Presence Of Cyclohexylamine Research Articles

Synthesis, physical and electrochemical characterizations of organically templated cobalt-aluminophosphate. Application to oxygen evolution

The hybrid semiconductor CYCHA-CoAl2P3O12·mH2O was elaborated by hydrothermal route at 453 K in presence of cyclohexylamine (CYCHA) as organic template. The X-ray diffraction pattern of the blue product indicates a zeolite type CAP-CHA 5 topology which crystallizes in a hexagonal system (SG:R $$ \overline{3} $$ ) with the lattice constants: a = 13.5494 (3) A, c = 15.2795 (5) A. The optical, physical and photo-electrochemical characterizations of the material were investigated. The diffuse reflectance indicates an optical transition at 1.84 eV, directly allowed due to the crystal field splitting of Co 3+ in tetrahedral coordination. The electrical conduction occurs by low polaron hopping with activation energy of 37 meV. The conduction band is formed by Co3+: e.g. orbital (5.15 eV) below vacuum. The valence band, deriving mostly from O2−: 2p orbital with a potential (6.85 eV), is adequately located with respect to O2/H2O level (~ 1.40 VSCE), thus leading to an oxidation of water under illumination. The best photoactivity was found at neutral pH (~ 7) with an oxygen evolution rate of 38 µmol min−1 g−1 and a quantum yield of 0.40%. The as-synthesized material also showed adsorption capacity of 90% of the methyl violet dye in aqueous solution with a half life of 43 min.

Genome-wide identification and characterization of genes encoding cyclohexylamine degradation in a novel cyclohexylamine-degrading bacterial strain of Pseudomonas plecoglossicida NyZ12

The Gram-negative strain of Pseudomonas plecoglossicida NyZ12 isolated from soil has the ability to degrade cyclohexylamine (CHAM). The genes encoding CHAM degradation by gram-negative bacteria, however, have not been reported previously. In this study, ORFs predicted to encode CHAM degradation by NyZ12 were identified by bioinformatics analysis. Differential expression of the proposed ORFs was analyzed via RNA-seq and quantitative reverse transcription-PCR (qRT-PCR), using RNA extracted from NyZ12 cultured with or without CHAM addition. One CHAM-inducible ORF, RK21_02867 predicted to encode a cyclohexanone monooxygenase (ChnB) was disrupted, as were five ORFs, RK21_00425, RK21_02631, RK21_04207, RK21_04637 and RK21_05539, that had weak homology to the only known cyclohexylamine oxidase (CHAO encoded by chaA) found in Brevibacterium oxydans IH-35A. We also found that a tandem array of five ORFs (RK21_02866-02870) shared homology with those in an operon responsible for oxidation of cyclohexanone to adipic acid, although the ORFs in strain NyZ12 were arranged in a different order with previously found in cyclohexane, cyclohexanol or cyclohexanone degradation strains. The ORFs in this cluster were all up-regulated when CHAM was supplied as the sole carbon source. When one of these five genes, RK21_02867 encoding cyclohexanone (CHnone) monooxygenase, was knocked out, NyZ12 could not grow on CHAM, but it accumulated equimolar amounts of CHnone. Our results show that strain NyZ12 metabolized CHAM directly to CHnone which was then further metabolized to adipate. Despite clearly identifying genes encoding the steps for metabolism of CHAM metabolites, not every one of the putative chaAs was differentially expressed in the presence of CHAM and deletion of each one individually did not completely eliminate the capacity of NyZ12 to degrade CHAM, though it did reduce its growth in several instances. Our results suggest that there is genetic redundancy encoding the initial step in the oxidation of CHAM to CHnone in NyZ12 and that its CHAOs differ considerably from the ChaA, originally described in Brevibacterium oxydans IH-35A.

