Chemistry - An Asian Journal,
Journal Year:
2023,
Volume and Issue:
18(22)
Published: Sept. 27, 2023
Pyrazinamide
is
an
important
medicine
used
for
the
treatment
of
tuberculosis(TB).
The
preparation
pyrazinamide
via
catalytic
hydration
2-cyanopyrazine
great
economic
interest
with
high
atomic
economy.
Heterogeneous
non-precious
transition
metal-catalyzed
nitriles
under
neutral
reaction
conditions
would
be
rather
attractive.
Herein
vanadium-nitrogen-carbon
materials
were
fabricated
and
employed
selective
using
water
as
both
solvent
reactant.
2-Cyanopyrazine
could
smoothly
converted
into
to
unique
substrate
specificity.
Additives
different
N
O
atoms
significantly
affect
due
competitive
adsorption/coordination
in
system.
This
work
provides
a
new
approach
metal
catalyzed
nitriles.
The Journal of Physical Chemistry A,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 5, 2025
A
theoretical
study
on
the
mechanism,
regioselectivity,
and
enantioselectivity
of
NHC-catalyzed
dearomatizing
annulation
benzoxazoles
with
enals
has
been
conducted
using
density
functional
theory
calculations.
Our
calculated
results
indicate
that
favored
mechanism
occurs
through
eight
reaction
steps:
initial
binding
NHC
to
enals,
followed
by
formation
Breslow
intermediate
via
proton
transfer.
Subsequent
oxidation
generates
α,β-unsaturated
acylazolium
intermediate,
which
can
undergo
Michael
addition
benzoxazoles.
Sequential
protonation/deprotonation/cyclization
produces
six-membered
cyclic
undergoes
catalyst
elimination,
leading
final
product.
DABCO·H+
was
found
play
important
roles
in
transfer
cyclization.
Without
DABCO·H+,
energy
barrier
up
44.2
kcal/mol
for
step
2
is
too
high
be
accessible.
With
corresponding
value
lowered
18.6
kcal/mol.
The
cyclization
7.4
DABCO·H+.
determines
both
regioselectivity.
According
NCI
analysis,
controlled
strong
interactions
(such
as
C-H···O,
C-H···N,
π···π)
between
We
also
discuss
solvent
substituent
effects
role
NHC.
mechanistic
insights
obtained
present
would
help
improving
current
systems
or
designing
new
synthetic
routes.
Inorganics,
Journal Year:
2023,
Volume and Issue:
11(10), P. 385 - 385
Published: Sept. 27, 2023
Five
silver(I)
complexes,
namely
chloro[1-methallyl-3-benzyl)benzimidazol-2-ylidene]
silver
(6),
chloro[1-methallyl-3-(2,3,5,6-tetramethylbenzyl)benzimidazol-2-ylidene]silver
(7),
chloro[1-methallyl-3-(3,4,5-trimethoxylbenzyl)benzimidazol-2-ylidene]silver
(8),
chloro[1-methallyl-
3-(naphthylmethyl)benzimidazol-2-ylidene]silver
(9),
and
chloro
[1-methallyl-3-(anthracen-9-yl-
methyl)benzimidazol-2-ylidene]silver
(10),
were
prepared
starting
from
their
corresponding
benzimidazolium
salts
oxide
in
71–81%
yields.
A
single-crystal
X-ray
structure
of
7
was
determined.
These
five
Ag-NHC
complexes
evaluated
for
antimicrobial
biofilm
formation
inhibition
properties.
Complex
10
exhibited
high
activities
comparable
to
those
obtained
with
standard
drugs
such
as
Fluconazole
contact
Staphylococcus
aureus,
Enterococcus
faecalis,
Escherichia
coli,
Acinetobacter
baumannii,
Candida
albicans.
The
latter
complex
has
been
shown
be
very
efficient
antibiofilm
activity,
92.9%
at
1.9
μg/mL
on
coli.
Additionally,
the
molecules
optimized
DFT-based
computational
methods
obtaining
insight
into
structure/reactivity
relations
through
relative
energies
frontier
orbitals.
also
analyzed
by
molecular
docking
method
against
DNA
gyrase
coli
CYP51
Hydration
reactions
consist
of
the
introduction
a
molecule
water
into
chemical
compound.
This
process
is
particularly
useful
method
to
allow,
for
instance,
conversion
alkynes
carbonyls,
which
are
strategic
intermediates
in
synthesis
plethora
compounds.
Herein
we
demonstrate
that
L-cysteine
can
catalyse
hydration
activated
very
effective
and
fully
regioselective
manner
access
β-ketosulfones,
amides
esters
aqueous
conditions.
The
mild
reaction
conditions
facilitated
integration
with
enzyme
catalysis
chiral
β-hydroxy
sulfones
from
corresponding
one-pot
cascade
good
yields
excellent
enantiomeric
excess.
These
findings
pave
way
towards
establishing
general
metal-free,
cost-effective,
more
sustainable
alkyne
processes
Molecular Catalysis,
Journal Year:
2024,
Volume and Issue:
559, P. 114055 - 114055
Published: March 22, 2024
Au-catalyzed
N,O-functionalization
of
1,4-diyn-3-ols
with
N-hydroxyanilines
provides
a
short
and
efficient
approach
to
construct
versatile
pyrrole
frameworks.
Using
DFT
calculations,
we
systematically
investigated
the
detailed
mechanisms
involved
in
this
reaction.
It
was
found
that,
commonly
asserted
NH/OH
activation
mechanism
unfavoured
due
high
energy
barrier.
The
main
reason
believed
be
associated
inversion
configuration
on
sp3-hybrid
C
atom
(generated
after
H(N)-shift)
which
results
significant
consumption
for
subsequent
H(O)-shift.
Therefore,
here
present
unique
"1,4-elimination/1,4-syn-protodeauration"
catalytic
mechanism,
(i)
charge
delocalization
carbon
cation
is
conductive
stability
1,4-elimination
TS;
(ii)
exergonicity
decreases
potential
surface
reaction;
(iii)
sp2-C
site
ensures
energy-efficient
retention
during
1,4-syn-protodeauration,
contrast
energy-consuming
classical
anti-protodeauration.
Chemistry - A European Journal,
Journal Year:
2024,
Volume and Issue:
unknown
Published: June 26, 2024
Gold(III)
complexes
containing
trifluoromethyl
ligands
are
efficient
catalysts
in
the
hydration
of
alkynes,
operating
at
low
catalyst
loadings,
without
additives,
using
environmentally
friendly
solvents
and
mild
conditions
(60
°C).
Hydration
terminal
internal
alkynes
provides
corresponding
ketones
quantitative
yields
special
precautions
as
dry
or
inert
atmospheres.
Remarkably,
asymmetric
proceeds
with
moderate
to
notable
regioselectivities,
providing
mixtures
two
possible
isomers
ratios
up
90
:
10.
