Theoretical and experimental NMR studies of the Swern oxidation of methyl 6<Emphasis Type="Italic">α</Emphasis>,7<Emphasis Type="Italic">β</Emphasis>-dihydroxyvouacapan-17<Emphasis Type="Italic">β</Emphasis>-oate

This work describes the synthesis of new derivatives of 6α,7β-dihydroxyvouacapan-17β-oic acid (1) employing the Swern method for the oxidation of C-6 and C-7 of methyl 6α,7β-di-hydroxyvouacapan-17β-oate (2) and the formation of methyl 6,7-dioxovouacapan-17β-oate (3). NMR structural studies associated with theoretical calculations of reaction intermediates and products are also reported. The mixture of methyl 7β-hydroxy-6-oxovouacapan-17β-oate (4; 21%) and methyl 6α-hydroxy-7-oxovouacapan-17β-oate (5; 79%) was the product from the first step of the oxidation of 2. The lower energy of 5, calculated by HF/6-31G* and DFT/BLYP/6-31G* methods, reinforces the thermodynamic control proposed for the reaction. After further Swern oxidation of the mixture of 4 and 5, the isomeric form methyl 6-hydroxy-7-oxovouacap-5-en-17β-oate (6) was obtained. Theoretical calculations indicate a lower energy for the mono-enol 6 than the 1,2-diketo 3 and the other mono-enol methyl 7-hydroxy-6-oxovouacap-7-en-17β-oate (7).     

Balanoinvolin,a new steroid derivative from <Emphasis Type="Italic">Balanophora involucrate</Emphasis>

A new compound, β-sitosterylglucoside-3′-O-linoleate, named balanoinvolin, and three known compounds coniferin, methylconiferin, and 4-O-β-D-glucopyranosylconiferyl aldehyde, were isolated from Balanophora involucrate Hook. f. and their structures were determined by MS and 1D/2D NMR spectra. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 315–317, May–June, 2009.     

Two new benzoyl esters of glucose from Lagotis yunnanensis

Two new benzoyl esters of glucose 1-O-(E)-4′-methoxybenzoyl-β-D-glucopyranose (1) and 1-O-(E)-4′-methoxybenzoyl-β-D-gluconic acid (2) were isolated from Lagotis yunnanensis, together with six previously known iridoid glucosides. The structures of these compounds were elucidated on the basis of spectral analysis, including 2D NMR spectroscopy. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 529–530, November–December, 2006.     

Cardiac glycosides from Strophanthus kombe

Twelve cardiac glycosides and aglycons were isolated from Strophanthus kombe seeds. Of these, eight were identified as cymarin, K-strophanthin-β, K-strophanthoside, periplocymarin, 17α-strophadogenin, erysimin (= helveticoside), erysimoside, and neoglucoerysimoside. Four glycosides, preliminarily designated Sk-x, Sk-y, Sk-z, and Sk-20, were new. Their chemical structures were established as 3β-O-β-D-glucopyranosyl-5β,14β,16β-trihydroxy-19-oxo-17α-card-20(22)enolide (17α-strophadogenin-3-O-β-D-glucoside), 3β-O-β-D-cymaropyranosyl-5β,14β,16β-trihydroxy-19-oxo-17α-card-20(22)enolide (17α-strophadogenin-3-O-β-D-cymaroside), 3β-O-β-D-cymaropyranosyl-4′-O-β-D-glucopyranosyl-6″-O-β-D-glucopyranosyl-5β, 14β,16β-trihydroxy-19-oxo-17α-card-20(22)enolide (17α-strophadogenin-3-O-strophanthotrioside), and 3-O-β-D-digitoxopyranosyl-4′-O-β-D-glucopyranosyl-6″-O-β-D-glucopyranosyl-5β,14β, 19-trihydroxy-card-20(22)enolide (strophanthidol-3-O-gentiobiosyldigitoxoside), respectively. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 156–159, March–April, 2006.     

