Characterization, Consideration and Catalytic Application of Novel Pyrazine-1,4-Diium Trifluoromethanesulfonate {[1,4-DHPyrazine](OTf)2} as a Green and Recyclable Ionic Liquid Catalyst in the Synthesis of Amidoalkyl Naphthol Derivatives

Article abstract of DOI:10.1002/jhet.2577

An efficient and green one-pot method has been developed for the synthesis of amidoalkyl naphthol derivatives using reusable {[1,4-DHPyrazine](OTf)₂} as an ionic liquid catalyst via condensation of aromatic aldehydes, β-naphthol and various ami

Full text of DOI:10.1002/jhet.2577

Month 2015
Characterization, Consideration and Catalytic Application of Novel
Pyrazine-1,4-Diium Trifluoromethanesulfonate {[1,4-DHPyrazine](OTf)2}
as a Green and Recyclable Ionic Liquid Catalyst in the Synthesis of
Amidoalkyl Naphthol Derivatives
*
Heshmatollah Alinezhad, Mahmood Tajbakhsh, and Mohammad Norouzi
Faculty of Chemistry, University of Mazandaran, Babolsar, Iran
*
E-mail: heshmat@umz.ac.ir
Received September 15, 2015
DOI 10.1002/jhet.2577
Published online 00 Month 2015 in Wiley Online Library (wileyonlinelibrary.com).
An efficient and green one-pot method has been developed for the synthesis of amidoalkyl naphthol de-
rivatives using reusable {[1,4-DHPyrazine](OTf)2} as an ionic liquid catalyst via condensation of aromatic
aldehydes, β-naphthol and various amides under solvent-free conditions.
J. Heterocyclic Chem., 00, 00 (2015).
INTRODUCTION
Therefore, the synthesis of amidoalkyl naphthols is an impor-
tant and valuable role in organic chemistry. Consequently,
because of their medicinal, biological and pharmacological
significance, many techniques have been developed for the
preparation of amidoalkyl naphthols from various aldehydes,
2-naphthols, and amides derivatives under thermal heating
and sonication conditions by catalysts such as [Msim]Cl,
[Dsim]Cl, [Msim]AlCl4 [6], N,N,N’,N’-tetra-bromobenzene-
1,3-disulphonamide [TBBDA] [7], {[HMIM]C(CN)3} [8],
trityl chloride [9,10], silica sulfuric acid [11], and [2-MPyH]
OTf [12].
The increased attention in ionic liquids (ILs) through
chemists and technologists obviously is because of the
efficacy of ionic liquids as solvents for reaction chemistry,
counting catalytic reactions. The tendency for “green” sol-
vents for industrial procedures is partially accountable for
this, however too many chemists now find out that ionic
Multi-component reactions have received significant con-
sideration because they are influential synthetic tools for the
synthesis of biologically active compounds [1]. In terms of
green chemistry, the extension and usage of multi-component
coupling reactions in aqueous media is favorable, as they
afford simple and rapid available to a large number of organic
molecules through a tolerable path [2]. Benefits of these reac-
tions contain the use of simple processes, time and energy
efficiency, high bond formation yields, and low cost [3].
Amidoalkyl naphthols are a significant group of compounds
because they have been found to have useful biological activ-
ities. Moreover, amidoalkyl naphthols can be converted to
useful and main biological building blocks, and their hydroly-
sis leads to 1-amino methyl-2-naphthols, compounds that
show hypotensive and bradycardia effects in humans [4,5].
© 2015 HeteroCorporation

H. Alinezhad, M. Tajbakhsh, and M. Norouzi
Vol 000
liquidssuggestionsomeuniquepropertiesassolvents.More-
over, ionic liquid solvents have the outlook for custom inten-
tion of the solvent to meet particular requirements for a
specific reaction category [13]. Room-temperature ionic
liquids (RTILs), salts that are liquid at ambient temperature,
are generally combined of relatively large organic cations
and inorganic or organic anions. Different molecular liquids,
ionic liquids, which are polar solvents, are eco-friendly
benign, nonflammable, nonvolatile; most of them have good
solubilityinwaterandarestable inair[14]. Ionicliquidscon-
tinue to attract attention as environmentally benign solvents
for green chemistry and electrolytes [15–17]. Ionic liquids
generally are 1–1 electrolytes (composed of an anion and a
cation) that have melting points below 100°C, and each of
these ions can be different, mostly via simple ion exchange
procedures.Thesesolventscanbesimplychangedforcertain
applications or to attain specific properties. Therefore, the
term “designer solvents” has come into usual use in describ-
ing ionic liquids. Ionic liquids that melt at and below room
temperature are known as room temperature ionic liquids
(RTILs). Theirlowmeltingpointsarerelatedtobasicproper-
ties of organic ions in strong electrostatic coupling. Ionic
liquids are functional liquids displaying many high electrical
conductivities, and high thermal stability [18–20].
