Iron-Based Imidazolium Salts as Versatile Catalysts for the Synthesis of Quinolines and 2- and 4-Allylanilines by Allylic Substitution of Alcohols

Article abstract of DOI:10.1002/adsc.201600315

Readily available iron(III)-based imidazolium salts have proven to be very versatile catalysts for the allylic substitution reaction of alcohols with anilines, allowing the synthesis of quinolines, 2-allylanilines and 4-allylanilines just by modulating the reaction conditions. Noteworthy, the formation of quinoline derivatives proceeds by ortho-allylation of the corresponding aniline and subsequent oxidative cyclization mediated by atmospheric oxygen. The reaction using anilines as nucleophiles is selective to the C-alkylation versus the N-alkylation, under any reaction conditions studied. (Figure presented.).

Full text of DOI:10.1002/adsc.201600315

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DOI: 10.1002/adsc.201600315
Iron-Based Imidazolium Salts as Versatile Catalysts for the
Synthesis of Quinolines and 2- and 4-Allylanilines by Allylic
Substitution of Alcohols
Paz Trilloa,* and Isidro M. Pastora,*
a
Department of Organic Chemistry, Faculty of Science and Instituto de Sꢀntesis Orgꢁnica (ISO), University of Alicante,
Apdo. 99, 03080 Alicante, Spain
Fax : (+34)-96-590-3549; e-mail: paz.trillo@ua.es or ipastor@ua.es
Received: March 22, 2016; Revised: July 4, 2016; Published online: && &&, 0000
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201600315.
Abstract: Readily available iron(III)-based imidazo- cyclization mediated by atmospheric oxygen. The re-
lium salts have proven to be very versatile catalysts action using anilines as nucleophiles is selective to
for the allylic substitution reaction of alcohols with the C-alkylation versus the N-alkylation, under any
anilines, allowing the synthesis of quinolines, 2-allyl- reaction conditions studied.
ACHTUNGTRENNUNGanilines and 4-allylanilines just by modulating the re-
action conditions. Noteworthy, the formation of
quinoline derivatives proceeds by ortho-allylation of Keywords: C-alkylation; allylic alcohols; imidazoli-
the corresponding aniline and subsequent oxidative um salts; iron(III) catalysts; quinolines
Introduction
development and study of efficient, cost-effective and
environmentally friendly processes, envisioned the
The search for and development of new strategies to- design of different iron(III)-based Lewis acidic ionic
wards the design of green and sustainable transforma- liquids (IBLAILs) (Figure 1). This type of metal-ion-
tions, which minimize waste production and avoid the containing ionic liquids has received attention in the
use of toxic or expensive reagents or catalysts, is a cur- last years.[4] Indeed, imidazolium-based ionic liquids
rent challenge for the organic chemical community. (ILs) containing anionic iron(III) has been reported
Indeed, sustainability is the main goal of green for extractive desulfurization of fuel oils,[5] being also
chemistry.[1] In this sense, and in the particular case of effective in the extraction coupled with oxidative de-
allylic substitution reactions, the replacement of the sulfurization.[6] Moreover, the 1-butyl-3-methylimida-
most commonly used ꢂbigꢃ leaving groups (e.g., carbo- zolium tetrachloroferrate has been employed as an ef-
nates and acetates) with the direct use of a hydroxy ficient catalyst in the coupling between aryl Grignard
group, is an attractive strategy from both practical reagents and alkyl halides[7] and in the dimerization
and environmental points of view, as water would be of norbornadiene,[8] recyclability of the catalyst also
the only by-product. However, this approach has two
main limitations, the poor ability of the hydroxy
group as leaving group and the formation of stoichio-
metric amounts of water, which could deactivate the
catalyst.
Remarkable efforts have been made in the last
years in the design of new catalytic systems which can
carry out this reaction and overcome these limita-
tions.[2] Recently, iron-based catalysts have emerged
as an interesting alternative to other more expensive
and toxic metallic catalysts.[3] These iron catalysts
cover a good range of transformations, but there is
still room for improvement and new discoveries in the
area. Being aware of that, our group, interested in the (IBLAILs).
Figure 1. Iron(III)-based Lewis acidic ionic liquids
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Table 1. Optimization of the reaction conditions.[a]
being possible. The three-component reaction be-
tween an aldehyde, a b-keto ester and urea (Biginelli
reaction) has been performed successfully in the pres-
ence of an iron-containing ionic liquid as solvent and
catalyst.[9]
Entry
IBLAIL (mol%)
T [8C]
Conversion [%][b]
3aa
4aa
1
I (5)
25
7
7
2
3
4
5
6
7
8
9
II (5)
25
25
25
25
25
50
70
100
50
18
25
30
15
21
32
24
61
40
42
73
9
40
37
28
18
35
68
84
63
90
65
75
22
47
25
36
12
14
16
16
11
10
34
32
21
43
32
27
6
25
17
17
14
23
32
16
37
–
The main advantages of these transition metal-
based ILs are their easy preparation and the fact that
they can be used as catalysts in green chemical proto-
cols. Inspired by previous works of Powel and
Dyson,[4b,10] we have designed different IBLAILs by
changing R1, R2 and R3 groups (Figure 1), which have
been analyszd by ICP-MS (ca. 15% of iron, see the
Supporting Information). The combination of the imi-
dazolium chloride and iron(III) chloride in a 1:1 ratio
provided the corresponding ionic liquid with the
anion [FeCl4]À, as described by different groups.[8,11]
Next, we studied the catalytic activity of these
IBLAILs I–V in the allylic substitution reaction with
allylic alcohols. Herein, we report the results obtained
from this study.
III (5)
IV (5)
V (5)
VI (5)
I (5)
I (5)
I (5)
10
11
12
13[c]
14[c]
15[c]
16[d]
17
18
19
20
21
22
23
24
25[c]
26[c]
27[e]
28[f]
29[g]
I (10)
I (10)
I (10)
I (10)
I (10)
I (10)
I (10)
II (10)
III (10)
IV (10)
IV (10)
V (10)
V (10)
VI (10)
VI (10)
V (10)
V (10)
V (10)
V (10)
V (10)
70
100
50
70
100
100
70
70
70
100
70
100
70
100
70
100
100
100
100
Results and Discussion
33
15
12
23
12
10
3
Catalytic Activity of the Iron(III)-Based Lewis Acidic
Imidazolium Salts
The reaction between (E)-1,3-diphenylprop-2-en-1-ol
(1a) and N-methylaniline (2a) was chosen as model
reaction to optimize the reaction conditions
(Scheme 1, Table 1). First, the reaction was carried
out with 5 mol% of Fe(III)-based Lewis acidic ionic
liquid I (Figure 1) at 258C under solvent-free condi-
tions. Unexpectedly, a 1:1 mixture of the para and
ortho alkylation products (3aa and 4aa, respectively)
was obtained, instead of the amination product, al-
though the conversion was low (Table 1, entry 1). Pre-
vious protocols in the literature reveal that anilines as
nucleophiles provide the corresponding N-allylani-
lines as predominant product regardless of the cata-
lyst employed [including iron(III) catalysts] and inde-
pendent of the aniline derivative.[12] In addition, the
reaction between activated alcohols and aromatic
compounds to produce C-alkylation products (Frie-
[a]
Reaction conditions: 1a (0.5 mmol), 2a (0.5 mmol). Reac-
tion performed in an open vessel.
