Reaction of 4-(N,N-Dimethylaminophenyl) magnesium Bromide with Palladium Tetrakis(triphenylphosphine)

Article abstract of DOI:10.1023/A:1025540203292

The influence of reaction conditions on catalyzed by Pd(PPh ₃)₄ cross-coupling of 4-N,N-dimethylaminophenylmagnesium bromide with 4-bromobenzonitrile in tetrahydrofuran was investigated. The yield of the product of the catalytic proc

Full text of DOI:10.1023/A:1025540203292

Russian Journal of Organic Chemistry, Vol. 39, No. 2, 2003, pp. 219
2003, pp. 242 248.
Original Russian Text Copyright C 2003 by Zavgorodnii, Klyuchinskii, Fauvarque, Lalleve, Bispo.
-225. Translated from Zhurnal Organicheskoi Khimii, Vol. 39, No. 2,
-
To the memory of A.A.Petrov
Reaction of 4-(N,N-Dimethylaminophenyl)magnesium Bromide
with Palladium Tetrakis(triphenylphosphine)
V. S. Zavgorodnii,1@ S. A. Klyuchinskii,1 J.-F. Fauvarque,2 G. Lalleve,2 and I. Bispo2
1St. Petersburg State Technological Institute, St. Petersburg, 190013 Russia
2Conservatoire national des arts et metiers, Paris, France
Received October 15, 2002
Abstract¾ The influence of reaction conditions on catalyzed by Pd(PPh3)4 cross-coupling of 4-N,N-
dimethylaminophenylmagnesium bromide with 4-bromobenzonitrile in tetrahydrofuran was investigated. The
yield of the product of the catalytic process, 4-N,N-dimethylamino-4'-cyanobiphenyl, and of the main product
of noncatalytic process, 4-N,N-dimethylaminophenyl 4'-bromophenyl ketone, is mainly governed by the order
of introduction of reagents and catalyst into the reaction zone. Experimental observations and analysis of side
products suggested conclusions on the processes resulting in deactivation of the catalyst.
Since in 1972 was discovered a fast and efficient
method of building up carbon-carbon bonds by cross-
coupling catalyzed with transition metals [1, 2] or-
ganomagnesium compounds were extensively used for
preparation of versatile compounds by this procedure
[3, 4]. However the application of Grignard reagents is
significantly limited by their high reactivity toward
such groups as Cº N, C=O, NO2, and therefore fre-
quently this method cannot be used for preparation of
compounds with these substituents. Further develop-
ment of the method consisted in the search for ligands
which increased the regioselectivity of palladium cata-
lyst in the cross-coupling processes.
cept on application limits for organomagnesium com-
pounds in cross-coupling with functionalized organyl
halides. The important factor in selection of the latter
was the maximum high reactivity of the C-Hal bond as
compared to that of the functional group. This is just
the reason why in the reactions with Grignard reagents
are used iodine derivatives.
Taking into account that bromides are more avail-
able that iodides we studied in this work reaction of
4-bromobenzonitrile (I) with N,N-dimethylamino-
phenylmagnesium bromide (II) in THF in the presence
of Pd(PPh3)4 (III). The latter was chosen because it
relatively readily transformed into the catalytic form
Pd(PPh3)2 under the reaction conditions. Additional
goal of the study was the need of convenient prepara-
tion method for 4-N,N-dimethylamino-4'-cyanobi-
phenyl that possessed specific electrooptical character-
istics [10].
The application of palladium complexes with bi-
dentate ligands, e.g. PdCl2(dppe), PdCl2(dppp),
PdCl2(dppb) [5], extended the range of functional
groups in haloaryl compounds fit for selective cross-
coupling with Grignard reagents. However even at the
use of the most efficient PdCl2(dppf) that provided a
possibility to obtain quantitative yield of cross-
coupling products from vinylmagnesium bromide with
aryl iodides [6- 8], in reaction with 4-iodobenzonitrile
the yield was considerably lower. A little later the
Grignard compounds were shown to be applicable in
cross-coupling with aryl iodides containing active
group in the presence of a large amount of Pd(PPh3)4
(10%) [9]. These studies significantly altered the con-
Without catalyst Grignard reagent II added at heat-
ing to the cyano group. Initially the reaction occurs
with heat evolution, but 4-N,N-dimethylaminophenyl
4'-bromophenyl ketone (IV) forms in a moderate yield
(see table, run no. 1). No product of cross-coupling,
4-N,N-dimethylamino-4'-cyanobiphenyl (V) was ob-
tained under these conditions. In the presence of
Pd(PPh3)4 the cross-coupling reaction proceeds along-
side the noncatalytic one.
