Steroids of the spirostan and furostan series from plants of the genus Allium. XXI. Structure of alliospiroside a and alliofuroside a from Allium cepa

Two new steroid glycosides have been isolated from the generative organs (pericarps and peduncles) ofAllium cepa L.: alliospiroside A and alliofuroside A. According to chemical transformations and spectral characteristics, alliospiroside A has the structure of (25S)-spirost-5-ene-1,3-diol 1-O-[O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside]. The structure of (25S)-furost-5-ene-1,3,22,26-tetraol 20-O--D-glucopyranoside 1-O-[O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside] has been established for alliofuroside A.Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 188–196, March–April, 1986.     

Triterpenoid Glycosides of Fatsia japonica. II. Isolation and Structure of Glycosides from the Leaves

The previously known triterpenoid 3-O--L-arabinopyranosides of oleanolic and echinocystic acids and hederagenin, 3-O--D-glucopyranosyl-(12)-O--L-arabinopyranosides of oleanolic acid and hederagenin, in addition to 28-O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl ethers of the 3-O--L-arabinopyranoside of hederagenin, and 3-O--D-glucopyranosyl-(12)-O--L-arabinopyranosides of oleanolic acid and hederagenin, respectively, are isolated from leaves ofFatsia japonica(Araliaceae). The structures of the glycosides are confirmed by chemical methods and ¹³ C NMR spectroscopy     

Complex polarizability as used to analyze dielectric relaxation measurements

The effect of representing dielectric properties in terms of the complex polarizability ^c = – i is examined. Loss curves ( and tan ) are shifted towards higher frequencies, revealing the existence of new relaxations and allowing the clarifications of ones already known. We have calculated the shift ratios (at maximum or tan )/ (at maximum or tan ) from the more conventional empirical equations representing the dielectric behavior. Some examples are given.     

Complex formation of unsaturated cyclodextrin solutions with various polymers

By using methyl orange as a competitive complexant, it was shown that solutions of poly(ethylene glycol), poly(propylene glycol) and poly(N-vinylpyrrolidone) equivalent to a concentration of 1.67 mM monomer are able to form soluble inclusion complexes with 0.20 mM solutions of -, - and -cyclodextrins. The complex formation is independent of polymer chain length. Poly(ethylene glycol) solutions complexed, on average with 40%, 45% and 75% of -, -, and -cyclodextrin, respectively. A poly(propylene glycol) solution complexed 55% -cyclodextrin, 80% -cyclodextrin and 90% -cyclodextrin. Poly(N-vinylpyrrolidone) solutions complexed on average with 90% of -, -, and -cyclodextrin.     

1H-NMR Investigation of the Binding of 2-Methylnaphthalene to α-Cyclodextrin in D2O Solutions

As -cyclodextrin (-CD) was added to D₂Osolutions of 2-methylnaphthalene, its proton signals shifted to lower fieldsat low concentrations of -CD. At 2.0 × 10^-2 moldm^-3 of -CD, however, a reverse, higher-field shift wasobserved for the H-8 signal, indicating the formation of 1 : 1 and 2 : 1-CD–2-methylnaphthalene inclusion complexes. Intrinsic chemicalshift differences of all the protons in 2-methylnaphthalene have beenevaluated for both the 1 : 1 and the 2 : 1-CD–2-methylnaphthalene inclusion complexes. These intrinsicchemical shift differences suggest that the first -CD molecule has noselectivity in accommodating one end of uncomplexed 2-methylnaphthalene;-CD binds to a methyl group, as well as a naphthalene ring-end havingno methyl group, to form the 1 : 1 inclusion complex, resulting in theformation of two kinds of 1 : 1 complexes.     

