Here,
we
present
the
first
mechanochemical
Fries
rearrangement
for
industrially
important
synthesis
of
para
hydroxyacetophenone,
inside
a
ball
mill
and
twin-screw
extruder.
Our
approach
leads
to
quantitive
conversion
in
as
little
90
minutes.
Furthermore,
utilisation
liquid-assisted
grinding
can
shift
isomer
ratio
resulting
an
excess
desired
product.
The
multigram
scale-up
via
continuous
extrusion
process
similar
results
only
three
minutes
residence
time
while
completely
avoiding
solvents.
temperature
75-100
°C
even
further
be
reduced
by
combining
at
50°C
with
subsequent
ageing
step.
Crystal Growth & Design,
Journal Year:
2023,
Volume and Issue:
23(11), P. 8094 - 8102
Published: Oct. 16, 2023
In
this
study,
we
investigated
the
mechanochemical
competitive
solvate
formation
of
polymorphic
Form
II
theophylline
in
presence
two
solvate/hydrate-forming
miscible
liquids,
namely,
water
and
2-pyrrolidone.
It
is
known
that
transforms
into
a
monohydrate
water,
while
2-pyrrolidone
gives
monosolvate
or
sesquisolvate,
depending
on
experimental
conditions.
Different
theophylline-to-liquid
molar
ratios
several
water:2-pyrrolidone
mixtures
were
used
to
understand
and/or
transformation
between
these
solvates.
Interconversion
studies
hydrate/monosolvate/sesquisolvate
forms
also
conducted.
The
obtained
results
suggest
have
detrimental
effect
multicomponent
phases,
as
they
dramatically
reduce
efficiency
incorporation
both
liquids
crystal.
fact,
all
milling
experiments
performed
suggested
higher
stoichiometric
ratio
needed
obtain
pure
form
specific
solvate.
Importantly,
additional
revealed
preferential
inclusion
over
water.
Based
datasets
performed,
conclude
propensity
liquid
consequence
complex
interplaying
physicochemical
kinetic
factors.
Crystals,
Journal Year:
2024,
Volume and Issue:
14(11), P. 986 - 986
Published: Nov. 15, 2024
Reactions
of
copper(II)
sulfate
with
2,2′-bipyridine
(bpy)
and
l-serine
(l-Hser)
were
investigated
using
different
solution-based
mechanochemical
methods.
Four
new
ternary
coordination
compounds
obtained
by
synthesis,
three
them
additionally
via
the
liquid-assisted
method:
α-[Cu(l-Ser)(H2O)(bpy)]2SO4
(1a-α),
β-[Cu(l-Ser)(H2O)(bpy)]2SO4
(1a-β),
[Cu(l-Ser)(H2O)(bpy)]2SO4·6H2O
(1a∙6H2O),
[Cu(l-Ser)(bpy)(CH3OH)]2SO4·2CH3OH
(1b∙3CH3OH).
The
characterized
single-crystal
powder
X-ray
diffraction,
infrared
spectroscopy,
thermal
analysis.
Structural
studies
revealed
two
polymorphs
(1a-α
1a-β)
solvatomorphs
(1a∙6H2O
1b∙3CH3OH).
To
investigate
stability
compounds,
crystalline
samples
exposed
to
conditions
relative
humidity
(RH)
an
atmosphere
methanol
vapours.
Successful
solid-state
transformation
1a∙6H2O
into
1a-α
was
established
at
lower
RH
values,
vice
versa
higher
while
both
partially
transitioned
1a-β
in
Compound
1b∙3CH3OH
decomposed
spontaneously
standing
air.
All
structural
transformations
underpinned
proposed
mechanisms.
Additionally,
showed
moderate
vitro
antiproliferative
activity
toward
a
human
breast
cancer
cell
line
(MCF-7),
colon
(HCT116),
lung
(H460).
Resonant
acoustic
mixing
(RAM)
enables
mechanoredox
catalysis
with
BaTiO3
as
the
piezoelectric
catalyst
on
model
diazonium
coupling
reactions.
RAM
proceeds
without
formal
grinding
or
impact
media,
is
faster
than
analogous
ball-milling
strategy,
and
readily
scalable
to
gram-scale.
Combined
X-ray
diffraction
spectroscopy
indicate
that
reusability
of
a
might
be
limited
by
unwanted
boration.
Here,
we
present
the
first
mechanochemical
Fries
rearrangement
for
industrially
important
synthesis
of
para
hydroxyacetophenone,
inside
a
ball
mill
and
twin-screw
extruder.
Our
approach
leads
to
quantitive
conversion
in
as
little
90
minutes.
Furthermore,
utilisation
liquid-assisted
grinding
can
shift
isomer
ratio
resulting
an
excess
desired
product.
The
multigram
scale-up
via
continuous
extrusion
process
similar
results
only
three
minutes
residence
time
while
completely
avoiding
solvents.
temperature
75-100
°C
even
further
be
reduced
by
combining
at
50°C
with
subsequent
ageing
step.