High-performance liquid chromatographic separation of unusual amino acid enantiomers derivatized with (1S,2S)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propyl-isothiocyanate

Summary A new chiral derivatizing agent (CDA), (1S,2S)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propylisothiocyanate, (S,S)-DANI, was applied to the separation of the enantiomers of unusual amino acids containing two chiral centers. Different β-methyl-α-amino acids (β-MePhe, β-MeTyr and β-MeTrp) and β-amino acids with cycloalkane skeletons (2-aminocyclopentanecarboxylic acid and 2-aminocyclohexanecarboxylic acid) were derivatized and the thiourea derivatives produced were separated by reversed-phase high-performance liquid chromatography. The applicability of this new CDA in the separation of unusual amino acids is demonstrated. The four stereoisomers of the investigated amino acids (except β-MePhe) could be separated in one chromatographic run. Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

Triterpene glycosides from Kalopanax septemlobum. VI. Glycosides from leaves of Kalopanax septemlobum var. typicum introduced to crimea

Thirteen known glycosides of hederagenin and oleanolic acid and the three new triterpene glycosides of oleanolic acid-28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester 3-O-β-D-glucopyranosyl-(1→4)-O-β-D-xylopyranosyl-(1→ 3)-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranoside of oleanolic acid and the 28-O-α-L-rhamnopyranosyl-(1→4)-O-6-O-acetyl-β-D-glucopyranosyl-(1→ 6)-O-β-D-glucopyranosyl esters 3-O-β-D-xylopyranosyl-(1→3)-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranoside of oleanolic acid and 3-O-β-D-glucopyranosyl-(1→4)-O-β-Dxylopyranosyl-(1→3)-O-α-L-rhamnopyranosyl-(1→ 2)-O-α-L-arabinopyranoside of oleanolic acid were isolated from leaves of Kalopanax septemlobum var. typicum introduced to Crimea. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 40–43, January–February, 2006.     

Prokaryotic Expression, Purification and Characterization of Aspergillus sulphureus β-Mannanase and Site-Directed Mutagenesis of the Catalytic Residues

Wild type (WT) DNA sequence, which encoded a mature β-mannanase of Aspergillus sulphureus, composed of 1,152 nucleotides (nt), was amplified from pUCm-T-mann by polymerase chain reaction (PCR). Based on this DNA fragment, mutants designated as E²⁰⁶G and E³¹⁴G were constructed by overextension PCR (OE-PCR). Glutamic acids of the 206th and 314th sites in the amino acid sequence of β-mannanase were separately replaced by glycine in these two mutants. The WT and mutant genes were ligated into prokaryotic vector pET-28a (+) and transformed into the Escherichia coli BL21 strain, respectively. The recombinant enzyme proteins were expressed by IPTG induction and detected by Western blot. The recombinant proteins purified with Ni-NTA column were dialyzed to correctly refold. The WT recombinant β-mannanase showed optimal activity at 50 °C and pH 2.4. The kinetic parameters of K _m and V _max for purified β-mannanase were 1.38 mg/ml and 72.99 U/mg, respectively. However, the mutant proteins did not show any activity. It was demonstrated that E²⁰⁶ and E³¹⁴ were the catalytic residues of β-mannanase.     

A new stilbene glycoside from the <Emphasis Type="Italic">n</Emphasis>-butanol fraction of <Emphasis Type="Italic">Veratrum dahuricum</Emphasis>

A new stilbene glycoside, 5-methylresveratrol-3,4′-O-β-D-diglucopyranoside (1), was isolated from the n-butanol fraction of the rhizomes of Veratrum dahuricum, together with five known stilbenoids: resveratrol-3-O-β-D-glycoside (2), 4′-methylresveratrol-3-O-β-D-glycoside (3), oxyresveratrol-4′-O-β-D-glycoside (4), oxyresveratrol-3-O-β-D-glycoside (5), and oxyresveratrol-3,4′-O-β-D-diglycoside (6), and found for the first time in the investigated plant. The structures of six isolates were identified on the basis of 1D and 2D NMR data. Compounds 1–6 showed platelet aggregation inhibition, and compound 1 had an IC₅₀ value of 383.6 μM against platelet aggregation induced by AA. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 279–282, May–June, 2009.     