1070-4280/00/3902-0219$25.00 Ó 2003 MAIK [ Nauka/Interperiodica ]

ZAVGORODNII et al.
220
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The ratio and yield of the products arising in these
mixed with the Grignard reagent to 4-bromo-
benzonitrile (see table, run no. 4) at 25°C resulted only
in slightly higher yield of ketone IV. Thus at room
temperature both catalyzed and noncatalyzed proc-
esses proceed slowly and ambiguously affording very
low yields of the reaction products.
reactions depend on the conditions. The transforma-
tion of Pd(PPh3)4 into Pd(PPh3)2 is known to occur
with an induction period, and its further participation
in the catalytic cycle depends both on the reaction
temperature and on the character of the aryl halide
[11]. The catalyst activation can be attained both by
preliminary heating of Pd(PPh3)4 with an aryl halide to
produce a complex Hlg Pd(PPh3)2Ar [12] that lies on
the coordinate of the catalytic cross-coupling process.
To this end a solution of the catalytic amount of
Pd(PPh3)4 (6.7 mol%) and 4-bromobenzonitrile in
THF were heated for 1 h. The gradual darkening of
the solution evidenced the reaction between its com-
ponents. The addition thereto at room temperature of
Grignard reagent II prepared from equimolar to bro-
mide I amount of 4-bromo-N,N-dimethylaniline (VI)
no visible changes in the reaction mixture were ob-
served. The reaction mixture was maintained for 120 h
at 25°C, and a sample thereof after hydrolysis was
analyzed by GLC using mesitylene as internal refer-
ence. The chromatogram contained peaks of the initial
4-bromobenzonitrile (prevailing), N,N-dimethylaniline
(VII), and reaction products: biphenyl V and ketone
IV in amounts not exceeding some percent (see table,
run no. 2). After subsequent heating and hydrolysis of
the reaction mixture a complex mixture of products
On addition to Grignard reagent (II) of catalyst III
solution in THF heat evolution was observed. The sub-
sequent fast addition of this solution to a solution of
bromide I in THF at room temperature did not result
in any changes in the reaction mixture. However at
heating the solution quickly turned cherry-red; the
same color acquired at heating the mixture of or-
ganomagnesium compound II with a catalytic amount
of Pd(PPh3)4 also without bromide I. After heating of
the reaction mixture for 3 h till 70% conversion of the
Grignard reagent the system was cooled, and crystals
precipitated whose 1H NMR spectrum was identical to
that of (PPh3)2PdCl2. The absence of chlorides in the
reaction mixture suggested assignment to the com-
pound obtained the structure of (PPh3)2PdBr2 (30%
with respect to the initial catalyst). On hydrolysis of
the reaction mixture were isolated initial bromide I,
dimethylaniline (VII), and tetramethylbenzidine
(VIII). Neither ketone IV or biphenyl V were detected
among the products (see table, run no. 5). The overall
1
1
amount of compounds VII and VIII according to H
was isolated. In the H NMR spectrum of the mixture
NMR spectrum was close to the quantity of the initial
bromide I. Probably under the given conditions the con-
centration of bromide I which is less reactive than the
Grignard reagent is insufficient for involvement into
both catalytic and noncatalytic reactions. At the same
time the heat evolution at adding the catalyst to the
Grignard reagent reveals their interaction, most proba-
bly consisting in insertion of palladium into the C-Mg
bond. The latter reaction, as shown in [13], leads to
formation of homocoupling product. As follows from
in the region 3 ppm appeared a series of signals be-
longing to dimethylamino groups of identified prod-
ucts: dimethylaniline (VII), bromodimethylaniline
(VI), biphenyl V, ketone IV tetramethylbenzidine
(VIII), and also unidentified compounds. The overall
yield of reaction products was no more than 10%.
Relatively fast (within several minutes) addition of
Grignard reagent to the freshly prepared solution of
catalyst with 4-bromobenzonitrile in THF (see table,
run no. 3) or addition of the catalyst preliminary
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 2 2002

REACTION OF 4-(N,N-DIMETHYLAMINOPHENYL)-MAGNESIUM BROMIDE
221
Conditions of reaction between 4-bromobenzonitrile (I) and 4-(N,N-dimethylaminophenyl)magnesium bromide (II),
and yields of the main reaction products
Run
no.
