Polyhydroxysteroids from the Far-Eastern starfishCtenodiscus crispatus

Four new polyhydroxysteroids, 5-cholesta-3,5,6,15,16,25,26-heptaol, 24-ethyl-5-cholesta-3,5,6,15,28,29-heptaol-29-sulfate, (22E)-24-methyl-5-cholest-22-ene-3,5,6,15,25,26-hexaol-26-sulfate, 24-propyl-5-cholesta-3,5,6,8,15,28,29-heptaol, and the known 5-cholesta-3,5,6,15,16,26-hexaol, have been isolated from the starfishCtenodiscus crispatus.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1821–1825, October, 1994.     

Prostanoids: LXXVII. Synthetic Approaches to Sterically Overcrowded Cyclopentenones

Condensation of (±)-5-allyl-2,3,5-trichloro-4,4-dimethoxy-2-cyclopentenone with phenylethynylmagnesium bromide in THF gave (±)-5-allyl-2,3,5-trichloro-4,4-dimethoxy-1-phenylethynyl-2-cyclopenten-1-ol which chemoselectively reacted with ozone at the terminal double bond, affording (±)-2,3,5-trichloro-5-formylmethyl-4,4-dimethoxy-1-phenylethynyl-2-cyclopenten-1-ol. Oxidation of the latter with H₂CrO₄ yielded a mixture of the expected product, (±)-5-carboxymethyl-2,3,5-trichloro-4,4-dimethoxy-1-phenylethynyl-2-cyclopenten-1-ol, and anomalous profound oxidation product, (±)-2,3,5-trichloro-5-carboxymethyl-4,4-dimethoxy-1-(2-oxo-2-phenylacetyl)-2-cyclopenten-1-ol. Attempts to remove protective methoxy groups in these compounds under standard conditions were unsuccessful.     

Triterpene glycosides ofHedera taurica XIV. Structures of glycosides St-G0–2, St-J, and St-K from the stems of Crimean ivy

The structures of new triterpene glycosides isolated from the stems of Crimean ivyHedera taurica Carr. (fam. Araliaceae) — St-J, St-K, and St-G_0–2 — have been established as the 3-0--L-glucopyranuronoside 28-O-[O-L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)--D-glucopyranoside]s of oleanolic acid and of hederagenin and the 3–0(6-O-ethyl--D-glucopyranuronoside) 28-O-[O-L-rhamnopyranosyl0(14)-O--D-glucopyranosyl-(16)-glucopyranoside of hederagenin, respectively.Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii No. 3, pp. 397–403, May–June, 1997.     

Some Pharmaceutical Properties of a New Branched Cyclodextrin, 6-O-α-(4-O- α-D-Glucuronyl)-D-glucosylβ-cyclodextrin

Some physicochemical and biological properties of a new branched cyclodextrin, 6-O--(4-O--d-glucuronyl)-d-glucosyl--cyclodextrin GUG--CyD) were investigated. Further, theinteraction of GUG--CyD with several drugs was studied by the solubility and spectroscopic methods, and compared with those of parent -CyD and 6-O--maltosyl--CyD(₂--CyD).The hemolytic activity of GUG--CyD on rabbit erythrocytes was lower than those of -CyD and ₂--CyD. GUG--CyD and ₂--CyD showed negligible cytotoxicity on Caco-2 cells up to at least 0.1 M. The inclusion ability of GUG--CyD to neutral and acidic drugs was comparable to or slightly smaller than those of -CyD and ₂--CyD, probably because of a steric hindrance of the branched sugar. On the other hand, GUG--CyD showed greater affinity for the basic drugs, compared with -CyD and ₂--CyD, owing to the electrostatic interaction of its carboxylate anion with positive charge of basic drugs. Thus GUG--CyD may be useful as a safe solubilizing agent particularly for basic drugs.     

New asterosaponins from the starfishDismolasterias nipon

Three new glycosides, D₁, D₂, and D₃, have been isolated from the Far Eastern starfishDistolasterias nipon. They have been identified by chemical and physicochemical methods as 5-cholestane÷3,6,8,15,24-pentaol 3,24-di-O--D-xylopyranoside, t-cholest-22-ene-3,6,8,15,24-pentaol 3,24-di-O--D-xylopyranoside (II), and 5-cholestane-3,6,8,15,24-pentaol 24-O--D-glucopyranoside 3-O--D-xylopyranoside (III).Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 250–255, March–April, 1987.     

