Macromolecular Chemistry and Physics,
Год журнала:
2023,
Номер
225(2)
Опубликована: Ноя. 22, 2023
Abstract
A
simple
and
modular
dialkylation
of
two
electron‐rich
pyridine
derivatives,
namely
4‐aminopyridine
or
1,2,3,4‐tetrahydropyrido[3,4‐b]pyrazine,
is
achieved
by
aza‐Michael
reactions
with
electron‐poor
olefins
(ethyl
acrylate
acrylonitrile).
Reducing
the
ester
groups
in
ethyl
acrylate‐derived
compounds
yielded
corresponding
hydroxyl‐containing
derivatives.
Subsequently,
homopolymerization
phenyl
glycidyl
ether
as
well
an
epoxy‐alcohol
polyaddition
are
catalyzed
using
introduced
compounds.
As
a
reference
catalyst,
4‐dimethylaminopyridine
used.
It
found
that
all
cases
irreversible
termination
polymerization
at
temperatures
above
100
°C
occurred.
The
decomposition
particularly
rapid
case
derivatives
containing
hydroxyl
groups.
In
contrast,
constant
temperature
°C,
latter
gave
fastest
high
conversions
for
However,
testing
catalysts
alcohol
concentrations
higher
than
resulted
similarly
moderate
cases.
ACS Catalysis,
Год журнала:
2023,
Номер
13(24), С. 16136 - 16147
Опубликована: Дек. 1, 2023
Herein,
we
report
the
rational
design
of
a
modular
dual
photoredox
and
cobalt
catalysis
paradigm
for
difunctionalization
unsaturated
hydrocarbons,
unlocking
synthesis
valuable
but
challenging
1,2-halonitroalkane
substrate
class.
The
protocol
relies
on
use
redox-active
organic
nitrating
reagent
N-nitrosuccinimide
as
source
nitryl
radicals
cobalt-mediated
radical
ligand
transfer
(RLT)
methodology
to
form
carbon–halogen
bond.
This
synergistic
cooperation
between
photocatalyst
high-valence
metal
center
occurs
under
mild
reaction
conditions
is
capable
delivering
1,2-chloronitro-
1,2-bromonitroalkanes
in
single
chemical
operation
while
exhibiting
high
functional-group
tolerance
exclusive
regioselectivity
variety
olefins.
Mechanistic
studies
based
both
experimental
spectroscopic
analysis
provided
insights
into
nature
this
catalytic
halo-nitration
process
including
evidence
halogen
catalyst.
Furthermore,
employing
net-neutral
radical/polar
crossover
(RPC)
approach
cobalt-free
allowed
us
accommodate
external
protic
nucleophiles,
thiols,
alcohols,
acids,
and,
notably,
substituted
amines.
Highly
functionalized
olefin
scaffolds
also
successfully
underwent
nitrative
difunctionalization,
demonstrating
viability
these
protocols
late-stage
functionalization
bioactive
molecules.
Pharmaceutics,
Год журнала:
2024,
Номер
16(11), С. 1379 - 1379
Опубликована: Окт. 27, 2024
Background/Objectives:
Current
promising
treatments
for
many
diseases
are
based
on
the
use
of
therapeutic
nucleic
acids,
including
DNA.
However,
list
nanocarriers
is
limited
due
to
their
low
biocompatibility,
high
cost,
and
toxicity.
The
design
synthetic
building
blocks
creating
universal
delivery
systems
genetic
material
an
unsolved
problem.
In
this
work,
we
propose
PAMAM
dendrimers
with
rigid
thiacalixarene
core
in
various
conformations,
i.e.,
PAMAM-calix-dendrimers,
as
a
platform
supramolecular
constructor
nanomedicine.
Results:
Third
generation
macrocyclic
three
conformations
(cone,
partial
cone,
1,3-alternate)
were
synthesized
first
time.
obtained
capable
binding
compacting
calf
thymus
DNA,
whereby
efficiency
improved
increasing
generation,
while
influence
was
reduced.
A
dramatic
effect
conformation
hemolytic
activity
PAMAM-calix-dendrimers
observed.
Specifically,
notable
reduction
hemotoxicity
associated
decrease
compound
amphiphilicity.
Conclusions:
We
hope
results
will
help
reduce
financial
labor
costs
developing
new
drug
dendrimers.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 12, 2024
β-Amino
acids
serve
as
crucial
building
blocks
for
a
broad
range
of
biologically
active
molecules
and
peptides
with
potential
peptidomimetics.
While
numerous
methods
have
been
developed
the
synthesis
β-amino
acids,
most
them
require
multistep
preparation
specific
reagents
substrates,
which
limits
their
synthetic
practicality.
In
this
regard,
homologative
transformation
abundant
readily
available
α-amino
would
be
an
attractive
approach
acid
synthesis.
Herein,
we
disclose
development
sequential
process
to
provide
diverse
from
derivatives
commercially
phosphonium
ylides
via
visible
light
photoredox
catalysis.
two-step
protocol,
function
bifunctional
linchpin:
they
act
carbon
nucleophile
forge
C-C
bond
in
first
step
carbon-centered
radical
source
modifications
scaffold
second
step.
The
orthogonal
activation
these
reactivities
under
mild
photocatalytic
conditions
enables
modular
three-component
assembly
access
dipeptides
high
structural
diversity.