A new phytoecdysteroid

A new phytoecdysteroid,viz, 2-deoxy-3-epi-4β, 20-dihydroxycedysone ((20R,22R)-3α,4β 14α,20,22,25-hexahydroxy-5β-cholest-7-en-6-one), named coronatasteronc, was isolated fromSerratula coronata and identified by NMR spectroscopy. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1954–1955, November, 2000.     

Production of cellulase/β-glucosidase by the mixed fungi culture of Trichoderma reesei and Aspergillus phoenicis on dairy manure

A cellulase production process was developed by growing the fungi Trichoderma reesei and Aspergillus phoenicis on dairy manure. T. reesei produced a high total cellulase titer (1.7 filter paper units [FPU]/mL, filter paper activity) in medium containing 10 g/L of manure (dry basis [w/w]), 2 g/L KH₂PO₄, 2 mL/L of Tween-80, and 2mg/L of CoCl₂. However, β-glucosidase activity in the T. reesei-enzyme system was very low. T. reesei was then cocultured with A. phoenicis to enhance the β-glucosidase level. The mixed culture resulted in a relatively high level of total cellulase (1.54 FPU/mL) and β-glucosidase (0.64 IU/mL). The ratio of β-glucosidase activity to filter paper activity was 0.41, suitable for hydrolyzing manure cellulose. The crude enzyme broth from the mixed culture was used for hydrolyzing the manure cellulose, and the produced glucose was significantly (p<0.01) higher than levels obtained by using the commercial enzyme or the enzyme broth of the pure culture T. reesei.     

New polyhydroxysteroids and steroid glycosides from the far east starfishCeramaster patagonicus

Two new polyhydroxysteroids and five new glycosides were isolated from the starfishCeramaster patagonicus and their structures were elucidated: 5α-cholestane-3β,6α,15β,16β,26-pentol, (22E)-5α-cholest-22-ene-3β,6α,8,15α,24-pentol, (22E)-28-O-[O-(2-O-methyl-β-d-xylopyranosyl)-(1→2)-β-d-galactofuranosyl]-24-hydroxymethyl-5α-cholest-22-ene-3β,4β, 6α,8,15β,16β,28-heptol (ceramasteroside C₁), (22E)-28-O-[O-(2,4-di-O-methyl-β-d-xylopyranosyl)-(1→2)-β-d-galactofuranosyl]-24-hydroxymethyl-5α-cholest-22-ene-3β, 6α,8,15β,16β,28-hexol (ceramasteroside C₂), (22E)-28-O-[O-methyl-β-d-xylopyranosyl)-(1→2)-β-d-galactofuranosyl]-24-hydroxymethyl-5α-cholest-22-ene-3β,6α,8,15β,16β 28-hexol (eramasteroside C₃), (22E)-28-O-[O-(2-O-methyl-β-d-xylopyranosyl)-(1→2)-β-d-galactofuranosyl]-24-methyl-5α-cholest-22-ene-3β,4β,6α,8, 15β, 26-hexol (ceramasteroside C₄), and (22E)-28-O-[O-(2-O-methyl-β-d-xylopyranosyl)-(1→2)-β-d-xylopyranosyl]-5α-cholest-22-ene-3β,6α,8,15β,24-pentol (ceramasteroside C₅)). Three known polyhydroxysteroids (24-methylene-5α-cholestane-3β,6α,8,15β,16β,26-hexol, 5α-cholestane-3β,6α,8,15β,16β,26-hexol, and 5α-cholestane-3β,6β,15α,16β,26-pentol) were also isolated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 190–195, January, 1997.     

Two new coumarin biosides from Angelica dahurica

Two new coumarin biosides, tert-O-β-D-apiofuranosyl-(1→6)-O-β-D-glucopyranosyl-byakangelicin (1) and 2′-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranosyl-peucedanol (2), were isolated from the fresh roots of Angelica dahurica. The structures of the new compounds were elucidated on the basis of spectral analysis. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 561–563, November–December, 2008.     

