Xiaoping Rao

Preparation and Characterization of Polymeric Surfactants Based on Epoxidized Soybean Oil Grafted Hydroxyethyl Cellulose

Epoxidized soybean oil (ESO) grafted hydroxyethyl cellulose (HEC) was prepared via ring-opening polymerization, in which the hydroxyl groups of HEC acted as initiators and the polymeric ESO were covalently bonded to the HEC. Hydrolysis of ESO-grafted HEC (ESO-HEC) was performed with sodium hydroxide, and the hydrolyzed ESO-HEC (H-ESO-HEC) products were characterized via Fourier transform infrared (FT-IR) and (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopies, high-temperature gel permeation chromatography (HT-GPC), and differential scanning calorimetry (DSC). The results indicated that ring-opening polymerization of ESO occurred with the hydroxyl groups of HEC as initiators. The molecular weights of the H-ESO-HEC products were varied by adjusting the mass ratio of HEC and ESO. Through neutralizing the carboxylic acid of H-ESO-HEC with sodium hydroxide, novel polymeric surfactants (H-ESO-HEC-Na) were obtained, and the effects of polymeric surfactants on the surface tension of water were investigated as a function of concentration of H-ESO-HEC-Na. The H-ESO-HEC-Na was effective at lowering the surface tension of water to 26.33 mN/m, and the critical micelle concentration (CMC) value decreased from 1.053 to 0.157 g/L with increases in molecular weights of the polymeric surfactants. Rheological measurements indicated that the H-ESO-HEC-Na solutions changed from pseudoplastic property to Newtonian with increasing shear rate.

Synthesis and quantitative structure–activity relationship (QSAR) studies of novel rosin-based diamide insecticides

In a continuing effort to develop novel natural product-based insecticidal agents endowed with low mammalian toxicity, two series of rosin-based diamides have been synthesized, and their insecticidal activities against Plutella xylostella and Mythimna separata were evaluated. Most of the synthesized compounds exhibited moderate to significant insecticidal activity. Among them, thiadiazole-containing diamides 6a–n displayed better activity than others, especially compounds 6f and 6n which exhibited excellent insecticidal activity against P. xylostella, with LC50 values of 0.223 and 0.214 mg L−1, respectively, which approximate to, or are lower than that of, the control flubendiamide (0.222 mg L−1). The preliminary structure–activity relationship analysis indicated that rosin-based diamides with electron-withdrawing groups on the benzene ring showed better insecticidal activity than those with electron-donating groups. Via a best multilinear regression analysis, the generated quantitative structure–activity relationship (QSAR) model (R2 = 0.9566) revealed a strong correlation of insecticidal activity against P. xylostella with molecular structures of these compounds. These consequences can be expected to instruct the design and development of new rosin-based insecticides.

One-pot synthesis and antimicrobial evaluation of novel 3-cyanopyridine derivatives of (−)-β-pinene

A series of novel 3-cyanopyridine derivatives of (-)-β-pinene were designed and synthesized by one-pot four-component domino reactions. The targeted compounds were evaluated for their antimicrobial activity against four bacteria (Klebsiella pneumoniae, Enterobacter aerogenes, Staphylococcus aureus, Staphylococcus epidermidis) and a fungus (Candida albicans). The results showed that most of the minimal inhibitory concentrations (MICs) of these 3-cyanopyridine derivatives against the tested strains was in the range of 15.6-125 mg/L. Among these 3-cyanopyridine derivatives, the MICs of compound 5h against S. epidermidis and C. albicans were 15.6 mg/L, which revealed that compound 5h featured double fluoro substituents at meta- and para-position was the most active compound. In addition, the preliminary structure-activity relationship analysis indicated that the change of substituents on the pyridine ring and benzene ring of 3-cyanopyridine derivatives was an important factor for inducing antimicrobial activity. This research would promote the development of heterocyclic derivatives of β-pinene with antimicrobial activity.

