin, indicating the carrier ligand with an alkyl moiety had an influence on the action mode of the complex. [ABSTRACT FROM AUTHOR]

The reaction of 2-acetylpyridine, cyclohexylamine and copper(II) perchlorate in methanol resulted in the dinuclear copper(II) complex [Cu2L2]·2ClO4, where L is the monoanionic form of 1-methoxy-1,3-dipyridin-2-ylbutane-1,3-diol. The complex was characterized by elemental analysis and IR spectroscopic method in the solid state. Single-crystal X-ray analysis was performed, which indicated that the complex possesses a crystallographic inversion center symmetry. The Cu atom in the complex is in a square pyramidal geometry. Thermal behavior and biological property on the bacteria strainsB. subtilis, E. coli, andS. aureusof the complex were studied. [ABSTRACT FROM PUBLISHER]

Two new salen copper(II) and nickel(II) complexes, Cu(salen) (1) and Ni(salen) (2), where salen =cis-(N,N′-bis(5-chlorosalicylidene)cyclohexane-1,2-di-amine, were synthesized and structurally characterized. The solid state structures of both complexes 1 and 2 present the slightly distorted square-planar MN2O2chromophore. The Cu···Cu distance in complex 1 is 6.054 Å, while the Ni···Ni distance in complex 2 is 3.448 Å. The experimental studies were complemented by theoretical calculations. [ABSTRACT FROM PUBLISHER]

The substitution of the aqua ligands from six Pt(II) complexes, viz., [Pt(H2O)(N,N-bis(2-pyridylmethyl)cyclohexylamine](ClO4)2(Pt1); [{Pt(H2O)}2(N,N,N?,N?-tetrakis(2-pyridylmethyl)-trans-1,4-cyclohexyldiamine)](ClO4)4(Pt2); [{Pt(H2O)}2(N,N,N?,N?-tetrakis(2-pyridylmethyl)-4,4?-methylenedicyclohexyldiamine)](ClO4)4(Pt3); [Pt(H2O)N,N-bis(2-pyridylmethyl)phenylamine)](ClO4)2(Pt4); [{Pt(H2O)}2(N,N,N?,N?-tetrakis(2-pyridylmethyl)-1,4-phenyldiamine](ClO4)4(Pt5); and [{Pt(H2O)}2(N,N,N?,N?-tetrakis(2-pyridylmethyl)-4,4?-methylenediphenyldiamine)](ClO4)4(Pt6), by nitrogen heterocyclic ligands{viz., pyrazole (Pz); 3-methylpyrazole (mPz); 1,2,4-triazole (Tz) and pyrazine (Pzn)} were studied in an aqueous 0.01?M perchloric acid medium. The substitutions were investigated under pseudo-first-order conditions as a function of the concentration of nucleophiles and reaction temperature using UV–visible spectrophotometry. The substitution of the aqua ligands by all the nitrogen donor heterocycles proceeded via a single step whose rate decreased in the respective orders:Pt1?>?Pt3?>?Pt2andPt4?>?Pt6?>?Pt5in the two sets of complexes. Of the nucleophiles used in this study, pyrazine was the most reactive and the complete order of the rate of aqua substitution wasPzn>>Pz?>?Tz?>?mPz. The large and negative activation entropies and low but positive enthalpies of activation values support a significant contribution from bond making in the transition state of the substitution process. [ABSTRACT FROM AUTHOR]

Explicit hydration of the neutral and charged cyclohexylamine and of the cyclohexyldiamine isomers in their mono- or diprotonated forms is investigated through classical molecular dynamics (MD) simulations in aqueous solutions combined with DFT calculations in amine–water complexes. The MD studies performed in the monoamines reveal that the structure of the hydration shell around the neutral amino group (NH2) is quite distinct from that around the charged one (NH3+). On average, the number of water molecules surrounding the two groups is calculated to be ∼2 and 3–4, respectively. The variation of the hydration structure prompted by the groups’ proximity is discussed based on the data found for the mono- and diprotonated diamines. To have a more detailed picture of the water molecules’ arrangement around the amino groups and of the amine–water hydrogen bonds, geometry optimisations in hydrates with up to six water molecules are carried out at the B3LYP/aug-cc-pVDZ level. Complexation energies are also computed. The main findings emerging from these calculations are found to be very helpful to rationalise the mutual influence of the amino groups and therefore to better elucidate the MD findings. The complementary nature of the two research methods is emphasised as an excellent tool in order to closely examine the hydration of polyamines, as exemplified for the cyclohexyldiamines. [ABSTRACT FROM PUBLISHER]

Bis(thio)urea receptors (1–4) based on 1,2-bisaminocyclohexane are shown to function as transmembrane anion antiporters. The results show thatcis-receptors have a greater propensity for anion transport than analogoustrans-receptors. Stability constants using1H NMR techniques highlight the significance of stereoisomerism on anion binding in solution, ascis-receptors bind anions more strongly thantrans-receptors. [ABSTRACT FROM AUTHOR]

Densities, ρ, viscosities, η, speeds of sound, u and refractive indices, nD, were measured for the binary systems of cyclohexylamine with 1-butanol, 2-butanol, isobutanol and t-butanol at 298.15 K over the entire composition range. From the experimental results, the excess volume, V E, the deviations in relative viscosity, Δη, and synergic index, IS, are derived by the equation developed by Kalentunc-Gencer and Peleg [J. Texture Studies 17, 61 (1986)] and Howell [Elucidation of protein-protein interactions in gels and foams, in Proceedings of 7th International Conference Wales 1993, edited by G.O. Phillips, P.A. Williams and D.J. Wedlock (Oxford University Press, New York, 1994)], respectively. Isentropic compressibility, [image omitted], and deviation in refractive indices, ΔnD, were also calculated. The above functions show the deviations from the additivity law, which depend on the nature of the carbon chain of the alcohols. [ABSTRACT FROM AUTHOR]

