Yanxiong Fang

Immobilization of β-Cyclodextrin as Insoluble β-Cyclodextrin Polymer and Its Catalytic Performance

Abstract Insoluble β-cyclodextrin polymers were prepared from β-cyclodextrin (β-CD) using epichlorohydrin (EPI) as crosslinking agent under basic conditions. The polymers were characterized by Fourier Transform Infrared (FTIR), Thermogravimetry (TG), X-ray diffraction (XRD) and TG-FTIR. The results demonstrated that the polymerization between EPI and β-CD indeed occurred, and a number of CD rings were interconnected to form a three-dimensional network. Moreover, different factors influencing the polymerization, e.g. molar ratio of EPI to β-CD, the concentration of NaOH and reaction temperature, have been investigated. The polymer prepared under the optimal conditions (the molar ratio EPI: β-CD of 44, the NaOH concentration 50% in mass, and the temperature at 65 °C) showed excellent thermal stability and insolubility in organic solvents or strong acid/base. In addition, the β-cyclodextrin polymers also presented high catalytic activity for aqueous oxidation of benzyl alcohol with hypochlorite as oxidant.

Blanc Reaction of Aromatic Compounds Catalyzed by Ionic Liquids

Ionic liquids have been used as catalysts for Blanc reaction of toluene. The effects of reaction temperature, reaction time and dosage of the ionic liquid catalyst have been investigated, and the catalytic performance of different ionic liquid catalysts for toluene chloromethylation was also studied. The reaction was found to proceed under mild conditions with excellent conversion (up to 90%) in the absence of Lewis acids. The ionic liquids could be recycled and reused without loss of their catalytic activities.

Variation in Essential Oil and Bioactive Compounds of Curcuma kwangsiensis Collected from Natural Habitats

The chemical compositions of essential oils (EOs) extracted from Curcuma kwangsiensis rhizomes collected from six natural habitats in P. R. China were evaluated using gas chromatography/mass spectrometry (GC/MS). Fifty‐seven components were identified from the six EOs, and their main constituents were 8,9‐dehydro‐9‐formyl‐cycloisolongifolene (2.37 – 42.59%), germacrone (6.53 – 22.20%), and l‐camphor (0.19 – 6.12%). The six EOs exhibited different DPPH radical‐scavenging activities (IC50, 2.24 – 31.03 μg/ml), with the activity of most of EOs being much higher than that of Trolox C (IC50, 10.49 μg/ml) and BHT (IC50, 54.13 μg/ml). Most EOs had potent antimicrobial effects against the tested bacteria and fungus. They also exhibited cytotoxicity against B16 (IC50, 4.44 – 147.4 μg/ml) and LNCaP cells (IC50, 73.94 – 429.25 μg/ml). The EOs showed excellent anti‐inflammatory action by significantly downregulating expression of pro‐inflammatory cytokines, cyclooxygenase‐2, and tumor necrosis factor‐α. This study provides insight into the interrelation among growth location, phytoconstituents, and bioactivities, and the results indicate the potential of C. kwangsiensis as natural nutrients, medicines, and others additives.

Shape-selective separation of geraniol and nerol via noncovalent interactionswith β-cyclodextrin

Abstract In this paper, selective separation of the isomeric compounds geraniol and nerol, based on the preferential affinity of β-cyclodextrin (β-CD) for geraniol was investigated. To demonstrate the potential application of β-CD for separation of geraiol from nerol, the structure of the inclusion complexes was characterized with various physico-chemical techniques. The selective noncovalent binding property of β-CD was confirmed by quantum-chemical calculations. For the mixture, which contains 50 wt% of geraniol and nerol, respectively, 96% of geraniol in complex can be obtained, and the similar separation efficiency was found after use for three times.

Efficient oxidation of cinnamon oil to natural benzaldehyde over β-cyclodextrin-functionalized MWCNTs

We have designed and prepared β-cyclodextrin (β-CD)-functionalized multi-walled nanotubes (MWCNTs-g-CD) for the oxidation of cinnamon oil to natural benzaldehyde under aqueous conditions. The synergistic effect of combining MWCNTs with β-CD led to a remarkable increase in the performance of the MWCNTs-g-CD for the catalytic oxidation of cinnamaldehyde, which exhibited 95% cinnamaldehyde conversion and 85% selectivity to natural benzaldehyde with a short reaction time of 10 min. The MWCNTs-g-CD also exhibited outstanding recyclability with good stability, showing no discernible decrease in their catalytic activity over five reaction cycles.

Methyl 4-bromo-3-hy-droxy-benzoate.

In the title compound, C8H7BrO3, the methoxycarbonyl group is twisted at a dihedral angle of 8.06 (4)° with respect to the benzene ring. In the crystal, molecules are connected by O—H⋯O hydrogen bonds into helical chains running along the b axis.

(3E,5E)-3,5-Bis(4-hy­droxy-3,5-di­methoxy­benzyl­idene)oxan-4-one monohydrate

In the title compound, C(23)H(24)O(8)·H(2)O, the six-membered ring of the oxan-4-one (tetra-hydro-pyran-4-one) ring displays an envelope conformation with the heterocyclic O atom at the flap position. The dihedral angles between the terminal benzene rings is 37.23 (10)°. Classical intermolecular O-H⋯O and weak C-H⋯O hydrogen bonds are present in the crystal structure.

Flavone Di-C-Glycosides from Selaginella uncinata and Their Antioxidative Activities

Selaginella uncinata (Desv.) Spring is used for the treatment of jaundice, dysentery, edema, and rheumatism in traditional Chinese medicine. It is widely distributed in southwest China [1]. Although biflavonoids are the main chemical constituents in Selaginella genus [2, 3], few reports have revealed the existence of flavone-di-C-glycoside constituents until now [4]. In our previous papers, we have reported biflavonoids, steroidal saponins, -lactone derivatives, terpenoids, and phenolic compounds from Selaginella uncinata [5–9]. In our continuous research work, five flavone di-C-glycosides, schaftoside (1), isoschaftoside (2), 6,8-di-C-L-arabinopyranoside-apigenin (3), 6-C-L-arabinopyranosyl-8-C-L-arabinopyranosylapigenin (4), and 6-C-L-arabinopyranosyl-8-C-L-arabinopyranosyl-apigenin (5), have been isolated from the n-butanol fraction of the 60% ethanolic extract of Selaginella uncinata. Compounds 1–5 were isolated from the Selaginella genus for the first time. The antioxidative activities of the five compounds were evaluated in the oxygen radical absorbance capacity (ORAC) assay. All the five compounds showed potent antioxidative activities. Compound 1, yellow amorphous powder. UV (MeOH, max, nm) (log ): 333 (4.25), 273 (4.23). ESI-MS m/z: 587 [M + Na]+, 563 [M – H]–. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 8.09 (2H, d, J = 8.7, H-2 , 6 ), 6.90 (2H, d, J = 8.7, H-3 , 5 ), 6.72 (1H, s, H-3), 4.76 (1H, d, J = 9.5, H-1 ), 4.69 (1H, d, J = 9.7, H-1 ), 4.09–3.23 (18H, m). 13C NMR (100 MHz, DMSO-d6, , ppm): 181.8 (C-4), 163.4 (C-2), 161.1 2 (C-5, 7), 159.7 (C-4 ), 154.7 (C-9), 129.0 2 (C-2 , 6 ), 121.4 (C-1 ), 116.0 2 (C-3 , 5 ), 108.7 (C-6), 104.5 (C-8), 102.1 2 (C-3, 10), 81.3 (C-5 ), 78.8 (C-3 ), 75.2 (C-1 ), 74.7 (C-2 ), 73.8 (C-1 ), 70.9 (C-3 ), 70.7 (C-2 ), 70.1 (C-4 ), 69.2 (C-4 ), 68.9 (C-5 ), 60.9 (C-6 ). The spectral data presented are in a good agreement with published data on schaftoside [10]. Compound 2, yellow amorphous powder. UV (MeOH, max, nm) (log ): 332 (4.36), 273 (4.35). ESI-MS m/z: 587 [M + Na]+, 563 [M – H]–. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 13.66 (1H, br.s, 5-OH), 8.00 (2H, d, J = 8.1, H-2 , 6 ), 6.90 (2H, d, J = 8.1, H-3 , 5 ), 6.76 (1H, s, H-3), 4.99–4.57 (7H, m), 3.91–3.51 (13H, m). 13C NMR (100 MHz, DMSO-d6, , ppm): 182.0 (C-4), 163.7 (C-7), 161.1 2 (C-2, 5), 158.4 (C-4 ), 155.1 (C-9), 128.9 2 (C-2 , 6 ), 121.6 (C-1 ), 115.9 2 (C-3 , 5 ), 108.2 (C-6), 105.1 (C-8), 102.5 2 (C-3, 10), 81.8 (C-5 ), 78.9 (C-3 ), 74.3 (C-1 ), 74.0 (C-2 ), 73.4 (C-1 ), 71.1 (C-3 ), 70.6 (C-2 ), 70.1 (C-4 ), 69.5 (C-4 ), 68.6 (C-5 ), 61.3 (C-6 ). The spectral data presented are in a good agreement with published data on isoschaftoside [10].

γ-Lactone Derivatives and Terpenoids from Selaginella uncinata and Their Protective Effect Against Anoxia

Selaginella uncinata (Desv. ex Poir.) Spring, a common and important species of Selaginella genus, is widely distributed in southwest China. As a traditional plant medicine, it is used for the treatment of jaundice, dysentery, edema, and rheumatism [1]. In our previous papers, we reported on the anti-anoxic effects of the 60% ethanolic extract of Selaginella uncinata and the anti-anoxic biflavonoids isolated from the EtOAc-soluble fraction of the 60% EtOH extract [2, 3]. In our continuous research work on the isolation of the anti-anoxic compounds, two -lactone derivatives, viburnolide A (1) and viburnolide B (2), and four terpenoids, isololiolide (3), dehydrololiolide (4), cis, trans-abscisic acid (5), and trans, trans-abscisic acid (6), have been isolated from the EtOAc-soluble and n-butanol-soluble fractions. Although the biflavonoids, flavonoids, chromone glycosides, and phenolic compounds are common in Selaginella genus [4–9], few reports have revealed the existence of -lactone derivatives and terpenoids constituents until now, and the six compounds 1–6 were isolated from this genus for the first time. Compound 1. Brown yellow, amorphous powder. UV (MeOH, max, nm) (log ): 356 (2.38), 276 (3.48), 227 (4.28). ESI-MS m/z: 507 [M + Na]+, 483 [M – H]– and 967 [2M – H]–1. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 2.90 (1H, dd, J = 17.4, 9.2, H-3A), 3.04 (1H, dd, J = 17.4, 12.2, H-3B), 3.07 (1H, m, H-5 ), 3.20 (1H, m, H-2 ), 3.22 (1H, m, H-3 ), 3.28 (1H, m, H-4 ), 3.51 (2H, m, H-6 ), 3.94 (1H, s, H-8), 3.96 (1H, dd, J = 9.1, 5.3, H-11B), 4.21 (1H, dd, J = 7.0, 5.3, H-12), 4.31 (1H, dd, J = 9.1, 7.0, H-11A), 4.70 (1H, d, J = 7.5, H-1 ), 4.80 (1H, dd, J = 12.2, 9.2, H-4), 6.76 (2H, d, J = 8.5, H-15, 17), 7.16 (2H, d, J = 8.5, H-14, 18). 13C NMR (100 MHz, DMSO-d6, , ppm): 174.2 (C-2), 170.8 (C-6), 157.7 (C-16), 122.8 (C-13), 130.0 2 (C-14, 18), 115.6 2 (C-15, 17), 107.2 (C-9), 89.1 (C-5), 96.1 (C-1 ), 88.2 (C-8), 77.1 (C-5 ), 76.7 (C-3 ), 73.4 (C-2 ), 73.2 (C-12), 69.1 (C-4 ), 75.0 (C-11), 59.9 (C-6 ), 43.0 (C-4), 32.5 (C-3). The spectral data presented are in a good agreement with published data on viburnolide A [10].

(3E,5E)-3,5-Bis(4-hy-droxy-benzyl-idene)oxan-4-one.

In the title compound, C19H16O4, there are two 4-hydroxybenzyl substituents on the oxan-4-one (tetrahydropyran-4-one) ring, which exhibits an envelope conformation. The dihedral angles between pyranone ring and the two benzene rings are 26.69 (9) and 36.01 (9)° while the benzene rings make a dihedral angle of 20.88 (10)°. In the crystal, molecules are linked by intermolecular O—H⋯O hydrogen bonds into a supramolecular three-dimensional twofold interpenetrating hydrogen-bonded network.