44 research outputs found
Palladium-Catalyzed, Asymmetric Mizoroki–Heck Reaction of Benzylic Electrophiles Using Phosphoramidites as Chiral Ligands
We report herein the first examples of asymmetric Mizoroki–Heck
reactions using benzyl electrophiles. A new phosphoramidite was identified
to be an effective chiral ligand in the palladium–catalyzed
reaction. The reaction is compatible with polar functional groups
and can be readily scaled up. Several cyclic olefins worked well as
olefin components. Thirty-one examples are included
Palladium-Catalyzed, Asymmetric Mizoroki–Heck Reaction of Benzylic Electrophiles Using Phosphoramidites as Chiral Ligands
We report herein the first examples of asymmetric Mizoroki–Heck
reactions using benzyl electrophiles. A new phosphoramidite was identified
to be an effective chiral ligand in the palladium–catalyzed
reaction. The reaction is compatible with polar functional groups
and can be readily scaled up. Several cyclic olefins worked well as
olefin components. Thirty-one examples are included
Development of a Scalable Process for α‑Amino-ω-methoxyl-dodecaethylene Glycol
We have developed a process for the
efficient and scalable preparation
of heteroÂfunctionÂalized dodecaÂethylene glycol from
the readily available tetraÂethylene glycol and its macroÂcyclic
sulfate. By employing the benzyl group as both a protecting group
and a separative tag, multiple chromatoÂgraphic separations were
avoided. With this method, α-amino-ω-methyl-dodecaÂethylene
glycol was prepared on a 53 g scale with high purity and 61% overall
yield in eight steps and one chromatoÂgraphic separation
Top-down Targeted Metabolomics Reveals a Sulfur-Containing Metabolite with Inhibitory Activity against Angiotensin-Converting Enzyme in <i>Asparagus officinalis</i>
The discovery of bioactive natural
compounds containing sulfur,
which is crucial for inhibitory activity against angiotensin-converting
enzyme (ACE), is a challenging task in metabolomics. Herein, a new
S-containing metabolite, asparaptine (<b>1</b>), was discovered
in the spears of <i>Asparagus officinalis</i> by targeted
metabolomics using mass spectrometry for S-containing metabolites.
The contribution ratio (2.2%) to the IC<sub>50</sub> value in the
crude extract showed that asparaptine (<b>1</b>) is a new ACE
inhibitor
Additional file 1: of Effects of the complete replacement of fish oil with linseed oil on growth, fatty acid composition, and protein expression in the Chinese mitten crab (Eriocheir sinensis)
Table S1. Differentially expressed proteins in the hepatopancreas of crabs fed with FO and LO. (XLSX 58Ă‚Â kb
Effect of photoperiod on DA<sub>2</sub> mRNA expression (normalized to 18S expression) in the cranial ganglia, thoracic ganglia and eyestalks of crabs cultured in different light conditions compared with the control treatment (L:D = 12h:12h).
<p>Values are the means± SE (n = 8–10). Bars with different letters indicate statistically significant differences (<i>P</i><0.05).</p
DA<sub>2</sub> mRNA expression levels in the hepatopancreas and intestines during different feeding statuses.
<p>Values are the means± SE (n = 6). Bars with different letters indicate statistical significant differences (<i>P</i><0.05).</p
Fe<sub>2</sub>O<sub>3</sub>‑Promoted Intermolecular Chlorotrifluoromethylthiolation of Alkenes
A simple, convenient
method for intermolecular chlorotrifluoromethylthiolation
of alkenes by using a low-cost and more abundant iron catalyst has
been developed. This protocol provides a straightforward way to synthesize
a variety of useful SCF<sub>3</sub>-containing chlorides from a wide
range of alkenes, including electron-deficient, aromatic, and unactivated
alkenes. Mechanistic studies indicate that this is a free radical
transformation, and the stronger electrophilic trifluoromethylthiolating
reagent CF<sub>3</sub>SCl was generated in situ under the employed
conditions. The synthetic applications of this approach were also
explored by a variety of synthetically useful transformations
Nucleotide and deduced amino acid sequences of the DA<sub>2</sub> gene.
<p>The nucleotide sequence is enumerated from the 192bp end and the single-letter amino acid code is shown above each corresponding codon. The start codon (ATG) and the stop codon (TAG) are indicated in the black boxes. The putative phosphorylation sites are indicated in the red boxes. The putative N-glycosylation sites are indicated in the green boxes. The seven transmembrane regions are underlined. Dashed boxes indicate the poly (A) tail.</p
Expression level of the DA<sub>2</sub> gene normalized to 18S expression in the thoracic ganglia, cranial ganglia, eyestalks, gill, heart, muscle, hepatopancreas, intestine, and haemolymph of the crab.
<p>Values are the mean ± SE (n = 4–6). *indicates that expression in the corresponding tissues is significantly different from expression in the control organ (intestine) at <i>P</i><0.05.</p