According to previous reports in the field of ionic liquid
and molten salt catalysts based on pyrazine [21,22], in con-
tinuance in this study, we wish to define our finding for the
three-component reaction of aromatic aldehydes, β-naphthol
and various amides in the synthesis of amidoalkyl naphthol
derivatives under thermal solvent-free condition in the pres-
ence of {[1,4-DHPyrazine](OTf)2} as an eco-friendly and
efficient ionic liquid catalyst (Scheme 1).
Scheme 1. The synthesis of amidoalkyl naphthol derivatives using
{[1,4-DHPyrazine](OTf)2}.
RESULT AND DISCUSSIONS
Characterization of pyrazine-1,4-diium trifluoromethane-
sulfonate {[1,4-DHPyrazine](OTf)2}.
The structure of
pyrazine-1,4-diium
trifluoromethanesulfonate {[1,4-
DHPyrazine](OTf)2} was characterized by FT-IR, 1H
NMR, 13C NMR and 19F NMR. In the IR spectrum of
{[1,4-DHPyrazine](OTf)2} (Fig. 1, b), the absorption
band at 3484cmÀ1 is related to stretching vibration of N–H
group, and the two peaks at 1271cmÀ1 and 1168cmÀ1 are
corresponding to vibrational modes of O–SO2 bonds. The
absorption correlated to S=O bond vibration observed at
1033cmÀ1. The absence of the aforementioned absorptions
Figure 1. The FT-IR spectra of pyrazine (a) and {[1,4-DHPyrazine](OTf)2} (b). [Color figure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
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Synthesis of Amidoalkyl Naphthol Derivatives
in the IR spectrum of the pyrazine (Fig. 1, a) clearly confirms
group together with a singlet at 7.93 ppm correlated to
the aromatic hydrogen’s.
structure of the catalyst.
1
The H NMR spectra of the {[1,4-DHPyrazine](OTf)2
Obvious of two signals in the 13C NMR (Fig. 3) is in
identity with the catalyst structure. Furthermore, a
(Fig. 2) displays a singlet at 8.68 ppm related to the N–H
Figure 2. The 1H NMR spectra of {[1,4-DHPyrazine](OTf). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]
Figure 3. The13CNMRspectraof{[1,4-DHPyrazine](OTf)2}. [Colorfigurecanbeviewedinthe onlineissue, whichis availableat wileyonlinelibrary.com.]
Journal of Heterocyclic Chemistry
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H. Alinezhad, M. Tajbakhsh, and M. Norouzi
Vol 000
quartet at 116.3–125.9 ppm in the 13C NMR and a sin-
glet at À77.79 ppm in the 19F NMR (Fig. 4) obviously
confirm the protonation of pyrazine via trifluor-
omethanesulfonic acid.
The mass spectrum of the ionic liquid catalyst is in
agreement with the structure of the catalyst and displayed
the parent peak at 380 m/z (Fig. 5).
Thermal gravimetric (TG) and differential thermal analy-
sis (DTA) of {[1,4-DHPyrazine](OTf)2} was also studied.
The constant diagrams are showed in Figures 6 and 7. The
thermal gravimetric (TG) and differential thermal gravimet-
ric (DTG) analysis showed that {[1,4-DHPyrazine](OTf)2}
as an ionic liquid catalyst was very stable, and there was
no obvious mass loss before 350°C. The significant weight
Figure 4. The 19F NMRspectra of {[1,4-DHPyrazine](OTf)2}. [Colorfigure canbe viewedin the onlineissue, which is availableat wileyonlinelibrary.com.]