Reagents, mmola
Pd (PPh3)4
mol%
Reaction
time,b
min
Order
of comp onents
mixingc
Yield of reaction
products, %
t, °C
(I)
(II)
5 (1)
5 (1)
(IV )
(V)
1
2
5 (1.5)
5 (0.2)
–
6.7
66
25
(10) 60
20
A
B
55
–
d
d
d
d
d
d
66
25
25
20 h
3
4
5
2 (0.6)
2 (0.6)
3 (0.1)
(1)
2 (1)
3 (0.3)
1
1
(5) 55
(5) 55
(5 c)
C
D
D
5
5
6.7
25
66
60
3 h
(20)
–
5
–
6
7
8
4 (1)
4 (1)
4 (1)
4 (1.2)
4 (1)
1
1
1
C
D
E
35
35
45
45
d
66
60–66
60
(20)
60
15
5
10
15
25
–
4 (1)
66
(20)
60
(20) 60
(10)
60
d
9
4 (1)
4 (1)
4 (1.2)
3 (1)
1
66
66
F
E
–
d
10
1.7
5
25
d
11
12
13
14
4 (1)
4 (1)
6 (1)
4 (1)
3 (1)
3 (1)
5 (1)
4 (1)
1.7
66
66
66
66
(10) 60
(10) 60
(15) 60
(10 c)
30
D
G
H
D
5
55
70
d
1+0.7
1
1
5
65
d
d
d
15
35
25
5
30
15
15
10
30
15
15 (1)
15 (1)
1
66
4 h
4 h
D
10
15
25
5
40
50
60
10
16
17
18
19
20
21
4 (1)e
4 (1)f
4 (1)
4 (1)
4 (1)
4 (1)
3 (1)
3 (1)
3 (1)
3 (1)
3 (1)
3 (0.2)
1
1
0.5
1.25
2
35–45
70
66
(20) 60
(20) 60
(10) 60
(10) 60
(10) 60
(15) 60
D
D
D
D
D
D
66
66
66
10
a
b
c
Initial concentrations of reagents, mol/l, is given in parentheses.
In parentheses is given the time of reagents addition, outside the parenthesis the overall time of reaction..
Order of reagents introduction into the reaction zone as follows: À – II to I; B – II to preliminary heated solution of I with III; C–II to
freshly prepared solution of I with III; D II with III to I; E – I with III to II; F – I with II to III; G – II with III to I with III; H – II in
parallel with III to I with III.
Several percent.
In ether.
d
e
f
In benzene.
the above, the concentration of bromide I in the reac
tion zone should be significantly higher than that of
the Grignard reagent. This can be achieved alongside
the increasing of bromide concentration also by grad-
ual addition of the Grignard reagent into the reaction
mixture. In its turn the the concentration of the catalyst
should be decreased due to its limited solubility. Actu-
ally, the tenfold increase in the initial concentration of
bromide I and relatively slow addition thereto of the
Grignard reagent at 66°C irrespective to which reagent
was primarily added the catalyst resulted in higher
yield of the cross-coupling product, biphenyl V (see
table, runs nos. 6,7) although the introduction of the
catalyst together with the Grignard reagent furnished
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 2 2002

ZAVGORODNII et al.
222
somewhat better yield of the target product (see table,
run no. 7). It should be noted that in this case the reac-
tion started at 60°C with heat evolution, and the reac-
tion mixture turned gray-green. Then within several
seconds the color of the reaction mixture became yel-
low, and nearly at once throughout the bulk of the so-
lution started formation of crystalline product V. In
both cases the cross-coupling reaction finished virtu-
ally immediately after the end of the Grignard reagent
addition. On the contrary, addition of bromide I to-
gether with the catalyst to Grignard reagent II (see
table, run no. 8) or of bromide I to a mixture of Grig-
nard reagent II with the catalyst (see table, run no. 9)
resulted in suppression of the cross-coupling. In the
latter case the ketone fornation is also suppressed, and
occurs formation of the product of homocoupling,
tetramethylbenzidine. These results show that the
preparation of a definite product is governed by the
way of all reagents introduction into the reaction zone.
this case at the use of bromides the reaction time
should be increased. Under these conditions it is diffi-
cult to avoid the concurrent noncatalytic processes.
These difficulties can be overcome by adding of a
small (< 1%) amount of catalyst into the solution of
bromide I, and constant uniform addition of the cata-
lyst together or parallel (see table, run no. 13) with the
Grignard reagent favors higher conversion of the bro-
mide.