Highly Efficient One-Pot Synthesis of α-Aminophosphonates Catalyzed by Ytterbium Triflate in Water

Abstract A facile one-pot, three-component synthesis of α -aminophosphonates catalyzed by ytterbium triflate [Yb(OTf)3] in water using polyoxyethanyl α -tocopheryl sebacate (PTS) as amphiphile has been developed. The catalytic system could be readily recycled and reused several times without significant loss in its activity. GRAPHICAL ABSTRACT

Dehydro­abietic acid

The title compound [systematic name: (1R,4aS,10aR)-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H⋯O hydrogen bonds.

Syntheses and antibacterial activity of Schiff bases from 16-isopropyl-5, 9-dimethyltetracyclo [10.2.2.01, 10.04, 9] hexadec-15-ene-5, 14-dicarboxylic acid

16-Isopropyl-5, 9-dimethyltetracyclo [10.2.2.01, 10.04, 9] hexadec-15-ene-5, 14-dicarboxylic acid (1b) was prepared from rosin through a Diels–Alder addition reaction. Then, a group of Schiff bases derived from 1b was synthesised. Their structures were characterised by IR,1H-NMR, MS and elemental analysis. The antibacterial activities of these newly synthesised Schiff bases were also investigated. The results show that these compounds possess antibacterial activities against Staphylococcus aureus and Escherichia coli. Among them, compounds 5a, 5b and 5c, exhibit remarkable antibacterial activity against E. coli.

A new dehydroabietic acid-based arylamine fluorescent probe: Synthesis, structure analysis and in vitro biodiagnose function.

A new fluorescent probe (methyl 13-(α-naphthalene)aminodeisopropyldehydroabietate) has been synthesized, and its structure was optimized by theoretical DFT calculation and determinated by single-crystal X-ray diffraction analysis. The optimized data are in agreement with the experimental values. The fluorescence properties, photostability, cell toxicity and in vitro fluorescence imaging of the compound have been investigated. The results indicated that it can be effectively taken up by HeLa, 7721, 7901 and A549 cells and strong blue fluorescence signals were detected in these cells.

The green approaches for the synthesis of N -dehydroabietic α -aminophosphonates

Three kinds of O,O-diethyl N-dehydroabietic aminoarylmethylphosphonates were synthesized from natural product derivatives by two steps of solvent-free reactions through imines intermediates and their structures were characterized by IR, 1H NMR and 31P NMR spectroscopy. The solvent-free reactions afforded good yields of N-dehydroabietic imines and α-aminophosphonates although the strong space block of dehydroabietylamine to amino group. The green approaches resulted negligible waste and the reactions were environment friendly without using noxious solvents.

7-Isopropyl-1,4a-dimethyl-1,2,3,4,4a,5,6,7,8,9,10,10a-dodeca­hydro­phenan­threne-1-carboxylic acid

The title compound, C20H32O2, has been isolated from hydrogenated rosin. There are two independent molecules in the asymmetric unit. In each molecule, the cyclohexane ring assumes a chair conformation, while the two cyclohexene rings adopt half-chair and envelope conformations. Intermolecular O—H⋯O hydrogen bonding between carboxyl groups links pairs of independent molecules into dimers.

Synthesis and crystal structure of maleopimaric acid

The title compound maleopimaric acid was synthesized by a Diels–Alder reaction between maleic anhydride and Pinus elliottii engelm oleoresin at room temperature and it was characterized by single crystal X-ray diffraction. The white crystals crystallized in the orthorhombic system, space group P2 12121 with cell dimensions: a = 7.6960 (15) Å, b = 11.851 (2) Å, c = 24.577 (5) Å, α = 90°, β = 90°, γ = 90°, V = 2241.6(8) Å3, and R 1 = 0.0716, wR 2 = 0.1975. The two fused and unbridged cyclohexane rings form a trans ring junction with chair conformation with two methyl groups in axis positions, the anhydride ring is planar. Crystal water existed in the molecular and stabilized the structure through intermolecular hydrogen bonds.