Search results for "hydrogen"
showing 10 items of 4254 documents
(1S,2R,4S)-1-[(Benzylamino)methyl]-4-(prop-1-en-2-yl)cyclohexane-1,2-diol
2010
The title compound, C17H25NO2, was synthesized by epoxidation of the double bond of (S)-perillyl alcohol [(S)-4-isopropenyl-1-cyclohexenylmethanol], followed by the oxirane ring-opening by benzylamine using [Ca(CF3CO2)2] as catalyst under solvent-free condition at 313 K. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond. In the crystal, molecules are linked by intermolecular N—H...O hydrogen bonds, forming chains parallel to the a axis, which are further connected by O—H...O hydrogen bonds into sheets parallel to (010). The absolute configuration of the molecule is known from the synthetic procedure.
Methyl 3-(4-methoxyphenyl)prop-2-enoate
2001
The title molecule, C(11)H(12)O(3), is almost planar, with an average deviation of the C and O atoms from the least-squares plane of 0.146(4)A. The geometry about the C=C bond is trans. The phenyl ring and -COOCH(3) group are twisted with respect to the double bond by 9.3(3) and 5.6(5) degree, respectively. The endocyclic angle at the junction of the propenoate group and the phenyl ring is decreased from 120 degree by 2.6(2) degree, whereas two neighbouring angles around the ring are increased by 2.3(2) and 0.9(2) degree. This is probably associated with the charge-transfer interaction of the phenyl ring and -COOCH(3) group through the C=C double bond. The molecules are joined together thro…
Conformational investigation of α,β-dehydropeptides. IX. N-Acetyl-(E)-α,β-dehydrobutyrine N′-methylamide: stereoelectronic properties from infrared a…
2009
The Fourier transform infrared spectra of Ac-(E)-deltaAbu-NHMe were analyzed to determine the predominant solution conformation(s) of this (E)-alpha,beta-dehydropeptide-related compound and the electron density perturbation in its amide groups. The measurements were performed in dichloromethane and acetonitrile in the region of mode vs (N-H), amide I, amide II and vs (C(alpha)=Cbeta). The equilibrium geometrical parameters, calculated by a method based on the density functional theory with the B3LYP functional and the 6-31G* basis set, were used to support spectroscopic interpretation and gain some deeper insight into the molecule. The experimental and theoretical data were compared with th…
Physiological, morphological and metabolic changes in Tetrahymena pyriformis for the in vivo cytotoxicity assessment of metallic pollution: Impact on…
2007
Abstract The individual cytotoxicity of cadmium chloride, iron sulphate and chromium nitrate has been investigated by using the freshwater ciliate Tetrahymena pyriformis. The metabolic enzymes and antioxidant defense biomarkers were assessed. The results obtained reveal that their metal salts have perturbed the physiology and morphology of T. pyriformis. Also, the biomarkers assessed were sensitive to the presence of metal salts and this sensitivity was metal salt and dose dependant. To estimate the impact of their metal salts on mitochondria, we studied their effects in vivo and in vitro on the d -β-hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30) inner mitochondrial membrane enzyme. The …
Encapsulation of secondary and tertiary ammonium salts by resorcinarenes and pyrogallarenes: the effect of size and charge concentration
2015
The binding of different categories of alkyl ammonium (secondary and tertiary mono- and di-ammonium) salts with resorcinarenes and a pyrogallarene through weak interactions was analysed in all phases. 1H NMR spectroscopy and electrospray ionisation mass spectrometry were utilized in analysing the complexes in solution and in the gas phase, respectively. The 1H NMR titration studies in methanol-d4 reveal that the association constants for the 1:1 complexes vary according to the electronic properties of the hosts as well as the size, geometric orientation and charge concentration of the guest cations with binding constants of up to 950 M−1 in some cases. Mass spectrometry reveals 1:1 monomeri…
Simulation of Metabolism for The Calculation of Enzyme Activities in Stress Metabolism
1988
Abstract Using data of indirect calorimetry, total energy turnover as well as the rate of combustion of carbohydrates, fat and amino acids can be calculated. For the evaluation, simple standard procedures (4) are used. These procedures presume, that several assumptions are satisfied, e.g. a complete degradation of the energy delivering substrates and undisturbed enzyme activities. To be able to interprete also measurements, which are performed in the post-traumatic state as well as for estimation of the extent and consequences of reduced enzyme activities, a new method for the simulation of metabolism was developed. Hie underlying model considers a reduced activity of key enzymes and a swit…
Tribenzylammonium chloride
2014
Single crystals of the title salt, C21H21NH+·Cl−, were isolated as a side product from the reaction involving [(C6H5CH2)3NH]2[HPO4] and Sn(CH3)3Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetrahedral environment, with angles ranging from 107.7 to 111.16 (10)°. In the crystal, the tribenzylammonium cations and chloride anions are linked through N—H...Cl and C—H...Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin.
Two phosphonodehydrotripeptides: Boc0–Gly1–Δ(Z)Phe2–α‐Abu3PO3Me2 and Boc0–Gly1–Δ(Z)Phe2–α‐Nva3PO3Et2
2012
The present paper reports the crystal structures of two short phosphonotripeptides (one in two crystal forms) containing one ΔPhe (dehydrophenylalanine) residue, namely dimethyl (3-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}propyl)phosphonate, Boc0–Gly1–Δ(Z)Phe2–α-Abu3PO3Me2, C21H32N3O7P, (I), and diethyl (4-{[tert-butoxycarbonylglycyl-α,β-(Z)-dehydrophenylalanyl]amino}butyl)phosphonate, Boc0–Gly1–Δ(Z)Phe2–α-Nva3PO3Et2, as the propan-2-ol monosolvate 0.122-hydrate, C24H38N3O7P·C3H8O·0.122H2O, (II), and the ethanol monosolvate 0.076-hydrate, C24H38N3O7P·C2H6O·0.076H2O, (III). The crystals of (II) and (III) are isomorphous but differ in the type of solvent. The phosphono gr…
Fast proton conduction in hydrogen bonded microheterogeneous systems: Bis(2-ethylhexyl)phosphoric acid/N-methyl formamide liquid mixtures
2009
Structural and dynamical properties of bis(2-ethylhexyl)phosphoric acid (HDEHP)/N-methyl formamide (NMF) liquid mixtures in the whole composition range have been investigated by Fourier Transform Infrared spectroscopy (FT-IR), X-rays Diffraction (XRD), and AC complex impedance spectroscopy. Driven by hydrogen bond interactions among HDEHP PO(4)H group and NMF CO and NH groups, and also by steric effects among the HDEHP alkyl chains, the system microstructure is mainly characterized by the coexistence of spatially separated hydrophilic and hydrophobic nanodomains showing local organization and short-range order. The evolution of this structural feature with system composition has been highli…
Anodic Dehydrogenative Cyanamidation of Thioethers: Simple and Sustainable Synthesis of N‐Cyanosulfilimines
2021
Abstract A novel and very simple to perform electrochemical approach for the synthesis of several N‐cyanosulfilimines in good to excellent yields was established. This method provides access to biologically relevant sulfoximines by consecutive oxidation using electro‐generated periodate. This route can be easily scaled‐up to gram quantities. The S,N coupling is carried out at an inexpensive carbon anode by direct oxidation of sulfide. Therefore, the designed process is atom economic and represents a new “green route” for the synthesis of sulfilimines and sulfoximines.