Reduction of mixing time of reagents to some sec-
onds decreases the ratio of bromide to Grignard re-
agent, and this prevents development of the cross-
coupling process (see table, run no. 14). The consid-
erably increased time of Grignard reagent addition (up
to several hours) reduces the yield of the cross-
coupling product V and increases the yield of ketone
IV (see table, run no. 15) due to passivation of the
catalyst and growing role of the side processes. Fur-
ther heating of the reaction mixture led only to de-
creased yields of products IV and V apparently be-
cause of their further transformations. The data ob-
tained are presented in the table.
It is especially clear from comparison of runs
nos. 10-12 (see table) where was used the same solu-
tion of Grignard reagent divided in three portions;
bromide I was taken in 30% excess, and the amount of
catalyst was somewhat increased. At addition of a
freshly prepared mixture of bromide I solution with
1,7% of Pd(PPh3)4 to the Grignard reagent at 66°C
only ketone IV was found in the reaction products (see
table, run no. 10). Addition of new portions of catalyst
(up to 5%) an longer reaction time did not favor in this
case the cross-coupling product formation, although
unreacted initial compounds I and II remained in the
reaction mixture. The addition of Grignard reagent II
with the same catalyst amount under the same condi-
tions to bromide I resulted in the predominant forma-
tion of biphenyl V (see table, run no. 11). However the
best result in cross-coupling was attained at dividing
the catalyst between the Grignard reagent (1%) and
bromide (0.7%) (see table, run no. 12). Apparently the
catalyst and bromide concentration at the start of the
reaction should be at the level ensuring fast formation
of the catalytic complex involved in the cross-coupling
process. But at adding 1- 2 mol% of the catalyst with
the Grignard reagent its fraction in the reaction mix-
ture at the initial moment may be less than 0.01%. It
was observed in [14] at arylation of aryl halides with
Grignard reagents in the presence of Pd(PPh3)4 in
THF that the decrease in the catalyst concentration to
0.0001 molar equivalent (i.e. to 0.01%) did not nota-
bly reduce the yield of the biphenyl compound, but in
In order to reveal the reasons of palladium catalyst
deactivation the formation of some side products was
analyzed. After prolonged heating of the reaction mix-
ture in the reaction products was detected a significant
amount (up to 10% from the content of compound V)
of compounds with fragments of tetrahydrofuran ring
opening. By column chromatography on silica gel
(eluent dichloromethane) a fraction of these com-
pounds was isolated from the products of run no. 15 as
oily yellow fluid.
1
In the H NMR spectrum of this fraction appeared
signals of aliphatic protons at d, ppm: 0.95 t, 1.45 m,
4.37 t, [3J(1H–1H) 7 Hz], corresponding to a butoxy
group. In the region of aliphatic protons were observed
signals at 7.53 d and 7.70 d ppm, [3J(1H–1H) 7.7 Hz],
characteristic of para-substituted aromatic rings. This
signals both in aliphatic and aromatic regions are over-
lapped with the resonances of the other groups thus
indicating that the fraction is not an individual com-
pound. The analysis of the strongest signals suggests
that the main compound in this fraction is 4-butoxy-
benzonitrile. No signals of dimethylamino group in the
3 ppm region and of hydroxy group around 10 ppm
show that the formation of a butoxy group was not
caused by direct reaction between THF and the Grig-
nard compound. I. Pri-Bar è J.K. Stille [15] demon-
strated that palladium triphenylphosphine complexes
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 2 2002

REACTION OF 4-(N,N-DIMETHYLAMINOPHENYL)-MAGNESIUM BROMIDE
223
catalyzed acylhalogenation of THF with ring opening.
It was found [16] that at polycondensation poly-
halobenzenes effected in the presence of magnesium
in THF the latter entered into copolymerization with
ring opening with aromatic compounds containing
more than three atoms of halogen in the ring. It was
explained by the presence of strong electron-acceptors
in the aromatic ring which caused reorientation of the
aryl halides, and instead of s -complex formation arose
arene p-complex of electron-acceptor type that in-
creased the Lewis acidity of the transition metal and
initiated its coordination at the oxygen atom of the
tetrahydrofuran ring followed by opening of the latter.
In our case the reorientation of 4-bromobenzonitrile
with its coordination at the cyano group is also possi-
ble. This process may be caused by deeper dissocia-
tion of palladium triphenylphosphine complexes at
their heating in 4-bromobenzonitrile solution. This
type of coordination was indirectly supported by the
GC-MS analysis that we carried out for the mixture of
nonvolatile reaction products obtained in the run no.
