ansa metallocene complexes of Ti, Zr and Hf were synthesized, characterized and tested as catalysts for homogeneous ethylene polymerization. The ligand system comprises two indenyl moieties tethered at the 1,1′-positions via a 2,2′-dimethyl biphenylene bridge. The ligand precursor was obtained...

Anodic fluorination of ethyl α-fluoro-α-(phenylseleno)acetate was successfully carried out to give ethyl α,α-difluoro-α-(phenylseleno)acetate in high yield. Photolysis of the difluorinated product in the presence of various olefins provided regioselective difluorometylene adducts in good to...

The stereochemistry of cyclopropanation reactions between allylsilanes and allylstannanes 6 with four representative diazoalkanes in the presence of rhodium acetate has been studied. Cyclopropanations with ethyl diazoacetate show a preference for the formation of the trans cyclopropane esters 7,...

Ethyl 3-aminobut-2-enoates MeC(NHR)=CHCO2Et (R = H, Me, Bn) whose reaction site is C(2) atom add to 2-R-3-nitro-2H-chromenes at their C(4) atom to give the corresponding trans,trans-2,3,4-trisubstituted chromanes. Analogous substrates MeC(NR2)=CHCO2Et (NR2 is piperidin-1-yl or morpholin-4-yl) re...

The first total synthesis of dioncophylline A (previously “triphyophylline”) and some selected stereoisomers is described, using an intramolecular-type mixed aryl coupling method via ester-type prefixed molecular moieties. Simultaneously, this synthesis establishes the complete (revised) stere...

The isolation and structural elucidation of dioncophylline E, a novel naphthylisoquinoline alkaloid from the rare West African liana Dioncophyllum thollonii, is described. The alkaloid displays an unusual 7,3′-linkage between the naphthalene and the isoquinoline portions. Due to the resulting m...

The naphthyl isoquinoline alkaloid “triphyophylline” is structurally re-investigated. The constitution, as well as the relative configurations at C-1 and C-3, are confirmed as published previously. “Triphyophylline” is found to be a stable rotational isomer with respect to the biaryl linkage...

The synthesis of jozimine A, the first non-natural dimer of a naturally occurring monomeric naphthylisoquinoline alkaloid, is described, starting from dioncophylline A, as isolated from Triphophyllum peltatum, resp. prepared by total synthesis. It is the first dimeric naphthylisoquinoline alkalo...

The naphthylisoquinoline alkaloid dioncophylline A was studied for antifeedant activity against larvae of the polyphagous herbivore Spodoptera littoralis. When neonate larvae were reared on artificial diet spiked with concentrations of dioncophylline A as present in plant material of Triphyophyl...

The isolation and structure elucidation of two new minor naphthylisoquinoline alkaloids from the stem bark of Triphyophyllum peltatum is described. From extended spectroscopic investigations, mainly NMR and CD spectroscopy, one of the alkaloids is deduced to be 5′-O-demethyl-8-O-methyl-7-epi-di...

The absolute configuration of the naphthylisoquinoline alkaloid dioncophylline A was determined by anomalous X-ray dispersion crystal structure analysis of its bisbenzylated bromo derivative. © 1997 Elsevier Science Ltd. All rights reserved

The larvicidal activity of dioncophylline A, a naphthylisoquinoline alkaloid derived from the tropical vine Triphyophyllum peltatum (Dioncophyllaceae), was investigated against the malaria vector Anopheles stephensi. In direct and indirect inhibition assays it was demonstrated that the younger l...

Although dioncophylline A (1) is the certainly best-investigated naphthylisoquinoline alkaloid, it still represents a challenging case for theoretical stereochemical investigations. Its biaryl axis, although being configurationally stable, still has a certain degree of rotational flexibility, ra...

This study describes an improved, simple, and specific gas chromatographic method for the determination of diltiazem (I) and deacetyldiltiazem (II) in human plasma using loxapine (III) as an internal standard. After extraction at pH 7.5 with anhydrous ether-ethyl acetate (1:1), II was silylated ...

A highly sensitive gas chromatographic method for the analysis of diltiazem and deacetyldiltiazem in plasma or serum is reported. After silylation with bis (trimethylsilyl) trifluoroacetamide, separation was obtained on a cross-linked fused-silica column and detection was by electron-capture. Th...

Diltiazem (DTZ) was given intravenously (i.v.), orally (p.o.) and hepatoportally (p.v.) in solution form to rats in order to assess the pharmacokinetic behavior of DTZ and its major metabolite, deacetyldiltiazem (DAD). The plasma half-life at postdistributive phase (t12,β), total body (plasma) ...

The present study aimed at isolation and purification of the bioactive terpenoids from the herb of Leonurus japonicus by chromatographic separations such as silica gel, sephadex LH-20 and C18 reversed phase silica gel, as well as preparative HPLC. As a result, leojaponic acids A (1, C17H24O4) an...

Treatment of 4-aryl-6-trifluoromethyl-2-pyrones with sodium azide in DMSO afforded the corresponding (Z)-3-(5-trifluoromethyl-1,2,3-triazol-4-yl)cinnamic acids in good yields. Similarly, 4-aryl-3-carbethoxy-6-trifluoromethyl-2-pyrones smoothly reacted with sodium azide in acetonitrile to produce...

Ethyl 5-aroyl-4-pyrone-2-carboxylates react with hydroxylamine in ethanol at –20 °C for 30 days to produce ethyl 4-(5-arylisoxazol-4-yl)-2,4-dioxobutanoates (yields 20–67%). The similar reaction of diethyl 4-pyrone-2,5-dicarboxylate gives ethyl 4-oxo-4H-pyrano[3,4-d]isoxazole-6-carboxylate in...

IntroductionThe small molecule 2-(5-(dimethylamino)naphthalene-1-sulfonamido)-2-(fluoromethyl)butanoic acid (NST732) is a member of the ApoSense family of compounds, capable of selective targeting, binding and accumulation within cells undergoing apoptotic cell death. It has application in molec...