Asymmetric Pauson-Khand reaction with chiral, electron-deficient mono- and bis-phosphine ligands

The intermolecular Pauson-Khand reaction between norbornene and dicobalt carbonyl complexes of phenylacetylene substituted with chiral phosphorus ligands has been investigated. High yields (?98%) and enantiomeric excesses of up to 56% have been observed.     

Synthesis of C-3' methyl taxotere (docetaxel)

Protected (3R,4S)-N-Boc-3-hydroxy-4-methyl-4-phenylazetidin-2-one has been synthesized stereoselectively and used to esterify protected 10-desacetylbaccatin III to give, following removal of the protecting groups, novel C-3' methyl taxotere (docetaxel).     

The role of post-translational modification in the photoregulation of Fe-type nitrile hydratase

The inactive, nitrosyl bound form of Fe-type nitrile hydratase (NHase) contains two active site cysteine residues that are post-translationally modified to sulfenate (SO-) and sulfinate (SO2-) ligands. DFT and INDO/S calculations support the hypothesis that these unusual modifications play a key role in modulating the electronic absorption spectra and photoreactivity of the Fe(III) centre in the enzyme.     

Interpretation of oscillatory structures in Rb− photodetachment

Oscillations observed by Frey et al. in the photodetachment cross section of Rb^? near the 5p _1/2 threshold are shown to derive from a static external electric field of strengthF ? 1.3 V/cm. This field was used in the experiment to discriminate between slow and fast electrons, but it causes a quasiperiodic energy dependence just above threshold, with a maximum peak separation of roughly 0.1 cm^?1.     

High-performance liquid chromatographic analysis of vancomycin in plasma, bone, atrial appendage tissue and pericardial fluid

Solid-phase extraction coupled with reversed-phase high-performance liquid chromatography and UV detection was employed for the analysis of the antibiotic vancomycin in patient plasma, bone, atrial appendage, and pericardial fluid. Vancomycin was quantitated in samples from patients undergoing cardiac surgery. Calibrations were linear in the range 3-100 micrograms/ml vancomycin; the lower limit of detection was approximately 3 micrograms/ml in fluids with an absolute limit of detection in bone samples of 0.75 microgram per injection.     

Determination of a new anti-allergenic agent, 1-[4-[3-[4-[bis-(4-fluorophenyl)hydroxymethyl]-1-piperidinyl] propoxy]-3-methoxyphenyl]ethanone, and its active acidic metabolite in plasma by high-performance liquid chromatography

High-performance liquid chromatographic (HPLC) methods were developed for the analysis of two compounds in a series of new antiallergenic agents, 1-[4-[3-[4-[bis(4-fluorophenyl)hydroxymethyl]-1-piperidinyl] propoxy]-3-methoxyphenyl]ethanone and its active acidic metabolite in plasma. The methods utilize ultraviolet or fluorescence detection, liquid-liquid extraction or solid-phase extraction and reversed-phase HPLC. The drugs were quantitated in samples from bioavailability studies performed in dogs. Calibrations were in the ng/ml concentration range for both compounds in plasma.     

Some results on sperner families

Let F be a Sperner family of subsets of {1,…,m}. Bollobás showed that if $\text{A ∈ F ?}\text{A}\text{= {1,…,m}βA ∈ F}$, and if the parameters of F are p₀,…,p_m then

$\text{∑}\text{i=0}\text{[}\text{m}\text{2}\text{Pi}\text{m?1}\text{i?1}\text{+}\text{∑}\text{i=[}\text{m}\text{2}\text{]+1}\text{m}\text{Pi}\text{m?1}\text{m?i?1}\text{? 2}$

Here we generalize this result and prove some analogues of it. A corollary of Bollobás' result is that $\text{|F| ? 2(}{}_{\mathrm{<mtext>[</mtext><mtext>m</mtext><mtext>2</mtext><mtext>]?1</mtext>}}{}^{\mathrm{m?1}}\text{)}$. Purdy proved that if $\text{A ∈ F ?}\text{A}\text{? F}$ then $\text{|F| ? (}{}_{\mathrm{<mtext>[</mtext><mtext>m</mtext><mtext>2</mtext><mtext>]+1</mtext>}}{}^{\mathrm{m}}\text{)}$, which implies Bollobás' corollary. We also show that Purdy's result may be deduced from Bollobás' by a short argument. Finally, we give a canonical form for Sperner families which are also pairwise intersecting.