15. In the fractions with time of passage in the range
50.946–51.16 and 56.18–56.27 min (significantly
greater than time of passage of biphenyl V, 38.18
min, and of ketone IV, 46.12 min) obtained in the
region 100- 310 m/z were found molecular ions of
benzonitrile trimer, (C6H5CN)3 (m/z 309) and its
fragmentation product, benzonitrile (m/z 103), and in
the fraction with the passage time 65.17- 65.25 min in
the region 100- 400 m/z were observed molecular
ions of mixed trimer from benzonitrile and bromo-
benzonitril [4-BrC6H4CN(C6H5CN)2]3 (pair ion m/z
387, 389 characteristic of compounds containing
bromine isotopes 79 and 80) and its fragment ions,
benzonitrile (m/z 103) and bromobenzonitrile (m/z
181, 183). The intensity of the latter corresponds to
sufficiently high content of bromine-containing
trimers. No molecular ions of dimers suggests that
apparently in the coordination sphere of palladium
occurs cyclotrimerization of benzonitrile monomer
starting with its coordination by the cyano group. The
dehalogenation apparently follows from bromine-
magnesium exchange readily occurring with com-
pounds possessing substituents with sufficiently dif-
ferent donor-acceptor properties, also in bromine-
containing nitriles [17]. In the system under investiga-
tion this exchange can be represented by the following
scheme.
___________________________
_____________________________
The molecular ion of phenyl 4-cyanophenyl ke-
tone found at GC-MS study in the region 100-300 m/z
with time of passage 49.61 min (m/z 207) may be re-
garded as a support of the scheme. It is possible that
the exchange is accelerated with palladium [13].
nitrogen. In the system under study we never observed
palladium black formation evidencing that in the
course of reaction arose a lot of substances capable of
palladium deactivation, and THF also might take part
in their generation. A partial replacement of THF with
ethyl ether (for dissolution of bromide I) resulted in
some decrease in the yield of the cross-coupling prod-
uct V (see table, run no. 16) probably because of lower
reaction temperature. The use of bromide in benzene
solution led to nearly complete suppresion of the
cross-coupling (see table, run no. 17).
The presence in the triazine ring of three pyridine
nitrogen atoms and also of an aromatic p-electron
sextet facilitates its coordination with palladium and
might affect its catalytic activity. It is also possible
that imine derivative (arising at noncatalytic reaction
between bromide I and the Grignard reagent) also
contributes to palladium deactivation for imines are
strong ligands [18] prone to form s -bonds with tran-
sition metals through of the unshared electron pair of
The multitude of processes proceeding in the coor-
dination sphere of the catalyst indicates that its quan-
tity should play certain role in formation of particular
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 2 2002

ZAVGORODNII et al.
224
reaction products. The comparative analysis of the
effect of the catalyst quantity on the yield of the main
reaction products (see table runs nos. 11, 18-20)
shows that at increase of catalyst amount from 0.5 to
2% the yield of the cross-coupling product simulta-
neously grows from 40 to 60%. However further in-
crease in the amount of catalyst (up to 10%) results in
a sharp decrease in the yield of biphenyl V (see
table, run no. 21). Although additional volume of sol-
vent was required for dissolving the catalyst we pre-
sume that the main cause of the cross-coupling sup-
pression was increased role of the parallel processes
and fast formation of products deactivating the cata-
lytic properties of Pd(PPh3)4.
For quantitative evaluation were averaged 3-5 de-
terminations, accuracy within 5%. GC-MS measure-
ments were carried out on a Hewlett Packard HP-5995
instrument at electron impact, ionizing electrons en-
ergy 70 eV. Temperature of separator and ion source
250°C, capillary quartz column 250006 ´ 0.32 mm, sta-
tionary phase ultra-2 (0.53m, 95% silicone, 5% phenyl-
methylsilicone). Preparative isolation was carried out on
a glass column 800´ 25 mm on silica gel 40-63 m
(Merck) with quartz protection of the upper sorbent
layer, eluents dichloromethane or toluene.
Pd(PPh3)4 (99%), 4-bromobenzonitrile (99%), 4-
bromo-N,N-dimethylaniline (99%), magnesium pre-
pared as thin plates for Grignard synthesis, and anhy-
drous THF sealed in ampules under argon were pur-
chased from Aldrich and used without further purifica-
tion.
Our results demonstrated that in reactions of
organomagnesium compounds with the functional-
ized aryl halides a significant role belongs not only to
the nature of reagents but also to the reaction condi-
tions, among them the ratio of all components of the
process, reagents concentrations, amount of catalyst,
reaction temperature, duration of the process, and
especially the order of introducing reagents and cata-
lyst into the reaction zone.