New glycosidic and other constituents from hulls of <Emphasis Type="Italic">Oryza sativa</Emphasis>

Three new compounds, 4-hydroxymethylene-7-(9,9,13-trimethylcyclohexyl)-heptanyl-3′,7′,7′-trimethylcyclohexa-2′,4′-dien-1′-oate (1), 1-(n-hexadec-7-enoxy)-6-(n-octadecanoxy)-β-D-glucopyranoside (2), and (Z)-12-hydroxy-9-octadecenoic acid-12-β-D-glucopyranoside (3), along with the known compound hexacosanoic acid (4), were isolated and identified from the rice hulls of Oryza sativa. Their structures were elucidated by 1D and 2D NMR spectroscopic techniques (¹H-¹H COSY, ¹H-¹³C HETCOR, DEPT) aided by EIMS, FABMS, HRFABMS, and IR spectra. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 344–347, July–August, 2007.     

Separation and Determination of Eremophilenolides from Ligulariopsis shichuana by Capillary Zone Electrophoresis

A new method of capillary zone electrophoresis (CZE) was established by simultaneous assay of four eremophilenolides, 3β-acetoxy-9β-angeloyloxy-1β,10β-epoxy-8α-hydroxyeremophil-7(11)-en-8β (12)-olide (1), 3β-senecioyloxy -1β,10β-epoxy-8α-hydroxyeremophil-7(11)-en-8β (12)-olide (2), 6α-hydroxy-1β,10β-epoxy-8α-hydroxyeremophil-7(11)-en-8β (12)-olide (3) and 3β-acetoxy- 6β-angeloyloxy-1β,10β-epoxy-8α-hydroxyeremophil-7(11)-en-8β (12)-olide (4) in the Chinese herbal extract from Ligulariopsis shichuana. The optimum buffer system was 20 mM borate buffer (pH 10.00). Voltage was 25 kV and detection at 214 nm. Regression equations revealed linear relationships (correlation coefficients 0.9986, 0.9990, 0.9992 and 0.9995) between the peak area of each compound and its concentration. The relative standard deviations of migration times and peak areas were <1.35 and 3.94% within 1 day, respectively. The effects of several CE parameters on the resolution were studied systematically. The contents of four eremophilenolides in Ligulariopsis shichuana were successfully determined with satisfactory repeatability and recovery.     

Synthesis of new derivatives of 3<Emphasis Type="Italic">β</Emphasis>-hydroxy18<Emphasis Type="Italic">β</Emphasis>H-olean-9,12-dien-30-oic acid

Ring A was transformed and new A-homo-4-aza- and 3-cyano-3,4-seco-olean-4-ene derivatives of 3β-hydroxy18βH-olean-9,12-dien-30-oic acid were synthesized. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 335–338, May–June, 2009.     

Polar steroidal compounds from the Far-Eastern starfish <Emphasis Type="Italic">Lethasterias fusca</Emphasis>

Nine steroidal compounds including three new steroidal glycosides, viz., sodium (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol 15-sulfate (fuscaside A), (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol (fuscaside B), and (22E,24R)-24-O-(β-D-xylopyranosyl)-5α-cholest-22-ene-3β,6α,8,15β,24-pentol (desulfated minutoside A); three previously known glycosides, viz., distolasterosides D₁ and D₂ and pycno-podioside A; two previously known polyhydroxysteroids, viz., 5α-cholestane-3β,6α,8,15β,16β,26-hexaol and 5α-cholestan-3β,4β,6α,7⇇8,15β,16β,26-octol; and the known sodium 24,25-dihydro-marthasterone 3-sulfate were isolated from the Far-Eastern starfish Lethasterias fusca. The structures of these compounds were elucidated by NMR spectroscopy and mass spectrometry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 196–200, January, 2008.     