Figure 5. The mass spectra of {[1,4-DHPyrazine](OTf)2}. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]
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Synthesis of Amidoalkyl Naphthol Derivatives
reaction conditions at 100°C is clearly the best choice
for these reactions.
To find simple and suitable conditions for synthesis
of amidoalkyl naphthols, the reaction of, 2,5-dimethoxy-
benzaldehyde, β-naphthol and acetamide was chosen as
a
model to form the N-((2,5-dimethoxyphenyl)
(2-hydroxynaphthalen-1-yl)methyl)acetamide (Table 3, en-
try 10), and reaction progress was considered under various
conditions via thin layer chromatography (TLC). A sum-
mary of accomplished results has been presented in Table 2.
Entries 1–12 in this table demonstrate the effect of various
amounts of {[1,4-DHPyrazine](OTf)2} as an ionic liquid cat-
alyst on the rate and yield of the reaction. As is detectable,
the best results were attained when the reaction was accom-
plished using 2mol% of ionic liquid catalyst under thermal
solvent-free reaction conditions (Table 2, entry 9). Table 2
obviously demonstrates that in the absence of ionic liquid
catalyst, the product was not prepared (Table 2, entries 1
and 2). Increasing the reaction temperature and catalyst load-
ing did not improve the rate of the reaction (Table 2, entries
10–12). A slight excess of the amide was found to be advan-
tageous, and hence, the molar ratio of aromatic aldehyde and
β-naphthol to amide was considered at 1:1:1.2.
Figure 6. The thermal gravimetric (TG) diagram of {[1,4-DHPyrazine](OTf)2}.
Subsequently optimizing the reaction conditions, to pros-
pect the utility and the scope of the offered process, various
amidoalkyl naphthol derivatives were synthesized via the
three-component condensation reaction of several aromatic
aldehydes, β-naphthol and different amides using a catalytic
amount of {[1,4-DHPyrazine](OTf)2} as an ionic liquid
catalyst under thermal solvent-free reaction conditions. The
results have been displayed in Table 3. The effect of substitu-
ents on the aromatic ring was showed estimated strong effects
in terms of yields under these reaction conditions. All aromatic
aldehydes having benzaldehyde and aldehydes including
electron-releasing substituents, electron-withdrawing substitu-
ents on their aromatic ring gave the linked products in high to
Figure 7. The differential thermal analysis (DTA) diagram of {[1,4-
DHPyrazine](OTf)2}.
loss followed in the range of 350–600°C, being qualified to
the loss of main {[1,4-DHPyrazine](OTf)2}.
Catalytic activity of pyrazine-1,4-diium trifluoromethane
sulfonate {[1,4-DHPyrazine](OTf)2}.
We have similarly
detected the effects of the solvent (under reflux conditions)
decided some studies. As a model reaction, the reaction of
2,5-dimethoxybenzaldehyde, β-naphthol, and acetamide
catalyzed by 2mol% {[1,4-DHPyrazine](OTf)2}as a novel
ionic liquid in various solvents is summarized in
Table 1. From Table 1, we can detect that solvent-free
Table 2
The effect of loading {[1,4-DHPyrazine](OTf)2} as an ionic liquid cata-
lyst and temperaturea.
Catalyst loading Temperature
Time
(min)
Yield
(%)b
Entry
(mol %)
(°C)
Table 1
The solvent effect in the synthesis of amidoalkyl naphthol catalyzed by
2 mol% {[1,4-DHPyrazine](OTf)2}a.
1
2
3
4
5
6
7
8
Catalyst-free
Catalyst-free
25
100
25
100
25
100
25
75
60
60
60
60
60
60
45
45
20
20
45
20
—
—
15
30
30
50
55
70
96
96
55
96
0.5
0.5
1
1
2
2
2
2
5
Entry
Solvent
Time (min)
Yield (%)b
1
2
3
4
5
6
7
Solvent-free
H2O
C2H5OH
CH3CN
CH3CO2Et
CH2Cl2
20
60
30
30
45
30
60
96
21
35
30
25
30
25
9
100
125
25
10
11
12
Toluene
5
100
a2,5-Dimethoxybenzaldehyde (1 mmol), β-naphthol (1 mmol), acetamide
a2,5-Dimethoxybenzaldehyde (1 mmol), β-naphthol (1 mmol), acetamide
(1.2 mmol).
