Solvent-free one-pot synthesis of 1-carbamatoalkyl-2-naphthols by a tin tetrachloride catalyzed multicomponent reaction

Article abstract of DOI:10.1007/s00706-013-0927-5

An efficient one-pot synthesis of 1-carbamatoalkyl-2-naphthols using tin tetrachloride as a catalyst for the three-component condensation reaction of 2-naphthol, aldehydes, and carbamates under thermal, solvent-free conditions is described. This new approach has advantages such as mild conditions, short reaction time, high yield, simple work-up, and an inexpensive catalyst. Graphical Abstract: [Figure not available: see fulltext.]

Full text of DOI:10.1007/s00706-013-0927-5

Monatsh Chem (2013) 144:975–980
DOI 10.1007/s00706-013-0927-5
ORIGINAL PAPER
Solvent-free one-pot synthesis of 1-carbamatoalkyl-2-naphthols
by a tin tetrachloride catalyzed multicomponent reaction
•
•
•
Min Wang Qing L. Wang Shuang Zhao
Xin Wan
Received: 19 June 2012 / Accepted: 12 January 2013 / Published online: 26 February 2013
Ó Springer-Verlag Wien 2013
Abstract An efficient one-pot synthesis of 1-carbama-
toalkyl-2-naphthols using tin tetrachloride as a catalyst for
the three-component condensation reaction of 2-naphthol,
aldehydes, and carbamates under thermal, solvent-free
conditions is described. This new approach has advantages
such as mild conditions, short reaction time, high yield,
simple work-up, and an inexpensive catalyst.
aldehydes, and amides to form amidoalkyl naphthol
derivatives [6]. In this paper, carbamate was used as a
nucleophile instead of an amide. Moreover, carbamates can
be deprotected more easily than an amide group [7]. Car-
bamatoalkyl naphthols can be present as protected
aminonaphthol derivatives and, after deprotection, they can
allow access to compounds which cannot be synthesized
via the classical procedure. Therefore, the clean synthesis
of 1-carbamatoalkyl-2-naphthols is very important.
To the best of our knowledge, only a few works have
focused on the synthesis of 1-carbamatoalkyl-2-naphthols
[8–22]. The reported methods suffer from disadvantages
such as expensive catalysts, high temperatures, and large
excesses of raw material. Recently, tin tetrachloride
has emerged as an efficient Lewis acid for promoting
various organic transformations, such as aromatization
[23], heterocycloadditions [24], a coupling reaction [25],
rearrangement of epoxides [26], oxidation [27], ring-
opening reactions [28], and amidoalkylation [29]. As a
continuation of our research into MCRs, we report here a
facile and efficient synthetic strategy for preparing 1-car-
bamatoalkyl-2-naphthols 4 from 2-napthol (1), aldehydes 2,
and carbamates 3 in short reaction times and with excel-
lent yields using tin tetrachloride (SnCl4Á5H2O) as a
catalyst (Scheme 1). Thirteen new compounds were reported
first.
Keywords 1-Carbamatoalkyl-2-naphthol Á
Three-component reaction Á Tin compound Á
One-pot synthesis Á Solvent-free
Introduction
Multicomponent reactions (MCRs) have gained much
attention in organic synthesis, as they can furnish the
desired products in a single operation without isolating the
intermediates, thus reducing reaction times and energy
consumption [1]. Therefore, researchers have made great
efforts to find and develop new MCRs.
Compounds containing 1,3-amino-oxygenated func-
tional groups are frequently found in biologically active
natural products and potent drugs such as nucleoside
antibiotics and HIV protease inhibitors [2–4]. Furthermore,
1-amidoalkyl-2-naphthols and 1-carbamatoalkyl-2-naph-
thols are important synthetic building blocks and are used
as precursors for the synthesis of 1-aminomethyl-2-naphthol
derivatives, which exhibit important cardiovascular activ-
ity [5]. Recently, we reported the reaction of 2-naphthol,
Results and discussion
Initially, we investigated the efficiencies of different
reaction media, amounts of catalyst, and reaction temper-
atures in a model reaction of 2-naphthol (1 equiv.),
2-nitrobenzaldehyde (1 equiv.), and methyl carbamate
(1.1 equiv.) in the presence of SnCl4Á5H2O (Table 1). It
M. Wang (&) Á Q. L. Wang Á S. Zhao Á X. Wan
College of Chemistry, Chemical Engineering and Food Safety,
Bohai University, Jinzhou 121000, China
e-mail: minwangszg@yahoo.com.cn
123

