One-pot synthesis of thiocarbamidoalkyl naphthols

Article abstract of DOI:10.3184/030823409X416910

An efficient, inexpensive and mild method for the synthesis of a-thiocarbamidoalkyl-p-naphthols, catalysed by p-toluenesulfonic acid at room temperature is reported. A set of thiocarbamidoalkyl naphthols have been synthesised in high yields from aromatic

Full text of DOI:10.3184/030823409X416910

162 RESEARCH PAPER
MARCH, 162-164
JOURNAL OF CHEMICAL RESEARCH 2009
One-pot synthesis of thiocarbamidoalkyl naphthols
Zhong-Ping Zhang, Jian-Ming Wen, Jing-Hua Li* and Wei-Xiao Hu
College of Pharmaceutical
Sciences, Zhejiang University of Technology, 310032, P. R. China
An efficient, inexpensive and mild method for the synthesis of a-thiocarbamidoalkyl-13-naphthols,
catalysed by
p-toluenesulfonic
acid at room temperature
is reported.
A
set of thiocarbamidoalkyl
naphthols have been
synthesised in high yields from aromatic aldehydes, 13-naphthol and N-phenylthiourea
involves a short reaction time and a simple experimental procedure.
or thiourea. The procedure
Keywords: multicomponent reactions, thiocarbamidoalkyl naphthols, Betti base
Compounds bearing 1,3-amino oxygenated functional groups
are found in biologically important natural products and drugs
including a number of nucleoside antibiotics and HIV protease
inhibitors, such as ritonavir and lipinavir.I-6Aminonaphthols
exhibit antihypertensive, adrenoceptor blocking, and Ca2+
channel blocking activities.7-9
Table 1 Effect of catalysts on the reaction of benzaldehyde,
~-naphthol and N-phenylthiourea"
Yield/%b
Entry
Catalyst
Solvent
1
2
3
4
5
6
7
8
9
Yb(OTfh
la(OTfh
Cu(OTfh
Zn(OTfh
HOTf
CH3S03H
CF3COOH
p- TSA
p- TSA
p- TSA
p- TSA
p- TSA
CH2CI2
CH2CI2
CH2CI2
CH2CI2
CH2CI2
CH2CI2
CH2CI2
CH2CI2
CICH2CH2CI
Toluene
<30
<30
73
Trace
52
<30
48
90
93
78
85
Multicomponent
reactions
(MCRs) have attracted
considerable attention since they do not require the isolation
of intermediates savings time, energy and raw materials.
Hence the discovery of new MCRs is still in demand. 10-14
Various methods have been reported for the straightforward
synthesis of Betti base derivatives by the aminoalkylation of
13-naphthol with aromatic aldehydes and heterocyclic
amines,15,16 pyrrolidine,17 iminium saltsl8,19 and methyl
carbamate.2o Amidoalkyl naphthols can be prepared from
the Betti base or by condensation of aromatic aldehydes,
13-naphthol and amides as the ammonia source. To our
knowledge, relatively few reports have appeared in this
field.21-28A straightforward synthesis of thiocarbamidoalkyl
naphthols from thiourea and its derivatives has not been
reported. We report here a mild, simple and efficient method
for the one-pot three-component condensation of aromatic
aldehydes, 13-naphtholand thioureas.
10
11
12
CH
3
0H
C2H50H
80
"Reaction conditions: solvent (5 ml), benzaldehyde (1 mmo!),
~-naphthol (1 mmo!), N-phenylthiourea (1.1 mmol), cat.
amount 10%,room temperature, 12 h. blsolatedyield.
electron-withdrawing groups reacted successfully. As expected
aromatic aldehydes with electron-withdrawing groups reacted
faster than the aromatic aldehydes with electron-donating
groups. When thiourea was used as the amine source, the
aminoalkylation of naphthol gave a lower yield and needed a
longer reaction time.
In our initial search for appropriate reaction conditions, we
chose the reaction of 13-naphtholwith benzaldehyde and N-
phenylthiourea as a model with a variety of catalysts in CH2Cl2
at room temperature (Scheme 1 and Table 1, entries 1-7).