(1.2 mmol).
bIsolated yield.
bIsolated yield.
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H. Alinezhad, M. Tajbakhsh, and M. Norouzi
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Table 3
The synthesis of amidoalkyl naphthol derivatives under thermal solvent-free reaction conditions using 2 mol% {[1,4-DHPyrazine](OTf)2} as an ionic
liquid catalysta.
Entry
1
Aldehydes
R
Product
Time (min)
40
Yield (%)
90
M.p (°C)b [Lit.]Ref.
NH2
180–182 [173–175]12
2
3
4
NH2
NH2
NH2
25
30
35
95
94
93
204–206 [200–202]8
163–165 [169–171]12
207–209 [206–208]8
5
NH2
30
94
191–193 [195–197]8
6
NH2
40
90
280–282 [279–281]8
7
CH3
25
94
230–232 [228–230]12
(Continued)
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Synthesis of Amidoalkyl Naphthol Derivatives
Table 3
(Continued)
Entry
8
Aldehydes
R
Product
Time (min)
10
Yield (%)
98
M.p (°C)b [Lit.]Ref.
CH3
237–239 [236–238]12
9
CH3
15
20
97
96
253–255 [236–238]12
10
CH3
279–281 [252–254]12
11
CH3
15
97
263–265 [265–267]8
12
CH3
25
94
225–227 [223–225]8
13
CH3
10
97
246–248 [244–246]8
14
Ph
30
92
236–238 [234–236]12
(Continued)
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H. Alinezhad, M. Tajbakhsh, and M. Norouzi
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Table 3
(Continued)
Entry
Aldehydes
R
Product
Time (min)
15
Yield (%)
96
M.p (°C)b [Lit.]Ref.
15
Ph
251–253 [244–246]12
16
17
Ph
Ph
20
25
95
94
203–205 [174–176]12
269–271 [271–273]8
18
Ph
20
95
295–297 [293–295]8
19
Ph
30
92
243–245 [244–246]8
20
Ph
15
95
279–281 [281–283]8
aAromatic aldehydes (1 mmol), β-naphthol (1 mmol), amide derivatives (1.2 mM).
bIsolated yield.
excellent yields in short reaction times. The reaction times
of aromatic aldehydes containing electron withdrawing
groups were rather faster than electron donating groups.
Furthermore, amide derivatives similarly practiced well to
the transformation. Additionally, in this reaction, condition
acetamide was reacted faster than benzamide and urea.
It should be shown that the products of this reaction could
be readily separated from catalyst. {[1,4-DHPyrazine](OTf)2}
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Synthesis of Amidoalkyl Naphthol Derivatives
as a novel ionic liquid catalyst is soluble in water, but the
products are not. Therefore, at the end of reaction, the prod-
ucts were insoluble in water and could be separated by a
simple filtration. {[1,4-DHPyrazine](OTf)2} catalyst was
similarly establish to be reusable five times. However, little
reduction in activity of catalyst was identified (Table 4).
Deactivation of the ionic liquid catalyst is low, although
reactant was expected. The reaction was scaled up to 5 mM
of 2,5-dimethoxybenzaldehyde, β-naphthol and acetamide
in the presence of 10mol% of ionic liquid catalyst under
solvent-free conditions at 100°C. The yield of the reaction
was 96% in 20min and 90% after the fifth run. The results
were summarized in Table 4.
In Scheme 2, we suggested a possible mechanism for the
synthesis of amidoalkyl naphthol derivatives in the presence
of{[1,4-DHPyrazine](OTf)2}asanionicliquidcatalyst. The
reaction of aromatic aldehydes with β-naphthol using ionic
liquid catalyst is probable to offer ortho-quinone methides
(o-QMs). The similar o-QMs, formed in situ, have been
reactedwithamidederivativestoprocessamidoalkylnaphthol
derivatives.Anappliedexplanationforthisresultcanbegiven
byconsideringthenucleophilicadditiontoo-QMsintermedi-
ate appropriate via conjugate addition on the α,β-unsaturated
carbonyl group, and finally, this intermediate will aromatize
toproducetheultimatearomaticcompound[8,23].