Hydrothermal conversion of magadiite into mordenite in the presence of cyclohexylamine

Hydrothermal conversion of magadiite, in the presence of cyclohexylamine (CHA), into a commercially important mordenite (MOR zeolite) has been investigated. The effects of various parameters such as the reactant H2O/SiO2 ratio, CHA/SiO2 ratio, reaction time, the presence of sodium ions and potassium ions are studied. Thermal and acid stability of the as-made MOR zeolite were examined. The pure MOR zeolite with high crystallinity, which is composed of parallelepiped crystals agglomerate, was obtained at 140°C for 28h with the molar composition: 0.14M2O:SiO2:xAl2O3:54H2O:16CHA (M2O=K2O+Na2O, K/K+Na=0.3, x=0.028 and 0.04). The structure of the sample was totally destroyed at 1100°C and the product is exceptionally stable towards strong acid.

Synthesis of (1R,2R)‐ and (1S,2R)‐1,2‐Epoxy‐3‐hydroxypropylphosphonates as Analogues of Fosfomycin

Cyclohexylammonium (1R,2R)-1,2-epoxy-3-hydroxypropylphosphonate was conveniently synthesized from dibenzyl (1S,2R)-2,3-O-cyclohexylidene-1,2,3-trihydroxypropylphosphonate by a reaction sequence including mesylation, hydrolysis of acetal, intramolecular Williamson reaction, and hydrogenation in the presence of cyclohexylamine. For dibenzyl (1S,2R)-2,3-O-cyclohexylidene-1,2,3-trihydroxypropylphosphonates the same approach was not successful, since prior the epoxide-ring closure tritylation of HO-C3 in dibenzyl (1R,2R)-2,3-dihydroxy-1-mesyloxypropylphosphonate was necessary and the hydrogenolysis of dibenzyl (1S,2R)-1,2-epoxy-3-trityloxypropylphosphonate yielded a complex reaction mixture.

Diamine Oxidase Activity During the Germinative and Post-Germinative Growth of the Embryonic Axis in Chickpea Seeds

Diamine oxidase (DAO, EC 1.4.3.6.), which participates in oxidative catabolism of polyamines (PAs), was not detected in the dry viable chickpea (Cicer arietinum L.) seeds. From the time when the embryonic axis acquired an aerobic metabolism, DAO increased concomitantly with the growth of the embryonic axis and at the same time with the deterioration of the cotyledons, although in these organs the values were clearly lower than in the axis. The highest DAO activity in the embryonic axis of seedlings grown for 72 and 96 h was found in the elongation, differentiation and hypocotyl zones, while the lowest was in the apex and plumule. The absence of cotyledons promoted the early appearance of DAO in the embryonic axis. When germination occurred at supraoptimal temperatures (30 – 35 °C), DAO activity was sharply inhibited both in the cotyledons and in the embryonic axis. This inhibition was accentuated further in the presence of cyclohexylamine, an inhibitor of spermidine synthase activity, to such a degree that DAO was undetectable in the cotyledons. DAO inhibition by EGTA and the pronounced reversal induced by Ca2+ implies that calcium may be related to DAO activity. The presence of putrescine, spermidine and spermine in the germination medium stimulated DAO activity, although this activity was inhibited when the exogenous PA was cadaverine.

Application of Rh(I)‐Catalyzed C—H Bond Activation to the Ring Opening of 2‐Cycloalkenones in the Presence of Amines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Application of Rh(I)-catalyzed C-H bond activation to the ring opening of 2-cycloalkenones in the presence of amines.

[reaction: see text]. Herein described is the application of the Rh(I)-catalyzed C-H bond activation to the ring-opening of 2-cycloalkenones in the presence of cyclohexylamine. This reaction includes the C-C double bond cleavage of 2-cycloalkenones through the conjugate addition of cyclohexylamine followed by the retro-Mannich-type fragmentation. The resulting ring-opened intermediates subsequently underwent either chelation-assisted hydroacylation to afford a ring-opened dicarbonyl compound or beta-alkylation via a ring contraction.

Practical cobalt carbonyl catalysis in the thermal Pauson--Khand reaction: efficiency enhancement using Lewis bases.