Triterpene glycosides of alfalfa VIII. Medinoside E from the leaves

From the leaves ofMedicago sativa L. (Leguminosae) we have isolated the glycoside soyasapogenol B — medinoside E. Medinoside E has the structure of olean-12-ene-3,22,24-triol 3-O-[O--L-rhamnopyranosyl-(12)-O--D-galactopyranosyl-(12)-O--D-glucopyranosyl-(12)--D-glucopyranuronoside].Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan Tashkent. Institute of Organic Chemistry, Russian Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 705–710, September–October, 1993.     

Steroids of the furostan and spirostan series from Nolina microcarpa II. structures of nolinospiroside D and nolinofurosides D, E, and F

Proofs are given of the structures of two new glycosides of the furostan series isolated from the leaves of the plantNolina microscarpa S. Wats. (family Dracaenaceae). Nolinofuroside D is (25S)-furost-5-ene-1,3,22,26-tetraol 1-O--D-galactopyranoside 26-O--D-glucopyranoside (I), and nolinofuroside F is (25S)-furost-5-ene-1,3,22,26-tetraol 1-O--D-fucopyranoside 26-O--D-glucopyranoside 3-O--L-rhamnopyranoside (VII). The latter was characterized as its 22-O-methyl ether (VIII). Nolinofuroside E (IV) has the structure of (25S)-furost-5-ene-1,3,22,26-tetraol 26-O--glucopyranoside 1-O-[O--L-rhamnopyranosyl-(12)--D-fucopyranoside], which followed from the structure of the fermentation product (VI). The products of the fermentation of the above-named compounds were present in the plant in only trace amounts. Only one of them — nolinospiroside D (III) — has not been described previously. This monoside of the spirostan series is (25S)-spirost-5-ene-1,3-diol 1-O--D-galactopyranoside.M. V. Frunze Simferopol' State University. Institute of Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 678–686, September–October, 1991.     

Solubility Study of Nimodipine Inclusion Complexation with α- and β-Cyclodextrin and some Substituted Cyclodextrins

The solubility of nimodipine was measured in aqueous solutions of the following cyclodextrins: -cyclodextrin (-CD), hydroxypropyl--CD (HP--CD), -cyclodextrin (-CD), random substituted methyl--CD (M--CD), three hydroxypropyl--CDs (HP--CD) with mutually different average degree of substitution, and hydroxypropyl--cyclodextrin (HP--CD). From the determined linear solubility diagrams the values of the binding constant K₁₁ of the inclusion complexes of nimodipine with the respective CDs were evaluated. The -CDs efficiently solubilized sparingly soluble nimodipine, the highest value of K₁₁ was found for M--CD (1680 M^-1), followed by -CD (550 M^-1) and HP--CDs, where the higher degree of substitution lowered K₁₁. Only slight solubilization of nimodipine was observed in the solutions of the -CDs and HP--CD.     

A reanalysis of the kinetic data on the boat pathway of the cope rearrangement of 1,5-hexadiene by comparing with quantum-chemical MINDO/3 results

An attempt has been made to match the availble kinetic data on the title process with the theoretical discovery that it is realized via an intermediate. A new fitting procedure is suggested which takes into account the presence of the intermediate.

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Studies on lanthanon(III) complexes ofN-methylisatin-β-amidinohydrazone

Summary The consecutive formation constants of 11 and 21 chelate species made by interaction ofN-methylisatin--amidinohydrazone (-MIAG) with tripositive lanthanons were determined potentiometrically at different ionic strengths (0.02, 0.05, 0.1 and 0.2 M NaClO₄) and at different temperatures (30, 40, 45 and 50 °C) in 50% v/v dioxan-H₂O. The formation constants log _n (calculated by a weighted least-squares method) for the complexes have been found to increase with the atomic number of the lanthanon, with a break at gadolinium. Thermodynamic parameters G, H and S of these complexation reactions were also evaluated.