Role of surfactant and micelle-promoted mild, efficient, sustainable synthesis of 2-aminobenzothiazolomethyl naphthols and 5-(2-aminobenzothiazolomethyl)-6-hydroxyquinolines in water at room temperature

Article abstract of DOI:10.1039/c4ra03847a

A new green protocol for the efficient surfactant catalyzed synthesis of 2-aminobenzothiazolomethyl naphthols and 5-(2-aminobenzothiazolomethyl)-6-hydroxyquinolines from substituted aromatic aldehydes, 2-aminobenzothiazole and 2-naphthol or 6-hydroxyquino

Full text of DOI:10.1039/c4ra03847a

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Role of surfactant and micelle-promoted mild,
efficient, sustainable synthesis of 2-
Cite this: RSC Adv., 2014, 4, 40414
aminobenzothiazolomethyl naphthols and 5-(2-
aminobenzothiazolomethyl)-6-hydroxyquinolines
in water at room temperature
ab
Praveen K. Sahuab and Dau D. Agarwalab
*
Pramod K. Sahu,
A new green protocol for the efficient surfactant catalyzed synthesis of 2-aminobenzothiazolomethyl
naphthols and 5-(2-aminobenzothiazolomethyl)-6-hydroxyquinolines from substituted aromatic
aldehydes, 2-aminobenzothiazole and 2-naphthol or 6-hydroxyquinoline at room temperature in water
was developed for the first time. The influence of the sodium lauryl sulphate (SLS) micelles and their
different concentrations on reactivity of 2-aminobenzothiazolomethyl naphthol was studied. It was
found that best yield was obtained with 10 mol% catalyst loading with minimum time as compared to
when other surfactants and catalysts were used. The best yield of product was achieved by using 10
mol% of SLS. This procedure resulted in a general and environmentally benign protocol and has the
advantages of better reusability of the catalyst system, excellent yield, short reaction time and ease of
work up.
Received 27th April 2014
Accepted 14th August 2014
DOI: 10.1039/c4ra03847a
www.rsc.org/advances
to combinatorial synthesis and modular manner. In addition,
the implementation of several transformations in a single
Introduction
manipulation is highly compatible with the goals of sustainable
and “green” chemistry.6–12
Designing new drugs is based on the development of hybrid
molecules by combining different pharmacophore fragments in
a single structure, which may lead to compounds with inter-
esting biological proles. As pathogenic bacteria continuously
evolve the mechanism of resistance to currently used antibac-
terials, so the discovery of novel and potent antibacterial drugs
is the best way to overcome bacterial resistance and to develop
effective therapies.1 The scaffold decoration of bioactive mole-
cules represents one of the most vibrant research areas in
organic chemistry and has a rich history within the realm of
fragment-based drug design. o-Quinone methides (o-QMs) are
highly reactive, transient species that have been applied as
intermediates in the synthesis of several natural compounds
including avonoids, isoavans, chromenes and benzopyr-
anes.2–5 Multicomponent reactions have been rened in recent
years into a powerful and useful tool in synthetic chemistry.