Conversion determined by GC analysis.
Microwave irradiation was employed to heat the reac-
tion. Microwaves conditions: 40 W (initial potency),
36 psi and 60 min.
Microwave irradiation conditions: 40 W (initial potency),
36 psi and 30 min.
Reaction performed with toluene (0.2 mL) as solvent.
Reaction performed with 1,2-dichloroethane (0.2 mL) as
solvent.
[b]
[c]
[d]
[e]
[f]
[g]
Reaction performed with dioxane (0.2 mL) as solvent.
del–Crafts reaction) has been reported by means of
different metal-based catalysts,[13] albeit there are only
few examples for the formation of C-alkylation prod-
ucts with anilines.[14]
Rising the temperature to 508C and using IBLAIL
I, the same mixture of products 3aa and 4aa was ob-
tained in 32% and 34% conversion, respectively
(Table 1, entry 7). An increase of the catalyst loading
to 10 mol% or of the temperature to 708C did not
produce a significant improvement in the results
(Table 1, entries 8, 10 and 11), although a slight selec-
tivity towards compound 3aa was observed at 708C.
Next, we performed the reaction at 1008C, obtaining
Scheme 1. Model reaction for optimization of the reaction
conditions.
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Table 2. Optimization of the reaction conditions for quino-
full conversion with 10 mol% of IBLAIL I, and ca.
3:1 selectivity ratio for the para-alkylated product 3aa
(Table 1, entry 12). Other reaction conditions such as
microwave irradiation at 50, 70 or 1008C were also
tested, but lower conversions to the desired products
were observed (Table 1, compare entries 13–16 with
entries 9–12).
line synthesis[a]
The properties of ionic liquids (such as imidazolium
salts) vary depending on the size of the different com-
ponents (i.e., cation and anion),[15] so different sub-
stituents in the imidazole nitrogens can modulate the
catalytic activity of the salts. Consequently, other
Fe(III)-based Lewis acidic ionic liquids, such as II–VI
(Figure 1), were evaluated as catalysts in the reaction
between 1a and 2a. The reactions were performed
with 10 mol% of IBLAIL (II–VI) at 25 and 708C, in
order to detect differences in the conversion and/or in
the selectivity of the reaction. The use of IBLAILs
II–VI provided comparable conversions and similar
regioselectivities in our model reaction than catalyst
IBLAIL I at 258C (Table 1, entries 2–6), but a differ-
ent catalytic activity was observed in all cases at 708C
(Table 1, entries 11, 17–19, 21 and 23). While catalysts
II and III provided lower conversions than I at 708C
(Table 1, entries 17 and 18), catalysts IV, V and VI
proved to be superior at that temperature (Table 1,
entries 19, 21 and 23). Gratifyingly, when the reaction
was performed at 1008C for 24 h under solvent-free
conditions, using IBLAIL V as catalyst, 90% of con-
version was obtained with complete regioselectivity
Entry
Catalyst (x mol%)
Conv. [%][b]
4ab
5ab
1
V (10)
V (10)
V (20)
no catalyst
27
32
8
35
62
92
2[c]
3[c]
4[c]
5[c]
6[c]
7
[d]
[d]
–
–
imidazolium chloride[e] (20)
FeCl3·6H2O (20)
{(Me)2[HO(CH2)2]NBn}FeCl4 (20)
[(Et)3NBn]FeCl4 (20)
20
7
26
38
–
30
66
50
8
[a]
Reaction conditions: 1a (0.5 mmol), 2a (0.5 mmol),
1008C. Reaction performed in an open vessel.
Conversion was determined by GC analysis.
Reaction time: 48 h.
Less than 10% of the N-allylaniline was observed in the
reaction crude together with the starting materials, but
neither 4ab nor 5ab were observed.
[b]
[c]
[d]
[e]
1-(Methoxycarbonylmethyl)-3-butylimidazolium chloride
(20 mol%) was used as catalyst.
towards the para-alkylation product 3aa (Table 1, ing Information) without any success. Only the use of
entry 22). Salts IV and VI were also tested at 1008C 1,2-dichloroethane provided the corresponding ortho-
(Table 1, entries 20 and 24), but the selectivity was alkylation product 4ab exclusively in 97% conversion
lower than with V. Using IBLAIL V, the reaction was (see the Supporting Information). Working under
performed under microwave irradiation (Table 1, en- ꢂneatꢃ reaction conditions and extending the reaction
tries 25 and 26), but no improvement was observed. time to 48 h, the conversion to the desired quinoline
Furthermore, different solvents were evaluated, such 5ab increased to 62% (Table 2, entry 2). Raising the
as toluene, 1,2-dichloroethane and dioxane (Table 1, catalyst loading of IBLAIL V to 20 mol%, provided
entries 27–29), all providing, in general, lower conver- 92% of quinoline 5ab after 48 h (Table 2, entry 3). It
sions and regioselectivities than ꢂneatꢃ reaction condi- is worth noting that in the absence of catalyst, no re-
tions (in the absence of solvent).
