Evaluation of 99mTc-HIDA complex as a cholescintigraphic agent (author's transl)

In the reaction labeling N-(2,6-dimethylphenylcarbamoylmethyl) iminodiacetic acid (HIDA) with 99mTc, several complexes with different chemical characteristics were observed to occur with slight changes in the labeling conditions. Among these complexes, a complex detected in the bile of rats was limited to one complex, named as complex II. The preparation method of 99mTc-HIDA complex II and the exchange reaction between this complex and penicillamine indicate that 99mTc is coordinated with HIDA as low-hydrolyzed 99mTc in this complex. This complex is excreted rapidly through the bile and within 1 hr, about 65% of the total activity injected is recovered from bile in rats. The organ distribution of this complex was studied in mice by radioassay and in rabbits by scintillation camera and, in both cases, the radioactivity was accumulated in the gallbladder. These results suggest that the 99mTc chemical state, low-hydrolyzed state, relates to the bile excretion behavior of this complex, a potentially useful cholescintigraphic agent.     

Daphmanidin A,a novel hexacyclic alkaloid from Daphniphyllum teijsmanii

A novel alkaloid with an unprecedented fused-hexacyclic skeleton, daphmanidin A (1), and a new pentacyclic alkaloid, daphmanidin B (2), have been isolated from the leaves of Daphniphyllum teijsmanii, and the structures were elucidated on the basis of spectroscopic data. The relative and absolute stereochemistry of 1 was determined by combination of NOESY correlations and a modified Mosher method.     

Furopyridines. IX. Syntheses and properties of 3-ethoxy derivatives of furo[2,3-b]-, furo[3,2-b]-, furo[2,3-c]- and furo[3,2-c]pyridine

Reaction of ethyl 3-ethoxycarbonylmethoxyfuropyridine-2-carboxylates 2a-2d with sodium ethoxide afforded 3-ethoxy derivatives 3a-3d which converted to 3-ethoxyfuropyridines 5a-5d by hydrolysis and decarboxylation of the ester group. Vilsmeier reaction of 5a and 5b gave 2-formyl-3-ethoxy derivatives 6a and 6b and 2-formyl-3-chloro derivatives 7a and 7b , while 5c and 5d did not give any formyl compound. Bromination of 3-ethoxyfuropyridines with 1 equivalent mole of bromine gave 2-bromo-3-ethoxyfuropyridines 9a-9d , whereas reaction with 3 equivalents of bromine yielded 2,2-dibromo-3,3-diethoxy-2,3-dihydrofuropyridines ( 10a and 10b ) and/or 2-bromo-3,3-diethoxy-2,3-dihydrofuropyridines 11b , 11c and 11d . Treatment of compounds 5a-5d with n-butyllithium in hexane-tetrahydrofuran at ?70° and subsequent addition of N,N-dimethylformamide yielded 2-formyl derivatives 6a-6d .     

Cd2+-induced interfacial structural changes of Langmuir-Blodgett films of stearic acid on solid substrates: a sum frequency generation study

The molecular structures and their stabilities at the outmost-layer of the Langmuir-Blodgett (LB) films of stearic acid on solid substrates have been investigated by a highly surface-sensitive spectroscopic technique, sum frequency generation (SFG), in air and in aqueous solution, using the combination of both normal and deuterated stearic acid. Peaks observed in the SFG spectra are mainly attributed to the terminal methyl group at the outmost layer of the LB films. The SFG spectra in air are virtually identical and are independent of the odd-even property and thickness (1-12) of the LB films, indicating that the even-numbered LB film changes its surface structure after passing through the interface between the water subphase and air, especially when the Cd2+ cation was included in the water subphase. Furthermore, we have demonstrated for the first time using in situ SFG measurement that the interfacial molecular structure at the LB bilayer of stearic acid on the hydrophilic substrates significantly change with immersion in the water subphase containing Cd2+ cation while such a structural change has not been observed in the water subphase without Cd2+. These results clearly indicate that a reorganization process takes place on the surface of the stearic acid bilayer induced by the Cd2+ cation. The electrostatic interaction between the carboxylate headgroup of stearic acid via the Cd2+ cation seems to play an important role in the surface reorganization process both in air and in solution.     

Microcolumn liquid chromatography/Fourier transform infrared spectrometry interface using a potassium bromide disk

Summary A redesigned interface is reported for use in the detection of microcolumn liquid chromatographic effluents with a Fourier transform infrared spectrometer. The solutes eluting from the column are continuously deposited onto a 50mm diameter KBr disk as a “buffer-memory”. The disk is rotated by a stepper motor with a controlling electronics. After the chromatographic run, the disk is simply transferred to the spectrometer and the transmission spectra are measured as the disk rotates. The use of such a large KBr disk as a substrate permits to obtain spectra of the components having a large capacity factor.     

Daphniglaucin C, a novel tetracyclic alkaloid from Daphniphyllum glaucescens

A novel Daphniphyllum alkaloid with an unprecedented tetracyclic ring system consisting of an octahydroindole and a hexahydroazulene rings, daphniglaucin C (1), has been isolated from the leaves of Daphniphyllum glaucescens and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data. Daphniglaucin C (1) inhibited the polymerization of tubulin.     

Influence of triplet—triplet excitation transfer on the decay function of donor luminescence

The triplet—triplet electronic excitation transfer from benzophenone to naphthalene in rigid solutions has been investigated by measuring the non-exponential decay curve of benzophenone photphorescence using a laser pulse for excitation. The results of measurements were satisfactorily reproduced by Inokuti—Hirayama's formula based on Dexter's theory of exchange interaction.     

Energy-density relations in momentum space

Rigorous relations are derived between the electronic energy and the electron momentum density of a molecular system whose Hamiltonian takes the form ofg(λ)T({r}) +h(λ)V({r};{R}) and depends on a parameter λ.     

Capillary electrophoresis of anthraquinones from Cassia siamea

The separation and determination of two anthraquinones, emodin and chrysophanol, and two bianthraquinones, cassiamin A and cassiamin B, were achieved by capillary electrophoresis (CE). The running electrolyte used in this method was 0.05 M hydroxypropyl-gamma-cyclodextrin in 0.1 M borate buffer (pH 9) containing 10% acetonitrile, with an applied voltage of 20 kV. Application of this technique in the determination of the main bianthraquinones, cassiamin A and cassiamin B, of Cassia siamea is demonstrated in this paper.     

Two cangorosin A type triterpene dimers from Maytenus chuchuhuasca

Two new cangorosin A type triterpene dimers, which composed of two triterpene units jointed by two ether linkages between the A and B rings, were isolated from the Brazilian medicinal plant "xuxuá" (Maytenus chuchuhuasca). Structures of new isolates, xuxuasins A (1) and B (2), were established based on several spectroscopic evidences.