Such processes enable the rapid elaboration of complex struc-
tures in a highly efficient, higher yield than almost any
sequential synthesis of the same target, a single purication
step, time and energy saving, low expenditures, easy adaptation
The ‘greening’ of global chemical processes has became a
major issue in the chemical industry.13 As a consequence, in
recent year much effort has been directed toward the use of water
as solvent for organic reactions.14–21 Drawback of solubility of
organic compounds can be solve by using surfactant. Literature
survey shows that many transformations have been promoted by
using the sodium dodecyl sulfate. Therefore safe, clean and
environmentally benign approach is well appreciable.22 Shaabani
et al. have synthesized the 2-aminobenzothiazolomethyl naphthol
and 5-(2-aminobenzothiazolomethyl)-6-hydroxyquinolin deriva-
tives with drawback such as long reaction time and large quantity
of catalyst at 90 ꢀC.23 Researcher have synthesized these
compounds with many drawbacks such as higher catalyst loading,
low yield, higher reaction temperature and no reusability of
catalyst.24 There is need to develop sustainable environmentally
benign method. The development of simple and efficient chem-
ical processes or methodologies for the synthesis of biologically
active compounds in water is one of the major challenges for
chemists, although water is a safe, very cheap, readily available,
and environmentally benign solvent.25 Although today's environ-
mental consciousness imposes the use of water as a solvent on
both industrial and academic chemists, organic solvents are still
used instead of water for mainly two reasons. First, most organic
substances are insoluble in water, and as a result, water does not
aSchool of Studies in Chemistry, Jiwaji University, Gwalior-474011, Madhya Pradesh,
India. E-mail: sahu.chemistry@gmail.com; researchdata6@gmail.com; Tel:
+91-9993932425; +91-8826757921
bDepartment of Industrial Chemistry, Jiwaji University, Gwalior-474011, Madhya
Pradesh, India
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Table
1
Effect of different solvents on synthesis of 2-amino-
benzothiazolomethyl naphthol derivativesa
Entry
Solvents (10 ml)
Time (h)
Yieldb (%)
1
2
3
4
5
6
7
8
9
Water
8
24
24
24
24
24
24
24
24
78
0
0
0
0
0
0
0
5
Dichloromethane
Methanol
Ethanol
Acetonitrile
Chloroform
Toluene
Hexane
—
a
Reaction was carried out without catalyst with 2-amino benzothiazole
(0.005 mol), 2-naphthol (0.005 mol) and benzaldehyde (0.005 mol).
Isolated yield.
b
other catalysts and it was remains constant thereaer. The
yield with respect to time in the presence of SLS at xed
concentration of SLS is shown in Table 2. The surfactant
concentration employed played a vital role in the outcome of
the reaction. From Table 2 also suggests that 10 mol% of the
sodium lauryl sulphate (SLS) gave the highest yield of target
product. Higher quantity of catalyst neither increases the
yield nor reduces the conversion time. So, 10 mol% of catalyst
was found to be the optimal quantity for promoting the
reaction. The extent of reaction is strongly dependent on
nature of surfactant. It was found that the type of surfactant
inuenced the yield, and that Triton X-100, a nonionic
surfactant, was effective (but required longer reaction time),
while signicant yield was obtained by cetrimide. Although
cetrimide was an effective promoter and could be a good
choice for synthesis, we discarded it because it is an expensive
reagent and toxic to marine organisms.
Scheme 1 Condition (i) SLS/cetrimide/Triton X-100 (10 mol%) used as
catalyst in water at room temperature.
function as a reaction medium. Second, many reactive substrates,
reagents, and catalysts are decomposed or deactivated by water.
Some of these problems were solved with the discovery of
surfactant combined catalysts by Kobayashi et al.26 Therefore,
three-component reaction which exploits different surfactants as
catalyst in water could reveal an ideal methodology, provided that
the catalyst shows high catalytic activity in water. Herein rst
time, we report the surfactant micellar catalyzed synthesis of
2-aminobenzothiazolomethyl naphthols and 5-(2-amino-
benzothiazolomethyl)-6-hydroxyquinolines by three-component
reaction of aldehydes, 2-aminobenzothiazole and 2-naphthol or
6-hydroxyquinoline in water at room temperature (Scheme 1).
The effectiveness of the anionic surfactant is attributed to a
high local concentration of sodium cation on the surfaces of
dispersed phases, which are surrounded by the surfactant
molecules. The highest yield of product was 93%, 86% and 85%
Results and discussion
To optimize the reaction conditions, rst of all we studied the
effect of different solvents. Table 1 showed that among all
solvent, reaction was well tolerate in water with signicant
yield isolated in comparable with short reaction time. That's
why water was chosen as solvent for further studies and all
catalyst has used in aqueous medium. From the viewpoint of
today's environmental consciousness, however, it is desirable
to avoid the use of harmful organic solvents. Therefore, we
next initiated investigations to develop a new system for
surfactant catalyzed reactions in water without using organic
solvents.
The main drawback in the use of water (low solubility of
most organic substances in water) could be overcome by using
surfactants, which solubilize organic materials or form
emulsions with them in water. To address this solubility
issue, therefore, we planned to use surfactants hopefully
small amounts of them for the surfactant catalyzed reactions
in water.