In this report we have shown that the commercially available Co(2)(CO)(8) and Co(4)(CO)(12), and enyne--Co(2)(CO)(6) complexes, are sufficiently effective in catalyzing the Pauson--Khand reaction under one atmosphere of CO pressure. It was further demonstrated that the efficiencies of these cyclization protocols could be enhanced by the presence of cyclohexylamine. These procedures have also rendered more practical and highly convenient alternatives for the catalytic Pauson--Khand reaction. Most importantly, we have dispelled the common belief that Co(4)(CO)(12) is inactive in the Pauson--Khand reaction under one atmosphere of carbon monoxide. Of mechanistic importance is that these studies have also shown that the probable formation of Co(4)(CO)(12) is not necessarily a dead end pathway in the Co(2)(CO)(8)-catalyzed Pauson--Khand reaction. It is also of interest that substoichiometric amounts of Co(2)(CO)(8), in DME and in the presence of cyclohexylamine, are sufficient for the cyclocarbonylation of enynes under a nitrogen atmosphere. Our findings have provided more practical protocols for the Pauson-Khand reaction using catalytic amounts of cobalt carbonyl complexes and a better understanding of the influence of Lewis bases on their efficiency. These reports on the activity of Co(4)(CO)(12) are anticipated to develop into a convenient and practical alternative for Co(2)(CO)(8) catalysis.

Synthesis and structure of an open-framework chlorophosphate, [C6NH14][ZnCl(HPO4)

A zinc chlorophosphate, of the composition [C6NH14][ZnCl(HPO4)], with a layered architecture has been synthesized, for the first time, in the presence of cyclohexylamine as the structure-directing agent. The structure comprises a network of ZnO3Cl and PO4 tetrahedra forming macroanionic layers with four- and eight-membered apertures. Charge compensation is achieved by the protonated amine occupying inter-lamellar space and interacts with the framework via hydrogen bonding. The crystal structure of the new compound was determined.

Effect of iodide ions on the synergistic inhibition of the corrosion of manganese-14 steel in acidic media

We investigate the synergistic effect of iodide ions on the corrosion inhibition of manganese-14 steel in 0.5 M H 2SO 4 in the presence of cyclohexylamine using potentiodynamic polarization and linear polarization techniques. In 0.5 M H 2SO 4, the corrosion rates of the steel decrease when amine the concentration decreases, while the inhibition efficiencies increase. The addition of iodide ions enhances the inhibition efficiency considerably. The presence of iodide ions increases the degree of surface coverage, while at low concentrations cyclohexylamine forms an insoluble complex by undergoing adsorption. The synergism parameters ( S θ ) calculated from surface coverage in the case of cyclohexylamine are found to be larger than unity. In addition, the adsorption of this amine on manganese-14 steel is found to follow a Langmuir isotherm. Thus inhibition occurs by adsorption.

A novel aluminophosphate precursor that transforms to AlPO4-5 molecular sieve at high temperature

A novel aluminophosphate microporous compound, denoted UHM-5, synthesized from an aqueous aluminophosphate gel at 150 °C in the presence of cyclohexylamine as the template, transforms upon calcination above 300 °C into AlPO4-5 molecular sieve.

Inhibition of polyamine synthesis by cyclohexylamine stimulates the ethylene pathway and accelerates the germination of Cicer arietinum seeds

Treatment with cyclohexylamine, an inhibitor of spermidine synthase, accelerated radicle emergence in chick‐pea (Cicer arietinum L. cv. Castellana) seeds. Stimulation in the growth of embryonic axis was correlated with: (a) a rise in putrescine (Put) and cadaverine (Cad); (b) a decrease in spermidine (Spd) and spermine (Spm), and (c) a concomitant acceleration of the transformation from S‐adenosylmethionine (SAM) into ethylene with increases in the levels of l‐aminocyclopropane‐l‐carboxylic acid (ACC), l‐(malonylamino)cyclopropane‐l‐carboxylic acid (mACC) and ethylene and ACC synthase and ethylene‐forming enzyme activities. Cyclohexylamine also stimulated the mitotic index in both apical and subapical zones of the radicle and the apical zone of the plumule. The sectional distribution of the ethylene pathway and polyamine content was studied in embryonic axes of seeds germinated for 65 h. Each axis was divided into 5 sections: radicle meristem, elongation zone, differentiation zone, hypocotyl and plumule. In the presence of cyclohexylamine, ACC synthase and ACC were strongly stimulated in both the differentiation and hypocotyl zones, whereas the mACC was stimulated in all sections of the embryonic axis. With respect to ethylene‐forming enzyme activity and ethylene production, the hypocotyl and the zones of elongation and differentiation were affected most by cyclohexylamine. Cyclohexylamine also induced an accumulation of free Put and Spm in the differentiation, hypocotyl and radicle zones, whereas Put and Spm bound to small substances increased most in the hypocotyl and plumule. The Spd bound to small substances decreased in all sections in the presence of cyclohexylamine. With respect to polyamines bound to macromolecules, cyclohexylamine stimulated only the accumulation of Put since Spd and Spm were strongly inhibited in all sections.