CONCLUSIONS
In this study, the effective, green, and applicability of
novel ionic liquid pyrazine-1,4-diium trifluoromethanesulfo-
nate {[1,4-DHPyrazine](OTf)2} as a new type, homoge-
neous catalyst for organic transformations was under
thermal solvent-free reaction conditions, fully characterized
1
by ionic liquid catalyst through IR, H NMR, 13C NMR,
19F NMR, mass, thermal gravimetric (TG), and differential
thermal analysis (DTA). Its catalytic activities in the synthe-
sis of amidoalkyl naphthol derivatives were identified and
appropriate results were attained. Additional studies display
that the ionic liquid acidity plays a significant role in the
acid-catalyzed consideration reaction. The promising estima-
tions for the achievable methodology are simplification,
comfort of product isolation, low cost, high yield, compara-
tively short reaction time, cleaner reaction and reusability of
the catalyst.
EXPERIMENTAL
General procedure for the synthesis of pyrazine-1,4-diium
trifluoromethanesulfonate {[1,4-DHPyrazine](OTf)2} as an
novel ionic liquid catalyst. Trifluoromethanesulfunic acid
(6.2 mM: 0.930g: 0.549mL) was added drop wise to 5 mL
a CH3CN solution of pyrazine (3 mM: 0.240 g) and stirred
at 0–5°C for 1 h. Subsequently, the reaction mixture was
stirred for an extra period of 1h at room temperature.
Then, the complation of the reaction montried by TLC the
solvent was removed by concentration under reduced
pressure, the product was dried under vacuum at 80°C for
2 h. A cream solid was formed (Scheme 1) quantitatively.
Spectral data for {[1,4-DHPyrazine](OTf)2}: M.p: 78–80°C;
Table 4
Investigation of the reusability of {[1,4-DHPyrazine](OTf)2} as an ionic
liquid catalyst in 20 mina.
Run
1
2
3
4
5
Yield (%)b
96
95
95
93
90
a2,5-Dimethoxybenzaldehyde (1 mmol), β-naphthol (1 mmol), acetamide
(1.2 mM).
bIsolated yield.
Scheme 2. The suggested mechanism for the synthesis of amidoalkyl naphthol derivatives catalyzed by {[1,4-DHPyrazine](OTf)2} as an ionic liquid.
[Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]
Journal of Heterocyclic Chemistry
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H. Alinezhad, M. Tajbakhsh, and M. Norouzi
Vol 000
Yield: 97%; Spectral data: IR (KBr): υ 3484, 3214, 3127,
3067, 2942, 1592, 1479, 1271, 1168, 1033, 764, 642cmÀ1
(s, 3H, —CH3), 4.53 (s, 1H, —CH), 5.40 (brs, 1H, —OH),
5.53 (d, 1H, J=5.2Hz, —CH aliphatic), 5.84 (brs, 2H,
—NH2), 6.96 (d, 1H, J=5.0Hz, ArH), 7.11 (t, 1H,
J=7.2Hz, ArH), 7.18 (t, 2H, J=7.4Hz, ArH), 7.30 (d, 5H,
J=5.8Hz, ArH), 7.42 (d, 1H, J=6.4Hz, —NH), 7.80 (t,
2H, J=9.0Hz, ArH); 13C NMR (100MHz, DMSO-d6): δ
13.4, 46.2, 75.9, 112.5, 119.0, 123.4, 123.5, 126.8, 128.6,
128.8, 128.9, 129.3, 129.5, 133.1, 146.1, 152.2, 157.8;
MS: m/z=332 [M]+.
;
1H NMR (400MHz, DMSO-d6): δ 7.93 (s, 4H, —CH),
8.68 (s, 2H, —NH); 13C NMR (100MHz, DMSO-d6): δ
116.3, 119.5, 122.7, 125.9, 145.5; 19F NMR (376MHz,
DMSO-d6): δ –77.8; MS: m/z=380 [M]+, 381 [M+H]+.
Reusability of {[1,4-DHPyrazine](OTf)2} as a novel ionic
liquid catalyst. In case of a novel ionic liquid, that is,
{[1,4-DHPyrazine](OTf)2}, the reaction mixture was
diluted in water and removed with CH2Cl2 (10 mL). The
combined organic extracts were washed with water, dried
over anhydrous Na2SO4, concentrated under vacuum, and
the resulting product was purified either through
recrystallization to give pure product. The ionic liquid
can be recovered either via extracting the aqueous phase
with CH2Cl2 or by evaporating the aqueous layer under
vacuum. The ionic liquid consequently attained was
added dried at 60°C under reduced pressure for use in
following runs.