Table 2 Effect of different catalysts at room temperature in water
Entry Catalysts
Time (min) Yielda (%)
1
2
3
4
5
6
7
8
L-Proline (10 mol%)
170
180
150
120
115
180
180
82
71
84
93
93
86
85
74
71
65
79
72
75
78
76
Sodium lauryl sulphate (2 mol%)
Sodium lauryl sulphate (5 mol%)
Sodium lauryl sulphate (10 mol%)
Sodium lauryl sulphate (15 mol%)
Cetrimide (10 mol%)
Triton X-100 (10 mol%)
p-Toluene sulphonic acid (10 mol%) 130
KCl
Mg(NO3)2 (10 mol%)
CaCl2 (10 mol%)
Montmorillonite K-10 (100 mg)
LiBr (10 mol%)
H2SO4 (10 mol%)
Sulphamic acid (10 mol%)
9
140
160
150
160
140
160
180
10
11
12
13
14
15
It was found that maximum yield was obtained by surfac-
tants in aqueous medium aer 2–3 hours as compared to
a
Isolated yield.
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Fig. 3 Comparison of reusability of different surfactants.
Fig. 1 Conversion of product with respect to time.
Aer optimization of reaction conditions the reaction was
carried out with various aromatic aldehydes, 2-naphthol or
6-hydroxyquinoline and 2-aminobenzothiazole to afford the
substituted 2-aminobenzothiazolomethyl naphthol and 5-(2-
with SLS, cetrimide and Triton X-100 respectively. Fig. 1 also
showed that better yield was obtained with SLS and compara-
tively takes lower time as compared to other surfactants used.
To gain the effect of mol% of sodium lauryl sulphate (SLS) as
catalysts on their catalytic activities, different mol% of SLS
ranging from 2 to 15 mol% were studied in three component
reaction. The results are shown in Fig. 2. As mol% of SLS was
raised from 2 to 10, yield of target product was increased.
However, by increasing the mol% from 10 to 15, a signicant
change in yield was not observed. Highest yield and conversion
was obtained with 10 mol% of SLS as 93 and 96 respectively.
Conversion of product has been determined by HPLC analysis.
aminobenzothiazolomethyl)-6-hydroxyquinoline
derivatives.
Catalytic activity of SLS has been explored for the synthesis of
these derivatives at room temperature in aqueous medium,
results are incorporated in Table 3. Table 3 revealed that reac-
tion proceeded efficiently with para substituted aldehydes with
good yield whereas ortho and meta substituted aldehydes gave
the slightly lower yield comparatively to para substituted
aldehydes.
Characterization of synthesized compounds
2-Aminobenzothiazolo-phenylmethyl-2-naphthol
derivatives
were characterized by IR, 1H NMR, 13C NMR and mass spectra.
IR spectra of all derivatives show peaks between 3200–
3600 cmÀ1 due to hydroxyl group stretching, peak between 2864
and 2916 cmÀ1 due to C–Hstr of benzene ring, peak between
1500–1600 cmÀ1 can be assign for C]Cstr. A peak around
1400 cmÀ1 and 1200 cmÀ1 can be assign for N–Hben and C–Nstr
respectively. 1H NMR of compound 5a showed the multiplet
between 6.96–7.93 d due to 16 hydrogen of which 15 hydrogen of
benzene rings and one aliphatic hydrogen of –CH. Singlet at
8.67 d and 10.11 d arise due to hydrogen attached with nitrogen
and hydroxyl group. Derivatives 5e has containing hydroxyl
moiety on aldehyde, show singlet at 10.34 d. Compound 5f
having methoxy group as substituent on aldehyde, reveal singlet
at 3.69 d. Methyl containing derivative 5g conrm the singlet for
at 2.23 d for corresponding group. Mass spectra of all
compound showed corresponding molecular ion peaks in mass
spectra.
Reusability of catalytic system
Reusability of this catalyst system is an advantage over the other
that catalyst which is a critical issue from environment point of
view. Catalyst was reused four times without loss of appreciable
yield (Fig. 3) which is within handling losses expected during
workup. From Fig. 3, it is clear that SLS shows the better reus-
ability among other surfactants. Thus, considering the effects of
reaction time, solvent effects and catalyst loading, ensuing
studies on the exploration of substrate were performed at room
temperature using a catalytic amount (10 mol%) of SLS as
catalyst. Overall results obtained with SLS were better among
other catalysts and surfactants, so choose this surfactant for
further investigation and studies.