Hydroacridines XXV [1]. First Synthesis of (4aα,8aα,9aβ,10aβ)-Tetradecahydroacridine and New Syntheses of (4aα,8aα,9aα,10aβ)- and (4aα,8aβ,9aα,10aβ)-Tetradecahydroacridine

Summary. On heating in dry DMSO, in the presence of potassium t-butoxide, the N-nitrosamine of (4aα,8aβ,9aβ,10aα)-tetradecahydroacridine is completely converted into the N-nitrosamine of (4aα,8aα,9aα,10aβ)-tetradecahydroacridine. Under similar conditions, the N-nitrosamine of (4aα,8aα,9aβ,10aα)-tetradecahydroacridine yields a ternary equilibrium mixture containing itself (19%), and the N-nitrosamines of (4aα,8aβ,9aα,10aβ)-tetradecahydroacridine (46%) and the so far unknown (4aα,8aα,9aβ,10aβ)-tetradecahydroacridine (35%). The resulting N-nitrosamines can be smoothly denitrosated to the corresponding secondary amines.     

Selective Pseudo-Rotaxane Type Complex Formation of Zinc(II) (t-butylatedtetraphenyl) porphyrin-Viologen Linked Compounds with tri-O-methyl-β-Cyclodextrin

Inclusion complexation behavior of 2,3,6−tri-O-methyl-β-cyclodextrin (TM-β-CD) with zinc(II) 5,10,15-tri-(4-t-butyl-phenyl)-20-(4-(n-alkyloxy)phenylporphyrin covalently linked with violgen by a polymethylene chain (Zn-t- bu-PC _n V²⁺; n=4, 6, 8, 10 and 12) was investigated by means of ¹H NMR, UV/Vis absorption spectroscopies in acetonitrile-water (1:1, v/v). The ¹H NMR spectra indicated that Zn-t-bu-PC _n V²⁺ presumably existed as a mixture of a dimer and a monomer in high concentration (>1×10⁻³ mol dm⁻³), and the dimer was degraded by the complex formation with TM-β-CD. The ¹H NMR spectra of these compounds as a function of [TM-β-CD] showed the selective formation of 1:1 (=Zn-t-bu-PC _n V²⁺: TM-β-CD) pseudo-rotaxane type complexes. The chemical modification by t-butyl groups on porphyrin showed a good protective effect on inclusion of benzene groups into the TM-β-CD cavity. These rotaxane formation constants (K) were determined by titration studies using UV/Vis absorption spectroscopy. These complex formation constants were somewhat affected by the spacer methylene chain between the porphyrin and viologen. The value of K for Zn-t-bu-PC₄V²⁺·TM-β-CD is 1.0×10³ M⁻¹ which is the smallest whereas those for Zn-t-bu-PC _n V²⁺·TM-β-CD (n=8, 10, 12) were similar (1.0×10⁴ M⁻¹).     

Three antibacterial compounds from the roots of <Emphasis Type="Italic">Pteris multifida</Emphasis>

A new eudesmane-type sesquiterpenoid, 3β-caffeoxyl-1β,8α-dihydroxyeudesm-4(15)-ene (1), together with two known compounds including ludongnin V (2) and isoneorautenol (3), were isolated from the roots of Pteris multifida. Their structures were determined by spectral and chemical methods, with their antibacterial activities being evaluated by the microdilution technique, respectively. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 41–43, January–February, 2009.     

Synthesis of 2,3,4,6-tetra-O-acetyl-β-D-gluco(galacto)pyranosylcaprolactams and 2,3,4,6-tetra-O-acetyl-β-D-gluco(galacto) pyranosylpyrrolidones

A new synthesis of certain lactam-containing N-glycosides was developed. 2,3,4,6-Tetra-O-acetyl-β-D-gluco(galacto)pyranosylcaprolactams and 2,3,4,6-tetra-O-acetyl-β-D-gluco(galacto)pyranosylpyrrolidones were synthesized by condensation at room temperature of acetobromoglucose and acetobromogalactose with ɛ-caprolactams and α-pyrrolidone. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 105–106, March–April, 2006.