Cyclohexene-sulfur bichloride adducts.: Stereochemical considerations.

The reaction of sulfur dichloride with cyclohexene produces two isomeric trans-adducts of meso and dl configurations. Derivatives of both series have been obtained and configurations have been assigned by means of pseudoasymmetry. General principles for the conformational analysis of systems which contain two inverting 6-membered rings have been discussed and the positions of conformational equilibria have been evaluated. The new conformational effect-stabilization of “heteroconformer”—has been found in the case of dl-bis(2-chlorocyclohexyl) sulfoxide.     

Berberis alkaloids. XXV. Structures of bernumidine and bernumicine

The alkaloid compositions of young shoots and leaves ofBerberis nummularia Bge. have been studied. The new alkaloids bernumidine (II) and bernumicine (III) have been isolated from the leaves, and their structures have been established.     

Raman and i.r. spectra of tetramethylcyclobutanedione and the fully deuterated derivative

Raman spectra of tetramethylcyclobutane-1,3-dione (TMCBD) as a polycrystalline solid and in solution in benzene and carbon tetrachloride have been recorded. Infrared and Raman spectra of the fully deuterated molecule have also been recorded. The spectra are consistent with predictions based on a centrosymmetric molecule with a planar cyclobutadione ring and point group D_2h. A fairly complete assignment of the observed spectra is presented for both molecules. A correlation of the frequencies of the fundamentals of TMCBD-h₁₂ and - d₁₂ has been made. Ground state frequencies of fundamentals involved in progressions in the n-π* electronic spectrum have been located.     

Asparagus polysaccharides. I. Isolation and characterization of polysaccharides ofA. neglectus: Glucomannans of the roots

Water-soluble polysaccharides and pectin substances have been isolated from various organs ofA. neglectus and their quantitative amounts and monosacchardie compositions have been determined. Native acetylated glucomannans (A, B, and C) containing 13, 15, and 20% of acetyl groups and being homogeneous according to the results of gel chromatography have been isolated from the roots. On the basis of the results of periodate oxidation, methylation, and IR spectroscopy it has been established that the neutral polysaccharides of the roots ofA. neglectus is a mixture of three glucomannans consisting of β-1→4 linear-bound D-gluco- and D-mannopyranose residues.     

Polysaccharides ofEremurus. XV. Structure of the glucomannan ofEremurus lactiflorus

Ten oligosaccharides have been isolated from the products of the partial hydrolysis of a native acetylated glucomannan obtained fromEremurus lactiflorus O. Fedtsch. Their structures have been studied with the aid of acid hydrolysis before and after reduction with NaBH₄, by the GLC method, and also by chromatography with markers. The compositions and sequence of the monomers in tetra- and heptaoligo-saccharides have been determined by the¹³C NMR method. The glucommannan ofE. lactiflorus differs from theEremurus glucomannans studied previously by the ratio of monosaccharides, the presence of 0-Ac groups, the degree of polymerization, and the presence of a cellobiose unit (Glcp-Glcp) in the polymer chain. The repeating unit consists of 14 hexose residues.     

Alkaloids ofHaplophyllum foliosum. II.

In addition to the alkaloids known previously from this plant, haplofoline and folifine, from the epigeal part ofHaplophyllum foliosum we have isolated norgraveoline with mp 288–289°C (decomp. from acetone), and myrtopsine with mp 201–202°C (from chloroform), [α]_D-5° (c 0.05; methanol), which were first obtained fromHaplophyllum dubium andMyrtopsis sellingii, respectively. We have confirmed by the PMR-spectroscopic method the positions of the substituents in the dihydrofuran ring of myrtopsine suggested previously on the basis of biogenetic considerations. In addition, it has been established that the substituents are present in the trans form. This is the first time that myrtopsine has been detected in plants of the genusHaplophyllum.     

Natural Products from Leaves of the Ancient Iranian Medicinal Plant Echium amoenum Fisch. & C. A. Mey.

