Beyerane derivatives and a sesquiterpene dimer from Japanese Cypress (Chamaecyparis obtusa)

In the course of studies on biological active constituents from woody plants, we previously reported the isolation of many lignan derivatives as neurite outgrowth-promoting compounds from an ethyl acetate soluble fraction of Japanese Cypress (Chamaecyparis obtusa). Further chemical investigation on the residual parts of the ethyl acetate soluble fraction of a methanol extract of Japanese Cypress resulted in the isolation of four new beyerene type derivatives and a novel sesquiterpene dimer formed between cryptomeridiol and hinokiic acid. Their structures were elucidated as 18-O-(Z)-p-coumaroylbeyer-15-ene-18-ol (1), 18-O-(E)-p-coumaroylbeyer-15-ene-18-ol (2), 18-O-(E)-p-coumaroylbeyer-15-ene-11beta,18-diol (3), 18-O-(Z)-p-coumaroylbeyer-15-ene-11beta,18-diol (4) and ent-cryptomeridiol-4-yl-hinokiiate (5) by (1)H-NMR, (13)C-NMR, 2D-NMR, and HR-MS spectral analysis.     

Neurite outgrowth-promoting active constituents of the Japanese cypress (Chamaecyparis obtusa)

In the screening of biologically active constituents from woody plants, the methanol extract of leaves of Chamaecyparis obtusa showed potent neurite outgrowth-promoting activity in neuronal PC12 cells. The ethyl acetate-soluble fraction of the methanol extract showed potent activity and was separated by means of various chromatographic methods to give the two new compounds 1 and 2, as well as 11 known lignan and sesquiterpene derivatives. The structures of the new compounds were determined to be 9-O-acetyldihydrosesamin (1) and 9-O-(11-hydroxyeudesman-4-yl)dihydrosesamin (2), respectively, in NMR studies including 2D-NMR experiments. Of the 13 compounds, the known compound hinokinin (5) and the new compound 2 showed potent neurite outgrowth-promoting activity in PC 12 cells.     

Effective Extraction of Limonene and Hibaene from Hinoki (Chamaecyparis obtusa) Using Ionic Liquid and Deep Eutectic Solvent

The essential oils of hinoki (Chamaecyparis obtusa) leaves have anti-bacterial, anti-fungal, and relaxation properties that are likely associated with the major components such as sabinene, α-terpinyl acetate, limonene, elemol, myrcene, and hibaene. The present study describes the use of a cellulose-dissolving ionic liquid (IL) [C₂mim][(MeO)(H)PO₂] and low-toxicity solvents called betaine-based deep eutectic solvents (DESs) for the efficient extraction of hinoki essential oils. As a control method, organic solvent extraction was performed using either hexane, ethyl acetate (EtOAc), or acetone at 30 °C for 1 h. Both the experimental and control methods were conducted under the same conditions, which relied on partial dissolution of the leaves using the IL and DESs before partitioning the hinoki oils into the organic solvent for analysis. Quantitative analysis was performed using gas chromatography–mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The results indicated that extraction using the [C₂mim][(MeO)(H)PO₂]/acetone bilayer system improved the yields of limonene and hibaene, 1.5- and 1.9-fold, respectively, when compared with the control method. In addition, extraction using betaine/l-lactic acid (molar ratio 1:1) gave the greatest yields for both limonene and hibaene, 1.3-fold and 1.5-fold greater, respectively, than when using an organic solvent. These results demonstrate the effective extraction of essential oils from plant leaves under conditions milder than those needed for the conventional method. The less toxic and environmentally begin DESs for the extraction are also applicable to the food and cosmetic industries.     

Novel diterpenes from the heartwood of Chamaecyparis obtusa var. formosana

Two novel diterpenes, obtusanal B (1) and obtusadione (2), along with obtusanal A (3), obtunone (4), 12-hydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial, 8,12-dihydroxydielmentha-5,9-diene-7,11-dione and myrcene, isolated from the heartwood of Chamaecyparis obtusa var. formosana, were characterized by spectroscopic means, including 2D-NMR techniques. Compounds 1 and 2 are 7(6-->2)abeoabietane and 14(8-->9)abeoabietane type diterpenes, respectively. Their biosyntheses were proposed.     

New lignans from the heartwood of Chamaecyparis obtusa var. formosana

Four new lignans, 3',4'-O,O-demethylenehinokinin (1), chamalignolide (2), 8'beta-hydroxyhinokinin (3) and 7beta,8beta-epoxyzuonin A (4), as well as (-)-hinokinin (5), and (-)-zuonin A (6), were isolated from the heartwood of Chamaecyparis obtusa var. formosana. The structures of these lignans were unambiguously determined by spectroscopic methods. And the absolute configuration of 1 was elucidated with a circular dichroism (CD) spectrum.     

New Dimeric Monoterpenes and Dimeric Diterpenes from the Heartwood of Chamaecyparis obtusa var. formosana

Two dimeric monoterpenes obtusal A and B, and two dimeric diterpenes obtusanol A and B, along with (−)‐(S)‐citronellol, (−)‐(S)‐citronellic acid, (+)‐borneol, (+)‐sugiol, and (−)‐6,12‐dihydroxyabieta‐5,8,11,13‐tetraen‐7‐one, have been isolated from the heartwood of Chamaecyparis obtusa var. formosana and were characterized by spectroscopic means, including 2D‐NMR techniques and chemical methods. Synthesis of (−)‐obtusal A and (+)‐obtusal B were carried out.     

Separation,identification, and structural characterization of sucrose ester isomers from tobacco

Sucrose esters (SEs) are crucial tobacco smoke flavor precursors and play a significant role in tobacco's functionality. Due to their structural complexity, the separation and analysis of SEs in tobacco remain a major challenge, and massive structures of SEs have not yet been fully identified. In this study, the fractions enriched in SEs were obtained from oriental and flue-cured tobacco through a series of pretreatments, and two types of SEs (Types I and II) were distinguished by liquid chromatography-tandem mass spectrometry (LC-MSⁿ) analysis, with Type II SEs newly characterized in tobacco. Five groups of main SEs were further purified using preparative high-performance LC (HPLC) coupled to an evaporative light scattering detector, and their structures were characterized by nuclear magnetic resonance spectrometry techniques including ¹H, ¹³C, correlation spectroscopy, heteronuclear single quantum correlation, and heteronuclear multiple bond correlation. By combining LC-MSⁿ and nuclear magnetic resonance spectrometry, the structures of eight SE isomers were finally proposed, of which four were newly identified. These findings further enhance the understanding of the structural diversity of SEs in tobacco, serving as a valuable reference for future research on the elucidation, synthesis, and metabolism of SEs.     

Facile Preparation of an Ionic Liquid Composite Mesoporous Polymer as a Solid Phase Extraction Adsorbent for the Separation and Purification of Flavonoids from Chamaecyparis obtusa

A new ionic liquid composite mesoporous polymer (ILCMP) was synthesized by one-pot copolymerization. The obtained ILCMP with good morphology, good pore diameter distribution, and high adsorption capacity was successfully applied as the sorbent in solid-phase extraction (SPE) to extract and separate quercitrin and myricetin from Chamaecyparis obtusa. 87.8–101.8% of satisfactory recoveries were obtained with RSDs less than 6.2% and the amounts of quercitrin and myricetin in Chamaecyparis obtusa were 0.38 and 0.12 mg/g, respectively. The proposed ILCMP-SPE-HPLC method was applied for the separation, purification, and determination of flavonoids from natural products.     

Preparation of a Hybrid Organic-inorganic Monolith for Extraction and Purification of Quercetin and Myricetin from Chamaecyparis obtusa

A new hybrid organic-inorganic monolithic cartridge was synthesized and used as the selective sorbent for the extraction and purification of quercetin and myricetin from Chamaecyparis obtusa via a solid-phase extraction method.The morphology of the monolithic material was examined by field emission-scanning electron microscopy and a Brunauer-Emmett-Teller（BET） test.The adsorption capacity of the obtained material for quercetin and myricetin was investigated by fitting the adsorption data to four different adsorption equations,of which the LangmuirFreundlich isotherm was selected as the most suitable model.Under optimized conditions,good calibration curves were observed at nine concentrations ranged from 0.5 μg/mL to 100.0 μg/mL of quercetin and myricetin.The extraction recovery ranged from 74.5％ to 84.6％ and the inter-and intra-day relative standard deviations were ＜6％.This type of hybrid monolith has potential for the separation and purification of bioactive compounds from natural plant extracts.     

Separation and identification of structural isomers by quadrupole collision-induced dissociation-hydrogen/deuterium exchange-infrared multiphoton dissociation (QCID-HDX-IRMPD)

A new approach that uses a hybrid Q-FTICR instrument and combines quadrupole collision-induced dissociation, hydrogen-deuterium exchange, and infrared multiphoton dissociation (QCID-HDX-IRMPD) has been shown to effectively separate and differentiate isomeric fragment ion structures present at the same m/z. This method was used to study protonated YAGFL-OH (free acid), YAGFL-NH₂ (amide), cyclic YAGFL, and YAGFL-OCH₃ (methyl ester). QCID-HDX of m/z 552.28 (C₂₉H₃₈N₅O₆) from YAGFL-OH reveals at least two distributions of ions corresponding to the b₅ ion and a non-C-terminal water loss ion structure. Subsequent IRMPD fragmentation of each population shows distinct fragmentation patterns, reflecting the different structures from which they arise. This contrasts with data for YAGFL-NH₂ and YAGFL-OCH₃, which do not show two distinct H/D exchange populations for the C₂₉H₃₈N₅O₆ structure formed by NH₃ and HOCH₃ loss, respectively. Relative extents of exchange for C₂₉H₃₈N₅O₆ ions from six sequence isomers (YAGFL, AGFLY, GFLYA, FLYAG, LYAGF, and LFGAY) show a sequence dependence of relative isomer abundance. Supporting action IRMPD spectroscopy data are also presented herein and also show that multiple structures are present for the C₂₉H₃₈N₅O₆ species from YAGFL-OH.     

Extraction and Determination of Quercetin and Myricetin from Chamaecyparis obtusa by Ionic Liquids‐based Monolithic Cartridge

A short ionic liquids (ILs)‐based monolithic cartridge was prepared and used as the selective extraction sorbent. After the material was evaluated by field emission‐scanning electron microscopy (FE‐SEM), a new approach for the extraction and determination of quercetin and myricetin from Chamaecyparis obtusa (C. obtusa) by using ILs‐based, monolithic cartridge system was developed. Chromatographic analysis was conducted on a C₁₈ column with UV detection at 372 nm, an eluting solution consisting of acetonitrile‐water (25/75,V/V) as the mobile phase, and a flow rate of 0.7 mL·min⁻¹. A good linear relationship was demonstrated when the concentrations of quercetin and myricetin were in the range of 0.5–100.0 µg·mL⁻¹. The recoveries ranged from 101.6% to 104.6% and the inter‐ and intra‐day relative standard deviations (RSD) were less than 5.0%. This method effectively removed the impurities and avoided tedious pretreatment. It provided a fast, economic and effective method for assaying trace drugs from natural plants.     

Polychlorinated dibenzo-p-dioxins. Separation and identification of isomers by gas chromatography-mas spectrometry.

Attempts were made to synthesize all polychlorinated dibenzo-p-dioxin isomers containing six to eight chlorine atoms by micro-scale pyrolysis of different polychlorophenates. Eight of the ten possible hexachlorodibenzo-p-dioxins, the two hepta- and the octachlorodibenzo-p-dioxin were observed and separated by gas chromatography using glass capillary columns. Without actual isolation of these toxic materials, isomers were characterized by gas chromatography and mass spectrometry. Commercial chlorinate phenols were analyzed for the presence of these isomers. The major hexachlorodibenzo-p-dioxin observed in two commerical products was the unexpected 1,2,3,7,8,9-substituted isomer, which was not formed as the main dioxin component in any of the pyrolysis experiments. The same isomer was reported to be isolated from toxic fat and identified by X-ray crystallography.     

Separation and identification of the Z and E isomers of 2-(3-pentenyl)pyridine by capillary electrophoresis and nuclear magnetic resonance spectroscopy

A mixture of the Z and E isomers of 2-(3-pentenyl)pyridine has been separated with baseline resolution by capillary electrophoresis. Using molecular modelling it was proposed that the smaller more rapidly migrating peak would be the Z isomer. This agreed with a 38:62 (Z/E) composition by nuclear magnetic resonance spectroscopy. The sample was also investigated by gas chromatography coupled to mass spectrometry.     

Separation of patuletin-3-O-glucoside, astragalin, quercetin, kaempferol and isorhamnetin from Flaveria bidentis (L.) Kuntze by elution-pump-out high-performance counter-current chromatography

Flaveria bidentis (L.) Kuntze is an annual alien weed of Flaveria Juss. (Asteraceae) in China. Bioactive compounds, mainly flavonol glycosides and flavones from F. bidentis (L.) Kuntze, have been studied in order to utilize this invasive weed, Analytical high-performance counter-current chromatography (HPCCC) was successfully used to separate patuletin-3-O-glucoside, a mixture of hyperoside (quercetin-3-O-galactoside) and 6-methoxykaempferol-3-O-galactoside, astragalin, quercetin, kaempferol and isorhamnetin using two runs with different solvent system. Ethyl acetate-methanol-water (10:1:10, v/v) was selected by analytical HPCCC as the optimum phase system for the separation of patuletin-3-O-glucoside, a mixture of hyperoside and 6-methoxykaempferol-3-O-galactoside, and astragalin. A Dichloromethane-methanol-water (5:3:2, v/v) was used for the separation of quercetin, kaempferol and isorhamnetin. The separation was then scaled up: the crude extract (ca 1.5 g) was separated by preparative HPCCC, yielding 12 mg of patuletin-3-O-glucoside at a purity of 98.3%, yielding 9 mg of a mixture of hyperoside and 6-methoxykaempferol-3-O-galactoside constituting over 98% of the fraction, and 16 mg of astragalin (kaempferol-3-O-glucoside) at a purity of over 99%. The pump-out peaks are isorhanetin (98% purity), kaemferol (93% purity) and quercitin (99% purity). The chemical structure of patuletin-3-O-glucoside and astragalin were confirmed by MS and 1H, 13C NMR.     

Infrared spectra of C(3)H(3)(+)-N(2) dimers: identification of proton-bound c-C(3)H(3)(+)-N(2) and H(2)CCCH(+)-N(2) isomers.

Mid-infrared photodissociation spectra of mass selected C(3)H(3)(+)-N(2) ionic complexes are obtained in the vicinity of the C-H stretch fundamentals (2970-3370 cm(-1)). The C(3)H(3)(+)-N(2) dimers are produced in an electron impact cluster ion source by supersonically expanding a gas mixture of allene, N(2), and Ar. Rovibrational analysis of the spectra demonstrates that (at least) two C(3)H(3)(+) isomers are produced in the employed ion source, namely the cyclopropenyl (c-C(3)H(3)(+)) and the propargyl (H(2)CCCH(+)) cations. This observation is the first spectroscopic detection of the important c-C(3)H(3)(+) ion in the gas phase. Both C(3)H(3)(+) cations form intermolecular proton bonds to the N(2) ligand with a linear -C-H...N-N configuration, leading to planar C(3)H(3)(+)-N(2) structures with C(2v) symmetry. The strongest absorption of the H(2)CCCH(+)-N(2) dimer in the spectral range investigated corresponds to the acetylenic C-H stretch fundamental (v(1) = 3139 cm(-1)), which experiences a large red shift upon N(2) complexation (Delta(v1) approximately -180 cm(-1)). For c-C(3)H(3)(+)-N(2), the strongly IR active degenerate antisymmetric stretch vibration (v4)) of c-C(3)H(3)(+) is split into two components upon complexation with N(2): v4)(a(1)) = 3094 cm(-1) and v4)(b(2)) = 3129 cm(-1). These values bracket the yet unknown v4) frequency of free c-C(3)H(3)(+) in the gas phase, which is estimated as 3125 +/- 4 cm(-1) by comparison with theoretical data. Analysis of the nuclear spin statistical weights and A rotational constants of H(2)CCCH(+)-N(2) and c-C(3)H(3)(+)-N(2) provide for the first time high-resolution spectroscopic evidence that H(2)CCCH(+) and c-C(3)H(3)(+) are planar ions with C(2v) and D(3h) symmetry, respectively. Ab initio calculations at the MP2(full)/6-311G(2df,2pd) level confirm the given assignments and predict intermolecular separations of R(e) = 2.1772 and 2.0916 A and binding energies of D(e) = 1227 and 1373 cm(-1) for the H-bound c-C(3)H(3)(+)-N(2) and H(2)CCCH(+)-N(2) dimers, respectively.     

Separation and characterization of three positional isomers of dimaltosyl-cyclomaltoheptaose (dimaltosyl-beta-cyclodextrin).

A mixture of maltosylcyclomaltoheptaoses (maltosyl-beta-cyclodextrins, G2-beta CDs) was prepared from maltose and beta-cyclodextrin (beta CD) through the reverse action of Klebsiella pneumoniae pullulanase. Three positional isomers of dimaltosyl-beta CD in the mixture were separated by high-performance liquid chromatography on a reversed phase column and a graphitized carbon column. Their molecular weights were measured by fast-atom bombardment mass spectrometry, and the structures were established by methylation analysis, hydrolysis with glucoamylase to the known compounds, three positional isomers of diglucosyl-beta CD, and 13C-nuclear magnetic resonance spectroscopy.     

伊曲茶碱中间体杂质的分离与鉴定

伊曲茶碱是一种新型选择性腺苷A2A受体拮抗剂,用于治疗帕金森氏病和改善帕金森氏病初期运动障碍.在伊曲茶碱中间体A1(6-氨基-1,3-二乙基-2,4-(1H,3H)-嘧啶二酮)的合成过程中,碱性条件或高温条件下会伴随生成至少2种副产物,在前期研究中我们已经对该中间体合成过程中的其中一种副产物进行过研究,确定其结构为(E...