On the Formation of AlPO4-Based Molecular-Sieves in the Presence of Cyclohexylamine

The hydrothermal synthesis of the AlPO4-17, SAPO-44, MnAPSO-44 and intermediate solid phases [samples (APO)N, (APSO)N and Mn (APSO)N] in the presence of cyclohexylamine (cha) is described. (APO)N, (APSO)N and Mn (APSO)N represent unknown, layer-type, crystalline phases with different chemical compositions. These phases are predominantly formed at a high cha concentration and low crystallization temperature. All synthesized materials contain protonated cha in their structure, but only in AlPO4-17, (APO)N,(APSO)N and Mn (APSO)N is the -OH group also found. The calcination of the unknown phases leads to the loss of crystallinity and causes a complete breakdown of the crystal structure above 270°C.

On the formation of CoAPSO-44

Hydrothermal synthesis of CoAPSO-44 in the presence of cyclohexylamine (CHA) as the template is generally accompanied by the formation of an unknown phase, “Co(APSO) N.” Electronic spectroscopy indicates that CO(APSO) N contains Co 2+ in a pentacoordinated environment. When Co(APSO) N is heated at 195°C in a water suspension under autogenic pressure, two processes occur: (a) a partial conversion of Co(APSO) N into CoAPSO-44 and (b) decomposition of Co(APSO) N into Co- and Al-phosphates. Thermal removal of CHA from Co(APSO) N results in a breakdown of the latter's cyrstal lattice.

The Templating Role of Cyclohexylamine in the Synthesis of Microporous Aluminophosphates

The investigation of the synthesis of AlPO4 molecular sieves from orthophosphoric acid and pseudoboehmite in the presence of cyclohexylamine shows that in this case the amine plays the role of template in the sense of "Template theory". The geometric shape of the template determines the dimensions of the channels within the AlPO4-lattices. The amount of template in the gel influences the void volumes, leading to different structures, however, with similar dimensions. The product composition is largely determined by the ratio amine/(Al,P)O2. The molecular sieves have been characterized by IR, X-ray, TG and DTA measurements.

Study on the speciation of copper(I) in the presence of cyclohexylamine in alkaline solution by differential pulse polarography

The strong complexation of Cu with cyclohexylamine in coolant waters of power stations containing this amine as a pH regulating anticorrosion agent may have technically significant consequences affecting the dissolution of copper from the alloy material of the heat exchanger components. The speciation of Cu(I) with cyclohexylamine (CHA) was studied in alkaline solutions in the pH range from 8.6 to 10 by differential pulse polarography. It was proved that the peaks correspond to the reversible reduction of Cu(I) complexes at the DME. The first reduction step Cu(II)/Cu(I) appeared only as a shoulder on the Hg-oxidation peak. The potentials of the Cu(I)-peaks are shifted more negatively with increase of the cyclohexylamine concentration and the pH. A modified DeFord-Hume-treatment was applied for the evaluation of the stoichiometric overall stability constantsβi andβij and ligand numbers of the formed simple complexes (Cu(CHA)2)+, (Cu(CHA)3)+, (Cu(OH)2)− and the mixed uncharged complex (Cu(OH) (CHA)) from the relationships between the peak potential shiftsΔE p and the ligand concentrations. The logarithms of the stability constants logβ between 11 and 17 indicate a strong binding of Cu(I). From the resulting stability constants the distribution of Cu(I) among these complexes was calculated and also presented graphically as three-dimensional plots of the dependence of the formation degree as well on the cyclohexylamine concentration as on pH.