N-((2-hydroxynaphthalen-1-yl)(naphthalen-1-yl)methyl)aceta-
mide (Table 3, entry 11). White solid; M.p: 263–265°C;
Yield: 97%; IR (KBr): υ 3413, 3057, 3006, 2937, 1647,
1628, 1582, 1512, 1332 cmÀ1
;
1H NMR (400MHz,
DMSO-d6): δ 1.92 (s, 3H, —CH3), 7.26 (d, 2H,
J = 8.8 Hz, ArH), 7.32 (t, 1H, J =7.4 Hz, ArH), 7.42 (d,
1H, J = 8.0 Hz, —CH aliphatic), 7.47 (t, 4H, J =6.8 Hz,
ArH), 7.64 (d, 1H, J = 8.0 Hz, ArH), 7.78 (d, 1H,
J = 8.8 Hz, ArH), 7.81 (d, 1H, J = 8.8 Hz, ArH), 7.93 (d,
1H, J= 9.6 Hz, ArH), 7.99 (d, 1H, J= 8.4 Hz, ArH), 8.06
(d, 1H, J = 9.2 Hz, ArH), 8.74 (d, 1H, J = 8.0 Hz, —NH),
10.04 (brs, 1H, —OH); 13C NMR (100MHz, DMSO-d6):
δ 22.9, 47.3, 118.7, 119.0, 122.7, 123.6, 123.9, 125.5,
125.7, 125.9, 126.5, 126.6, 127.9, 128.9, 129.0, 129.1,
129.7, 131.4, 133.2, 134.0, 137.8, 153.7, 168.9; MS:
m/z = 341 [M]+.
General procedure for the preparation of amidoalkyl
naphthol derivatives.
To the mixture of aromatic
aldehydes (1 mM), β-naphthol (1 mM), amide derivatives
(1.2 mM) in a round bottom flask, 2 mol% of {[1,4-
DHPyrazine](OTf)2} as a novel ionic liquid catalyst was
added, and the mixture was ground under thermal
(100°C) solvent-free conditions for the appropriate time
described in Table 3. After completion of the reaction
which was observed via TLC (n-hexane/ethyl acetate:
5/2), the mixture was washed with water and separated
from ionic liquid catalyst, the solid product was purified
by recrystallization from ethanol. All of the preferred
products were characterized through comparison of their
physical data with those of known compounds. Some
characterization data for selected known products are
given below.
N-(1-(2-hydroxynaphthalen-1-yl)-2-methyl-3-phenylallyl)aceta-
mide (Table 3, entry 12). White solid; M.p: 225–227°C;
Yield: 94%; IR (KBr): υ 3395, 3055, 3023, 2965, 1627,
1524, 1515, 1371, 1274 cmÀ1
;
1H NMR (400MHz,
DMSO-d6): δ 1.67 (s, 3H, —CH3), 1.94 (s, 3H, —CH3),
6.45 (s, 1H, ArH), 6.53 (d, 1H, J = 8.4 Hz, —CH
aliphatic), 7.21 (t, 4H, J = 8.8 Hz, ArH), 7.28 (d, 1H,
J = 6.8 Hz, ArH), 7.32 (d, 2H, J = 7.6 Hz, ArH), 7.44 (t,
1H, J= 7.2 Hz, ArH), 7.75 (d, 1H, J= 8.8 Hz, ArH), 7.81
(d, 1H, J = 7.6 Hz, ArH), 8.12 (d, 1H, J =8.4 Hz, ArH),
8.28 (d, 1H, J =8.4 Hz, —NH), 9.95 (brs, 1H, —OH); 13C
NMR (100 MHz, DMSO-d6): δ 16.7, 23.1, 51.3, 117.7,
118.9, 122.8, 123.4, 123.5, 126.5, 126.6, 128.6, 128.8,
128.9, 129.1, 129.6, 133.3, 138.1, 138.4, 153.8, 169.4;
MS: m/z =331 [M]+.