Asymmetric halogenation and hydrohalogenation of styrene in crystalline cyclodextrin complexes

Asymmetric halogenation and hydrohalogenation of styrene in microcrystalline cyclodextrin complexes were studied in the gas-solid state, and compared with the homogenous reactions in aqueous or dimethyl sulfoxide solutions. The gas-solid brominations in the - and -cyclodextrin complexes produced predominantly (–)-1,2-dibromo-l-phenylethane. The chiral induction for the reaction of the -cyclodextrin complex rose to 9 times that of the -cyclodextrin complex. Brominations in the homogenous solutions containing the - or -cyclodextrin complexes gave no dibromide but racemic bromohydrin. In the gas-solid chlorination, the -cyclodextrin complex gave (–)-dichloride,S-(+)-2-chloro-l-phenylethanol (14% ee) and (+)-1,2,2-trichloro-l-phenylethane, and the -cyclodextrin complex produced (+)-dichloride,S-(+)-chlorohydrin (8% ee) and (+)-trichloride. The chiral induction of the gas-solid halogenation using the solid cyclodextrin complexes is attributed to the ability to hold rigidly a chiral conformation of the crystalline state. However, the gas-solid hydrohalogenation all gave racemic products.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986.     

Cyclodextrin-accelerated oxidation of iodide by oxygen in aqueous solutions containing HClO4

The oxidation of iodide to I ₃ ^– by oxygen dissolved in water containing HClO₄ has been found to be accelerated by -cyclodextrin (-CD). Among -, -, and -CDs, -CD is the most effective mediator for the oxidation reaction of iodide by oxygen. The oxidation rate of iodide is first order in the concentrations of -CD and HClO₄, whereas it is second order in the KI concentration.Part of this work was carried out at Department of Physics, Miyazaki Medical College, Miyazaki 889-16, Japan.     

A spectrophotometric determination of the formation constants of the inclusion complexes ofα- andβ-cyclodextrins with the azonium and ammonium tautomers of methyl orange and methyl yellow

The color fading caused by the addition of-cyclodextrin or-cyclodextrin to an aqueous solution of a tautomeric mixture of methyl orange or methyl yellow is studied spectrophotometrically at pH 1.1 and 25.0°C. A model involving 1 : 1 stoichiometry has been used to analyze the spectrophotometric data. The addition of a cyclodextrin shifts the tautomeric mixture towards the side of the ammonium tautomer. An expression allowing the calculation of the tautomeric equilibrium constant of the inclusion complexes is derived. The formation constants of the inclusion complexes of the individual tautomers are determined. Both- and-cyclodextrins bind the ammonium tautomer stronger than the azonium tautomer. The inclusion complexes of-cyclodextrin are more stable than the corresponding ones of-cyclodextrin.     

Contribution to the study of the esterification mechanism in the gas phase of substituted benzoic acids on AlPO4

An A_AC2 type mechanism is proposed for the esterification of several substituted benzoic acids on AlPO₄ in the gas phase. The rate-controlling step is the surface reaction between an adsorbed molecule of acid and an unadsorbed molecule of ethanol. The K_A and constants, and the apparent E_a are determined.

---

2 AlPO₄ . , , . - , .

     

Spectroscopic investigation of cyclodextrin monomers,derivatives, polymers and azo dyes (1)

Circular dichroism (CD) and visible spectra of inclusion compounds between Methyl Orange (MO) analogues and -, -, -cyclodextrin (cdx), 2,6-dimethyl-and 2,3,6-trimethyl--cdx, water soluble -, -, -cdx polymer products were investigated. In the CD-spectroscopic investigation, the complex with -cdx epichlorohydrin condensate showed a large amplitude and splitting of the induced ^* band. Fractions of glyceryl ether of less than 2000 and polymer of more than 10000 dalton molecular mass were separated. Complexes of above two fractions and MO showed the same splitting spectral pattern. Job's plots from visible spectra showed the formation of the 11 complex and CD-data suggested the co-existence of the 21 MO-cdx complex. This splitting pattern showed the reversal of the signs when -cdx-ethyleneglycol-bis(epoxypropyl) ether was used and disappeared when larger host molecules and azo dyes were used. The splitting was explained by exciton interaction.     