Requirement for 7-methylguanosine in translation of globin mRNA in vivo

The 7-methylguanosine (m7G) residue present in the m7G5' ppp5'X-"CAP" structure of rabbit globin mRNA was removed quantitatively by periodate oxidation followed by beta-elimination in the presence of cyclohexylamine. The RNA thus treated was intact and exhibited no signs of degradation as examined by polyacrylamide gel electrophoresis in formamide. Assay for protein synthesis using a wheat germ cell-free system showed that the globin mRNA lacking m7G had lost most of its messenger activity. Identical treatment, of satellite tobacco necrosis virus (STNV) RNA, which does not contain the 5'-terminal "CAP" structure, resulted in no loss of its mRNA activity. Since the importance of the m7G residue in eukaryotic mRNA has not yet been shown essential for translation in vivo, both untreated and treated globin mRNAs were injected into frog oocytes and their translation into globin was measured at intervals over a ninety-six hour period. Globin mRNA either treated with periodate alone or lacking in m7g altogether were both found to have lost more than 90% of their activity in vivo.

Preparation and characterization of poly(isobutylene oxide)

High molecular weight poly(isobutylene oxide) has been synthesized and characterized. Two novel catalysts were found: (1) a Zn-S composition made by reacting ZnEt2 and H2S in presence of cyclohexylamine and (2) a ternary system consisting of ZnEt2 a metal compound (such as ZnO, ZnS, or Zn titanate), plus cyclohexylamine. Products with reduced specific viscosities of 1.5 to 13 dl/g were easily made. Highest yields were obtained at 110°C, but these products had lower molecular weights than products synthesized at 70°C. The activity of the Nippon-Carbide catalyst was increased two to three times by heating it with a small amount of styrene oxide. High molecular weight poly(isobutylene oxide) appears to have an attractive balance of properties which are in the range of many engineering thermoplastics.

Synthesis of ribonucleoside 5-S-methyl phosphorothiolates and ribonucleoside3:5-cyclic phosphates from nucleosides applying a new phosphorylating agent, MTBO.

When adenosine (Ia) was allowed to react with 2-methylthio-4H-l,3,2-benzodioxaphosphorin-2-oxide (MTBO) (II), a new phosphorylating agent, in the presence of cyclohexylamine, adenosine 5′-S-methyl phosphorothiolate (IVa) and adenosine 2′: 3′-cyclic phosphate (Va) were obtained.Ribonucleoside 5′-S-methyl phosphorothiolates (IV) were selectively synthesized directly from borate complexes of ribonucleosides (VI) and MTBO in the presence of cyclohexylamine, followed by removal of metaboric acid by co-distillation with methanol, in 68~86% yields.Under anhydrous conditions, the phosphorothiolates (IV) were cyclized to give ribonucleoside 3′: 5′-cyclic phosphates (X) by iodine oxidation. Five 3′: 5′-cyclic nucleotides including cyclic AMP were synthesized by this procedure in 38~64% yields after purification.

Determination of Cyclohexylamine in Various Artificially Sweetened Foods and Artificial Sweeten

Abstract Procedures for the determination of cyclohexylamine in various dietetic products (carbonated beverages, dry beverage bases, canned fruits, fruit juice drinks, liquid and dry weight control formulations, and food sweetener preparations) and in sodium and calcium cyclamates have been developed. Recoveries were as follows: dietetic products 90-100% at the 0.2 ppm level, and sodium and calcium cyclamates 90-100% at the 2.0 ppm level. Cyclohexylamine was isolated from the following products at the indicated levels: carbonated beverages 0.0-6.5 ppm, dry beverage bases 0.0-480 ppm, canned fruits 0.3-0.9 ppm, fruit juice drink 0.7 ppm, liquid and dry weight control formulations 0.0-2.8 ppm, liquid and dry base food sweetener preparations 1.4-95 ppm, and cyclamates 3.8-54 ppm. The presence of cyclohexylamine was confirmed by either infrared spectrophotometry or mass spectrometry.