1-((2,5-Dimethoxyphenyl)(2-hydroxynaphthalen-1-yl)methyl)urea
(Table 3, entry 4). Pale yellow solid; M.p: 207–209°C;
Yield: 84%; IR (KBr): υ 3493, 3386, 3082, 2994, 1662,
1
1529, 1495, 1271cmÀ1; H NMR (400 MHz, DMSO-d6):
δ 3.49 (s, 3H, —OCH3), 3.65 (s, 3H, —OCH3), 4.29 (brs,
2H, —NH2), 6.74 (s, 1H, ArH), 6.80 (d, 1H, J= 9.2 Hz,
—CH aliphatic), 7.12 (d, 2H, J = 8.4 Hz, ArH), 7.19 (d,
1H, J = 8.4Hz, ArH), 7.25 (t, 1H, J = 7.4 Hz, ArH), 7.42
(t, 1H, J = 7.6Hz, ArH), 7.69 (d, 1H, J= 8.8 Hz, ArH),
7.76 (d, 1H, J = 8.0 Hz, ArH), 8.18 (d, 1H, J= 8.8 Hz,
ArH), 8.34 (d, 1H, J= 8.4 Hz, —NH), 9.83 (brs, 1H,
—OH); 13C NMR (100 MHz, DMSO-d6): δ 44.8, 55.7,
56.3, 111.4, 112.2, 116.3, 119.0, 119.3, 122.6, 123.8,
126.2, 128.6, 128.7, 129.1, 132.1, 133.0, 151.2, 153.2,
153.7, 168.8; MS: m/z = 352 [M]+.
N-((2,5-dimethoxyphenyl)(2-hydroxynaphthalen-1-yl)methyl)
benzamide (Table 3, entry 17). Yellow solid; M.p: 269–271°C;
Yield: 94%; IR (KBr): υ 3420, 3160, 3065, 2993, 1640,
1577, 1526, 1492, 1275 cmÀ1 1H NMR (400 MHz,
;
DMSO-d6): δ 3.61 (s, 3H, —CH3), 3.66 (s, 3H, —CH3),
6.79 (d, 1H, J = 3.2 Hz, ArH), 6.90 (d, 1H, J = 8.8 Hz,
—CH aliphatic), 7.08 (s, 1H, ArH), 7.20 (d, 1H,
J = 8.8 Hz, ArH), 7.28 (t, 1H, J = 7.4 Hz, ArH), 7.45 (t,
4H, J = 6.4 Hz, ArH), 7.52 (d, 1H, J = 7.2 Hz, ArH), 7.74
(d, 1H, J = 8.8 Hz, ArH), 7.79 (d, 1H, J = 8.4 Hz, ArH),
7.84 (d, 2H, J= 7.2 Hz, ArH), 8.26 (d, 1H, J= 8.8 Hz, ArH),
8.83 (d, 1H, J=8.0Hz, —NH), 10.17 (brs, 1H, —OH); 13C
NMR (100MHz, DMSO-d6): δ 45.7, 55.6, 56.6, 111.9,
112.5, 116.4, 119.0, 119.2, 122.9, 123.6, 126.5, 127.6,
1-(1-(2-Hydroxynaphthalen-1-yl)-2-methyl-3-phenylallyl)urea
(Table 3, entry 6). Yellow solid; M.p: 280–282°C; Yield:
90%; IR (KBr): υ 3513, 3383, 3271, 3064, 2969, 1659,
1
1600, 1230cmÀ1; H NMR (400MHz, DMSO-d6): δ 1.10
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2015
Synthesis of Amidoalkyl Naphthol Derivatives
128.7, 128.8, 128.9, 129.4, 131.3, 131.6, 132.9, 135.0,
151.3, 153.3, 153.7, 165.4; MS: m/z=413 [M]+.
(brs, 1H, —OH); 13C NMR (100MHz, DMSO-d6): δ
49.5, 118.7, 119.1, 123.2, 127.0, 127.1, 127.3, 127.5,
127.6, 127.8, 128.8, 129.0, 129.1, 129.4, 129.9, 131.9,
132.8, 134.7, 139.0, 140.4, 141.7, 153.7,166.2; MS:
m/z = 429 [M]+.