Crystal structures of cyclodextrin complexes with chiral molecules

The chiral recognition by cyclodextrins and permethylated cyclodextrins have been investigated on the basis of the X-ray data of crystalline inclusion complexes. The macrocyclic ring of - and -cyclodextrin shows a round and symmetrical structure. -Cyclodextrin includes racemic 1-phenylethanol with the statistical disorder of the hydroxyl group. A pair of the R- and S-isomers of flurbiprofen are included within the cylindrical cavity formed by dimeric -cyclodextrin molecules with a head-to-head arrangement. The macrocyclic ring of permethylated cyclodextrins is remarkably distorted from the regular polygonal symmetry and has more flexibility in the conformational change than cyclodextrins. Owing to the distorted conformation and steric hindrance involving methyl groups, permethylated cyclodextrins do not equally include both isomers, as demonstrated by the permethylated -cyclodextrin complexes with mandelic acids. Permethylated -cyclodextrin binds D-mandelic acid more tightlyvia a host-guest hydrogen bond and induced-fit conformational change. Permethylated -cyclodextrin forms a hydrated crystalline complex with R-flurbiprofen, but S-flurbiprofen forms a non-hydrated crystalline complex. Significant differences between the two complexes are found in the orientation of the phenyl group and hydrogen-bond formation involving the carboxyl group.     

Triterpene glycosides from Pulsatilla chinensis

Four triterpene glycosides were isolated from the roots of Pulsatilla chinensis (Bunge) Regel (Ranunculaceae). Two new glycosides, chinensiosides A (1a) and B (2), were identified as 3-O-[-L-rhamnopyranosyl-(12)--L-arabinopyranosyl]-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid and 3-O-{-L-rhamnopyranosyl-(12)-[-D-glucopyranosyl-(14)]--L-arabinopyranosyl}-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid. The other two glycosides were identified as previously known hederasaponin C (3) from Hedera helix and glycoside III (4) from Pulsatilla cernua.     

Interactions of Nabumetone with Cyclodextrins in Solution and in the Solid State

The interactions of nabumetone (NAB) with -cyclodextrin (-CD) and-cyclodextrin (-CD) were studied in aqueous solution by meansof phase-solubility analysis. Solid dispersions of NAB with -cyclodextrin(-CD), -cyclodextrin (-CD), methyl- (M-CD),hydroxypropyl-cyclodextrin (HP-CD) were prepared by coevaporationand kneading and also by coprecipitation in the case of -CD. X-ray diffractometry, thermal analysis and infrared spectroscopy (FTIR) were used to study the possibility of complexation of the drug with the different cyclodextrins. Solid dispersions of nabumetone with -CD showed a remarkable improvement in the dissolution rate of nabumetone.     

GC-MS characterization and quantification of sterols and cholesterol oxidation products

Summary A GC-MS method has been studied for characterization and quantification of phytosterols, cholesterol and cholesterol oxidation products. Baseline separations have been achieved between cholesterol, cholesterol 5-6-epoxide, 5-cholestene-3-ol-7one (7-keto-cholesterol), cholestene-3-5-6-triol, 5-cholestene-3-25-diol (25-hydroxycholesterol), 5-cholestene-3-20-diol (20-hydroxycholesterol), 5-cholestene-3-7-diol (7-hydroxycholesterol) and 5-cholestene-3-19-diol (19-hydroxycholesterol) as well as between -cholestane, cholesterol, stigmasterol, campesterol and -sitosterol. Excellent linearity of response has been obtained permitting reliable quantification. The characterization of each derivatized sterol has been performed by mass-spectrometry. The results confirm the utility of combined gas chromatography-mass spectrometry in the analysis and characterization of sterols and cholesterol oxidation products.     