A new approach to modify silica for the purpose of optimizing the mechanical properties of filled natural rubber was carried out in this study. Based on the acidic characteristics of the silica surface, a basic cyclohexylamine (CA) solution was used as a modifer and the modification was successfully confirmed by FT-IR, TGA and XPS analysis. Compared with the pure silica, the CA modified silica improved the mechanical properties of the filled natural rubber. DMA results showed that the tanδ values at 60°C and 90°C were effectively decreased, which corresponds to a lower rolling resistance and heat generation of the filled natural rubber vulcanizates. These results were attributed to a high cross linking density and a good dispersion of the newly modified silica in rubber matrix. For comparison, the mechanical properties of natural rubber filled with Si69 modified silica was also investigated. [ABSTRACT FROM AUTHOR]

Poly(ethylene terephthalate) (PET) waste materials were depolymerized by propylene glycol (PG) in presence of a novel catalytic system (zinc acetate with cyclohexylamine as a co-catalyst) and the effect of co-catalytic system on glycolysis reaction was compared with that of a commonly used catalytic compound (zinc acetate). The glycolyzed product was reacted with maleic anhydride (MA) and phthalic anhydride (PA) to prepare unsaturated polyester resin. The characteristics of the reaction products in each step were studied by 1H-NMR, FT-IR, GPC and intrinsic viscosity (IV). It was found that the depolymerization of PET bottles in the presence of co-catalytic system proceeded faster compared with zinc acetate-catalyzed reaction. Moreover, in synthesis of unsaturated polyester resins, it was observed that the reaction rate of glycolyzed ingredients prepared by co-catalytic system with anhydrides was higher than that of glycolyzed product made by zinc acetate. It was concluded that cyclohexyleamine has a catalytic effect on unsaturated polyester resin synthesis. [ABSTRACT FROM AUTHOR]

A novel two-dimensional Cr(VI) complex. (C6H11NH3]2 [CrO4], has been prepared and structurally characterized by X-ray diffraction methods. The complex is triclinic, space group P1 with a = 6.575(2), b = 8.384(2), c = 15.075(3)Å α = 75.14(2), &beta = 78.09(2), γ = 89.45(2)o, V = 785.1(3) Å, Z = 2. The crystal structure of the complex consists of tetrahedral [CrO4]2- dianion layers and organic [C6H11NH3]+ cation layers. The chromate anions and protonated cyclohexylammonium cations are mainly stabilized through ionic bonding. An N-H---O hydrogen bond network between the Ncyclohexylammonium and Ochromate atoms ensures the cohesion and stability of the crystal structure. [ABSTRACT FROM AUTHOR]

A novel two-dimensional Cr(VI) complex. (C6H11NH3]2 [CrO4], has been prepared and structurally characterized by X-ray diffraction methods. The complex is triclinic, space group P1 with a = 6.575(2), b = 8.384(2), c = 15.075(3)Å α = 75.14(2), &beta = 78.09(2), γ = 89.45(2)o, V = 785.1(3) Å, Z = 2. The crystal structure of the complex consists of tetrahedral [CrO4]2- dianion layers and organic [C6H11NH3]+ cation layers. The chromate anions and protonated cyclohexylammonium cations are mainly stabilized through ionic bonding. An N-H---O hydrogen bond network between the Ncyclohexylammonium and Ochromate atoms ensures the cohesion and stability of the crystal structure. [ABSTRACT FROM AUTHOR]

A novel inclusion compound, [C 6 H 11 NH 3 ][Cu 2 (CN) 3 ] · 2C 6 H 5 NH 2 , has been synthesized and structurally characterized by X-ray crystallographic methods. It crystallizes in the monoclinic space group P 2 1 / n with a = 8.839(1), b = 18.894(2), c = 14.080(3) Å, β = 93.76(1)°, V = 2346.5(7) Å 3 , Z = 4. The structure is composed of the anionic layered two-dimensional host [Cu 2 (CN) 3 ] - and the cationic onium guest [C 6 H 11 NH 3 ] + and neutral guests, C 6 H 5 NH 2 . Each Cu(I) atom is bonded to three cyanide ligands and exhibits trigonal coordination. Cu(I)-CN-Cu(I) bridges from puckered hexagons with all edges shared. The cyclohexylammonium and aniline guests are situated between host layer sheets. The cyclohexylammonium ion has a chair conformation and lies perpendicular to the host layer. The aniline molecules are arranged perpendicular and inclined at approximately 45° to the host layer, respectively. Both guest molecules are held together by a network of hydrogen bonds. [ABSTRACT FROM AUTHOR]

Cyclamate and its metabolite cyclohexylamine affect male fertility in high dose animal studies, but this affect has not been investigated in epidemiological studies. This paper reports the first epidemiological study designed to investigate the possibility of a relationship between cyclamate and cyclohexylamine and male fertility in humans, in which 405 cases of clinically defined infertility in men and 379 controls were surveyed. Semen evaluation, urine analysis for cyclamate and cyclohexylamine and dietary questionnaires were compared between cases and controls. No evidence was found of a significant association between cyclamate intake and male infertility; neither high cyclamate nor high cyclohexylamine excretion were associated with elevated risk. The lack of association remained after adjusting by age, area of residence, education, total energy intake and other variables. No significant correlations were observed between cyclamate intake, metabolism or excretion, and sperm count and motility. The results demonstrate no effect of cyclamate or cyclohexylamine on male fertility at the present levels of cyclamate consumption. [ABSTRACT FROM AUTHOR]