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Palladium-catalyzed cross-coupling between 2,3-naphthoxadisilole and aryl halides in the presence of tetrabutylammonium fluoride afforded 2-aryl naphthalenes. This is first report that oxadisilole served as a partner in the palladium-catalyzed cross-coupling reactions. The reaction mechanism was also studied.

Diastereoselective methylation of dimethyl (S)-malate 7, followed by two, three-step reductive de-hydroxylation procedures afforded dimethyl (R)-2-methylsuccinate 11 in 80.2% e.e. and 84.7% e.e., respectively. The latter compound was further transformed into the natural enantiomers of the ant venom alkaloids (R)-leptothoracine 1 and (R)-3-methyl-N-(2-phenylethyl)-pyrrolidine 2.

Seven aliphatic alcohols were derivatized to dithiocarbonates under phase transfer catalysis by tetrabutylammonium hydrogen sulphate and directly determinated by capillary zone electrophoresis. A satisfactory separation was achieved within 6 min. Theoretical plates ranging from 500,000 to 136,000 were achieved. The analysis was carried on a bare fused-silica capillary with an electrolyte of 10 mM borate buffer (pH 9.2) and detection at 300 nm. Calibration graphs were linear. The reproducibility in terms of the migration times was less than 0.3% R.S.D. and in terms of corrected peak area was better than 5% R.S.D. The detection limits ranged from 1.470 μg/ml to 7.906 μg/mL for alcohols of different chain length.

In this paper, based on theoretical calculations, new schemes to increase the deuterium density in palladium over its initial value are presented. A high deuterium concentration in palladium is needed for application to solid-state fusion. The first deuterium enrichment scheme makes use of plasma ion implantation, which consists of a cylindrical palladium rod (target) preloaded with deuterium atoms, coated with diffusion barrier material, and immersed in a deuterium plasma. The palladium rod is connected to a high-power modulator, which provides a series of negative voltage pulses. During these negative pulses, deuterium ions fall on the target, penetrate the diffusion barrier, and are implanted inside the palladium. For reasonable system parameters allowed by current technology, theoretical calculations indicate that the saturation deuterium density after prolonged ion implantation can be several times the palladium atomic number density. The second deuterium enrichment scheme makes use of temperature gradient effects on the deuterium solubility in palladium. A heat source at temperature T{sub 2} and a heat sink at temperature T{sub 1} (where T{sub 2} {gt} T{sub 1}) are in contact with two different parts of a palladium sample, which has been presoaked with deuterium atoms and has been coated with diffusion barrier material ormore » has been securely locked in a metal case. The temperature gradient created in the sample from such an arrangement forces the deuterium atoms in the hot region to migrate into the cold region, resulting in higher deuterium density in the cold region.« less

Two chelating resins, containing trithiocarbonate and dithiocarbamate groups, respectively, were synthesized efficiently from a commercially available cross-linked chloromethylated polystyrene. The pH dependence of the metal extraction for Pb(II), Cu(II), Ni(II) and Co(II) was studied. Both resins exhibited high affinity toward Pb(II) and Cu(II). The sorptive capacity of trithiocarbonate and dithiocarbamate resin with respect to Cu(II) was 3.5 and 4.4 mg/g of dry resin at pH 6. The application of the resins for selective adsorption and the concentration of metal ions from aqueous solutions has been investigated.

O-Alkyl, S-methyl dithiocarbonates of phenol, benzyl, primary and secondary alcohols were prepared in a one pot procedure under phase transfer catalysis conditions.

A method has been developed to study the mechanism of epididymal secretion in the anesthetized rat in vivo. Secretion of the cauda epididymidis was affected by altering the intraluminal calcium ion concentration. Removal of calcium caused a rise and high calcium (10 X normal) caused a fall in the rate of secretion. Exocytosis did not seem to be operative in the epididymidis. The perfusate collected from the cauda epididymidis stimulated the forward motility of the washed caudal epididymal spermatozoa. This effect was concentration-dependent. At low concentration the perfusate stimulated the forward motility and at high concentration it caused a fall. A similar relationship between concentration and effect was noted for the epididymal plasma. When the diluted perfusate was used as the stimulant, there was a time lag of 15 min before any stimulation of forward motility was observed. However, the effect of the diluted epididymal plasma was immediate. The effect of the perfusate but not the plasma was inhibited by pretreatment of the sperm with cyclohexamide (10(-4) M). This difference in the action of the two fluids was discussed in relation to the proteins present in the fluids as revealed by SDS polyacrylamide gel electrophoresis.

The requirements for activation of the transformation potential of the human c-fos proto-oncogene were investigated. Recombinant plasmids containing the Moloney murine leukemia virus long terminal repeat directing transcription of the c-fos coding region and either the authentic c-fos 3' untranslated region (UTR) or the 3' UTR from human c-myc were inefficient at inducing transformation. In contrast, a recombinant that substituted most of the c-fos 3' UTR with the 3' portion of the simian virus 40 T-antigen gene transformed cells well. This difference in transformation efficiency appeared to be due to significantly higher levels of fos mRNA and protein expressed from the transforming recombinant. This, in turn, was due to the much greater stability of its mRNA compared with those from the poorly transforming recombinants containing the c-fos or c-myc 3' UTR. Thus, the 3' UTR of the human c-fos mRNA is responsible for its rapid degradation and limits the steady-state levels of transcript and protein. Cells transformed by the activated human c-fos plasmids contained increased amounts of partially modified c-fos protein (c-Fos). This form of c-Fos turned over much more rapidly than the highly modified form of c-Fos induced by serum stimulation.

Symmetrical and cyclic alkyl trithiocarbonates were synthesized by reacting CS2 and 33% aqueous NaOH with alkyl hal-ides under phase transfer catalysis conditions