17 research outputs found
A simple and convenient protocol for the synthesis of seven- and eight-membered phosphorus heterocycles
<p>A simple procedure for the synthesis of eight-membered 6-(2-chloroethyl)/bis(2-chloroethyl)-amino-12-oxo-dibenzo[d,g][1,3,2]dioxaphosphocin 6-oxides (<b>3a–b</b>) and seven-membered 6-(2-chloroethyl)/bis-(2-chloroethyl)aminodibenzo[d,f][1,3,2]dioxaphosphepin 6-oxides (<b>5a–b</b>) from cyclocondensation of equimolar ratios of 2,2′-dihydroxybenzophenone (<b>1</b>) and 2,2′-dihydroxybiphenol (<b>4</b>), respectively with 2-chloroethylphosphonicdichloride (<b>2a</b>) and bis(2-chloroethyl)phosphoramidic dichloride (<b>2b</b>) in dry toluene in the presence of triethylamine at 45–50 °C is described. All synthesized compounds possessed significant growth inhibition for their antibacteria against ‘Bacillus subtilis’ and ‘Klebsiella pneumonia’ and antifungi activity on “Curvularia lunata” and “Aspergillus niger.”</p
Design, Synthesis, and Evaluation of a Neurokinin-1 Receptor-Targeted Near-IR Dye for Fluorescence-Guided Surgery of Neuroendocrine Cancers
The
neurokinin-1 receptor (NK1R) is implicated in the growth and
metastasis of many tumors, including cancers of the brain (e.g., gliomas,
glioblastomas, and astrocytomas), skin (e.g., melanomas), and neuroendocrine
tissues (cancers of the breast, stomach, pancreas, larynx, and colon).
Because overexpression of NK1R has been reported in most of these
malignancies, we have undertaken designing an NK1R-targeted near-infrared
(NIR) fluorescent dye for fluorescence-guided surgeries of these cancers.
We demonstrate here that an NK1R-binding ligand linked to the NIR
dye LS288 selectively accumulates in NK1R-expressing tumor xenografts
with high affinity (<i>K</i><sub>d</sub> = 13 nM), allowing
intraoperative imaging of these cancers in live mice. Because tumor
accumulation is nearly quantitatively blocked by excess unlabeled
ligand, and because NK1R-negative tumors and normal tissues display
virtually no uptake, we conclude that the observed tumor retention
is NK1R-mediated. Results on the synthesis, in vitro characterization,
and animal testing of NK1R-targeted NIR dye are presented
A Convergent Total Synthesis of the Potent Cephalostatin/Ritterazine Hybrid -25-<i>epi</i> Ritterostatin G<sub>N</sub>1<sub>N</sub>
The
convergent synthesis of 25-<i>epi</i> ritterostatin
G<sub>N</sub>1<sub>N</sub> is described for the first time, starting
from hecogenin acetate (HA). Stereoselective dihydroxylation employing
the chiral ligand (DHQ)<sub>2</sub>PHAL was used as the key step to
introduce the C25 <i>epi</i>-stereocenter on the north 1
segment. The title compound was obtained through a coupling reaction
between the C3-keto-azide (cstat North 1) and North G
A Convergent Total Synthesis of the Potent Cephalostatin/Ritterazine Hybrid -25-<i>epi</i> Ritterostatin G<sub>N</sub>1<sub>N</sub>
The
convergent synthesis of 25-<i>epi</i> ritterostatin
G<sub>N</sub>1<sub>N</sub> is described for the first time, starting
from hecogenin acetate (HA). Stereoselective dihydroxylation employing
the chiral ligand (DHQ)<sub>2</sub>PHAL was used as the key step to
introduce the C25 <i>epi</i>-stereocenter on the north 1
segment. The title compound was obtained through a coupling reaction
between the C3-keto-azide (cstat North 1) and North G
A Convergent Total Synthesis of the Potent Cephalostatin/Ritterazine Hybrid -25-<i>epi</i> Ritterostatin G<sub>N</sub>1<sub>N</sub>
The
convergent synthesis of 25-<i>epi</i> ritterostatin
G<sub>N</sub>1<sub>N</sub> is described for the first time, starting
from hecogenin acetate (HA). Stereoselective dihydroxylation employing
the chiral ligand (DHQ)<sub>2</sub>PHAL was used as the key step to
introduce the C25 <i>epi</i>-stereocenter on the north 1
segment. The title compound was obtained through a coupling reaction
between the C3-keto-azide (cstat North 1) and North G
A Convergent Total Synthesis of the Potent Cephalostatin/Ritterazine Hybrid -25-<i>epi</i> Ritterostatin G<sub>N</sub>1<sub>N</sub>
The
convergent synthesis of 25-<i>epi</i> ritterostatin
G<sub>N</sub>1<sub>N</sub> is described for the first time, starting
from hecogenin acetate (HA). Stereoselective dihydroxylation employing
the chiral ligand (DHQ)<sub>2</sub>PHAL was used as the key step to
introduce the C25 <i>epi</i>-stereocenter on the north 1
segment. The title compound was obtained through a coupling reaction
between the C3-keto-azide (cstat North 1) and North G
A Convergent Total Synthesis of the Potent Cephalostatin/Ritterazine Hybrid -25-<i>epi</i> Ritterostatin G<sub>N</sub>1<sub>N</sub>
The
convergent synthesis of 25-<i>epi</i> ritterostatin
G<sub>N</sub>1<sub>N</sub> is described for the first time, starting
from hecogenin acetate (HA). Stereoselective dihydroxylation employing
the chiral ligand (DHQ)<sub>2</sub>PHAL was used as the key step to
introduce the C25 <i>epi</i>-stereocenter on the north 1
segment. The title compound was obtained through a coupling reaction
between the C3-keto-azide (cstat North 1) and North G