Determination of Dufulin Residue in Vegetables, Rice, and Tobacco Using Liquid Chromatography with Tandem Mass Spectrometry.

A rapid and accurate LC/MS/MS method using positive electrospray ionization was established for the determination of residues of the novel plant antiviral agent dufulin in samples of tobacco leaf (dry), tomato, cucumber, and rice. Samples were extracted with acetonitrile; cleaned up by dispersive SPE using primary secondary amine, C18, and graphitized carbon black sorbents; separated on a C18 column; and confirmed by multiple reaction monitoring mode MS with a matrix effect of -21.5-19.6%. The method showed satisfactory linearity (R2≥0.9912) for the target compound. The LOD and the LOQ were 0.05 and 0.15 µg/kg, respectively. The mean recoveries from four matrixes varied from 71.9 to 93.6% with intraday RSD in the range of 2.9 to 9.0% and interday RSD 6.9 to 15.2%. The method was successfully applied for analysis of dufulin in actual trial samples.

Metal free catalytic hydroboration of multiple bonds in methanol using N-heterocyclic carbenes under open atmosphere.

An easy to operate method of catalytic hydroboration of unsaturated compounds has been developed with wide substrate scope. Reactions of various aldimines, ketimines, α,ß-unsaturated carbonyl compounds, and alkynes were successfully executed with bis(pinacolato)diboron and N-heterocyclic carbenes in methanol without requiring a transition metal or inert atmosphere.

Chiral cinchona alkaloid-derived thiourea catalyst for enantioselective synthesis of novel ß-amino esters by Mannich reaction.

A cinchona alkaloid-derived thiourea catalyst has been designed to access new asymmetric ß-amino esters bearing benzothiazole moiety by utilizing a Mannich reaction between an imine and a malonate. A simultaneous activation of the two imine functionalities and malonate by the bifunctional chiral organocatalyst is proposed to account for the good yields (71-91%) and high enantiomeric excess (89.4-98.5%) under mild conditions.

Antiviral activity and mechanism of action of novel thiourea containing chiral phosphonate on tobacco mosaic virus.

Using half-leaf method O,O'-diisopropyl (3-(L-1-(benzylamino)-1-oxo-3- phenylpropan-2-yl)thioureido)(phenyl)methyl phosphonate (2009104) was studied for its activity on tobacco mosaic virus (TMV). It showed good curative activity in vivo and the curative activity at 500 µg/mL was found to be 53.3%. In vivo treatment with the control agent Ningnanmycin at 500 µg/mL resulted in 51.2% inhibition and curative inhibition rates respectively. Dot-ELISA test was employed to verify the efficacy of activity of compound 200910 for anti-TMV activity. The mechanism of action of compound 2009104 to resist TMV was also studied. The results showed that the resistance enzymes PAL, POD, SOD activity and chlorophyll content after TMV inoculation K(326) (Nicotiana tabacum K(326)) of tobacco plants followed by treatment with compound 2009104 were significantly enhanced. The study of the effect of compound 2009104 on TMV capsid protein (CP) showed that it inhibited the polymerization process of TMV-CP in vitro.

Antiproliferation and cell apoptosis inducing bioactivities of constituents from Dysosma versipellis in PC3 and Bcap-37 cell lines.

BACKGROUND: Recently, interest in phytochemicals from traditional Chinese medicinal herbs with the capability to inhibit cancer cells growth and proliferation has been growing rapidly due to their nontoxic nature. Dysosma versipellis as Bereridaceae plants is an endemic species in China, which has been proved to be an important Chinese herbal medicine because of its biological activity. However, systematic and comprehensive studies on the phytochemicals from Dysosma versipellis and their bioactivity are limited. RESULTS: Fifteen compounds were isolated and characterized from the roots of Dysosma versipellis, among which six compounds were isolated from this plant for the first time. The inhibitory activities of these compounds were investigated on tumor cells PC3, Bcap-37 and BGC-823 in vitro by MTT method, and the results showed that podophyllotoxone (PTO) and 4'-demethyldeoxypodophyllotoxin (DDPT) had potent inhibitory activities against the growth of human carcinoma cell lines. Subsequent fluorescence staining and flow cytometry analysis indicated that these two compounds could induce apoptosis in PC3 and Bcap-37 cells, and the apoptosis ratios reached the peak (12.0% and 14.1%) after 72 h of treatment at 20 µM, respectively. CONCLUSIONS: This study suggests that most of the compounds from the roots of D. versipellis could inhibit the growth of human carcinoma cells. In addition, PTO and DDPT could induce apoptosis of tumor cells.

Inorganic base-catalyzed formation of antivirally active N-substituted benzamides from α-amido sulfones and N-nucleophile.