For several millennia, leaves of Echium amoenum Fisch. & C. A. Mey., an important Iranian medicinal plant with nutritional value as nutraceutical, have been used as tea for the treatment of several conditions, including inflammation. The nutritional value of intake of E. amoenum tea has mainly been correlated to its rich content of mainly water-soluble antioxidants. Although the entire plant is utilized, only natural products of the flowers have previously been thoroughly investigated. The rare natural products bis(3-(3,4-dihydroxyphenyl)-1-methoxy-1-oxopropan-2-yl)-1-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1,2-dihydronaphthalene-2,3-dicarboxylate, 4-Oxy-(E)-caffeoyl-2,3-dihydroxybutanoic acid methyl ester and 4-Oxy-(Z)-caffeoyl-2,3-dihydroxybutanoic acid methyl ester, in addition to the widely distributed compounds rosmarinic acid methyl ester and (E)-caffeic acid, were purified and characterized from leaves of Echium amoenum. The structures were determined by a combination of several 2D NMR spectroscopic techniques, circular dichroism spectroscopy and high-resolution mass spectrometry. The fact that bis(3-(3,4-dihydroxyphenyl)-1-methoxy-1-oxopropan-2-yl)-1-(3,4-dihydroxyphenyl)-6,7-dihydroxy-1,2-dihydronaphthalene-2,3-dicarboxylate belongs to a rare group of natural products which have previously been patented for their significant anti-inflammatory activity may rationalize the traditional treatment of inflammations with E. amoenum.     

A.c. or d.c. imposed on enzyme systems: Monitoring of monostable systems and memory in multistable systems

The construction of a theory of enzyme diffusion-electromigration-reaction regimes has been attempted. An electric field acts on the ionic species present in the membrane; when these species are proton, substrate, activator or inhibitor, they constitute the mediators of the action of the electric field on the enzyme membrane activity. Depending on the reaction scheme and the values of the different parameters (conductivity level, model structure, existence or non-existence of multiple steady states), various results have been obtained: continuous effects (enzyme membrane activity modulations) with monostable systems (a.c. and d.c.), and discontinuous ones (hysteresis and memory induction) have been pointed out.     

Studies on amine hydrothiocyanates. II. Solubilities and heats of solution in some organic solvents

The solubilities of piperidine hydrothiocyanate, piperazine monohydrothiocyanate, ethylenediamine dihydrothiocyanate, and propylenediamine dihydrothiocyanate in some or all of the solvents methanol, ethanol, and acetone have been determined. Linear regression analysis of the solubility data indicates a good fit in each case to the equation in S = (A/T) + B. Heats of solution have been calculated from the linear relationships.     

Biogenetically significant triterpenes in a species of meliaceae: Cabralea polytricha A.Juss.

Four triterpenes have been isolated from the fruits of Cabralea polytricha A.Juss. (Meliaceae). Two of them are new C₃₀ compounds whose structures have been established as the C-3, C-24 epimer of ocotillol-II and the C-24 epimer of ocotillone-II: 20S, 24S-epoxy-dammarane-3α,25-diol (IIa) and the corresponding 3-keto compound (IVa).     

Polysaccharides ofEremurus. X. Characteristics of the polysaccharides ofEremurus lactiflorus andE. luteus

Water-soluble polysaccharides have been isolated from two species ofEremurus — E. lactiflorus andE. luteus — with yields of 13.5% and 20.5%, respectively. They contained mainly glucose and mannose in ratios of 1:5 and 1:3.1. The polysaccharides ofE. lactiflorus were separated from a column of DEAE-cellulose. The yield of neutral fraction was 10.3%. Gel filtration of the polysaccharides on Sephadex G-200 showed their polydispersity. Homogeneous fractions were obtained by fractional precipitation with ethanol. They have been characterized with respect to monosaccharide composition, molecular weight, and IR spectra.     

Polarized laser Raman and i.r. spectra of dibenzyl sulphide

Polarized laser Raman and i.r. absorption spectra of dibenzyl sulphide have been investigated. Vibrational frequencies observed in both the spectra have been correlated and assigned to different normal modes of vibrations assuming C_s point group symmetry for the molecule.     

Carbohydrates ofAllium. IV. Glucofructans ofAllium longicuspis

Water-soluble polysaccharides have been isolated from the bulbs ofAllium longicuspis Rgl. By fractionating the combined water-soluble polysaccharides, homogeneous polysaccharides with molecular weights of 15,500 and 5100 have been isolated. It has been shown by spectral and chemical methods that they consist of glucofructans of a mixed type containing glycosidic bonds of the inulin (2 → 1) and levan (2→6) types in a ratio of 2.1:1.     