action was observed (Table 2, entry 4 and footnote
[d]). When the imidazolium salt precursor of V, with-
out iron [i.e., 1-(methoxycarbonylmethyl)-3-butylimi-
dazolium chloride] was tested as catalyst, only the
ortho alkylation product 4ab with low conversion
(20%) was obtained after 48 h of heating at 1008C
Quinoline Synthesis by Allylic Substitution and
Oxidative Cyclization
Next, we decided to explore para substituted anilines (Table 2, entry 5). Furthermore, a mixture of both
as nucleophiles. To our surprise, the reaction of p-tol- products 4ab and 5ab was obtained when 20 mol% of
uidine (2b) with allylic alcohol 1a at 1008C in the FeCl3·6H2O was used as catalyst under the same reac-
presence of V (10 mol%) in the absence of solvent tion conditions (Table 2, entry 6), although with very
(Table 2) provided a mixture of the ortho alkylation low conversion. Other ammonium tetrachloroferrate
product 4ab and the quinoline 5ab (Table 2, entry 1). salts [i.e., benzyl(2-hydroxyethyl)dimethylammonium
The formation of the quinoline can be explained by tetrachloroferrate and benzyl(triethyl)ammonium tet-
an oxidative cyclization process[16] after the allylic rachloroferrate] in the absence of an imidazolium
substitution reaction. In an attempt to improve the se- cation, were also tested in the reaction. These ammo-
lectivity of the process and favor the quinoline forma- nium salts catalyzed the reaction between 1a and 2b
tion, we evaluated different solvents (see the Support- with high conversion but giving a mixture of both
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compounds 4ab and 5ab (Table 2, entries 7 and 8). gen groups, such as chloro and bromo, were also com-
From these experiments, we concluded that the com- patible with the present reaction conditions, affording
bination of an iron(III) source with the imidazolium the corresponding quinolines 5ae and 5af, respective-
salt constitutes a better catalytic system in terms of ly, in good yields (Table 3).
activity and selectivity. IBLAIL V was highlighted as
To broaden the scope to other allylic alcohols we
the optimal catalyst for the process, at a loading of carried out the reaction with cinnamyl alcohol (1b),
20 mol%. It is remarkable that the amount of (E)-4-phenylbut-3-en-2-ol (1c) and its isomeric allylic
iron(III) employed is about 3 mol% (20 mol% of V, alcohol (E)-1-phenylbut-2-en-1-ol (1c’). Using p-tolui-
which contains ca. 15% of iron as measured by ICP). dine (2b) as nucleophile, quinolines 5bb (76% from
With the optimized reaction conditions for the alcohol 1b) and 5cb (65% from alcohol 1c and 60%
preparation of quinolines in hand, we examined the from 1c’) were obtained as exclusive regioisomers
scope of the present reaction with different anilines (Table 3). This fact can be explained by the stability
and allylic alcohol 1a (Table 3). As mentioned before, of the double bond instead of the intermediate
p-toluidine was transformed into the corresponding formed in the reaction media.[12] Besides, (E)-3-(4-me-
quinoline 5ab with excellent conversion (>90%), thoxyphenyl)-1-phenylprop-2-en-1-ol (1d) produced
being isolated in 70% yield. The electron-rich substi- a mixture of both possible regioisomers 5db and 5db’
tuted p-methoxyaniline provided quinoline 5ac in (in a 2:1 ratio, Table 3), the difference, in this case,
high yield (Table 3), however, the presence of two being lower in terms of stability between both inter-
methoxy groups in the aniline caused lower yields mediates.
(product 5ad, Table 3). Anilines provided with halo-
Mechanistic Considerations in the Formation of
Quinoline Derivatives
Table 3. Quinoline synthesis: scope.[a]
Several tests were performed in order to get a better
insight into the reaction mechanism for the formation
of the quinoline derivatives. First, the reaction flask
was flushed with a stream of air, to understand if at-
mospheric oxygen was the oxidant agent. Indeed,
both yield and conversion of the corresponding quino-
line 5ab increased (full conversion and 79% isolated
yield). On the contrary, only product 4ab was ob-
served when the reaction was carried out under argon
inert atmosphere (Scheme 2).
To reinsure that the atmospheric oxygen is the true
oxidant in the process, the reaction, under an inert at-
mosphere, was attempted on the ortho-alkylated
product 4ab. After 48 h, unaltered product 4ab was
obtained as main product, together with a small
amount of quinoline 5ab (less than 5%, Scheme 3). In
a parallel experiment, 4ab was treated with catalyst V
under the optimized standard reaction conditions (air
atmosphere), and quinoline 5ab was quantitatively
obtained (Scheme 3). These experiments prove the
[a]
Reaction conditions: 1a (0.5 mmol), 2 (0.5 mmol), V
(20 mol%), 1008C for 48 h. Reaction performed in an
open vessel. In parentheses: isolated yield after flash
chromatography.
PMP=para-methoxyphenyl.
Scheme 2. Experiments under an (a) air stream and (b)
argon atmosphere. Isolated yields.
[b]
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FeCl3·6H2O as catalyst at high temperatures. With
this in mind, we decided to test whether this inter-
mediate was involved in our catalytic system, with the
reaction going through a Doebner–Miller (or Skraup)
synthesis.[18] Thus, allylic alcohol 1a was stirred in the
presence of IBLAIL V without aniline at 1008C, and
after 48 h, chalcone (6) was observed as the main
product (Scheme 4). Next, the reaction of chalcone
(6) with p-toluidine, under the optimized conditions,
Scheme 3. Experiments for oxidative cyclization under an was attempted, however, only starting materials were
(a) air stream and (b) argon atmosphere. Isolated yields.
recovered after 48 h (Scheme 4). Therefore, the for-
mation of the imine intermediate can be discarded
from our mechanistic pathway.
importance of the atmospheric oxygen in our reac-
tion. Consequently, it can be postulated that first the
ortho-alkylated intermediate 4ab is formed in the re-
action media followed by an oxidative cyclization that
leads to the formation of the corresponding quino-
line.[16] To corroborate this point, the product distribu-
tion profiles were obtained for the reaction between
1a and 2b (Figure 2), under the optimal reaction con-
ditions (Table 2, entry 4). From this study, different
conclusions can be drawn: (i) the corresponding prod-
uct of ortho-alkylation (4ab) is formed in more than
90% in the first 5 min of the reaction (Figure 2); (ii)
this intermediate undergoes oxidative cyclization to
form the corresponding quinoline during the rest of
the reaction time (Figure 2). Moreover, the formation
of the amination intermediate can be ruled out since
it is not detected in the reaction profile.
Scheme 4. Oxidation of allylic alcohol to the chalcone under
the optimized reaction conditions.
Based on these experiments and on similar transfor-
mations previously reported,[16] we speculate that the
Previous work by others,[12b,17] demonstrates that mechanism for the formation of the corresponding
the allylic alcohol (E)-1,3-diphenylprop-2-en-1-ol (1a) quinolines involves an ortho-allylation process and
could be oxidized to chalcone in the presence of a subsequent oxidation, as represented in Scheme 5.