BACKGROUND: Heteronucleophiles as well as carbanionic reagents can be used to react with α-amido sulfones, thus giving the opportunity to prepare a large array of amino derivatives. Since, novel 1,3,4-oxadiazole-2-thiol derivatives can serve as potent nucleophiles, we employed 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the nucleophilic source of nitrogen in the reaction with α-amido sulfones. RESULTS: A series of N-substituted benzamides bearing 1,3,4-oxadiazol unit were prepared for the first time by the reaction of in situ generated protected imine from α-amido sulfones with 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the source of nitrogen nucleophile. Some of the synthesized products displayed favourable antiviral activity against cucumber mosaic virus (CMV) in preliminary antiviral activity tests. The title compounds 5c, 5o and 5r revealed curative activity of 42.2%, 48.7% and 40.5%, respectively against CMV (inhibitory rate) compared to the commercial standard Ningnanmycin (53.4%) at 500 µg/mL. CONCLUSION: A practical synthetic route to N-benzoyl-α-amido sulfones by the reaction of 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the source of nitrogen nucleophiles with in situ generated protected imine from N-benzoyl-α-amido sulfones is presented. The reaction catalyzed by an inorganic base has considerable significance to exploit the potential of α-amido sulfones in organic synthesis.

Analytical and semi-preparative HPLC enantioseparation of novel pyridazin-3(2H)-one derivatives with α-aminophosphonate moiety using immobilized polysaccharide chiral stationary phases.

The direct HPLC enantioseparation of a novel series of chiral pyridazin-3(2H)-one derivatives with α-aminophosphonate moiety was performed on two immobilized polysaccharide chiral stationary phases (Chiralpak IA, Chiralpak IC) using n-hexane (n-Hex)/dichloromethane (DCM) mobile phase with 5% alcohol additive. Good baseline separation of the enantiomers was achieved using amylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phases (Chiralpak IA) on analytical scale. The analytical method was further scaled up to semi-preparative loading to obtain small amounts of both the enantiomers of pyridazin-3(2H)-one derivative. The semi-preparative resolution of all compounds was successfully achieved with n-hexane/dichloromethane/ethanol (EtOH) as mobile phase using a semi-preparative Chiralpak IA column. The first fractions were isolated with purities of >99.9% (enantiomeric excess (e.e.), and the second fractions were obtained with purities of >98.2% (enantiomeric excess). The assignment of the absolute configuration was established for the F1 fraction of compound a-2 by single-crystal X-ray diffraction method.

Production and selected fuel properties of biodiesel from promising non-edible oils: Euphorbia lathyris L., Sapium sebiferum L. and Jatropha curcas L.

A comparative study on the composition, biodiesel production and fuel properties of non-edible oils from Euphorbia lathyris L. (EL), Sapium sebiferum L. (SS), and Jatropha curcas L. (JC) was conducted. Under optimal conditions, the FAME content and yield of the three oils were greater than 97.5 wt.% and 84.0%, respectively. The best biodiesel was produced from EL due to its high monounsaturation (82.66 wt.%, Cn: 1), low polyunsaturation (6.49 wt.%, Cn: 2, 3) and appropriate proportion of saturated components (8.78 wt.%, Cn: 0). Namely, EL biodiesel possessed a cetane number of 59.6, an oxidation stability of 10.4 h and a cold filter plug point of -11 °C. However, the cetane number (40.2) and oxidative stability (0.8 h) of dewaxed SS kernel oil (DSSK) biodiesel were low due to the high polyunsaturation (72.79 wt.%). In general, the results suggest that E. lathyris L. is a promising species for biodiesel feedstock.

Novel 3-(2-(3-methyl-5-substituted-phenyl-4,5-dihydropyrazol-1-yl)-2-oxoethoxy)-2-substituted-phenyl-4H-chromen-4-one: synthesis and anticancer activity.

Ten novel 3-(2-(3-methyl-5-substituted-phenyl-4,5-dihydropyrazol-1-yl)-2-oxo-ethoxy)-2-substituted-phenyl-4H-chromen-4-one derivatives were synthesized and characterized by 1H NMR and 13 C NMR. All of the compounds have been screened for their anticancer activity. The bioassay tests show that compound 6af exhibited potentially high activity against human gastric cancer cell SGC-7901 with IC50 value of 4.01±0.97 µg/mL. Also, the title compounds were assayed for telomerase inhibition. The results show that compounds 6cf, 6af can strongly inhibit telomerase with IC50 values of 4.89±0.11 and 5.02±0.91 µM, respectively. Docking simulation was performed to position compound 6cf into the telomerase (3DU6) active site to determine the probable binding model.

Synthesis and antiviral activity of 5­(4­chlorophenyl)-1,3,4-thiadiazole sulfonamides.

