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New steroidal 3β,21-disulfates (2–4), steroidal 3β,22-disulfate (5), and the previously known related steroidal 3β,21-disulfate (1) were isolated from the ethanolic extract of the Far Eastern starfish Pteraster marsippus, collected off Urup Island in the Sea of Okhotsk. The structures of these compounds were determined by intensive NMR and HRESIMS techniques as well as by chemical transformations. Steroids 2 and 3 have an oxo-group in the tetracyclic nucleus at position C-7 and differ from each other by the presence of the 5(6)-double bond. The Δ24-22-sulfoxycholestane side chain of the steroid 5 has not been found previously in the starfish or ophiuroid steroids. The cytotoxic activities of 1, 4, 5, and the mixture of 2 and 3 were determined on the models of 2D and 3D cultures of human epithelial kidney cells (HEK293), melanoma cells (SK-MEL-28), small intestine carcinoma cells (HuTu80), and breast carcinoma cells (ZR-75-1). The mixture of 2 and 3 revealed a significant inhibitory effect on the cell viability of human breast carcinoma ZR-75-1 cells, but other tested compounds were less effective. [ABSTRACT FROM AUTHOR]

Metabolomics is an expanding field of medical diagnostics since many diseases cause metabolic reprogramming alteration. Additionally, the metabolic point of view offers an insight into the molecular mechanisms of diseases. Due to the complexity of metabolic assignment dependent on the 1D NMR spectral analysis, 2D NMR techniques are preferred because of spectral resolution issues. Thus, in this work, we introduce an automated metabolite identification and assignment from 1H-1H TOCSY (total correlation spectroscopy) using real breast cancer tissue. The new approach is based on customized and extended semi-supervised classifiers: KNFST, SVM, third (PC3) and fourth (PC4) degree polynomial. In our approach, metabolic assignment is based only on the vertical and horizontal frequencies of the metabolites in the 1H–1H TOCSY. KNFST and SVM show high performance (high accuracy and low mislabeling rate) in relatively low size of initially labeled training data. PC3 and PC4 classifiers showed lower accuracy and high mislabeling rates, and both classifiers fail to provide an acceptable accuracy at extremely low size (≤9% of the entire dataset) of initial training data. Additionally, semi-supervised classifiers were implemented to obtain a fully automatic procedure for signal assignment and deconvolution of TOCSY, which is a big step forward in NMR metabolic profiling. A set of 27 metabolites were deduced from the TOCSY, and their assignments agreed with the metabolites deduced from a 1D NMR spectrum of the same sample analyzed by conventional human-based methodology.

Co-oligomers of carbon dioxide and propylene oxide with high carbonate content and terminated by hydroxyl groups are practically important polyols to synthesize block copolymers. Despite this, the 1H and 13C spectra of such co-oligomers have not been described in detail so far. In this article, a new metal-free synthesis of carbon dioxide/propylene oxide co-oligomers by a triethylborane/organic base (organic base is PPNCl) catalytic system in the presence of diols (1,2-propanediol, 1,4-butanediol) is briefly introduced. The resonances in the 1H and 13C NMR spectra of the synthesized products were assigned using 2D NMR spectrometry methods (COSY, TOCSY, selective HMBC, and HSQC). As a result, the signals of different types of chain ends and of propylene oxide units forming ether linkages were found in addition to the peaks of carbonate blocks. Moreover, our study confirmed the occurrence of an efficient chain transfer during the co-oligomerization, which is additionally supported by MALDI TOF mass spectrometry results.

Synthesis, NMR spectral data and crystal structure of 9,12-dibromo derivative of ortho-carborane are reported.

The equilibrium structure of the 3,3,6-trimethyl-1,5-diazabicyclo[3.1.0]hexane (TMDABH) molecule was studied for the first time by means of gas-phase electron diffraction (GED) supplemented with quantum chemical calculations. TMDABH exists as a mixture of two conformers of Cs point group symmetry, namely, a chair and a boat. The fractions of these two forms are 74 and 26% respectively, if the reference approximation was obtained at the MP2/aug-cc-PVTZ level, and 81 and 19%, if the reference approximation was generated at the DFT-B3LYP/cc-pVTZ level. The agreement between the theoretical and experimental molecular intensities is characterized by Rf disagreement factors of 5.06 and 6.93%, respectively. Based on the more accurate MP2/aug-cc-PVTZ quantum chemical approximation, the energy difference between the global minimum, which corresponds to the chair conformer of TMDABH, and the local minimum of the boat on the potential energy surface (PES) was found to be 1.39 kcal/mol. Moreover, NMR, IR, and Raman spectroscopic studies were carried out. According to the joint analysis of the data obtained, the most important equilibrium parameters of the chair and boat TMDABH conformers were determined to be as follows (bond lengths in Å, angles in degrees, for boat form in square brackets, Cs symmetry): N1N5 = 1.554(2) [1.520(2)], C2C3 = 1.525(2) [1.539(2)], N1C2C3 = 105.7(14) [108.8(14)], θ = C2-C3-C4/C2-N1-N5-C4 = 37.4(6) [−16.6(6)], φ = N1-C6-N5/C2-N1-N5-C4 = 72.9(3) [73.9(3)]. Comparison of especially NN bond lengths reveals a strong dependence on the bicyclic system conformation. [ABSTRACT FROM AUTHOR]

Alkali-activated binders based on metakaolin, fly ash and slag without curing were exposed directly in air, Na2SO4 and MgSO4 solutions for studying the evolution in mechanical strength and microstructure. A series of binders were synthesized and characterized on 7, 21, 45, 60, 75 and 90 days, respectively. Compressive strength measurement, scanning electron microscope (SEM) mapping, X-ray diffraction (XRD) and unclear magnetic resonance (NMR) were applied in the study. It is found that the exposure in sulfate solutions leaded to the deterioration of the binders by the dissolution of alkalis. In Na2SO4 solution, a higher percentage of zeolite was formed in the binders. While in MgSO4, a precipitate layer (e.g., brucite and gypsum), forming on the binder surface plays an important role in protecting the formation of gel, promoting the compressive strength improvement of alkali-activated slag, and compensating the decrease in compressive strength of alkali-activated metakaolin. These results provide clues for the direct preparation of alkali-activated concrete in aggressive sulfate environment.

The unstable title compound has been characterized for the first time. Its melting point, UV, IR, 1H and 13C-NMR and high-resolution mass spectra are presented. The X-ray structure has also been determined and shows a rather long C–Br bond perpendicular to the otherwise planar molecule.

The 3-halogen and 3,6-dihalogen derivatives of ortho-carborane 3-X-1,2-C2B10H11 and 3,6-X2-1,2-C2B10H10 (X = Cl, Br, I) were prepared by Cu-assisted halodeboronation of the corresponding pinacolborate derivatives 3-Bpin-1,2-C2B10H11 and 3,6-(Bpin)2-1,2-C2B10H10. It was shown that decapitation of 3-Cl-1,2-C2B10H11, similarly to the corresponding bromo and iodo derivatives, proceeds regioselectively with the retention of the B-Cl bond. Crystal structures of 3,6-Cl2-1,2-C2B10H10 and Cs [3-Cl-7,8-C2B9H11] were determined by single crystal X-ray diffraction.

Three new ceramides (1–3) and three new cerebrosides (4, 8, and 9), along with three previously known cerebrosides (ophidiocerebrosides C (5), D (6), and CE-3-2 (7)), were isolated from a deep-sea starfish species, the orange cookie starfish Ceramaster patagonicus. The structures of 1−4, 8, and 9 were determined by the NMR and ESIMS techniques and also through chemical transformations. Ceramides 1–3 contain iso-C21 or C23 Δ9-phytosphingosine as a long-chain base and have C16 or C17 (2R)-2-hydroxy-fatty acids of the normal type. Cerebroside 4 contains C22 Δ9-sphingosine anteiso-type as a long-chain base and (2R)-2-hydroxyheptadecanoic acid of the normal type, while compounds 8 and 9 contain saturated C-17 phytosphingosine anteiso-type as a long-chain base and differ from each other in the length of the polymethylene chain of (2R)-2-hydroxy-fatty acids of the normal type: C23 in 8 and C24 in 9. All the new cerebrosides (4, 8, and 9) have β-D-glucopyranose as a monosaccharide residue. The composition of neutral sphingolipids from C. patagonicus was described for the first time. The investigated compounds 1–3, 5–7, and 9 exhibit slight to moderate cytotoxic activity against human cancer cells (HT-29, SK-MEL-28, and MDA-MB-231) and normal embryonic kidney cells HEK293. Compounds 2, 5, and 6 at a concentration of 20 µM inhibit colony formation of MDA-MB-231 cells by 68%, 54%, and 68%, respectively. The colony-inhibiting activity of compounds 2, 5, and 6 is comparable to the effect of doxorubicin, which reduces the number of colonies by 70% at the same concentration.

Reaction of ortho-carborane with anhydrous AlCl3 in chloroform results in a mixture of 9-chloro, 9,12-dichloro, and 8,9,12-trichloro derivatives with 9,12-dichloro-ortho-carborane being the main product. Molecular crystal structure of 9,12-dichloro-ortho-carborane was determined by the single crystal X-ray diffraction. The crystal structure of 9,12-Cl2-1,2-C2B10H10 appeared to be nearly isostructural to 9,12-dibromo-ortho-carborane: the crystal packing is built of layers in which molecules are connected via weak hydrogen and halogen bonds. A synthetic scheme for preparation of the hexachloro derivative of cobalt bis(dicarbollide) Cs[8,8′,9,9′,12,12′-Cl6-3,3′-Co(1,2-C2B9H8)2] from 9,12-dichloro-ortho-carborane has been proposed.

[Display omitted] • New compound 2-methyl-3,5-dinitro-6-(2-phenylhydrazinyl)pyridine was synthesized. • Its structure was studied using XRD, NMR, IR and Raman methods. • Electron absorption and emission spectra with femtosecond excitation were measured. • The experimental results were analysed in terms of DFT and NBO calculations. • The depopulation mechanism of electron excited states was proposed. A new methyl-dinitro-phenylhydrazinyl-pyridine derivative [2-methyl-3,5-dinitro-6-(2-phenylhydrazinyl)pyridine] was synthesised and characterised by means of structural and spectroscopic measurements. The X-ray diffraction studies revealed that the compound crystallises in the centrosymmetric monoclinic space group P 2 1 / n , with two symmetry-independent molecules in the asymmetric unit with Z = 8. Hydrazo bridge C-NH-NH-C links two fragments composed of phenyl ring and pyridine unit substituted with methyl and nitro groups. Such a structure was confirmed by 1H and 13C NMR studies as well as IR, Raman, UV–Vis, and emission spectra. The results were analysed using the quantum-chemical DFT calculations. The paper reports the vibrational characteristics and discusses dynamical properties of this moiety. The full set of the normal modes typical of the hydrazo bridge was identified and assigned to respective IR and Raman bands. The results of structural and spectroscopic studies were used to find the dependence between the conformation of the θ–NH-NH-ϕ system and its optic properties. The experimental UV–Vis and emission spectra were discussed in terms of the calculated singlet and triplet states that allowed assigning the unique spectral pattern originating from the electrons of the hydrazo-bridge system. [ABSTRACT FROM AUTHOR]

The reaction of 1,5-dimethyibispidin-9-one with acetone, acting as both a solvent and a reagent, affords 2,2,5,7-tetramethyl-1,3-diazaadamantan-6-one. The structure of the monohydrate of the target compound, which is a hydrogen-bonded supramolecular polymer, was determined by X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

The ion mobility and conduction in the (NH4)6LiHf2Zr2F23 compound are studied by 1H, 19F NMR and impedance spectroscopy methods. The types of ion motion in fluoride and ammonium sublattices are determined in the temperature interval from 150 to 450 K. As a result of the order‑disorder phase transition at the temperature above 400 K, the metastable high-temperature β-modification of this compound with ionic diffusion in both sublattices is formed. The conductivity in this compound at 450 K is found to be 4.5 × 10–3 S/cm. [ABSTRACT FROM AUTHOR]

New steroidal 3β,21-disulfates (2–4), steroidal 3β,22-disulfate (5), and the previously known related steroidal 3β,21-disulfate (1) were isolated from the ethanolic extract of the Far Eastern starfish Pteraster marsippus, collected off Urup Island in the Sea of Okhotsk. The structures of these compounds were determined by intensive NMR and HRESIMS techniques as well as by chemical transformations. Steroids 2 and 3 have an oxo-group in the tetracyclic nucleus at position C-7 and differ from each other by the presence of the 5(6)-double bond. The Δ24-22-sulfoxycholestane side chain of the steroid 5 has not been found previously in the starfish or ophiuroid steroids. The cytotoxic activities of 1, 4, 5, and the mixture of 2 and 3 were determined on the models of 2D and 3D cultures of human epithelial kidney cells (HEK293), melanoma cells (SK-MEL-28), small intestine carcinoma cells (HuTu80), and breast carcinoma cells (ZR-75-1). The mixture of 2 and 3 revealed a significant inhibitory effect on the cell viability of human breast carcinoma ZR-75-1 cells, but other tested compounds were less effective.

The results of previously published NMR studies of amino acid complexes of antimony (iii) and indium(iii) fluorides are critically analyzed. Correlations between the NMR data, ion mobility, and structure of the complexes in question are considered. The interpretation of the low-temperature 19F NMR spectra of amino acid complexes of antimony(iii) fluorides is corrected and certain figures were changed for better informativity. Mechanisms of the onset of ion mobility in the studied complexes of Sb(iii) and In(iii) fluorides are proposed and the possibility of application of these compounds in the design of functional materials is assessed. [ABSTRACT FROM AUTHOR]

The calculation of the 13C and 15N NMR chemical shifts by a combined molecular mechanics (Pcmodel 9.1/MMFF94) and ab initio (GIAO (B3LYP/DFT, 6‐31 + G(d)) procedure is used to investigate the conformations of a variety of alkyl substituted anilines. The 13C shifts are obtained from the GIAO isotropic shielding (Ciso) with separate references for sp3 and sp2 carbons (δc = δref − Ciso). The 15N shifts are obtained similarly from the GIAO isotropic shielding (Niso) with reference to the 15N chemical shift of aniline. Comparison of the observed and calculated shifts provides information on the molecular conformations. Aniline and the 2,6‐dialkylanilines exist with a rapidly inverting symmetric pyramidal nitrogen atom. The 2‐alkylanilines have similar conformations with the NH2 group tilted away from the 2‐alkyl substituent. The N,N‐dialkylanilines show more varied conformations. N,N‐dimethylaniline has a similar structure to aniline, but N‐ethyl, N‐methylaniline, N,N‐diethylaniline, and N,N‐diisopropylaniline are conformationally mobile with two rapidly interconverting conformers. In contrast, the anilines substituted at C2 and the nitrogen atom exist as one conformer where the steric interaction between the C2 substituent and the N substituent determines the conformation. In 2‐methyl‐N‐methylaniline, the nitrogen atom is pyramidal as usual with the N‐methyl opposite to the 2‐methyl, but in 2‐methyl‐N,N‐dimethyl aniline, the NMe2 group is now almost orthogonal to the phenyl plane. This is also the case with 2‐methyl‐N,N‐diethylaniline and 2,6‐diisopropyl‐N,N‐dimethylaniline. The comparison of the observed and calculated 15N chemical shifts confirms the above findings, in particular the pyramidal conformation of aniline and the above observations with respect to the conformations of the N,N‐dialkylanilines. [ABSTRACT FROM AUTHOR]