The iron(III) salt assists in the formation of an incipi-
ent allylic carbocation (intermediate A),[19] which
reacts with the aniline to produce the 2-allylaniline
derivative 4 and a molecule of water via a Friedel–
Crafts reaction.[13] Compound 4 could be in equilibri-
um with the cyclized tetrahydroquinoline B, although
we believe this equilibrium must be shifted towards 4,
since the tetrahydroquinoline B has never been ob-
served. Next, the dehydrogenation with molecular
oxygen (from air) promoted by iron generates quino-
line 5 and two molecules of water (Scheme 5).[20] The
oxidation mediated by iron has been described before
via a radical pathway.[21] At this point, a control ex-
periment between 1a and 2b in the presence of a radi-
cal scavenger (i.e., cumene)[22] under the standard
conditions, was performed. After the reaction time
(48 h), quinoline 5ab was only obtained in 9%, where-
as 2-allylaniline 4ab was produced in 89% conversion.
Accordingly, it has been proved that the first step of
the mechanism of the reaction is anionic (the forma-
tion of 4ab not being affected), but the second step
(oxidation to 5ab) involves radicals (a process that
has been inhibited in the presence of the radical scav-
enger).
Figure 2. Product distribution profiles (by GC analysis) in
*
the reaction media vs. reaction time (minutes): ( ) starting
&
allylic alcohol 1a; ( ) ortho-alkylation product 4ab; (ꢀ)
quinoline 5ab. Error bars represent standard deviation from
three experiments.
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Table 4. 2-Allylanilines synthesis: scope.[a]
Scheme 5. Possible mechanism for the allylation and subse-
quent oxidation.
ortho-Allylation of Aniline Derivatives
Our optimization studies (vide supra) showed that
milder reaction conditions favor the formation of
ortho-alkylation products. For this reason, we decided
to study the scope of the reaction between allylic al-
cohol 1a and different anilines, at 508C for 2 h
(Table 5). Under these conditions, the corresponding
2-allylanilines were selectively obtained in good to
high yields, without detecting, in any case, the forma-
tion of the quinoline via oxidative cyclization. Thus,
4-substituted anilines with electron-donating groups,
such as methyl, methoxy and phenoxy, provided the
corresponding anilines 4ab, 4ac and 4ah, respectively,
in good yields (Table 4). Surprisingly and, to our de-
[a]
Reaction conditions:
1 (0.5 mmol), 2 (0.5 mmol), V
(20 mol%), 508C for 2 h. Reaction performed in an open
vessel. In parentheses: isolated yield after flash chroma-
tography.
light, anilines with electron-withdrawing groups (e.g., cleophile containing two methoxy groups at the 2 and
Br, Cl), which give no reaction or poor results with 5 positions gave a mixture of ortho- and para-alkyla-
previously described catalytic systems,[14,23] allowed tion products with a preference for the ortho-alkyla-
the formation of products 4ae and 4af in high yields tion product in a 2:1 ratio (compound 4ag in Table 4
(Table 4). Furthermore, this methodology could be and compound 3ag in Table 5).
successfully extended to anilines bearing a strong
electron-withdrawing group (e.g., NO2), providing 4aj
in high yield (Table 4). Additionally, when the reac- para-Allylation of Aniline Derivatives
tion was performed with 4-ethynylaniline, the product
4ai was obtained with good yield (Table 4) due to Lastly, we extended our study on the catalytic activity
a triple bond hydration during the reaction.
of IBLAIL V to anilines without para substituents. As
Finally, a mixture of both 2-allyl- and 4-allylaniline far as we know, this class of substrates has been
was obtained, when the N-methylaniline was em- scarcely studied in protocols involving the synthesis of
ployed as nucleophile. Compound 4aa was isolated in C-allylanilines.[14] As detailed in Table 5, with our cat-
43% yield under the reaction conditions detailed in alytic system, if the para and one or both ortho posi-
Table 4, although the corresponding regioisomer 3aa tions are available on the aniline ring, para-alkylation
was observed in 20% yield. Similarly, the aniline nu- was preferentially observed instead of ortho-alkyla-
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Table 5. 4-Allylanilines synthesis: scope[a]
Scheme 6. Scaled-up synthesis of 2-allylaniline 3ab.
Conclusions
To conclude, we have demonstrated the efficacy of
Fe(III)-based Lewis acidic ionic liquids, which are
easy to prepare, as catalysts for the allylic substitution
reactions of alcohols with anilines. In contrast with
previously reported iron-catalyzed procedures with al-
lylic alcohol and anilines, IBLAIL catalysts did not
promote N-allylations, but C-allylation reactions.
About 3 mol% of iron is employed in the different
transformations, given that 20 mol% of the IBLAIL
are used as catalyst, which contains ca. 15% of iron.
The catalytic system proved versatile. Modulating
the reaction conditions (temperature, reaction time),
the catalytic system can be employed selectively in
the preparation of quinoline derivatives, 2-allylani-
lines and 4-allylanilines. The synthesis of quinolines,
in a one-pot reaction, involved an allylic substitution
reaction in the ortho-position of the aniline and a sub-
sequent oxidative cyclization promoted by atmospher-
ic oxygen.
[a]
Reaction conditions:
1 (0.5 mmol), 2 (0.5 mmol), V
(20 mol%), 1008C for 24 h. Reaction performed in an
open vessel. In parentheses: isolated yield after flash
chromatography.
Experimental Section
tion. In general, the corresponding 4-allylanilines
were obtained in good to excellent yields (65–80%)
when performing the reaction at 1008C as previously
optimized (vide supra). Only the 2,5-dimethoxy-sub-
stituted aniline provided lower results (50% yield).
General
All reagents and solvents were used as supplied commercial-
ly. Analytical thin-layer chromatography (TLC) was per-
formed on 0.2 mm coated Science silica gel (EM 60-F254)
plates purchased from Merck, Germany. Visualization was
achieved by UV light (254 nm). Flash column chromatogra-
phy was performed using silica gel and a gradient solvent
system (hexane-ethyl acetate as eluent). 1H and 13C NMR
spectra were measured on 300 and 400 MHz spectrometers
and the residual solvent peak was used as an internal refer-
ence: proton (chloroform d=7.26 ppm) and carbon (chloro-
Scale-Up and Recycling
The catalytic activity of IBLAIL V was also examined
on a larger scale, under neat conditions. Thus, when
the ortho-alkylation reaction between 1a and 2b was form d=77 ppm). Chemical shifts (ppm) were recorded
with tetramethylsilane (TMS) as the internal reference stan-
dard. Multiplicities are given as s (singlet), brs (broad sin-
glet), d (doublet), t (triplet), dd (doublet of doublets) or m
(multiplet). The number of protons (n) for a given reso-
nance is indicated by nH and coupling constants are report-
ed as J values in Hz. The conversions of the reactions and
purity of the products were determinate by GC analysis
using a Younglin 6100GC, equipped with a flame ionization
detector and a Phenomenex ZB-5 MS column (5% PH-ME
siloxane): 30 m (length), 0.25 mm (inner diameter) and
0.25 mm (film).
scaled up to 10 mmol, 1.90 g of compound 4ab were
obtained (64% isolated yield, Scheme 6).