Starting from 4-chlorobenzoic acid, 10 new 5-(4-chlorophenyl)-N-substituted-N-1,3,4-thiadiazole-2-sulfonamide derivatives were synthesized in six-steps. Esterification of 4-chlorobenzoic acid with methanol and subsequent hydrazination, salt formation and cyclization afforded 5-(4-chlorophen-yl)-1,3,4-thiadiazole-2-thiol (5). Conversion of this intermediate into sulfonyl chloride 6, followed by nucleophilic attack of the amines gave the title sulfonamides 7a-7j whose structures were confirmed by NMR, IR and elemental analysis. The bioassay tests showed that compounds 7b and 7i possessed certain anti-tobacco mosaic virus activity.

Synthesis and in vitro study of pseudo-peptide thioureas containing α-aminophosphonate moiety as potential antitumor agents.

Twenty pseudo-peptide thioureas IIa-l containing α-aminophosphonate moiety were synthesized from the reaction of chiral α-amino carboxamide derivatives Ia-c with O,O'-dialkylisothiocyanato(phenyl)methylphosphonate 5. The synthesized compounds were completely characterized by elemental analysis, physical and spectral (IR, (1)H NMR, (13)C NMR) data. According to the preliminary studies on antitumor activities, compounds IIa-l could inhibit tumor cells PC3, Bcap37 and BGC823. These compounds displayed low to high activity by MTT assays. Among them, L-IIk, D-IIa and D-IIe were identified as potent inhibitors, with IC(50) values ranging from 4.7 to 11.2 µM according to in vitro assay.

Asymmetric synthesis of alpha-aminophosphonates using the inexpensive chiral catalyst 1,1'-binaphthol phosphate.

Asymmetric addition under mild conditions of dialkyl phosphites on aldimines derived from cinnamaldehyde catalyzed by the inexpensive chiral organocatalyst (R)-3,3'-[4-fluorophenyl](2)-1,1'-binaphthol phosphate has been found effective to give new alpha-amino-phosphonates 9 in moderate yields (30-65%) and enantiomeric excess (8.4%-61.9%).

Synthesis and molecular docking studies of novel 2-chloro-pyridine derivatives containing flavone moieties as potential antitumor agents.

A series of novel 2-chloro-pyridine derivatives containing flavone, chrome or dihydropyrazole moieties as potential telomerase inhibitors were synthesized. The bioassay tests showed that compounds 6e and 6f exhibited some effect against gastric cancer cell SGC-7901 with IC(50) values of 22.28+/-6.26 and 18.45+/-2.79 microg/mL, respectively. All title compounds were assayed for telomerase inhibition by a modified TRAP assay, the results showed that compound 6e can strongly inhibit telomerase with IC(50) value of 0.8+/-0.07 microM. Docking simulation was performed to position compound 6e into the active site of telomerase (3DU6) to determine the probable binding model.

Enantioseparation and plant virucidal bioactivity of new quinazoline derivatives with alpha-aminophosphonate moiety.

Enantiomers of some new quinazoline derivatives bearing alpha-aminophosphonate moiety were separated under normal-phase conditions on two immobilized polysaccharide-based chiral stationary phases (Chiralpak IA and Chiralpak IC). The role of two chiral stationary phases (CSPs), polar modifier and column temperature on retention time and separation factor was studied. Apparent thermodynamic parameters were deduced from Van't Hoff plots and plausible mechanism of chiral recognition has been discussed. The semi-preparative separation of some compounds was executed successfully in n-hexane/isopropyl alcohol (IPA) on the Chiralpak IA column. The preliminary bioassay showed that both the enantiomers of the investigated series of compounds possessed similar anti-tobacco mosaic virus (TMV) activities.

Synthesis and antiviral bioactivities of 2-cyano-3-substituted-amino(phenyl) methylphosphonylacrylates (acrylamides) containing alkoxyethyl moieties.

An efficient reaction under microwave irradiation has been developed for the synthesis of a series of novel 2-cyano-3-substituted-amino(phenyl) methylphosphonylacrylates (acrylamides) II. The products obtained in shorter reaction time with moderate yields are fully characterized by elemental analysis, IR, (1)H, (13)C, and (31)P NMR spectral data. The role of introducing various substituents and the effect of incorporating alpha-aminophosphonates with an alkoxyethyl moiety into the parent cyanoacrylate (acrylamide) structure are investigated. Among the studied compounds, both II-17 and II-24 displayed good in vivo curative, protection, and inactivation effects, which were comparable to those of the commercial reference ningnanmycin (inhibitory rates of 58.8, 60.2, 78.9% and 60.0, 58.9, 85.5%, respectively, at 500 mg/L against TMV). To the best of the authors' knowledge, this is the first report on the synthesis and antiviral activity of the title compounds II.