As shown in Table 1, the best result was obtained when
Table 2 One-pot synthesis of thiocarbamidoalkyl naphthols
in the presence of p- TSA"
No.
t/h
p-toluenesulfonic acid (p-TSA) was used as
a catalyst
(Table 1, entry 7). We then examined the reaction in various
solvents in the presence of 10%p- TSA(Table 1, entries 7-11).
We found that 1,2-dichloroethane and CH2Cl2 gave high
yields of the product. However, 1,2-dichloroethane is toxic
and so we chose CH2Cl2as a solvent for the reactions.
Under the reaction conditions established as above, various
thiocarbamidoalkyl naphthols were then synthesised in good
to excellent yields by the reaction of different aromatic
aldehydes with 13-naphtholand N-phenylthiourea or thiourea.
The results are summarised in Table 2. Among them, 3a
was identified, by Rf value (on TLC), IH NMR and m.p.,
as the same compound as prepared from Betti base and
isothiocyanatobenzene in toluene at room temperature. In all
cases, aromatic aldehydes bearing either electron-donating or
3a
3b
3c
3d
3e
3f
3g
3h
3i
H
p-CI
o-CI
2,4-dichloro
m-N02
p-F
p-OH
p-CH 0
3,4-dimethyl
H
m-N02
o-CI
3,4-dimethyl
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
H
90
91
88
86
93
92
78
81
74
72
78
77
58
12
8
10
10
8
9
24
24
24
24
18
20
24
3
3j
3k
31
3m
H
H
H
"Reactioncondition: CH2CI2assolvent (5 ml), aromatic aldehyde
(1 mmo!), ~-naphthol (1 mmo!), N-phenylthiourea or thiourea
(1.1mmo!), cat. amount 10%,room temperature. blsolatedyield.
Rtf"
I
~
R
~ITJ
'X+
H
0
Scheme 1
* Correspondent.E-mail:lijh@zjut.edu.cn

JOURNAL OF CHEMICAL RESEARCH 2009 163
8.76 (ss, lH), 8.21 (s, br, lH), 8.11-8.06 (m, 3H), 7.89 (t, J= 9.0 Hz,
In conclusion,
convenient
derivatives
aldehydes, 2-naphthol and N-phenylthiourea
the presence of p- TSA. This method offers several significant
advantages: high conversions, mild reaction conditions and
easy handling, which makes it a useful and attractive process
for the convenient synthesis of substituted thiocarbamidoalkyl
naphthols.
we have developed
synthesis of l-thiocarbamidoalkyl-2-naphthol
by three-component
an efficient
and
2H), 7.63-7.55 (m, 5H), 7.39-7.35 (m, 3H), 7.26 (d, J
lH), 7.16 (t, J 7.5 Hz, lH); l3C NMR (125 MHz, DMSO-d6):
0181.2,153.8,148.2,145.6,139.5,133.2,132.7,130.7,130.2,129.3,
= 8.5 Hz,
=
a
condensation
of aryl
or thiourea in
129.2, 128.7, 127.9, 125.1, 123.8, 123.5, 122.7, 122.0, 120.7, 118.9,
118.1,53.3; MS (EI) m/z (%): 348 (3), 231 (50),202 (25),144 (100),
115 (17); Anal. Calcd for C24H19NP3S: C, 67.12; H, 4.46; N, 9.78.
Found: C, 67.15; H, 4.45; N, 9.81%.