Steroid compounds from the starfish Lysastrosoma anthosticta collected in the Sea of Japan

Six polyhydroxylated steroids and their derivatives were isolated from the starfish Lysastrosoma anthosticta collected in the Posyet Bay, Sea of Japan. These include a new glycoside of the steroid polyol, lysastroside A (1), which was identified as (25S)-26-O--d-xylopyranosyl-5-cholestane-3,6,8,15,16,26-hexaol, and the previously known pycnopodioside C monoglycoside (2), marthasterone sulfate (3), (25S)-5-cholestane-3,6,8,15,16,26-hexaol (4), (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (5), and (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (6). The compounds were tested for the haemolytic activity and the action on the embryogenesis of the sea urchin Strongylocentrotus intermedius.     

Steroid compounds of marine sponges. VII. Preparation of derivatives of sokotrasterol and halistanol sulfates and structure-activity interrelationships among these compounds

Five new sulfated derivatives of sokotrasterol and halistanol have been obtained: 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate); 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate) 23-palmitate; 24,25-dimethyl-5-cholestane-2,3,6-triol 3-(sodium sulfate); 24,25-dimethyl-5-cholestane-2,3,6-triol 6-(sodium sulfate); and 24,25-dimethyl-5-cholestane-2,3,6-triol 2,6-di(sodium sulfate). The inhibiting and membranolytic properties of the polysulfated steroids from sponges and their derivatives have been studied. It has been shown that physiological activity in this series of compounds depends on biphilicity.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 441–445, July–August, 1986.     

Deuterium relaxation time ofα-d-tryptophan included in cyclodextrin host molecules

Deuterium relaxation times ofd- andl--d-tryptophan included in -cyclodextrin derivatives were directly measured by deuterium NMR spectroscopy. The results showed that the molecular motion of the tryptophan molecule was strongly restricted even in the cavity of unmodified -cyclodextrin and the additional recognition groupings — ammonium and carboxylate — on -cyclodextrin did not affect the molecular motion of tryptophan, though the association constants were significantly enhanced.Deceased on March 22, 1987.     

Supramolecular Polymers Formed by Modified Cyclodextrins

6-Hydrocinnamoyl -cyclodextrin(6-HyCiO--CD), 6-hydrocinnamoyl -cyclodextrin(6-HyCiO--CD), 6-cinnamoyl -cyclodextrin(6-CiO--CD), and 6-cinnamoyl -cyclodextrin (6-HyCiO--CD) have been prepared.6-HyCiO--CD formed an intramolecular complex in an aqueous solution. 6-HyCiO--CD formed weak intermolecular complexes.6-CiO--CD formed intermolecular complexes to give supramolecular oligomers. 6-CiO--CD formed insoluble supramolecular complexes in the solid state. The structures of these complexes are discussed.     

Charge-transfer Interaction: A Driving Force for Cyclodextrin Inclusion Complexation

PM3 calculations were performed on the complexation of -cyclodextrin (-CD) with nitrobenzene, benzoic acid, benzoate anion, 4-nitrophenol, and 4-nitrophenolate anion. The results, in agreement with the experimental observations, indicated that the complex -CD-benzoic acid was more stable than -CD-nitrobenzene, and -CD-4-nitrophenolate was more stable than -CD-4-nitrophenol. Frontier orbital analysis suggested that charge-transfer interaction led to such behaviors, and hence constituted a nontrivial driving force in the molecular recognition of -CD.     

Quinazolines X. Synthesis of 6,6'-methylenebisdeoxyvasicinone and its homologs

Summary 6,6-Methylenebisdeoxyvacisinone and its homologs have been synthesized by the reaction of methylenebisanthranilic acid with lactams (-butyrolactam, -valerolactam, -caprolactam, and -chloro- and ,-dichloro--caprolactams). The condensation of anthranilic acid and its derivatives (4-nitro-, 5-bromo-, 5-iodo-, and 5-nitroanthranilic acids) with ,-dichloro--caprolactam has given seven-membered analogs of deoxyvasicinone containing two chlorine atoms in the polymethylene ring.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 544–547, July–August, 1977.