Moreover, IBLAIL V could be recovered from the
reaction mixture by simple washes with ethyl acetate
and centrifugation of the reaction crude. The recov-
ered IBLAIL V showed catalytic activity for the next
three cycles, although a slight decrease in activity was
observed (range 80–70% conversion, see the Support-
ing Information). This fact maybe due to the reaction
being carried out on a 10 mmol scale.
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General Procedure for Quinoline Synthesis
118.9, 21.9, 19.0; MS: m/z (%)=233 (100) [M+], 232 (27),
218 (41), 217 (12).
To a 10-mL tube, IBLAIL (20 mol%), the corresponding
allylic alcohol (0.5 mmol) and aniline (0.5 mmol) were se-
quentially added. The resultant reaction mixture was stirred
at 1008C for 48 h in an open vessel. After this time, the re-
action mixture was diluted with ethyl acetate (5 mL) and
washed with water (3ꢅ10 mL). The organic extract was
dried over anhydrous MgSO4. The solvent was removed
under reduced pressure to provide the crude product, which
was purified by flash column chromatography on silica gel
using hexane-ethyl acetate as eluent.
2-(4-Methoxyphenyl)-6-methyl-4-phenylquinoline
(5db)
and 4-(4-Methoxyphenyl)-6-methyl-2-phenylquinoline
(5db’):[31] 1H NMR (300 MHz, CDCl3): d=8.18–8.08 (m,
6H), 7.75 (s, 1H), 7.73 (s, 1H), 7.62 (s, 1H), 7.56–7.49 (m,
14H), 7.09 (d, J=8.8 Hz, 1H), 7.09 (d, J=8.9 Hz, 2H), 3.92
(s, 3H), 3.88 (s, 3H), 2.48 (s, 3H), 2.46 (s, 3H); 13C NMR
(75 MHz, CDCl3): d=160.7, 155.6, 148.3, 147.4, 138.8, 136.1,
135.8, 132.4, 131.6, 130.9, 130.8, 129.9, 129.6, 129.5, 129.1,
128.8, 128.5, 128.2, 127.5, 126.3, 125.4, 124.4, 124.3, 119.4,
118.9, 114.2, 114.1, 113.9, 55.4, 55.38, 21.8, 21.77; MS (5db):
m/z (%)=325 (100) [M+], 324 (46), 310 (30), 281 (12); MS
(5db’): m/z (%)=325 (100) [M+], 324 (43), 311 (14), 310
(46), 294 (21), 281 (19), 280 (12), 267 (14), 207 (14).
6-Methyl-2,4-diphenylquinoline (5ab):[24] Orange oil;
1H NMR (300 MHz, CDCl3): d=8.18–8.13 (m, 3H), 7.77 (s,
1H), 7.64 (s, 1H), 7.56–7.22 (m, 9H), 2.46 (s, 3H);
13C NMR: d=155.9, 148.4, 147.4, 139.7, 138.6, 136.2, 131,7,
129.8, 129.5, 129.1, 128.8, 128.6, 128.3, 127.5, 125.7, 124.4,
119.4, 21.8; MS: m/z (%)=295 (100) [M+], 294 (83), 281
(14), 280 (59), 189 (12), 140 (11), 139 (13).
General Procedure for 2-Allylanilines Synthesis
6-Methoxy-2,4-diphenylquinoline (5ac):[25] Brown oil;
1H NMR (300 MHz, CDCl3): d=8.13–8.18 (m, 3H), 7.78 (s,
1H), 7.26–7.58 (m, 9H), 7.20 (d, J=3 Hz, 2H), 3.81 (s, 3H);
13C NMR (75 MHz, CDCl3): d=131.6, 129.3, 128.9, 128.8,
128.7, 128.3, 127.3, 126.3, 121.8, 119.7, 103.7, 55.5, 29.7; MS:
m/z (%)=311 (100) [M+], 310 (34), 296 (41), 267 (10), 148
(10).
To
a 10-mL tube were successively added IBLAIL
(20 mol%), allylic alcohol (0.5 mmol) and aniline
(0.5 mmol). The resultant reaction mixture was stirred at
508C for 2 h. After this time, the reaction mixture was dilut-
ed with ethyl acetate (5 mL) and washed with water (3ꢅ
10 mL). The organic extract was dried over anhydrous
MgSO4. The solvent was removed under reduced pressure
to provide the crude product which was purified by flash
column chromatography on silica gel using hexane-ethyl
acetate as eluent.
6,7-Dimethoxy-2,4-diphenylquinoline (5ad):[26] Brown oil;
1H NMR (300 MHz, CDCl3): d=8.14 (d, J=8.1 Hz, 2H),
7.67 (s, 1H), 7.59–7.43 (m, 8H), 7.17 (s, 2H), 4.08 (s, 3H),
3.86 (s, 3H); 13C NMR (75 MHz, CDCl3): d=155.1, 152.4,
149.7, 147.5, 145.9, 138.9, 129.3, 128.9, 128.8, 128.7, 128.3,
127.3, 121.0, 117.9, 108.7, 103.3, 56.2, 55.9; MS: m/z (%)=
341 (100) [M+], 340 (11), 326 (16), 311 (33), 254 (14).
6-Chloro-2,4-diphenylquinoline (5ae):[27] Brown oil;
1H NMR (400 MHz, CDCl3): d=7.21–7.34 (m, 2H), 7.48–
7.57 (m, 6H), 7.67 (dd, J=2.2, 8.9 Hz, 1H), 7.84 (s, 1H),
7.86 (d, J=2.2 Hz, 1H), 8.16–8.19 (m, 3H); 13C NMR
(100 MHz, CDCl3): d=120.1, 124.5, 126.3, 126.5, 127.5,
128.7, 128.8, 128.9, 129.4, 129.6, 130.4, 131.7, 132.2, 137.7,
139.2, 147.2, 148.5, 157.1; MS: m/z (%)=315 (92) [M+], 314
(100), 280 (30), 278 (16), 201 (13), 176 (11), 140 (17), 139
(20).