Role of surfactants
The catalytic effect of the micellar solution of may be attributed
to the hydrophobic nature of organic substrates. Formation of
emulsion droplets takes place in water in the presence of
surfactant and substrate molecules. It is suggested that most of
the organic substrates are concentrated in these spherical
droplets, which act as a hydrophobic reaction sites and results
in an increase in the effective concentration of the organic
reactants. In micellar solution, organic substrates are pushed
away from water molecules towards the hydrophobic core of
Fig. 2 Effect of mol% of SLS on conversion and yield.
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Table 3 Synthesis of 2-aminobenzothiazolomethyl naphthols and 5-(2-aminobenzothiazolomethyl)-6-hydroxyquinolines
SLS catalyzed
Time (min)
M.P. (ꢀC)
Found
R
X
Product
Yield (%)
Reported
H
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
N
5a
5b
5c
5d
5e
5f
5g
5h
5i
5j
5k
5l
5m
5n
5o
120
120
100
120
120
100
120
100
140
110
140
140
140
140
140
93
92
94
93
89
96
94
95
79
86
75
82
86
79
88
203–204
174–175
192–194
190–192
162–163
172–173
180–181
208–209
188–190
>250
197–198
209–210
193–194
180–181
208–209
204–205 (ref. 23)
4-OH-3-OCH3
4-N(CH3)2
4-NO2
2-OH
4-OCH3
4-CH3
4-Cl
189–191 (ref. 24a)
175–176 (ref. 23)
182–183 (ref. 23)
209–210 (ref. 23)
3-OH
2,4-Cl2
3-NO2
H
4-CH3
3-NO2
4-Cl
198–199 (ref. 23)
211–212 (ref. 23)
195–196 (ref. 23)
184–186 (ref. 23)
209–210 (ref. 23)
N
N
N
micelle droplets thus inducing efficient collisions between
organic substrates which eventually enhance the reaction rate
and result in rapid reactions in water.26,27
Mechanism and role of aqueous medium
We speculate that in the presence of organic substrates, SLS
molecules form stable colloidal particles in which the surfac-
tant moiety of the SLS surrounds the organic substrates and the
counter cations are attracted to the surface of the particles
through electrostatic interactions between the anionic surfac-
tant molecules. Although each sodium cation is hydrated by
several water molecules, they can be readily replaced by a
substrate because of the high exchange rate of sodium for
substitution of inner sphere water ligands.28 The substrates to
be activated move to the interface from the organic phase,
coordinate to the cations, and then react with nucleophilic
substances there. The hydrophobic interior of the micelles
swily excludes the water molecules generated during the
reaction, thus shiing the equilibrium towards the desired
product that ultimately leads to an increase in the reaction
yield.29,30
According to results found above, SLS worked well only in
water (Table 2). A comparable study of different solvents in the
three component reaction revealed that the reaction in water
was faster. In addition, the reaction under neat conditions was
slower than that in water and resulted in a lower yield (5%,
Table 1, entry 9), showing the advantage of the use of water in
this reaction.
Fig. 4 Micelle formation detected by light microscopy.
Plausible reaction mechanism
We proposed a possible pathway for one-pot three component
reaction (Scheme 2). Most probably the reaction proceeds
through the formation of an o-QM intermediate followed by
Michael addition by 2-aminobenzothiazole (2-ABT) to give the
desired product. Conrmation of involvement of o-QM and
imine as intermediates for synthesis of product has been
ruled out by examining the corresponding intermediate in situ
with further addition of 2-ABT and 2-naphthol and it was
found that imine intermediate did not form the product
which is also supported by literature.24,36 This observation
show the mechanism follow by o-QM intermediate. Thus, the
micelle intervention consists probably of the concentration
and disposition of the chemical species where the exterior
coat of the SDS micelle structure would strongly bind to all the
reactants (precursors and intermediaries) as well as the nal
product according to its structural features and electrostatic
interactions. Therefore, our proposed scheme is explained in
terms of the anionic SDS micelle nature and the concentra-
tion effect (hydrophobic interaction between reactants and
aqueous medium).37,38
In the SLS-catalyzed reactions stated in this article, most of
the reaction mixtures became turbid, and formation of these
colloidal dispersions is a characteristic feature for the present
reaction system. Thus, we have tried to observe the SLS-induced
colloidal particles. This observation implies the formation of
micelle or micelle like colloidal aggregates, analyzing an aliquot
of the reaction mixture, we observed that the spherical particles
were clearly formed which is supported by literature (Fig. 4).31–35
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Scheme 2 Plausible reaction mechanism.