Thermodynamic behaviour of some glycol—water mixtures. Excess and partial volumes

Densities of water—glycol (mono- di-, tri- and tetraethyleneglycol) mixtures have been measured over the entire composition range at 298. 15 K. Mixtures involving monoethyleneglycol (MEG) have also been studied at different temperatures from 308.15 to 288.15 K. Deviations, V^E, from ideal volumes of mixing have been calculated: negative values are observed for all systems. They increase with the number of ether functions present in the organic molecule; a slight dependence of V^E towards temperature has been shown in the water—MEG mixtures. Partial molal volumes have also been calculated for both components of each system; they exhibit an extremum in the water-rich region.     

Organometallic oxime and allied derivatives II. Synthesis and properties of some tri-n-butylgermanium oximates

Tributylgermanium oximates have been prepared by reactions (a) of tributylgermanium chloride with (i) oximes in the presence of a base, (ii) sodium oximates, and (iii) organotin oximates, as well as (b) of tributylgermanium ethoxide and oxide with oximes.The derivatives have been characterised by elemental analyses, molecular weight measurements and IR spectra. Their reactions have been studied in detail.     

Homochiral ketals in organic synthesis. Enantioselective synthesis of [m.n.1] Propellanones

Optically active [m.n.1]propellanones have been prepared by diastereoselective cyclopropanation of homochiral one ketals derived from 1,4-di-O-benzyl-L-threitol and readily available bicyclic enones.     

The i.r. and Raman spectra of solid trichloroacetonitrile

The i.r. and Raman spectra of polycrystalline films of CCl₃CN have been recorded at liquid nitrogen temperature. Chlorine isotope splitting has been resolved for the v₃ fundamental and crystal splittings have been observed for five of the fundamentals. A possible crystal structure is discussed. Raman wavenumbers and depolarization ratios are included for liquid CCl₃CN.     

Gas phase i.r. spectrum and vibro-rotational analysis of CH2BrCl

The gas phase i.r. spectrum of CH₂BrCl with natural isotopic abundance has been measured under medium resolution in the range 4000-350 cm⁻¹. Accurate inspection of the band contours enabled us to positively identify most of the observed absorptions including fundamentals, overtones and combinations. The frequency value of the lowest fundamental ν₆, lying below the spectral range examined, has been evaluated by difference of suitable combinations and “hot” bands. B- and C-type absorptions exhibiting resolved rotational structure have been analyzed in terms of perpendicular bands in the symmetric rotor approximation and molecular parameters have been deduced.     

Cis and trans methyl nitrite: Gas phase i.r. spectra,band envelope analysis,hot band progressions and assignments

The gas phase vibrational spectrum of methyl nitrite has been recorded over the range 4000-300 cm⁻¹. All the fundamental modes of both the cis and trans conformers have been assigned. The complex rotational band envelopes arising from overlap of different vibrational transitions of the two conformers have been simulated as superpositions of intensity weighted vibration—rotation bands. The simulation process allowed estimates for relative magnitudes of different components of transition moments contributing to these band intensities. For the cis conformer, hot band progressions arising from the methyl and NO torsions have been identified for a number of fundamental modes. The simulation of the complete band contour in such cases yields information about Boltzmann factors for the torsional excited states from which reliable estimates of the torsional frequencies are obtained. The hot bands also provide accurate information about anharmonicity constants. For the trans conformer hot band progressions were found to be too complex because of nearly free internal rotations of the methyl group.A large number of combination modes have also been assigned. These assignnents yield estimates for the two torsional modes of the cis conformer which are in agreement with those obtained from relative intensities of hot bands. An estimate of the NO torsional frequency of the trans species has also been obtained from the combination modes.     

Aminolyses of reactive monomers and polymers—II. N-hydroxyphthalimide esters

Some N-hydroxyphthalimide esters of N-methacrylated ω-amino acids have been prepared and copolymerized with N-(2-hydroxypropyl)methacrylamide. The rates of aminolysis of monomers and copolymers have been compared.