(E)-2-(1,3-Diphenylallyl)-N-methylaniline (4aa): Amber
oil; FT-IR (neat): n=3058, 3024, 2921, 2814, 1601, 1509,
1491, 1459, 1448, 1377, 1307, 1263, 1222, 1158 cmÀ1
;
1H NMR (300 MHz, CDCl3): d=7.38–7.17 (m, 11H), 7.07
(dd, J=7.6, 1.4 Hz, 1H), 6.75 (td, J=7.5, 1.1 Hz, 1H), 6.76–
6.69 (m, 2H), 6.24 (dd, J=15.9, 1.1 Hz, 1H), 4.84 (d, J=
6.8 Hz, 1H), 2.74 (s, 3H); 13C NMR (75 MHz, CDCl3): d=
146.7, 141.8, 137.1, 131.7, 131.4, 128.9, 128.8, 128.5, 127.8,
127.6, 127.3, 127.1, 126.8, 126.3, 117.1, 110.5, 49.2, 30.8; MS:
m/z (%)=299 (12) [M+], 209 (17), 208 (100), 206 (16), 194
(13), 193 (23); HR-MS (ESI): m/z=299.1664, calcd. for
C22H21N (M+): 299.1674.
(E)-2-(1,3-Diphenylallyl)-4-methylaniline (4ab):[14] Orange
oil; 1H NMR (400 MHz, CDCl3): d=7.38–7.21 (m, 10H),
6.90 (s, 1H), 6.68 (dd, J=15.9, 7.1 Hz, 1H), 6.60 (d, J=8.5
Hz, 1H), 6.28 (d, J=15.9 Hz, 1H), 4.87 (d, J=7.1 Hz, 1H),
3.41 (brs, 2H), 2.23 (s, 3H); 13C NMR (100 MHz, CDCl3):
d=141.9, 141.7, 137.2, 131.6, 131.5, 129.7, 128.8, 128.7, 128.5,
128.1, 127.3, 126.7, 126.4, 116.7, 49.62, 29.7; MS: m/z (%)=
299 (27) [M+], 209 (18), 208 (100), 207 (36), 206 (11), 194
(12), 193 (19), 191 (11).
6-Bromo-2,4-diphenylquinoline (5af):[28] Yellow oil;
1H NMR (300 MHz, CDCl3): d=7.49–7.57 (m, 8H), 7.79 (d,
J=8.9 Hz, 1H), 7.83 (s, 1H), 8.09 (s, 1H), 8.12 (s, 1H),
8.16–8.20 (m, 2H); 13C NMR (75 MHz, CDCl3): d=119.4,
120.1, 127.6, 127.6, 127.8, 128.6, 128.7, 128.9, 129.4, 129.6,
131.9, 133.0, 137.8, 139.1, 147.6, 148.3, 157.2; MS: m/z (%)=
359 (100) [M+], 358 (85), 282 (10), 281 (17), 280 (59), 279
(16), 278 (38), 277 (15), 203 (12), 202 (22), 201 (20), 176
(18), 139 (39), 138 (35).
(E)-4-Methoxy-2-(1,3-diphenylallyl)aniline
(4ac):[14]
6-Methyl-2-phenylquinoline (5bb):[29] Brown oil; H NMR
1
Brown oil; 1H NMR (300 MHz, CDCl3): d=7.38–7.21 (m,
10H), 6.71–6.62 (m, 4H), 6.30 (d, J=15.9 Hz, 1H), 4.90 (d,
J=6.9 Hz, 1H), 3.71 (s, 3H), 3.30 (s, 2H); 13C NMR
(75 MHz, CDCl3): d=152.9, 141.6, 137.9, 131.6, 131.1, 128.8,
128.7, 128.5, 127.9, 127.4, 126.8, 126.5, 117.5, 115.8,
112.1,55.6, 49.6; MS: m/z (%)=315 (69) [M+], 225 (18), 224
(100), 223 (28), 210 (14), 209 (23), 207 (12), 193 (12), 191
(14), 180 (12), 178 (10), 167 (14), 165 (11), 115 (13), 91 (18).
(E)-4-Chloro-2-(1,3-diphenylallyl)aniline (4ae):[12c] Orange
(300 MHz, CDCl3): d=8.16–8.12 (m, 3H), 8.07 (d, J=
8.5 Hz, 1H), 7.84 (d, J=8.6 Hz, 1H), 7.63–7.38 (m, 5H),
2.55 (s, 3H); 13C NMR (75 MHz, CDCl3): d=156.5, 146.9,
139.8, 136.1, 129.4, 129.1, 128.8, 127.5, 127.127.2, 126.3,
118.9, 21.6; MS: m/z (%)=220 (17) [M+ +1], 219 (100)
[M+], 218 (47), 217 (12), 204 (15), 109 (11).
4,6-Dimethyl-2-phenylquinoline
(5cb):[30]
1H NMR
(300 MHz, CDCl3): d=2.57 (s, 3H), 2.74 (s, 3H), 7.14 (s,
1H), 7.41–7.59 (m, 5H), 7.68–7.85 (m, 2H), 8.05–8.16 (m,
1H); 13C NMR (75 MHz, CDCl3): d=140.0, 136.1, 135.9,
131.9, 131.5, 129.9, 128.8, 128.3, 127.4, 126.3, 122.6, 119.8,
1
oil; H NMR (300 MHz, CDCl3): d=7.40–7.18 (m, 9H), 7.1
(d, J=8.9 Hz, 2H) 6.60–6.49 (m, 3H), 6.34 (dd, J=15.9,
6.1 Hz, 1H),5.01 (d, J=6.1 Hz, 1H), 4.10 (brs, 2H);
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13C NMR (75 MHz, CDCl3): d=145.7, 141.6, 136.4, 131.3,
130.2, 128.9, 128.8, 128.7, 128.5, 127.8, 127.6, 127.1, 126.5,
122.3, 114.7, 60.7; MS: m/z (%)=319 (5) [M+], 194 (21), 193
(100), 192 (12), 191 (13), 178 (19), 127 (23), 115 (59), 91
(16).
(0.5 mmol). The resultant reaction mixture was stirred at
1008C for 24 h. After this time, the reaction mixture was di-
luted with ethyl acetate (5 mL) and washed with water (3ꢅ
10 mL). The organic extract was dried over anhydrous
MgSO4. The solvent was removed under reduced pressure
to provide the crude product which was purified by flash
column chromatography on silica gel using hexane-ethyl
acetate as eluent.
(E)-4-Bromo-2-(1,3-diphenylallyl)aniline (4af):[16] Yellow
oil; 1H NMR (300 MHz, CDCl3): d=7.17–7.34 (m, 12H),
6.59 (dd, J=15.9, 7.0 Hz, 1H), 6.52 (d, J=8.95 Hz, 1H),
6.26 (dd, J=15.9, 1.1 Hz, 1H), 4.80 (d, J=6.8 Hz, 1H), 3.51
(brs, 2H); 13C NMR (75 MHz, CDCl3): d=143.3, 140.9,
136.8, 132.1, 131.9, 131.7, 130.3, 130.3, 130.1, 128.9, 128.7,
128.5, 127.6, 127.1, 126.4, 117.9, 116.6, 110.7, 49.5; MS: m/z
(%)=363 (18) [M+], 284 (22), 274 (28), 273 (42), 272 (29),
271 (39), 206 (26), 193 (100), 191 (21), 165 (15), 102 (12), 91
(18).