determined in open capillaries and are uncorrected. AR grade of
2-naphthol, aldehydes, SLS, cetrimide, Triton X-100 and other
catalysts were purchased from HiMedia Laboratory Ltd.,
Mumbai, India. 2-Amino benzothiazole was purchased from
Sigma Aldrich.
Conclusion
We have developed an efficacious and green approach
for synthesis of substituted 2-aminobenzothiazolomethyl
naphthols and 5-(2-aminobenzothiazolomethyl)-6-hydroxy-
quinolines via three component reaction of aromatic aldehydes,
2-naphthol or 6-hydroxyquinoline and 2-amino benzothiazole.
Surfactant catalyze the reaction efficiently at room temperature
with reusability of catalyst system, simple work up procedure,
neutral conditions (suitable for acid and base sensitive
substrates), without use of any harmful organic reagents and
solvents, excellent yield and short reaction time makes the
method advantageous over other catalyst. Water as a solvent is
not only inexpensive and environmentally benign, it also plays a
distinguished role in reactivity and good catalytic activity of SLS.
This study has provide a rather mild procedure for synthesis,
SLS has advantages that low quantity promote the reaction,
easily availability of reactants, biodegradability and catalyst
provide direct access to 2-aminobenzothiazolomethyl naphthol
and 5-(2-aminobenzothiazolomethyl)-6-hydroxyquinoline deriv-
atives. This is rst attempt to synthesis of amino-
benzothiazolomethyl naphthols derivatives using surfactant in
water at room temperature.
One-pot three-component reaction
Typical procedure. A mixture of substituted aromatic alde-
hydes (0.005 mol), 2-naphthol or 6-hydroxyquinoline (0.005
mol), and 2-amino benzothiazole (0.005 mol) were stirrer at
room temperature in water (10 ml) using SLS/cetrimide/Triton
X-100 as catalyst (10 mol%). The reaction was monitored by TLC
(ethyl acetate–hexane; 8 : 2). Aer completion of the reaction,
the reaction mixture was cooled to room temperature and solid
mass was ltered then washed with water. Filtrate water con-
taining catalyst was rescued for the next run. The crude prod-
ucts were puried by recrystallization from acetone–water
(10 : 1).
Reusability of catalyst. Filtrate water containing catalyst was
reused for four times as such with a mixture of aldehydes
(0.005 mol), 2-naphthol (0.005 mol), and 2-amino benzothiazole
(0.005 mol) under optimized reaction conditions.
1-((Benzo[d]thiazol-2-ylamino)(phenyl)methyl)naphthalene-2-ol
(5a). White powder, mp 203–204 ꢀC, IR (KBr) (nmax, cmÀ1): 3381
(OHstr), 1599 (C]Cstr), 1542 (N–Hben), 1515 (C–Hben), 1449
(C–Hben); 1H NMR (400 MHz, DMSO): dH 6.96–7.93 (16H, m,
Materials and methods
Experimental
The 1H NMR spectra were measured using BRUKER AVANCE II 15H-arom and 1H–CH), 8.67 (1H, s, NH), 10.11 (1H, s, OH); 13
C
400 NMR spectrometer with tetramethylsilane as an internal NMR (100 MHz, DMSO): 53.36, 118.02, 118.57, 118.81, 120.49,
standard at 20–25 ꢀC; data for 1H NMR are reported as follows: 120.84, 122.27, 123.58, 125.23, 126.04, 127.83, 128.34, 128.56,
chemical shi (ppm), integration, multiplicity (s, singlet; d, 129.28, 130.59, 132.12, 142.25, 151.96, 153.19, 166.33; ESI-MS:
doublet; t, triplet; q, quartet; m, multiplet, and br, broad), m/z calculated for C24H18N2OS 382; found [M + H]+ 283.3.
