The knoevenagel condensation of ethyl acylpyruvates

Extensive studies of the Knoevenagel condensation of aromatic aldehydes and active methyl-lene compounds have been reported (2). In 1894, Knoevenagel reported (3) the reaction of benz-aldehyde with ethyl benzoylpyruvate in the presence of piperidine to give ehtyl benzyl-(bis-benzoyl)pyruvate, m.p. 162°, but no yield of the product was reported. This paper deals with the interesting results of the reactions of ethyl acetylpyruvate ( 2 ) ( 4 ) and ethyl benzoylpyruvate ( 3 ) (5) with some aromatic aldehydes ( 1a-f ).     

6-Exo-spiro (alkoxycarbonylamino)methyl radical cyclization: highly regio- and stereoselective synthesis of (-)-sibirine

[reaction: see text] The (methoxycarbonylamino)methyl radical can be readily generated from its PhSe precursor and undergoes preferential 6-exo-spiro cyclization when PhSO(2) is attached at the distal alkene carbon. This property was applied to the synthesis of the racemic and optically active spirocyclic alkaloid sibirine.     

Estimation of absorbed dose in 131I therapy of metastasis of thyroid cancer

The radiation absorbed dose was estimated for 131I therapy of metastatic lesions of thyroid cancer, by the quantitative gamma-camera imaging. Uptake for eleven lesions in five cases (out of four patients) was measured for two times after 131I administration. Activities were calculated from opposed images with corrections for distance and depth using empirical formulae. An activity time curve was assumed as a reminder of two exponentials and fitted to measured values. The sizes of lesions were evaluated using the multi-slice CT images. An increase of frequency of activity measurement, particularly within a few days after 131I administration is desirable, for the purpose of an improvement of accuracy of dosimetry.     

Neutron and photon activation analyses of twenty four GSJ and six KIER rock reference samples

Fifteen GSJ (Geological Survey of Japan) and six KIER (Korean Institute of Energy and Resources; now Korean Institute of Geology, Mining and Materials, KIGAM) igneous rock series and nine GSJ sedimentary rock series reference samples were analysed for 21–29 elements by neutron and/or photon activation analysis (NAA and PAA); 14 MeV-NAA for Si and Al, fission track method for U, radiochemical and instrumental NAA for rare earth elements, with reactor neutrons for the latter two. Instrumental neutron and photon AA for the remaining elements were performed with reactor neutrons and bremsstrahlung of end-point energy of 30 MeV, respectively. The reactor irradiations were performed at core sites and also a thermal column of the Kyoto University Research Reactor. All of the radioassays were performed by -ray spectrometry with HPGe-detectors. The present results from the different types of irradiation are compared and discussed in terms of elemental abundances and rock types.     

Au(I)-catalyzed highly efficient intermolecular hydroamination of alkynes

[reaction: see text] Addition of aniline derivatives to aromatic and aliphatic alkynes proceeds efficiently in the presence of a gold(I) catalyst (0.01-1.0 mol %) to afford ketimines in good yields     

A concise synthesis of furostifoline by tetrabutylammonium fluoride-promoted indole ring formation

Furostifoline, a furo[3,2-a]carbazole alkaloid, was synthesized in 10% overall yield in four steps from 2-acetyl-3-bromofuran. The key step of this synthesis was the 2-substituted indole formation with tetrabutylammonium fluoride (TBAF) from 2-(2-propenyl)-3-((2-ethoxycarbonylamino)phenylethynyl)furan, which was easily prepared from ethyl 2-ethynylphenylcarbamate with 3-bromo-2-(2-propenyl)furan by the Sonogashira reaction.     

Liquid imidazole-borane complex

Physical properties of liquid imidazole-borane complex were investigated to demonstrate their utility as aprotic polar solvents or liquid electrolytes appropriate for selective ion transport.     

Triterpenes and triterpene saponins from the stems of Akebia trifoliata

To characterize the stems of Akebia trifoliata chemically, a detailed phytochemical examination was carried out on A. trifoliata stems, with particular attention to the triterpene and triterpene saponin constituents, and resulted in the isolation of three new triterpenes (1-3) and three new triterpene saponins (11-13), together with seven known triterpenes (4-10) and 12 known triterpene saponins (14-25). The structures of the new compounds were determined on the basis of spectroscopic analysis, including two-dimensional NMR spectroscopic data, and the results of hydrolysis. Four saponins (22-25), which were obtained in good yields and were not isolated from Akebia quinata stems, are concluded to be applicable as marker compounds in chemically distinguishing between A. trifoliata and A. quinata by conventional TLC examination. To the best our knowledge, the current work is the first chemical investigation of A. trifoliata.     

Sugars within a hydrophobic scaffold: glycodendrimers from polyphenylenes

A new glycodendrimer type has been introduced that is designed on the basis of shape-persistent polyphenylene dendrimers. The sugar installation occurs not only on the dendrimer surface but also within the hydrophobic internal scaffold. The synthesis has been accomplished via both convergent and divergent routes by employing the Schmidt glycosylation and the Diels-Alder reaction. This new glycodendrimer has been found to exhibit water-solubility, while conserving hydrophobicity of the interior environment despite the incorporation of sugars.     

Asymmetric synthesis of a xanthine dehydrogenase inhibitor (S)-(−)-BOF-4272: Utility of chiral alkoxysulfonium salts

A practical synthetic method for a xanthine dehydrogenase inhibitor, (S)-(−)-BOF-4272, was established utilizing an asymmetric oxidation of diaryl sulfide BOF-4269. The oxidation of the sulfide with 1-chlorobenzotriazole carried out in the presence of 4-cyanopyridine and chiral 2-phenylcyclohexanol gave a high enantiomeric excess (73%ee). The sulfoxides in each enantiomerically pure form could be obtained by treating with alkaline hydrolysis or thermolysis of one the diastereomeric intermediate sulfonium salts (>99%de). Thus the transformation into the sulfoxides occur with virtually perfect inversion (alkaline hydrolysis) or retention (thermolysis). It is therefore possible to obtain the target sulfoxide, (S)-(−)-BOF-4272, from both the two diastereomeric sulfonium intermediates.