(E)-4-(1,3-Diphenylallyl)-N-methylaniline (3aa): Amber
oil; FT-IR (neat): n=3058, 3024, 2929, 2881, 1613, 1491,
1448, 1317, 1265, 1183 cmÀ1 1H NMR (400 MHz, CDCl3):
;
d=7.36 (d, J=8.2 Hz, 2H), 7.33–7.15 (m, 8H), 7.05 (d, J=
8.3 Hz, 2H), 6.65 (dd, J=15.8, 7.5 Hz, 1H), 6.57 (d, J=
8.3 Hz, 2H), 6.32 (d, J=15.8 Hz, 1H), 4.79 (d, J=7.5 Hz,
1H), 2.82 (s, 3H); 13C NMR (75 MHz, CDCl3): d=147.8,
144.2, 137.4, 133.3, 132.0, 130.7, 129.3, 128.7, 128.6, 128.4,
128.3, 127.0, 126.2, 126.1, 112.4, 53.3, 30.7; MS: m/z (%)=
299 (100) [M+], 298 (50), 222 (17), 191 (14), 165 (12), 120
(19); HR-MS (ESI): m/z=299.1666, calcd. for C22H21N
(M+): 299.1674.
(E)-2-(1,3-Diphenylallyl)-3,5-dimethoxyaniline (4ag): Pale
yellow oil; FT-IR (neat): n=3371, 3023, 2934, 2837, 1597,
1
1491, 1448, 1202, 1153, 1120, 1078 cmÀ1; H NMR (300 MHz,
CDCl3): d=7.39 (dd, J=8.3 Hz, 1.2 Hz, 1H), 7.09–7.32 (m,
8H), 6.94 (dd, J=15.9, 8.5 Hz, 1H), 6.48 (d, J=15.8 Hz,
1H), 5.92 (s, 2H), 5.39 (d, J=8.5 Hz, 1H), 3.66 (s, 6H);
13C NMR (75 MHz, CDCl3): d=158.9, 146.5, 144.9, 128.2,
132.4, 130.2, 128.3, 127.6, 127.4, 126.6, 126.2, 125.1, 110.6,
92.5, 55.7, 42.9; MS: m/z (%)=345 (100) [M+], 315 (26), 314
(87), 268 (19), 254 (20), 239 (15), 207 (11), 167 (11), 166
(82), 164 (11), 153 (27), 152 (13), 124 (12), 115 (16), 91 (19);
HR-MS (ESI): m/z=345.1722, calcd for C23H23NO2 (M+):
345.1729.
(E)-4-(1,3-Diphenylallyl)-3,5-dimethoxyaniline
(3ag):
Yellow solid; mp 144.28C; FT-IR (neat): n=3420, 3341,
3058, 3025, 2936, 2835, 1607, 1594, 1491, 1466, 1449, 1428,
1238, 1216, 1203, 1153, 1090 cmÀ1
;
1H NMR (300 MHz,
CDCl3): d=7.14–7.43 (m, 10H), 6.84 (dd, J=15.9, 7.5 Hz,
1H), 6.47 (dd, J=15.9, 1 Hz, 1H), 6.02 (d, J=2.4 Hz, 1H),
5.82 (d, J=2.4 Hz, 1H), 5.54 (d, J=7.4 Hz, 1H), 3.74 (s,
3H), 3.72 (s, 3H); 13C NMR (75 MHz, CDCl3): d=159.8,
159.1, 146.4, 142.7, 137.5, 131.5, 128.5, 128.4, 128.38, 128.3,
127.6, 127.5, 127.0, 126.2, 126.1, 108.3, 94.4, 89.7, 55.8, 54.9,
42.5; MS: m/z (%)=345 (70) [M+], 315 (14), 314 (54), 255
(17), 254 (100), 253 (46), 240 (15), 239 (15), 224 (10), 223
(13), 192 (18), 191 (28), 178 (13), 167 (11), 166 (28), 165
(10), 153 (15), 115 (14), 91 (15); HR-MS (ESI): m/z=
345.1730, calcd. for C23H23NO2 (M+): 345.1729.
(E)-2-(1,3-Diphenylallyl)-4-phenoxyaniline
(4ah):[14]
Brown oil; 1H NMR (300 MHz, CDCl3): d=7.35–722 (m,
11H), 7.02–6.89 (m, 5H), 6.79 (dd, J=8.5, 2.74 Hz, 1H),
6.67 (d, J=8.5 Hz, 1H), 6.62 (dd, J=15.9, 7.0 Hz, 1H), 6.29
(dd, J=15.9, 1.1 Hz, 1H), 4.88 (d, J=7.0 Hz, 1H), 3.47 (brs,
2H); 13C NMR (75 MHz, CDCl3): d=158.8, 148.6, 141.3,
140.5, 136.9, 131.8, 130.9, 129.9, 129.5, 128.8, 128.7, 128.5,
127.5, 127.3, 126.9, 126.4, 121.9, 121.3, 119.1, 117.4, 117.1,
49.6; MS: m/z (%)=370 (31) [M+À77], 299 (100), 207 (12).
(E)-1-[4-Amino-3-(1,3-diphenylallyl)phenyl]ethanone
(E)-4-(1,3-Diphenylallyl)-N,N-dimethylaniline
(3ak):[32]
Red oil; 1H NMR (300 MHz, CDCl3): d=7.38–7.19 (m,
10H), 7,10 (d, J=8.6 Hz, 2H), 6.72–6.62 (m, 3H), 6.33 (d,
J=15.9 Hz, 1H), 4.81 (d, J=7.6 Hz, 1H), 2.92 (s, 6H);
13C NMR (75 MHz, CDCl3): d=149.2, 144.2, 136.3, 133.3,
130.8, 129.2, 128.6, 128.4, 128.3, 127.6, 127.1, 126.3, 126.2,
112.8, 53.3, 40.8; MS: m/z (%)=313 (100) [M+], 312 (44),
236 (21), 210 (10), 191 (22), 165 (18), 134 (21), 117 (11).