coupling constant (Hz). IR spectra were recorded by SHI-
1-((Benzo[d]thiazol-2-ylamino)(4-nitro phenyl)methyl)naphtha-
MADZU; IR spectrometer of sample dispersed in KBr pellet or lene (5d). White powder, mp 120–122 ꢀC; IR (KBr) (nmax, cmÀ1):
Nujol is reported in terms of frequency of absorption (cmÀ1). E- 3348 (OHstr), 2933 (C–Hstr), 1625 (C]Cstr), 1510 (N–Hben), 1267
Merck pre-coated TLC plates, RANKEM silica gel G for prepar- (C–Nstr), 962–812 (C–Hdef); 1H NMR (400 MHz, DMSO): dH 6.88–
ative thin-layer chromatography were used. Melting points were 8.25 (15H, m, 14H-arom and –CH), 8.65 (1H, s, NH), 10.00 (1H, s,
40418 | RSC Adv., 2014, 4, 40414–40420
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OH); 13C NMR (100 MHz, DMSO): 53.43, 117.47, 117.81, 118.31,
118.58, 119.59, 120.41, 121.46, 122.54, 122.91, 123.24, 122.98,
125.20, 125.33, 126.65, 127.32, 128.57, 128.98, 129.89, 145.99,
150.68, 153.38, 166.69; ESI-MS: m/z calculated for C24H17N3O3S
427.2; found [M + H]+ 428.1.
3 S. H. Mashraqui, M. B. Patil, H. D. Mistry, S. Ghadigaonkar
and A. Meetsmay, Chem. Lett., 2004, 33, 1058.
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5075.
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Adv. Synth. Catal., 2004, 346, 607.
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S. Mathen and L. Balagopal, Acc. Chem. Res., 2003, 36, 899.
8 D. J. Ramon and M. Yus, Angew. Chem., Int. Ed., 2005, 44,
1602.
1-((Benzo[d]thiazol-2-ylamino)(2-hydroxy phenyl)methyl)naph-
ꢀ
thalene (5e). Off white powder, mp 162–163 C; IR (KBr) (nmax
,
cmÀ1): 3504 (OHstr), 2941 (C–Hstr), 1627 (C]Cstr), 1508
1
(N–Hben), 1280 (C–Nstr), 962–813 (C–Hdef); H NMR (400 MHz,
DMSO): dH 6.68–8.13 (15H, m, 14H-arom and –CH), 8.68 (1H, s,
NH), 10.04 (1H, s, OH), 10.34 (1H, s, OH); 13C NMR (100 MHz,
DMSO): 51.82, 116.74, 116.95, 117.76, 118.84, 119.40, 120.60,
9 A. A. Domling, Chem. Rev., 2006, 106, 17.
121.11, 121.24, 125.54, 122.52, 126.31, 128.20, 128.98, 129.80, 10 A. Domling and I. Ugi, Angew. Chem., 2000, 112, 3300.
131.73, 132.12, 136.31, 150.86, 152.65, 154.47, 160.83, 166.54; 11 L. F. Tietze and A. Modi, Med. Res. Rev., 2000, 20, 304.
ESI-MS: m/z calculated for C24H18N2O2S 398.2; found [M + H]+ 12 J. Zhu, Eur. J. Org. Chem., 2003, 1133.
399.1.
1-((Benzo[d]thiazol-2-ylamino)(4-methoxy phenyl)methyl)naph-
13 (a) R. T. Baker and W. Tumas, Science, 1999, 284, 1477; (b)
P. T. Anastas and J. C. Warner, Green Chemistry: Theory and
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J. Haggin, Chem. Eng. News, 1994, 72, 22; (d)
E. M. Kirschner, Chem. Eng. News, 1994, 72, 13; (e)
D. L. Illman, Chem. Eng. News, 1994, 72, 22.
ꢀ
thalene (5f). Off white powder, mp 172–173 C; IR (KBr) (nmax
,
cmÀ1): 3510 (OHstr), 3012 (C–Hstr), 2922 (C–Hstr), 1625 (C]Cstr),
1500 (N–Hben), 1278 (C–Nstr); 1H NMR (400 MHz, DMSO): dH
3.69 (3H, s, OCH3), 6.69–7.97 (15H, m, 14H-arom and –CH), 8.51
(1H, s, NH), 10.53 (1H, s, OH); 13C NMR (100 MHz, DMSO): 14 N. Azizi, A. K. Amiri, R. Baghi, M. Bolourtchian and
54.81, 113.33, 118.11, 119.03, 119.12, 120.58, 122.53, 125.52, M. M. Hashemi, Monatsh. Chem., 2009, 140, 1471.
126.22, 127.42, 128.47, 128.79, 129.38, 130.22, 132.16, 133.56, 15 P. A. Grieco, Organic synthesis in water, Blackie Academic and
151.69, 153.35, 158.00, 166.84; ESI-MS: m/z calculated for
25H20N2O2S 412.2; found [M + H]+ 413.1.
Professional, 1998.
16 C. J. Li, Chem. Rev., 1993, 93, 2023.
C
1-((Benzo[d]thiazol-2-ylamino)(4-methyl phenyl)methyl)naph- 17 C. J. Li, Chem. Rev., 2005, 105, 3095.
thalene (5g). White powder, mp 180–181 ꢀC; IR (KBr) (nmax
cmÀ1): 3007 (C–Hstr), 2922 (C–Hstr), 1625 (C]Cstr), 1510
,
18 C. J. Li and T. H. Chan, Organic reaction in aqueous media,
Wiley New York, 1997.
(N–Hben), 1267 (C–Nstr); 1H NMR (400 MHz, DMSO): dH 2.23 19 M. C. Pirrung and K. D. Sarma, J. Am. Chem. Soc., 2004, 126,
(3H, s, CH3), 6.95–8.10 (15H, m, 14H-arom and –CH), 8.66
(1H, s, NH), 10.14 (1H, s, OH); 13C NMR (100 MHz, DMSO): 20 A. Shaabani, A. Rahmati, A. H. Rezayan, M. Darvishi, Z. Badri
20.60, 53.33, 118.00, 118.66, 118.92, 120.51, 120.85, 122.27, and A. Sarvari, QSAR Comb. Sci., 2007, 26, 973.
125.26, 126.03, 128.34, 128.50, 128.60, 129.22, 130.55, 132.13, 21 W. Wei, C. C. K. Keh, C. J. Li and R. S. Varma, Environ. Sci.
444.
135.17, 139.13, 151.97, 153.20, 166.39; ESI-MS: m/z calculated
Policy, 2004, 6, 250.
for C25H20N2OS 396.2; found [M]+ 396.1.
22 (a) Y. Mori, K. Kakumoto, K. Manabe and S. Kobayashi,
Tetrahedron Lett., 2000, 41, 3107; (b) K. Manabe and
S. Kobaashi, Tetrahedron Lett., 1999, 40, 3773.
1-((Benzo[d]thiazol-2-ylamino)(4-chloro
phenyl)methyl)naph-
thalene (5h). White powder, mp 208–209 ꢀC; IR (KBr) (nmax
,
cmÀ1): 3504 (OHstr), 1627 (C]Cstr), 1267 (C–Nstr), 1122 23 A. Shaabani, A. Rahmati and E. Farhangi, Tetrahedron Lett.,
(C–Hben); 1H NMR (400 MHz, DMSO): dH 6.97–7.98 (15H, m,
14H-arom and –CH), 8.57 (1H, s, NH); 13C NMR (100 MHz, 24 (a) A. Kumar, M. S. Rao and V. K. Rao, Aust. J. Chem., 2010,
2007, 48, 7291.
DMSO): 53.48, 117.71, 118.13, 118.44, 118.96, 120.95, 121.12,
122.43, 122.47, 125.81, 126.82, 127.30, 127.78, 128.22, 129.54,
130.32, 131.39, 134.52, 138.16, 151.61, 153.28, 155.11, 166.89; ESI-
MS: m/z calculated for C24H17N2OClS 416.4; found [M + H]+ 417.2.
63, 1538; (b) M. Pariasami, S. Anwar and M. N. Reddy,
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T. Anastas and T. C. Williamson, American Chemical
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Acknowledgements
We are grateful thanks to Chandigarh and Punjab University,
Chandigarh for spectral analytical data.
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