All operations were performed in usual laboratory
equipment for air-sensitive compounds, dried in a vac-
uum with heating by an open flame and cooled in an
atmosphere of dry argon free of oxygen. The stirring
was performed on magnetic stirrers. The exact dosing
of solutions and sampling for analysis was carried out
with syringes.
In the system we studied the most favorable for
cross-coupling to occur are the following conditions:
excess aryl bromide with respect to Grignard reagent,
reagents concentration close to that of saturated solu-
tion, catalyst amount of 1.5-2 mol%, reaction tem-
perature maintained by slight boiling of the THF so-
lution, slow addition of the Grignard reagent together
with 75% of the catalyst to the solution of bromide in
THF containing 25% of the catalyst. It should be
noted however that overall increase in the amount of
the reaction mixture may result in lower yield of the
cross-coupling product due to growing importance of
processes of catalyst passivation at prolonged reac-
tion time.
N,N-dimethylaminophenylmagnesium bromide
(II). Into a flask was placed 3 mmol (with 5% excess)
of magnesium, 0.5 ml of THF, and several drops of
dibromoethane. At slight heating gas bubbles ap-
peared on the magnesium surface. The flask was
cooled, and from the dropping funnel containing a
solution of 3 mmol of 4-bromo-N,N-dimethylaniline
in 3 ml of THF was added several drops of the solu-
tion. If the reaction did not start within 30 min, the
reaction mixture was heated to boiling without stir-
ring. The heating was stopped after the reaction be-
gan as seen from the darkening of the solution. The
remaining bromide solution was added with the rate
maintaining self-sustaining boiling, and after the end
of addition the heating was carried on for another 30
min. The analysis for Grignard reagent usually
showed 95% yield.
EXPERIMENTAL
1H and 13C NMR spectra were registered on spec-
trometer Bruker AM-200 (at operating frequencies
200.132 and 50.323 MHz respectively) from solu-
tions in CDCl3. GLC analyses were performed on a
Hewlett Paccard 5890 (II) instrument equipped with a
capillary quartz column 25000 ´ 0.22 mm, stationary
phase methylsilicone HP-1, flame-ionization detector,
automatic temperature control in 250°C mode. As
reference compounds were used mesitylene and do-
decylbenzene.
Our attempts of preparation of this Grignard re-
agent in ethyl ether were unsuccessful.
4-Bromophenyl 4'-N,N-dimethylaminophenyl ke-
tone (IV). To a solution of 4-bromobenzonitrile in
THF was added dropwise at stirring the solution of
Grignard reagent (II). The reaction mixture therewith
turned light orange and self-heated. After heating on a
water bath the reaction mixture was hydrolyzed with
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 2 2002

REACTION OF 4-(N,N-DIMETHYLAMINOPHENYL)-MAGNESIUM BROMIDE
1996, p. 2184.
225
water, the volatile products were removed by steam
distillation. On cooling in the reaction flask below the
water layer on the bottom collected a viscous sub-
stance that solidified on cooling. The water was de-
canted, the residue was dried under slight heating in a
vacuum of a water-jet pump. The organic substance
was dissolved in dichloromethane, and the ketone
was isolated by column chromotography. On remov-
ing the solvent light-yellow crystals were obtained,
mp 129–130°C [19]. 13C NMR spectrum (CDCl3), d,
ppm: 110.49, 124.2, 125.7, 130.02, 131.15, 132.52
137.97, 153.32 (arom), 193.72 (C=O).
5. Minato, A., Tamao, K., Hagashi, T., Suzuki, K., and
Kumada, M., Tetrahedron Lett., 1980, vol. 21, p. 845.
6. Bumagin, N.A., Andryukhova, N.P., and Beletskaya,
I.P., Izv. Akad. Nauk SSSR, Ser. Khim., 1987, p. 1681.
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4-N,N-Dimethylamino-4'-cyanobiphenyl (V).
The reaction conditions for biphenyl V preparation
are presented in table and described in the text of
the paper. Biphenyl V was isolated by the same
procedure as ketone IV, mp 222- 223°C, long nee-
dle-like crystals, opalescent solutions.
13C NMR spectrum (CDCl3), d, ppm: 108.89,
112.45, 126.20, 127.76, 132.39, 145.45, 150.63
(arom), 40.22 (C–N), 119.31 (Cº N).
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 2 2002