(E)-4-(1,3-Diphenylallyl)-2-methylaniline (3al):[14] Pale
yellow oil; 1H NMR (300 MHz, CDCl3): d=7.38–7.19 (m,
10H), 6.91 (s, 1H), 6.88 (s, 1H), 6.65 (dd, J=15.4, 7.5 Hz,
1H), 6.32 (d, J=15.4 Hz, 1H), 4.77 (d, J=7.5 Hz, 1H), 3.59
(s, 2H), 2.08 (s, 3H); 13C NMR (75 MHz, CDCl3): d=144.1,
142.9, 137.4, 133.6, 133.3, 130.8, 130.7, 128.6, 128.4, 128.3,
127.1, 127.0, 126.3, 126.2, 122.4, 115.0, 53.4, 17.5; MS: m/z
(%)=299 (100) [M+], 298 (31), 285 (15), 284 (64), 222 (17),
208 (12), 207 (14), 206 (19), 193 (14), 192 (14), 191 (23), 180
(16), 165 (11), 120 (24), 115 (15).
(4ai): Orange oil; FT-IR (neat): n=3349, 3058, 3027, 1654,
1591, 1522, 1491, 1449, 1420, 1357, 1271, 1177 cmÀ1
;
1H NMR (300 MHz, CDCl3): d=7.78 (d, J=8.8 Hz, 2H),
7.19–7.48 (m, 9H), 6.57–6.62 (m, 3H), 6.37 (dd, J=15.9,
6.0 Hz, 1H), 5.18 (t, J=5.4 Hz, 1H), 4.70 (brs, 2H), 2.46 (s,
3H); 13C NMR (75 MHz, CDCl3): d=196.3, 150.9, 131.7,
130.6, 129.4, 128.9, 128.6, 127.8, 127.1, 126.5, 112.4, 59.9,
25.9; MS: m/z (%)=327 (5) [M+], 207 (12), 194 (21), 193
(100), 178 (20), 135 (20), 120 (37), 115 (52), 92 (19), 91 (16);
HR-MS (ESI): m/z=327.1616, calcd. for C23H21NO (M+):
327.1623.
(E)-2-(1,3-Diphenylallyl)-4-nitroaniline (4aj):[16] Yellow
1
solid; mp 128.38C; H NMR (300 MHz, CDCl3): d=8.02 (d,
J=9.2 Hz, 2H), 7.13–7.51 (m, 9H), 6.50–6.66 (m, 3H), 6.36
(dd, J=15.9, 6.1 Hz, 1H), 5.19 (t, J=4.8 Hz, 1H), 4.99 (d,
J=4.1 Hz, 2H); 13C NMR (75 MHz, CDCl3): d=152.1,
140.2, 132.2, 129.1, 128.6, 128.5, 128.1, 127.1, 126.5, 126.2,
112.1, 59.9; MS: m/z (%)=330 (2) [M+], 194 (27), 193
(100), 178 (19), 116 (11), 115 (18), 108 (11), 91 (13).
(E)-4-(1,3-Diphenylallyl)-2,5-dimethylaniline
Orange oil; FT-IR (neat): n=3023, 2923, 2854, 1624, 1598,
1572, 1491, 1461, 1447, 1290, 1204, 1028 cmÀ1 1H NMR
(3am):
;
(300 MHz, CDCl3): d=7.39–7.12 (m, 10H), 6.83 (s, 1H),
6.64 (dd, J=15.9, 6.9 Hz, 1H), 6.50 (s, 1H), 6.19 (d, J=15.9,
1H), 4.95 (d, J=6.9 Hz, 1H), 3.49 (brs, 2H), 2.16 (s, 3H),
2.09 (s, 3H); 13C NMR (75 MHz, CDCl3): d=143.5, 142.8,
137.6, 134.8, 133.3, 131.6, 130.7, 130.6, 128.8, 128.4, 128.2,
127.1, 126.3, 126.0, 119.8, 117.3, 49.8, 19.32, 17.0; MS: m/z
General Procedure for ortho-Alkylation Products
To
a 10-mL tube were successively added IBLAIL
(20 mol%), allylic alcohol (0.5 mmol) and aniline
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(%)=313 (92) [M+], 298 (100), 236 (15), 221 (13), 220 (16),
207 (13), 206 (14), 193 (12), 192 (11), 191 (25), 165 (10), 134
(33), 115 (14), 91 (11); HR-MS (ESI): m/z=313.1826, calcd.
for C23H23N (M+): 313.1833.
Guo, T. Zhang, T. Liu, J. Du, B. Jia, S. Gao, J. Yu, En-
viron. Sci. Technol. 2015, 49, 5697–5703; e) T. S. Rodri-
gues, F. Machado, P. M. Lalli, M. N. Eberlin, B. A. D.
Neto, Catal. Commun. 2015, 63, 66–73; f) O. Nacham,
K. D. Clark, J. L. Anderson, RSC Adv. 2016, 6, 11109–
11117; g) T. Tian, X. Hu, P. Guan, Y. Tang, J. Chem.
Eng. Data 2016, 61, 721–730.
(E)-2-Chloro-6-(1,3-diphenylallyl)aniline (3an):[14] Yellow
oil; 1H NMR (300 MHz, CDCl3): d=7.38–7.20 (m, 10H),
7.11 (d, J=2.0 Hz, 1H), 6.92 (dd, J=8.2, 2.0 Hz, 1H), 6.71
(d, J=8.2 Hz, 1H), 6.60 (dd, J=15.8, 7.4 Hz, 1H), 6.32 (d,
J=15.8 Hz, 1H), 4.76 (d, J=7.4 Hz, 1H), 3.97 (brs, 2H);
13C NMR (75 MHz, CDCl3): d=143.4, 141.3, 137.2, 134.5,
132.4, 131.4, 129.3, 128.6, 128.5, 128.4, 127.9, 127.3, 126.5,
126.3, 119.3, 115.9; MS: m/z (%)=319 (100) [M+], 318 (26),
284 (61), 242 (15), 241 (14), 206 (41), 193 (28), 192 (31), 191
(31), 180 (25), 178 (15), 165 (15), 152 (13), 140 (23), 115
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(E)-2-Bromo-6-(1,3-diphenylallyl)aniline (3ao):[14] Yellow
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6.98–6.97 (m, 1H), 6.70 (d, J=8.2 Hz, 1H), 6.59 (dd, J=
15.8, 7.4 Hz, 1H), 6.32 (d, J=15.8 Hz, 1H), 4.76 (d, J=
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29.7; MS: m/z (%)=365 (99) [M+], 364 (46), 363 (99), 362
(25),285 (28), 284 (100), 283 (21), 208 (20), 207 (66), 206
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Acknowledgements
This work was financially supported by the University of Ali-
cante.
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