7 research outputs found
Pd-Catalyzed Regiodivergent Hydroesterification of Aryl Olefins with Phenyl Formate
An
effective Pd-catalyzed regiodivergent hydroesterification of
aryl olefins with phenyl formate is described. Either linear or branched
phenyl arylpropanoates can be obtained in good yields with high regioselectivities
by the judicious choice of ligand without the use of toxic CO gas
Palladium-Catalyzed Highly Regio- and Enantioselective Hydroesterification of Aryl Olefins with Phenyl Formate
An
effective Pd-catalyzed regio- and enantioselective hydroesterification
of aryl olefins with phenyl formate is described. A variety of phenyl
2-arylpropanoates can be obtained in good yields with high b/l ratios
and ee’s without using toxic CO gas
Triphenylphosphine‑<i>m</i>‑sulfonate/Carbon Tetrabromide as an Efficient and Easily Recoverable Catalyst System for Friedel–Crafts Alkylation of Indoles with Carbonyl Compounds or Acetals
A solid
complex, conveniently prepared from commercially available
sodium triphenylphosphine-<i>m</i>-sulfonate (TPPMS) and
carbon tetrabromide, can be used as an easily recoverable and reusable
catalyst system for Friedel–Crafts alkylation of indoles with
carbonyl compounds or acetals to produce bisÂ(indolyl)Âalkane products
(BIAs)
An Effective Pd-Catalyzed Regioselective Hydroformylation of Olefins with Formic Acid
An effective palladium-catalyzed
regioselective hydroformylation
of olefins with formic acid is described. The ligand plays a crucial
role in directing the reaction pathway. Linear aldehydes can be obtained
in up to 93% yield with >20:1 regioselectivity using 1,3-bisÂ(diphenylphosphino)Âpropane
(dppp) as the ligand. The reaction process is operationally simple
and requires no syngas
Imaging Tiny Hepatic Tumor Xenografts via Endoglin-Targeted Paramagnetic/Optical Nanoprobe
Surgery is the mainstay
for treating hepatocellular carcinoma (HCC). However, it is a great
challenge for surgeons to identify HCC in its early developmental
stage. The diagnostic sensitivity for a tiny HCC with a diameter less
than 1.0 cm is usually as low as 10–33% for computed tomography
(CT) and 29–43% for magnetic resonance imaging (MRI). Although
MRI is the preferred imaging modality for detecting HCC, with its
unparalleled spatial resolution for soft tissue, the commercially
available contrast agent, such as Gd<sup>3+</sup>-DTPA, cannot accurately
define HCC because of its short circulation lifetime and lack of tumor-targeting
specificity. Endoglin (CD105), a type I membrane glycoprotein, is
highly expressed both in HCC cells and in the endothelial cells of
neovasculature, which are abundant at the tumor periphery. In this
work, a novel single-stranded DNA oligonucleotide-based aptamer was
screened by systematic evolution of ligands in an exponential enrichment
assay and showed a high binding affinity (<i>K</i><sub>D</sub> = 98 pmol/L) to endoglin. Conjugating the aptamers and imaging reporters
on a G5 dendrimer created an HCC-targeting nanoprobe that allowed
the successful visualization of orthotopic HCC xenografts with diameters
as small as 1–4 mm. Significantly, the invasive tumor margin
was clearly delineated, with a tumor to normal ratio of 2.7 by near-infrared
(NIR) fluorescence imaging and 2.1 by <i>T</i><sub>1</sub>-weighted MRI. This multimodal nanoprobe holds promise not only for
noninvasively defining tiny HCC by preoperative MRI but also for guiding
tumor excision via intraoperative NIR fluorescence imaging, which
will probably gain benefit for the patient’s therapeutic response
and improve the survival rate