976
M. Wang et al.
Scheme 1
R1
NHCO2R2
OH
1 mol%
SnCl4·5H2O
OH
R1CHO
NH2CO2R2
+
+
Solvent-free
60 °C
1
2
3
4a-4x
Table 1 Screening of reaction conditions for the condensation of
2-naphthol, 2-nitrobenzaldehyde, and methyl carbamate
Table 2 Reaction of 2-naphthol, 2-nitrobenzaldehyde, and methyl
carbamate using different acid catalysts
Entry Solvent/cm3 Catalyst/mo% Temp/°C Time/h Yield/%
Entry
Catalyst
Time/h
Yield/%
1
2
H2O (3)
2.0
2.0
70
2.0
1.0
3.0
0.1
0.1
0.25
0.3
0.2
0.1
4.0
0
7
1
SrCl2Á6H2O
3.0
3.0
3.0
8.0
3.0
8.0
2.5
1.5
0.5
1.5
0.3
0.2
0
0
EtOH (3)
Reflux
Reflux
70
2
CdCl2Á2.5H2O
Bi(NO3)3Á5H2O
HOAc
3
CH3CN (3) 2.0
49
92
91
90
90
94
87
0
3
28
43
47
51
58
60
73
78
87
94
4
–
–
–
–
–
–
–
2.0
1.0
0.5
1.0
1.0
1.0
0
4
5
70
5
Al(NO3)3Á9H2O
ZnCl2
6
70
6
7
50
7
AlCl3Á6H2O
8
60
8
Al(CH3SO3)3Á4H2O
Cu(p-CH3C6H4SO3)2Á6H2O
(NH4)2Ce(NO3)6
SnCl2Á2H2O
9
80
9
10
70
10
11
12
was found that solvent-free conditions were the best choice
(Table 1, entries 1–4). Compared with reactions carried out
in organic solvent, condensation without solvent required
only 0.1 h to furnish an excellent yield (Table 1, entry 4).
After screening several trials, the best results were obtained
with 1 mol % SnCl4Á5H2O at 60 °C (Table 1, entry 8). In
addition, no conversion to product was obtained in the
absence of catalyst, even after 4.0 h (Table 1, entry 10).
Next, the catalytic activities of several Lewis acids
(1 mol %) were compared with that of SnCl4Á5H2O in the
same model reaction at 60 °C, the results were shown in
Table 2. It could be noted that SnCl4Á5H2O was the most
efficient catalyst, since it results in the highest conversion
to the desired product in the shortest reaction time
(Table 2, entry 12).
SnCl4Á5H2O
carbamate were studied in the amidoalkylation reaction; all
of these showed good reactivity.
A possible mechanism for this transformation is pro-
posed in Scheme 2. As reported in the literature [6], the
reaction of 2-naphthol with aldehyde in the presence of an
acid catalyst is known to give ortho-quinone methide
(o-QM). The o-QM generated in situ reacted with carba-
mate via conjugate addition to form 1-carbamatoalkyl-2-
naphthol derivative 4.
Conclusion
The scope of the reaction in the presence of SnCl4Á5H2O
(1 mol %) under solvent-free conditions at 60 °C was
studied (Table 3). A variety of aromatic aldehydes and
aliphatic aldehydes, 2-naphthol, and different carbamates
(including methyl carbamate, ethyl carbamate, and benzyl
carbamate) were subjected to these reaction conditions.
Most products were obtained in good to excellent yields.
The aromatic aldehyde with an electron-withdrawing group
reacted much more easily than the aromatic aldehyde with
an electron-donating group (Table 3, entries 1–9). The
position of the substituent on the aromatic ring did not have
much of an effect on the yield of the product. The aliphatic
aldehyde failed to yield any product (Table 3, entry 10).
Besides methyl carbamate, ethyl carbamate and benzyl
In summary, SnCl4Á5H2O has been demonstrated to be a
mild and efficient catalyst for the one-pot three-component
reaction of 2-naphthol, aromatic aldehydes, and methyl/
ethyl/benzyl carbamates under solvent-free conditions at
60 °C. Most reactions proceed within short reaction times
and produce high yields. We believe that this method could
be an attractive alternative to existing methods for the
synthesis of 1-carbamatoalkyl-2-naphthols.
Experimental
Melting points were determined using an RY-1 micro-
melting point apparatus (Tianjin Tianguang Optical
123

Solvent-free one-pot synthesis of 1-carbamatoalkyl-2-naphthols
977
Table 3 Synthesis of carbamatoalkyl naphthols in the presence of SnCl4Á5H2O
Entry
R1
R2
Time/h
Product
Yield/%
M.p. (lit. m.p.)/°C
1
C6H5
Me
0.2
0.2
4a
4b
4c
4d
4e
4f
83
94
96
88
94
90
93
Trace
Trace
0
217–219 (217–218 [9])
2
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
2-ClC6H4
Me
241–243 (241–242 [10])
3
Me
0.1
244–246 (253–255 [10])
4
Me
0.1
211–213 (206–208 [18])
5
Me
0.1
218–220
6
4-ClC6H4
Me
0.1
202–204 (203–205 [10])
7
2,4-Cl2C6H3
4-CH3C6H4
4-OCH3C6H4
CH3CH2CH2
C6H5
Me
0.2
4g
4h
4i
210–212
8
Me
10.0
10.0
10.0
0.2
–
9
Me
–
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Me
4j
–
Et
4k
4l
87
90
95
90
92
93
91
89
90
94
92
90
88
87
203–204 (195–196 [16])
214–216
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
2-ClC6H4
Et
0.15
0.1
Et
4m
4n
4o
4p
4q
4r
4s
236–238
Et
0.1
229–231
Et
0.15
0.15
0.2
216–217
4-ClC6H4
Et
217–219
2,4-Cl2C6H3
C6H5
Et
196–198
CH2Ph
CH2Ph
CH2Ph
CH2Ph
CH2Ph
CH2Ph
CH2Ph
1.0
182–184 (180–182 [10])
211–213
2-NO2C6H4
3-NO2C6H4
4-NO2C6H4
2-ClC6H4
0.7
0.2
4t
206–208 (205–207 [10])
202–204
0.2
4u
4v
4w
4x
0.3
211–213
4-ClC6H4
0.5
173–175
2,4-Cl2C6H3
0.2
211–213
General procedure for the synthesis
of 1-carbamatoalkyl-2-naphthol derivatives 4
Instrument Ltd. Co., Tianjin City, China). Infrared
spectra were recorded on a Varian (Palo Alto, CA, USA)
Scimitar 2000 series Fourier transform instrument. 1H
and 13C NMR spectra were recorded on an Agilent
(Santa Clara, CA, USA) 400-MR instrument in DMSO-
d6 using TMS as an internal standard. Mass spectra were
obtained with an Agilent 1100 series LC/MSD VL ESI
instrument. Elemental analyses (C, H, N) were conducted
using the EA 2400II elemental analyzer (PerkinElmer,
Waltham, MA, USA), and the results obtained were
found to be in good agreement ( 0.3 %) with the cal-
culated values.
SnCl4Á5H2O (0.05 mmol) was added to a mixture of
2-naphthol (1, 5 mmol), aldehyde 2 (5 mmol), and carba-
mate 3 (5.5 mmol). The reaction mixture was magnetically
stirred at 60 °C in a water bath and the reaction was fol-
lowed by TLC. After completion, the mixture was cooled
to room temperature, washed with cold water, and recrys-
tallized from aqueous EtOH (60 %, v/v). The products
1
were characterized by IR, H NMR, 13C NMR, LC/MS,
and elemental analysis.
Scheme 2
R2O
R1
O
Ar
H
NH
OH
NH2CO2R2
SnCl4
R1CHO
SnCl4
O
OH
o-QM
4
123

978
M. Wang et al.
Methyl [(2-chlorophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4e, C19H16ClNO3)
CH), 4.08 (q, 2H, J = 6.8 Hz, CH2), 1.18 (t, 3H, J =
6.8 Hz, CH3) ppm; 13C NMR (125 MHz, DMSO-d6): d =
156.7, 153.5, 148.1, 145.5, 133.2, 132.3, 130.3, 130.1,
129.1, 128.7, 127.2, 123.5, 123.1, 121.9, 120.9, 118.8,
118.3, 60.7, 50.3, 15.0 ppm; LC/MS: m/z (%) = 365
[(M–H)-, 100].
ꢀ
White solid; IR (KBr): m = 3,431, 3,220, 1,690, 1,527,
1
1,340, 1,052, 819, 753, 706 cm-1; H NMR (400 MHz,
DMSO-d6): d = 9.96 (s, 1H, OH), 8.04 (d, 1H,
J = 8.2 Hz, NH), 7.86 (d, 1H, J = 7.1 Hz, ArH), 7.77
(dd, 2H, J = 17.4, 8.3 Hz, ArH), 7.52 (d, 1H, J = 4.6 Hz,
ArH), 7.40 (dd, 2H, J = 12.3, 6.8 Hz, ArH), 7.26 (d, 3H,
J = 13.9 Hz, ArH), 7.16 (d, 1H, J = 8.6 Hz, ArH), 6.91
(d, 1H, J = 7.8 Hz, CH), 3.54 (s, 3H, OCH3) ppm; 13C
NMR (125 MHz, DMSO-d6): d = 156.5, 153.9, 139.8,
133.0, 132.9, 130.3, 129.9, 129.7, 129.0, 128.8, 128.7,
126.9, 126.7, 123.3, 122.7, 119.0, 117.4, 51.9, 50.1 ppm;
LC/MS: m/z (%) = 340 [(M–H)-, 100].
Ethyl [(4-nitrophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4n, C20H18N2O5)
ꢀ
White solid; IR (KBr): m = 3,430, 3,185, 1,685, 1,518,
1
1,350, 1,049, 821, 739, 708 cm-1; H NMR (400 MHz,
DMSO-d6): d = 10.21 (s, 1H, OH), 8.15 (d, 2H,
J = 8.8 Hz, ArH), 7.94–7.73 (m, 4H, NH and ArH), 7.49
(d, 2H, J = 8.6 Hz, ArH), 7.43 (t, 1H, J = 7.5 Hz, ArH),
7.30 (t, 1H, J = 7.5 Hz, ArH), 7.23 (d, 1H, J = 8.8 Hz,
ArH), 6.97 (d, 1H, J = 7.7 Hz, CH), 4.07 (q, 2H,
J = 6.7 Hz, CH2), 1.17 (t, 3H, J = 6.7 Hz, CH3) ppm;
13C NMR (125 MHz, DMSO-d6): d = 156.7, 153.5, 151.1,
146.4, 132.3, 130.3, 129.0, 128.8, 127.5, 127.2, 123.8,
123.2, 123.0, 118.8, 118.4, 60.7, 50.5, 15.0 ppm; LC/MS:
m/z (%) = 365 [(M–H)-, 100].
Methyl [(2,4-dichlorophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4g, C19H15Cl2NO3)
ꢀ
White solid; IR (KBr): m = 3,403, 3,260, 1,678, 1,519,
1
1,062, 873, 753, 718 cm-1; H NMR (400 MHz, DMSO-
d6): d = 9.97 (s, 1H, OH), 8.02 (d, 1H, J = 8.5 Hz, NH),
7.96 (d, 1H, J = 7.8 Hz, ArH), 7.78 (dd, 2H, J = 17.8,
8.4 Hz, ArH), 7.57–7.38 (m, 4H, ArH), 7.28 (t, 1H,
J = 7.3 Hz, ArH), 7.14 (d, 1H, J = 8.7 Hz, ArH), 6.85 (d,
1H, J = 8.0 Hz, CH), 3.55 (s, 3H, OCH3) ppm; 13C NMR
(125 MHz, DMSO-d6): d = 156.6, 154.0, 139.3, 133.6,
133.0, 132.3, 131.6, 130.1, 129.0, 128.9, 128.6, 127.0,
126.9, 123.0, 122.8, 118.9, 116.7, 52.0, 49.8 ppm; LC/MS:
m/z (%) = 375 [(M–H)-, 100].
Ethyl [(2-chlorophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4o, C20H18ClNO3)
ꢀ
White solid; IR (KBr): m = 3,420, 3,229, 1,685, 1,525,
1
1,336, 1,051, 821, 753, 706 cm-1; H NMR (400 MHz,
DMSO-d6): d = 10.19 (s, 1H, OH), 8.28 (d, 1H, J =
8.5 Hz, NH), 8.04–7.97 (m, 3H, ArH), 7.77 (d, 1H,
J = 5.9 Hz, ArH), 7.66–7.48 (m, 5H, ArH), 7.39 (d, 1H,
J = 8.7 Hz, ArH), 7.15 (d, 1H, J = 8.3 Hz, CH), 4.22 (q,
2H, J = 7.1 Hz, CH2), 1.36 (t, 3H, J = 7.1 Hz, CH3) ppm;
13C NMR (125 MHz, DMSO-d6): d = 156.1, 153.9, 139.8,
133.0, 132.9, 130.3, 129.9, 129.7, 129.0, 128.8, 128.6,
126.9, 126.7, 123.3, 122.7, 119.0, 117.5, 60.3, 50.0,
15.0 ppm; LC/MS: m/z (%) = 354 [(M–H)-, 100].
Ethyl [(2-nitrophenyl)(2-hydroxynaphthalen-1-yl)methyl]-
carbamate (4l, C20H18N2O5)
ꢀ
White solid; IR (KBr): m = 3,402, 3,277, 1,686, 1,530,
1
1,334, 1,038, 813, 744, 697 cm-1; H NMR (400 MHz,
DMSO-d6): d = 9.79 (s, 1H, OH), 7.92 (d, 1H,
J = 8.6 Hz, NH), 7.81–7.72 (m, 4H, ArH), 7.64–7.58 (m,
2H, ArH), 7.44 (dt, 2H, J = 17.0, 6.0 Hz, ArH), 7.29–7.26
(m, 2H, ArH), 7.05 (d, 1H, J = 8.7 Hz, CH), 4.04 (q, 2H,
Ethyl [(4-chlorophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4p, C20H18ClNO3)
J = 7.0 Hz, CH2), 1.15 (t, 3H, J = 7.0 Hz, CH3) ppm; 13
C
ꢀ
White solid; IR (KBr): m = 3,424, 3,197, 1,676, 1,517,
1
1,329, 1,042, 821, 751, 711 cm-1; H NMR (400 MHz,
NMR (125 MHz, DMSO-d6): d = 156.4, 154.0, 149.0,
136.9, 133.3, 132.5, 130.3, 129.4, 128.9, 128.5, 128.1,
126.9, 124.4, 123.0, 122.8, 118.8, 116.5, 60.5, 48.1,
15.0 ppm; LC/MS: m/z (%) = 365 [(M–H)-, 100].
DMSO-d6): d = 10.15 (s, 1H, OH), 7.93 (d, 1H, J =
8.3 Hz, NH), 7.80 (dd, 2H, J = 12.8, 6.8 Hz, ArH), 7.58
(d, 1H, J = 8.2 Hz, ArH), 7.41 (t, 1H, J = 7.3 Hz, ArH),
7.33–7.22 (m, 6H, ArH), 6.87 (d, 1H, J = 8.1 Hz, CH),
4.05 (q, 2H, J = 7.2 Hz, CH2), 1.17 (t, 3H, J = 6.9 Hz,
CH3) ppm; 13C NMR (125 MHz, DMSO-d6): d = 156.6,
153.3, 141.9, 132.3, 131.4, 130.0, 129.0, 128.7, 128.4,
128.3, 127.4, 127.1, 123.6, 123.0, 118.8, 60.7, 50.2,
14.9 ppm; LC/MS: m/z (%) = 354 [(M–H)-, 100].
Ethyl [(3-nitrophenyl)(2-hydroxynaphthalen-1-yl)methyl]-
carbamate (4m, C20H18N2O5)
ꢀ
White solid; IR (KBr): m = 3,395, 3,277, 1,678, 1,527,
1
1,348, 1,045, 808, 752, 701 cm-1; H NMR (400 MHz,
DMSO-d6): d = 10.24 (s, 1H, OH), 8.13 (d, 1H, J =
8.2 Hz, NH), 8.07 (d, 1H, J = 8.1 Hz, ArH), 7.98 (d, 1H,
J = 7.8 Hz, ArH), 7.82 (t, 3H, J = 8.4 Hz, ArH), 7.64 (d,
1H, J = 7.8 Hz, ArH), 7.56 (t, 1H, J = 8.0 Hz, ArH), 7.44
(t, 1H, J = 7.5 Hz, ArH), 7.31 (t, 1H, J = 7.5 Hz, ArH),
7.23 (d, 1H, J = 8.8 Hz, ArH), 6.97 (d, 1H, J = 7.8 Hz,
Ethyl [(2,4-dichlorophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4q, C20H17Cl2NO3)
White solid; IR (KBr): ꢀm = 3,412, 3,071, 1,683, 1,514,
1
1,336, 1,052, 815, 743, 721 cm-1; H NMR (400 MHz,
DMSO-d6): d = 9.93 (s, 1H, OH), 8.04 (d, 1H,
123

Solvent-free one-pot synthesis of 1-carbamatoalkyl-2-naphthols
979
J = 8.6 Hz, NH), 7.81–7.75 (m, 3H, ArH), 7.58 (d, 1H,
J = 8.5 Hz, ArH), 7.49 (d, 1H, J = 1.5 Hz, ArH), 7.44
(t, 1H, J = 7.5 Hz, ArH), 7.38 (dd, 1H, J = 6.8, 1.8 Hz,
ArH), 7.28 (t, 1H, J = 7.4 Hz, ArH), 7.14 (d, 1H,
J = 8.8 Hz, ArH), 6.86 (d, 1H, J = 8.1 Hz, CH), 3.98
(q, 2H, J = 6.7 Hz, CH2), 1.14 (t, 3H, J = 6.4 Hz, CH3)
ppm; 13C NMR (125 MHz, DMSO-d6): d = 156.1, 154.0,
139.3, 133.5, 132.9, 132.3, 131.6, 130.1, 129.0, 129.0,
128.6, 127.0, 126.9, 123.1, 122.8, 119.0, 116.8, 60.4, 49.7,
15.0 ppm; LC/MS: m/z (%) = 389 [(M–H)-, 100].
128.1, 127.8, 126.9, 126.7, 123.3, 122.7, 118.9, 117.3,
65.8, 50.1 ppm; LC/MS: m/z (%) = 416 [(M–H)-, 100].
Benzyl [(4-chlorophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4w, C25H20ClNO3)
ꢀ
White solid; IR (KBr): m = 3,402, 3,200, 1,681, 1,515,
1
1,321, 1,042, 813, 746, 696 cm-1; H NMR (400 MHz,
DMSO-d6): d = 10.15 (s, 1H, OH), 7.93 (d, 1H, J =
8.2 Hz, NH), 7.82–7.77 (m, 3H, ArH), 7.39-7.23 (m, 12H,
ArH), 6.90 (d, 1H, J = 8.1 Hz, CH), 5.11 (d, 1H, J =
12.6 Hz, CH2), 5.01 (d, 1H, J = 12.6 Hz, CH2) ppm; 13C
NMR (125 MHz, DMSO-d6): d = 156.5, 153.4, 141.8,
137.3, 132.3, 131.3, 129.9, 129.0, 128.9, 128.7, 128.4,
128.3, 128.2, 127.4, 127.0, 123.7, 123.4, 122.8, 119.0,
118.7, 66.1, 50.3 ppm; LC/MS: m/z (%) = 416 [(M–H)-,
100].
Benzyl [(2-nitrophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4s, C25H20N2O5)
ꢀ
White solid; IR (KBr): m = 3,424, 3,250, 1,702, 1,527,
1
1,334, 1,046, 835, 752, 696 cm-1; H NMR (400 MHz,
DMSO-d6): d = 9.81 (s, 1H, OH), 8.08 (d, 1H, J = 7.9 Hz,
NH), 7.94 (d, 1H, J = 8.2 Hz, ArH), 7.79 (d, 1H,
J = 8.0 Hz, ArH), 7.74 (t, 2H, J = 7.3 Hz, ArH),
7.62–7.26 (m, 11H, ArH), 7.08 (d, 1H, J = 8.5 Hz, CH),
5.12 (d, 1H, J = 12.8 Hz, CH2), 5.06 (d, 1H, J = 12.8 Hz,
CH2) ppm; 13C NMR (125 MHz, DMSO-d6): d = 156.3,
154.1, 149.0, 137.5, 136.9, 133.3, 132.5, 130.4, 129.7,
129.4, 128.9, 128.7, 128.5, 128.2, 128.1, 127.8, 127.2,
127.0, 124.5, 123.0, 122.9, 118.8, 116.4, 65.9, 48.3 ppm;
LC/MS: m/z (%) = 427 [(M-H)-, 100].
Benzyl [(2,4-dichlorophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4x, C25H19Cl2NO3)
ꢀ
White solid; IR (KBr): m = 3,416, 3,066, 1,686, 1,522,
1
1,341, 1,055, 819, 744, 719 cm-1; H NMR (400 MHz,
DMSO-d6): d = 9.92 (s, 1H, OH), 8.06–8.01 (m, 2H, NH
and ArH), 7.80 (d, 1H, J = 8.0 Hz, ArH), 7.75 (d, 1H,
J = 8.8 Hz, ArH), 7.56 (d, 1H, J = 8.4 Hz, ArH),
7.50–7.26 (m, 9H, ArH), 7.14 (d, 1H, J = 8.7 Hz, ArH),
6.87 (d, 1H, J = 6.7 Hz, CH), 5.09 (d, 1H, J = 12.8 Hz,
CH2), 5.01 (d, 1H, J = 12.8 Hz, CH2) ppm; 13C NMR
(125 MHz, DMSO-d6): d = 156.0, 154.0, 139.2, 137.5,
133.6, 133.0, 132.3, 131.6, 130.1, 129.1, 129.0, 128.7,
128.6, 128.1, 127.9, 127.0, 126.9, 123.1, 122.8, 119.0,
116.6, 65.8, 49.8 ppm; LC/MS: m/z (%) = 451 [(M–H)-,
100].
Benzyl [(4-nitrophenyl)(2-hydroxynaphthalen-1-yl)-
methyl]carbamate (4u, C25H20N2O5)
ꢀ
White solid; IR (KBr): m = 3,414, 3,064, 1,686, 1,515,
1
1,347, 1,049, 825, 745, 695 cm-1; H NMR (400 MHz,
DMSO-d6): d = 10.21 (s, 1H, OH), 8.15 (d, 2H, J =
8.7 Hz, ArH), 7.99 (d, 1H, J = 6.6 Hz, NH), 7.93 (d, 1H,
J = 6.4 Hz, ArH), 7.82 (t, 2H, J = 8.7 Hz, ArH), 7.50
(d, 2H, J = 8.5 Hz, ArH), 7.41–7.28 (m, 7H, ArH), 7.24
(d, 1H, J = 8.8 Hz, ArH), 7.01 (d, 1H, J = 7.8 Hz, CH),
5.14 (d, 1H, J = 12.6 Hz, CH2), 5.08 (d, 1H, J = 12.6 Hz,
CH2) ppm; 13C NMR (125 MHz, DMSO-d6): d = 156.6,
153.5, 151.1, 146.5, 137.2, 132.3, 130.3, 129.0, 128.8,
128.7, 128.2, 127.5, 127.2, 123.8, 123.3, 123.0, 118.7,
118.3, 66.3, 50.6 ppm; LC/MS: m/z (%) = 427 [(M–H)-,
100].
Acknowledgments This research work was financially sup-
ported by the Education Committee of Liaoning Province of China
(No. L2011198).
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ꢀ
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