3f: Colourless crystals; m.p. 166-168°C; IR (KEr) em-I: 3368,
3170,3016, 1630, 1544, 1520, 1506, 1439, 1330, 1269, 1186,835,
751; 'H NMR (500 MHz, DMSO-d6): 0 10.22 (s, lH), 10.20 (s, lH),
8.70 (s, br, lH), 8.13 (s, br, lH), 7.96-7.95 (ss, lH), 7.86 (d,J= 8.0 Hz,
lH), 7.83 (d, J= 8.5 Hz, lH), 7.55-7.33 (m, 6H), 7.24-7.09 (m, 6H);
'3C NMR (125 MHz, DMSO-d6): 0180.3,161.9,160.0,153.2,139.0,
138.4, 132.3, 129.7, 128.8, 128.7, 128.2, 127.8, 127.7, 127.1, 125.5,
124.6, 123.3, 122.8, 122.3, 118.5, 118.3, 114.9, 114.8,52.8; MS (EI)
m/z (%): 251 (7), 249 (100), 231 (6), 144 (50),115 (20); Anal. Calcd
for C24H19FNpS: C, 71.62; H, 4.76; N, 6.96. Found: C, 71.53; H,
4.85; N, 6.83%.
Experimental
Melting points were determined on a Biichi B-540 melting apparatus
and are uncorrected. The NMR spectra were measured on a Broker
Advance III 500 instrument using DMSO-d
as the internal standard. IR spectra were recorded using KEr pellets
on a Nicolet 6700 FI-IR spectrophotometer. Mass spectra were
measured with GCT Premier CAB 075. Elemental analyses were
performed on Thermo Fiunigan EAII12 elemental analyser.
6
as the solvent with TMS
3g: Pale yellow crystals; m.p. 162-164°C; IR (KEr) cm-': 3527,
3369,3190,3016,
1629, 1546, 1513, 1437, 1331, 1258, 1176,832,
747; 'H NMR (500 MHz, DMSO-d6): 0 10.14 (s, lH), 10.11 (s, lH),
9.21 (br, lH), 8.71 (s, br, lH), 8.12 (s, br, lH), 7.89-7.79 (m, 3H),
7.52-7.31 (m, 6H), 7.22 (d, J= 9 Hz, lH), 7.21-7.10 (m, lH), 7.01
(d, J= 8.5 Hz, 2H), 6.66 (d, J= 8.5 Hz, 2H); l3C NMR (125 MHz,
DMSO-d6): 0 180.2, 156.5, 153.5, 139.4, 132.9, 132.7, 129.7, 129.3,
129.0, 128.6 x 2, 127.7, 127.3, 125.0, 123.8, 123.2, 119.2, 119.0,
115.3,53.6; MS (EI) m/z (%): 249 (4), 247 (42), 231 (16), 144 (100),
115 (35); Anal. Calcd for C24H20N202S:C, 71.98; H, 5.03; N, 6.99.
Found: C, 71.94; H, 4.92; N, 6.81%.
General procedure for preparation of3a-m
A mixture of aromatic aldehyde (I mmol), ~-naphthol (I mmol),
N-phenylthiourea or thiourea (1.1 mmol) and TsORHp (0.1 mmol)
in CH2Cl2 (5 mL) was stirred at room temperature for the appropriate
time (Table 2). The progress of the reaction was monitored by TLC
(2: I hexane: ethyl acetate). After completion of the reaction, as
indicated by TLC, the reaction mixture was filtered and the precipitate
washed throughly with CH2Cl2 and then with water. The crystalline
product was collected without further purification. The physical and
spectroscopic data of the compounds 3a-m are as follows.
3h: Colourless crystals; m.p. 174-176°C; IR (KEr) cm-': 3364,
3195,30156,1628,1543,1511,1327,1246,1177,830,747;
'H NMR
3a: Colourless crystals; m.p. 178-180°C; IR (KEr) cm-': 3447,
(500 MHz, DMSO-d6): 0 10.16 (s, lH), 10.14 (s, lH), 8.71 (s, br, lH),
8.12 (s, br, lH), 7.92-7.90 (ss, lH), 7.85 (d, J= 8.0 Hz, lH), 7.80 (d,
J= 9.0 Hz, lH), 7.52-7.31 (m, 6H), 7.22 (d, J= 9.0 Hz, lH), 7.14 (t,
J= 7.5 Hz, lH), 7.10 (d, J= 8.5 Hz, 2H), 6.85-6.82 (dd, J= 9.0 Hz,
3285,3172,3066,
1626, 1605, 1546, 1515, 1436, 1360, 1259, 1144,
811, 747; 'H NMR (500 MHz, DMSO-d6): 0 10.20 (s, lH), 10.16
(s, lH), 8.71-8.70 (ss, br, lH), 8.16 (s, br, lH), 8.00-7.98 (ss, lH),
7.86 (d, J= 8.0 Hz, lH), 7.82 (d, J= 8.5 Hz, lH), 7.54-7.48 (m, 3H),
J
=
2.0 Hz, 2H), 3.68 (s, 3H); l3C NMR (125 MHz, DMSO-d6):
7.34 (q, J
= 8 Hz, 3H), 7.28-7.13 (m, 7H); l3C NMR (125 MHz,
0158.4,153.5,139.4,134.6,132.8,129.8,129.3,129.1, 128.6, 128.5,
DMSO-d6): 0 180.7, 153.6, 142.8, 139.4, 133.0, 130.0, 129.3, 129.1,
128.6, 127.5, 126.8, 126.3, 125.0, 123.8, 123.2, 122.9, 119.1, 119.0,
53.8; MS (EI) m/z (%): 231 (100), 202 (20), 144 (75), 115 (29); Anal.
Calcd for C24H20N20S C, 74.97; H, 5.24; N, 7.29. Found: C, 74.87;
H, 5.46; N, 7.47%.
127.6, 127.4, 125.0, 123.8, 123.2, 119.0 x 2, 114.0,55.5, 53.5; MS
(EI) m/z (%): 380 (M-34, 2), 263 (10), 261 (100), 231 (78), 144 (73)
115 (28); Anal. Calcd for C2sH22N202S: C, 72.44; H, 5.35; N, 6.76.
Found: C, 72.24; H, 5.33; N, 6.72%.
31:Colourless crystals; m.p. 168-170 °C; IR (KEr) cm-': 3363, 3186,
3012, 1630, 1544, 1518, 1438, 1265,822,745; 'H NMR (500 MHz,
DMSO-d6): 010.14 (s, lH), 10.11 (s, lH), 8.67 (s, br, lH), 8.15 (s, br,
lH), 7.92-7.90 (ss, lH), 7.84 (d, J= 8.0 Hz, lH), 7.80 (d, J= 9.0 Hz,
lH), 7.51-7.31 (m, 6H), 7.20 (d, J= 8.0 Hz, lH), 7.14 (t, J= 7.5 Hz,
lH), 7.01 (d, J= 8.0 Hz, lH), 6.96 (s, lH), 6.89 (d, J= 8.0 Hz, lH),
2.14 (s, 3H), 2.11 (s, 3H); l3C NMR (125 MHz, DMSO-d6): 0 180.4,
153.6, 140.2, 139.5, 136.1, 134.7, 132.9, 129.8, 129.7, 129.3, 129.1,
128.6, 128.5, 127.4, 127.3, 126.0, 125.0, 123.9, 123.7, 123.2, 123.0,
119.3, 119.0,53.6,20.1, 19.4; MS (EI) m/z (%): 412 (M, 2), 262 (2),
245 (100), 144 (31); Anal. Calcd for C26H24NpS: C, 75.70; H, 5.86;
N, 6.79. Found: C, 75.64; H, 5.85; N, 6.75%.
3h: Colourless crystals; m.p. 164-166°C; IR (KEr) cm-': 3363,
3191,3018, 1629, 1543, 1518, 1489, 1328, 1267,812,747; 'H NMR
(500MHz,DMSO-d6):
010.23 (s, 2H), 8.68-8.67 (ss, br, lH), 8.14(s, br,
lH), 7.97-7.95 (ss, lH), 7.87 (d,J= 8.0 MHz, lH), 7.83 (d, J= 9.0 Hz,
lH), 7.54-7.33 (m, 8H), 7.24-7.22 (ss, lH), 7.19-7.13 (m, 3H); l3C
NMR (125 MHz, DMSO-d6): 0 18D.4, 153.2, 141.5, 139.0, 132.4,
130.9, 129.8, 128.8, 128.7, 128.2, 128.1, 127.7, 127.1, 125.5, 124.6,
123.3, 122.8, 122.3, 118.5, 118.2,52.8; MS (EI) m/z (%): 384 (M-34,
1),267 (28), 231 (100),202 (30), 144(60), 115 (23); Anal. Calcd for
C24H19CIN20S C, 68.81; H, 4.57; N, 6.69. Found: C, 68.70; H, 4.56;
N,6.54%.
3c: Colourless crystals; m.p. 174-176°C; IR (KEr) cm-': 3382,
3j: Colourless crystals; m.p. 180-182°C; IR (KEr) em-I: 3417,
3302,3191, 1614, 1514, 1435, 1350, 1262, 1210, 1173, 811, 697;
'H NMR (500 MHz, DMSO-d6): 0 10.02 (s, lH), 8.41-8.39 (ss, lH),
8.13 (s, br, lH), 7.84 (d, J= 8.0 Hz, lH), 7.80 (d, J= 9.0 Hz, lH),
7.76-7.74 (ss, lH), 7.50-7.47 (m, 3H), 7.32 (t, J = 7.5 Hz, lH), 7.25-
7.20 (m, 4H), 7.16 (t, J= 7.5 Hz, lH), 7.11 (d, J= 8.0 Hz, lH); l3C
NMR (125 MHz, DMSO-d6): 0 183.7, 153.7, 143.4, 133.0, 129.8,
129.0, 128.6, 128.4, 127.2, 126.6, 126.2, 123.2, 123.0, 119.7, 119.0,
54.3; MS (EI) m/z (%): 274 (M-34, 2), 231 (55),202 (14),144 (100),
115 (33); Anal. Calcd for C'8H'6NPS: C, 70.10; H, 5.23; N, 9.08.
Found: C, 69.97; H, 5.25; N, 9.13%.
3186,3009,1629,1592,1540,1515,1435,1371,1331,1266,
811, 747;
'H NMR (500 MHz, DMSO-d6): 0 10.04 (s, lH), 9.99 (s, lH), 8.47 (d,
J = 8.5 Hz, lH), 8.27 (d, J = 8.5 Hz, lH), 7.82 (d, J = 8 Hz, 2H), 7.78
(d, J= 8.0 Hz, lH), 7.65-7.64 (ss, lH), 7.63-7.48 (m, 3H), 7.34-7.22
(m, 6H), 7.14 (d, J= 9.0 Hz, lH), 7.08 (d, J= 7.5 Hz, lH); l3C NMR
(125 MHz, DMSO-d6): 0 179.7, 153.7, 139.5 x 2,132.7, 132.1, 130.0,
129.8, 129.2, 128.6, 128.5, 128.2, 128.1, 126.6, 126.2, 124.0, 123.1,
122.6,122.5,118.5,117.2,52.4;
MS (EI) m/z (%): 384 (M-34, 1),231
(100),202 (15), 144(60), 115 (36); Anal. Calcd for C24H19CIN20S C,
68.81; H, 4.57; N, 6.69. Found: C, 68.84; H, 4.59; N, 6.62%.
3d: Colourless crystals; m.p. 152-154°C; IR (KEr) cm-': 3380,
3160, 1628, 1541, 1517, 1266, 1195,814,744; 'H NMR (500 MHz,
3k: Yellow crystals; m.p. 168-170°C; IR (KEr) cm-': 3422, 3356,
3096,1626,1529,1437,1350,1267,1210,1171,813,749;
'HNMR
DMSO-d6): 0 10.06 (s, lH), 9.98 (s, lH), 8.48 (d, J
8.24 (d, J= 9.0 Hz, lH), 7.82 (d, J= 7.5 Hz, lH), 7.79 (d, J= 8.5 Hz,
lH), 7.74-7.73 (ss, lH), 7.67-7.65 (m, 3H), 7.56 (d, J 8.0 Hz,
lH), 7.47-7.45 (m, 2H), 7.33-7.29 (m, 3H), 7.13-7.17 (m, 2H); l3C
NMR (125 MHz, DMSO-d6): 0 180.3, 154.3, 139.9, 139.5, 133.1,
= 8.5 Hz, lH),
(500 MHz, DMSO-d6): 0 10.09 (s, lH), 9.17 (s, br, lH), 8.13 (s, 2H),
8.12 (s, lH), 8.03-8.02 (ss, lH), 7.84-7.80 (dd, J = 11 Hz, J= 2.5 Hz,
2H), 7.63-7.49 (m, 3H), 7.31 (t, J= 7.5 Hz, lH), 7.19 (d, J= 9.0 Hz,
lH); l3C NMR (125 MHz, DMSO-d6): 0 184.3, 153.9, 148.2, 146.3,
133.0, 132.8, 130.6, 130.1, 129.2, 128.7, 127.5, 123.2, 121.7, 120.7,
118.8, 118.3,53.6; MS (EI) m/z (%): 319 (M-34, 3), 276 (20), 202
(3), 144 (100), 115 (19); Anal. Calcd for C'8H,sNP3S: C, 61.18; H,
4.28; N, 11.89. Found: C, 61.26; H, 4.30; N, 11.97%.
=
133.0,132.1,131.8,130.6,129.1,129.0,128.9,
128.6, 127.2, 126.8,
124.5, 123.3, 123.1, 123.0, 118.9, 117.0,52.5; MS (EI) m/z (%): 418
(M-34, 2), 265 (100), 202 (13), 144(42), 115 (15); Anal. Calcd for
C24H'8Cl2NpS C, 63.58; H, 4.00; N, 6.18. Found: C, 63.64; H,
4.15; N, 6.22%.
31: Colourless crystals; m.p. 166-168°C; IR (KEr) cm-': 3447,
3e: (Yellow crystals); m.p. 142-144°C; IR (KEr) cm-': 3422,
3334, 3165, 1628, 1522, 1475, 1352, 1319, 1245, 1190, 807, 744;
'HNMR (500 MHz, DMSO-d6): 0 10.37 (s, lH), 10.31 (s, lH), 8.77-
3285,3172,3066,
747; 'HNMR (500 MHz, DMSO-d
lH), 8.31 (d, J= 4.5 Hz, lH), 7.79 (d, J= 8.0 Hz, lH), 7.74 (d,
1605, 1546, 1515, 1436, 1360, 1260, 1144,811,
6
):0 9.85 (s, lH), 8.33 (d, J= 5 Hz,

164 JOURNAL OF CHEMICAL RESEARCH 2009
6
7
A.Y. Shen, C.L. Chen and C.l. Lin, Chin. J Physiol., 1992,35,45.
K.S. Atwal, B.C. O'Reilly, E.P. Ruby, C.F. Turk, G. Aberg, M.M. Asaad,
J= 9.0 Hz, lH), 7.60 (t, J= 9.0 Hz, 2H), 7.48 (t, J= 7.5 Hz, lH),
7.33-7.20
(m, 6H), 7.09 (d, J= 8.5 Hz, lH); l3C NMR (125 MHz,
J.L. Bergey, S. Moreland and J.R. Powell,
M. Gruodke, H.M Himmel, E. Wettwer, H.O. Borbe and U. Ravens,
Cardiovasc. Pharmacol., 1991,18,918.
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DMSO-d6):
1) 183.1, 154.0, 140.8, 133.3, 132.3, 130.4, 130.1, 129.4,
128.9, 128.6, 128.3, 126.9, 126.4, 123.8, 122.9, 119.0, 118.1, 53.5;
MS (EI) m/z (%): 308 (M-34, 3), 231 (100),202 (20),144 (53),115
C, 63.06; H, 4.41; N, 8.17.
J
9
(20); Anal. Calcd for C'8H'sC1NpS:
Found: C, 63.14; H, 4.45; N, 8. 26%.
10 1.Devi and P.J. