AC_222_PINO


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COMMUNICATIONS
Thenitrationof
withNO
byNHPIproceededsmoothly
at70
Ctogivenitrocyclohexane(
,70%basedonNO
used;
Table1,run1)andcyclohexylnitrite(
,7%)alongwitha
smallamountofanoxygenatedproduct,cyclohexanol(5%).
[4]J.Ruiz,V.Riera,M.Vivanco,M.Lanfranchi,A.Tiripicchio,
chargeonapplicationtoCCDC,12UnionRoad,Cambridge
CB21EZ,UK(fax:(
44)1223-336-033;e-mail:[email protected]
SupportinginformationforthisarticleisavailableontheWWWunder
http://www.angewandte.comorfromtheauthor.
Table1.NHPI-catalyzednitrationof
withNO
underselectedcondi-
tions.
RunNHPI[mmol]
8C]Yieldof
[b]10.67070
0.67043
3±70
40.66058
50.65039
60.37056
0.67063
97053
[a]ReactionswererunasdescribedintheExperimentalSection.[b]Yields
areaveragevaluesobtainedfromseveralrunsandarebasedonNO
[c]Underargon.[d]Recoveredcatalystfromrun1wasused.[e]The
reactionwascarriedoutusing
(50mL)andNO
(33mmol).Theyieldof
isbasedonisolatedproduct.
TIONS
.
Chem.
Int.
Ed.
2001
,
40
,
No
.
1

WILEY
-VCH
V
erlag
GmbH,
D-69451
W
einheim,
2001
1433-7851/01/4001-0223
$
17
.50+.50/0
As
discuss
ed
below
,
it
is
important
that
the
NHPI-cata
lyzed
nitration
is
conducted
under
air,
since
NO
generated
in
the
course
of
the
reaction
can
be
reoxid
ized
to
NO
O
F
or
the
analogou
s
nitration
of
1
in
the
absence
of
air,
the
yield
of
2
decreas
ed
to
43
%
(run
2
).
Needless
to
say
,
the
nitration
of
1
was
difficult
to
carr
y
out
withou
t
NHPI
under
these
con-
dition
s
(run
3).
T
he
nitratio
n
took
place
even
at
50
8
C
to
give
2
in
39
%
yield
(run
5).
When
the
amount
of
NHPI
was
halve
d
(0.3
mmol),
2
was
formed
in
slightly
lower
yield
(56
%,
run
6).
T
he
nitratio
n
of
1
using
recovered
NHPI
produced
2
in
63
%
yield
(run
7).
T
he
large-sc
ale
nitratio
n
allowed
the
iso
lation
of
2
in
53
%
yie
ld
(run
8).
Scheme
1
shows
the
reaction
pathway
for
the
vapor
-phase
nitration
of
alkanes
by
NO
to
this
mechanis
m,
one-thir
d
of
the
NO
is
conve
rted
into
N
O
via
H
NO
H
R
H
R
HNO
NO
NO
R
NO
R
H
HNO
H
NO
+
+
+
+
+
+
+
+
2
3
2
+
e
1
.
T
he
reactio
n
pathw
ay
for
the
convention
al
alkane
nitratio
n
with
NO
Henc
e
,
the
maximum
yiel
d
of
nitroalkanes
by
this
R
H
NHPI
R
H
R
NO
O
HNO
NO
NO
NO
HNO
HNO
H
2
+
+
+
+
+
+
+
+
+
+
3
4
3
+
3
+
2
2
e
2.
A
possi
ble
reactio
n
pathw
ay
for
the
NHPI-ca
talyzed
alkane
nitratio
n
with
NO
r
air.
he
nitratio
n
may
be
initiat
ed
by
hydrogen-at
om
abstrac-
tion
from
the
hydroxyimide
group
of
NHPI
by
NO
generat
e
a
PINO
radical
as
described
previo
usly
.
T
he
PI
NO
radical
readily
abstracts
the
hydrogen
atom
from
an
alkane
to
form
an
alkyl
radical,
which
undergoes
nitration
with
NO
give
a
nitroalkan
e
.
It
has
been
report
ed
that
HNO
conve
rted
into
HNO
H
,
and
NO
.
our
conditions
,
the
NO
formed
i
s
expect
ed
to
be
oxidiz
ed
by
O
NO
and
the
generated
NO
reused
in
the
nitration.
T
herefore
,
the
yield
of
nitrocyclohexane
is
over
66.7
%
.
In
fact,
when
the
reaction
mixtu
re
was
extracted
with
water
after
the
reactio
n,
the
aqueous
phase
was
acidic,
probably
becau
se
of
the
formatio
n
of
HNO
T
he
most
promising
feature
of
the
NHPI
-catalyzed
nitra-
tion
of
alkanes
by
NO
that
the
nitratio
n
is
conducted
in
the
presence
of
air
(O
under
mild
conditions
.
Owing
to
the
higher
concentrat
ion
of
N
O
air,
the
alkyl
rad
icals
formed
can
react
selectively
with
NO
than
O
give
nitroalkan
es
in
prefer
ence
to
oxygenated
products
.
In
con-
trast,
the
conventio
nal
nitratio
n
is
difficult
to
carry
out
in
the
presence
of
air,
since
under
the
high
temp
eratures
used
(250
±
400
8
C)
the
result
ing
alkyl
radicals
react
not
only
with
NO
also
with
O
provide
a
complex
mixture
of
product
s
.
he
results
of
the
nitration
of
other
alkanes
by
the
pr
esent
able
2.
NHPI-ca
talyzed
nitratio
n
of
alkanes
with
NO
r
selected
condit
ions
.
Subs
trate
Produ
ct
46
6
66
7
70
[a]
Reaction
s
were
carried
out
unde
r
air
(1
atm)
at
70
8
C
for
14
h.
TIONS
WILEY
-VCH
V
erlag
GmbH,
D-69451
W
einheim,
2001
1433-7851/01/4001-0224
$
17
.50+.50/0
Angew
.
Chem.
Int.
Ed.
2001
,
40
,
No
.
1
of
Redo
x-Activ
e
Ligands
on
an
Electrode
:
The
Dendrimer
Route**
ran
ck
Le
Derf
,
Eric
Levilla
in,
Gae
È
lle
T
rippe
Â
,
Alain
Gorgues
,
Ma
rc
Sa
lle
Â
,*
Rosa-
María
Se
bastían,
Anne-M
arie
Ca
minade
,
an
d
J
ean-Pi
erre
Maj
oral*
cyc
lic
system
s
that
respon
d
electro
chemically
when
intera
cting
with
a
guest
ion
have
been
extensively
studied,
y
in
connec
tion
with
their
potential
applic
ations
as
chemos
ensors
.
In
such
host
molec
ules
,
the
complexing
ability
of
the
ligand
can
be
tuned
by
the
electrochem
ical
poten
tial
applied.
Most
of
these
compounds
are
built
by
covalen
t
grafting
of
a
receptor
subunit
onto
a
redox
-active
component.
T
hus
,
in
the
case
of
ed
than
ks
to
a)
electropoly
meriza-
tion
of
suitably
substitute
d
redox-respo
nsive
li
gands
(e
.g.
,
a
pyrrole-
or
a
thiophene-b
ased
mono
mer),
4]
b)
pr
epara-
tion
of
self-assembled
monol
ayers
.
electrodes
were
also
recently
obtaine
d
by
Casado
F
.
L.
Albrig
ht,
Chem
.
Eng.
1966
,
73
,
149
±
156,
and
references
there
in
;
C
.
P
.
P
rof
M.
Salle
Â
,
Dr.
F
.
Le
Derf
,
Dr.
E.
Levillain,
G
.
T
rippe
Â
,
P
rof
.
A.
Gorgues
Labo
ratoir
e
dIng
e
Â
nierie
Mole
Â
culaire
orting
inform
ation
for
this
article
is
available
on
the
WWW
under
http
://www
.angew
andte
.com
or
from
the
author.

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