Synthesis and antiviral activities of chiral thiourea derivatives containing an alpha-aminophosphonate moiety.

Starting from benzaldehyde 1, the title compounds 8 were synthesized in six steps. Benzaldehyde 1 was reacted with ammonium hydroxide, and the resulting imine was then treated with dialkyl phosphite 3 to give dialkyl N-(arylmethylene)-1-amino-1-aryl methylphosphonates 4. Phosphonates 4 were then easily hydrolyzed to give dialkyl 1-amino-1-aryl-methylphosphonates 6, which on treatment with triethylamine, carbon disulfide, and phosphorus oxychloride provided 7. Target compounds 8 were then prepared by the reaction of 7 with substituted chiral amine. The structures were clearly verified by spectroscopic data (IR, (1)H, (13)C, and (31)P NMR, and elemental analysis). The bioassay of these compounds revealed them as antivirally active. It was found that title compounds 8g, 8e, 8k, and 8m had the same curative effects of TMV (inhibitory rate = 54.8, 50.5, 50.4, and 50.4%, respectively) as the commercial product Ningnanmycin (56.2%). This would appear to be the first report of the synthesis and antiviral activity of chiral thiourea derivatives containing an alpha-aminophosphonate moiety.

Synthesis, structure and antibacterial activity of new 2-(1-(2-(substituted-phenyl)-5-methyloxazol-4-yl)-3-(2-substitued-phenyl)-4,5-dihydro-1H-pyrazol-5-yl)-7-substitued-1,2,3,4-tetrahydroisoquinoline derivatives.

A series of new 2-(1-(2-(substituted-phenyl)-5-methyloxazol-4-yl)-3-(2-substitued-phenyl)-4,5-dihydro-1H-pyrazol-5-yl)-7-substitued-1,2,3,4-tetrahydroisoquinoline derivatives were synthesized. The results showed that compounds 9q and 10q can strongly inhibit Staphylococcus aureus DNA gyrase and Bacillus subtilis DNA gyrase (with IC(50s) of 0.125 and 0.25 microg/mL against S. aureus DNA gyrase, 0.25 and 0.125 microg/mL against B. subtilis DNA gyrase). On the basis of the biological results, structure-activity relationships were also discussed.

An effective route to fluorine containing asymmetric alpha-aminophosphonates using chiral Bronsted acid catalyst.

Asymmetric addition of dialkyl phosphites (--CH2CH3, --CH2CH2CH3, --CH(CH3)2, --CH2(CH2)3CH3, --CH2CH2OCH3 and --CH2CH2OC2H5) induced by chiral organocatalyst e.g. (R)- and (S)-3,3'-[3,5-bis(trifluoromethyl)phenyl]2-1,1'-binaphthyl phosphate on fluorinated aldimines derived from cinnamaldehyde has been found effective to give new bioactive alpha-aminophosphonates in good yields (58-73%) and high enantiomeric excess (64.6%-90.6%) under mild conditions.

Synthesis and antiviral activities of pyrazole derivatives containing an oxime moiety.

Target compounds 4a- n were obtained by the reaction of 1-substituted phenyl-3-methyl-5-substituted phenylthio-4-pyrazolaldoximes (3) with chloromethylated heterocyclic compounds (ClCH 2-R 3) under reflux conditions in ethanol. Subsequently, the oxidation of 4a- e with KMnO 4 in HOAc at room temperature afforded eight new compounds, 5a- h. The synthesized compounds were characterized by physical constants, and the structures of the title compounds were confirmed by IR, (1)H NMR, (13)C NMR, and elemental analysis. The bioassay revealed that the compounds possessed antiviral activities. It was found that title compounds 4a and 4g had the same inactivation effects against TMV (EC 50 = 58.7 and 65.3 microg/mL) as the commercial product Ningnanmycin (EC 50 = 52.7 microg/mL). To the best of our knowledge, this is the first report on the antiviral activity of pyrazole derivatives containing an oxime moiety.

Synthesis and antiviral activity of novel pyrazole derivatives containing oxime esters group.

Fourteen title compounds, 1-substituted-5-substitutedphenylthio-4-pyrazolaldoxime ester derivatives 4a-4n, were synthesized from the starting material 1-substitutedphenyl-3-methyl-5-substitutedphenylthio-4-pyrazolaldoximes 3 by treatment with acyl chloride. The synthesized compounds were characterized by physical constants, and the structures of the title compounds were further confirmed by IR, 1H NMR, 13C NMR and elemental analysis. The bioassay results showed that title compounds possessed weak to good anti-TMV bioactivity with 4l showing significant enhancement of disease resistance in tobacco leaves with high affinity for TMV CP.