N-((2-hydroxynaphthalen-1-yl)(naphthalen-1-yl)methyl)benza-
mide (Table 3, entry 18). White solid; M.p: 293–295°C;
Yield: (nano molten salt: 95%, nano SnO2: 85%); IR (KBr):
1
υ 3424, 3128, 3031, 1629, 1536, 1342, 1250cmÀ1; H
NMR (400 MHz, DMSO-d6): δ 7.28 (d, 1H, J= 3.6 Hz,
—CH aliphatic), 7.30 (d, 1H, J =5.2 Hz, ArH), 7.40 (t, 3H,
J =6.0 Hz, ArH), 7.44 (d, 2H, J= 7.6 Hz, ArH), 7.51 (t, 1H,
J =7.2 Hz, ArH), 7.57 (d, 2H, J= 8.0 Hz, ArH), 7.85 (t, 4H,
J =8.2 Hz, ArH), 7.90 (d, 1H, J = 7.2 Hz, ArH), 7.95 (d, 1H,
J =8.0 Hz, ArH), 7.99 (d, 1H, J = 8.0 Hz, ArH), 8.09 (d, 1H,
J =7.6 Hz, ArH), 8.27 (d, 1H, J = 8.0 Hz, ArH), 9.26 (d, 1H,
J =8.4 Hz, —NH), 10.22 (brs, 1H, —OH); 13C NMR
(100 MHz, DMSO-d6): δ 48.4, 118.3, 119.2, 122.9, 123.9,
125.7, 126.1, 126.5, 126.9, 127.9, 128.4, 128.7, 129.0,
129.1, 129.2, 129.8, 131.7, 131.8, 133.3, 134.1, 134.7,
136.7, 154.1, 165.8; MS: m/z = 403 [M]+.
Acknowledgments. Financial support of this work from the Research
Council of University of Mazandran gratefully acknowledged.
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N-(1-(2-hydroxynaphthalen-1-yl)-2-methyl-3-phenylallyl)benza-
mide (Table 3, entry 19). Yellow solid; M.p: 243–245°C;
Yield: 92%; IR (KBr): υ 3419, 3065, 3026, 2905, 1629,
1
1514, 1340, 1272cmÀ1; H NMR (400 MHz, DMSO-d6):
δ 1.87 (s, 3H, —CH3), 6.40 (s, 1H, —CH), 6.75 (d, 1H,
J =8.4 Hz, —CH aliphatic), 7.20 (t, 3H, J= 7.0 Hz, ArH),
7.25 (d, 1H, J= 8.8 Hz, ArH), 7.31 (t, 3H, J= 5.8 Hz,
ArH), 7.49 (d, 2H, J =7.6 Hz, ArH), 7.54 (d, 2H,
J =7.2 Hz, ArH), 7.81 (t, 2H, J= 9.6 Hz, ArH), 7.86 (d,
2H, J = 7.2Hz, ArH), 8.22 (d, 1H, J = 8.4 Hz, ArH), 8.82
(d, 1H, J = 8.4Hz, —NH), 10.20 (brs, 1H, —OH); 13C
NMR (100 MHz, DMSO-d6): δ 16.7, 53.1, 117.5, 119.1,
123.0, 123.4, 124.8, 126.7, 126.9, 127.6, 128.6, 128.8,
128.9, 129.0, 129.1, 129.7, 131.7, 133.2, 134.9, 137.8,
137.9, 153.9, 166.2; MS: m/z = 393 [M]+.
N-(biphenyl-4-yl(2-hydroxynaphthalen-1-yl)methyl)benzamide
(Table 3, entry 24). White solid; M.p: 281–283C; Yield:
(nano molten salt: 96%, nano SnO2: 86%); IR (KBr): υ
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3414, 3071, 3026, 2940, 1631, 1538, 1342 cmÀ1 1H
;
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—CH aliphatic), 7.33 (d, 2H, J = 7.2 Hz, ArH), 7.38 (t,
3H, J = 7.4Hz, ArH), 7.45 (t, 2H, J = 7.6 Hz, ArH), 7.51
(t, 3H, J = 7.4Hz, ArH), 7.61 (d, 5H, J= 8.8 Hz, ArH),
7.83 (d, 1H, J = 8.8 Hz, ArH), 7.87 (d, 1H, J = 7.62Hz,
ArH), 7.90 (d, 2H, J =8.4 Hz, ArH), 8.15 (d, 1H,
J =8.4 Hz, ArH), 9.10 (d, 1H, J = 8.8 Hz, —NH), 10.41
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet