A Molibdenum(VI)–Gallein–Diphenhydramine Ion Associate and Its Application to the Extraction-Photometric Determination of Diphenhydramine

Optimum conditions for the formation and extraction of a slightly soluble ion associate of diphenhydramine with the anionic complex molibydenum–gallein were determined. The ternary complex was extracted with butanol at pH 4–7. In the presence of diphenhydramine, the color strength became stronger, which was manifested in the absorption spectra as hypsochromic and bathochromic shifts. Some physicochemical characteristics of the complex were determined, the specificity of the reaction with respect to diphenhydramine was studied, and the probable complexation scheme was proposed. It was found that the molybdenum–gallein–diphenhydramine complex forms at a component ratio of 1: 2: 2. A procedure for the extraction–photometric determination of diphenhydramine in injection solutions and tablets was developed (RSD = 15–20%). The linearity range of the calibration graph was 0.02–0.20 mg/mL.     

Syntheses based on norfluorocurarine. 5. NMR spectra of monomeric norfluorocurarine derivatives

NMR spectra of norfluorocurarine and seven of its derivatives were studied. The NMR spectral parameters were related to stereochemical features using molecular modeling by the semi-empirical AM1 approximation. The resulting steric characteristics of the molecules in solution agreed well with x-ray structure data. The only difference from the x-ray structure data was the ability of several substituents to rotate.     

Crystal structure of indoline alkaloids kopsinilam,kopsinine, and the salts of the latter

Indoline alkaloids kopsinilam and kopsinine extracted from the plant Vinca erecta have been studied by X-ray crystallography; mono and double salts of the latter alkaloid also have been examined. Experimentally determined positions of Н atoms suggest sp ³ hybridization of the indoline nitrogen atom N1 in the bases and the salts. Tetrahedral hybridization of the atom N1 in indoline alkaloids favors the formation of their double salts, what is unlikely for indole and indolinine alkaloids. In the halogen double salts there is an intramolecular Н bond between one of the protons of the NH₂ group and the oxygen of the methoxycarbonyl group, that is absent in the mono salts and pure bases.     

Water-soluble polysaccharides of seeds of the genusGleditsia

The water-soluble polysaccharides of the seeds of eight species of Gleditsia have been isolated and studied. They are galactomannans with different viscosities, specific rotations, and ratios of galactose and mannose. A study of their chemical transformations and IR spectral data has shown that the monosaccharide residues are pyranoses linked by β-1-4-glycosidic bonds having in the second componentD-galactose with the α-configuration of the glycosidic center and the most probable chair conformation of the pyranose ring. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 727–730, November–December, 1998.     

Imperialine esters and their M2-choline-blocking activity

Four new imperialine esters, with butyric, isovaleric, pyromucic, and benzoic acids, have been synthesized, and their M₂-choline-blocking activity has been studied. Deceased     

Syntheses based on norfluorocurarine. 3. Structures of (−)-norfluorocurarine, (±)-norfluorocurarine,and fluorocurarine

Structures of the alkaloids (−)-norfluorocurarine, its racemate (±)-norfluorocurarine from Vinca erecta, and fluorocurarine obtained by N(β)-methylation of (−)-norfluorocurarine were established by x-ray crystal structure analyses. The alkaloid crystallized with two molecules in the asymmetric unit for the first two crystals. The asymmetric unit of (±)-norfluorocurarine crystal consisted of two antipods. The asymmetric unit in the crystal of the last compound consisted of the N(β)-methylated cation and a hydroxide anion. The formation of bimolecular associates through intermolecular N–H…O H-bonds was typical of these crystal- line structures. An associate in the crystal structure of fluorocurarine involved two hydroxide anions.     

Lipids and flavolignans from <Emphasis Type="Italic">Silybum marianum</Emphasis>

Lipids from the air-dried aerial part (AP) and seeds of Silybum marianum (L.) Gaerth. (Asteraceae) were studied. The class and fatty acid compositions of neutral lipids (AP, seeds) and glyco- and phospholipids (AP) were determined. Neutral lipids (NL) with a complicated set of lipophilic components, mainly triterpenols, sterols, and their esters predominated in the AP. The fatty acids of the AP were dominated by 16:0, 18:2 (glycolipids), and 18:3 (neutral lipids, phospholipids); of seed NL, by 18:2 and 18:1. The content and composition of flavolignans isolated from defatted seeds and the content of total protein in the meal were found.     

Synthesis, NMR and quantum chemical studies of the [Cp3Rh3Se2]2+ clusters (Cp = η5-C5Me5, η5-C5Me4Et, η5-C5H3 t Bu2)

Reactions of [CpRhCl₂]₂ (Cp = η⁵-C₅Me₅ (Cp*), η⁵-C₅Me₄Et (Cp′), η⁵-C₅H₃ ^t Bu₂(Cp″)) with in situ generated H₂Se give triangular [Cp₃Rh₃Se₂]²⁺ clusters. These clusters were isolated as PF₆ salts and characterized with ESI-MS, ⁷⁷Se, ¹H NMR and DFT calculations. [Cp₃Rh₃Se₂] undergoes two reversible two-electron reduction steps. Quantum-chemical calculations reveal non-trivial bonding situation in the cluster core and changes in the hapticity of the Cp* ligand upon reduction. Crystal structure of [Cp ₃ ^* Rh₃Se₂][Re₂(μ-Cl)₃(CO)₆]Cl · 3.3H₂O has been determined.     

Structure of galactomannan from seeds ofGleditsia macracantha

The structure of galactomannan from seeds ofGleditsia macracantha is studied by methylation, periodate oxidation, and partial acid hydrolysis. The principal polyglycoside chain consists of β-1→4-bonded mannopyranose units, where the mannose is substituted in the 6-position by single α-D-galactopyranose units. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 573–576, September–October, 1999.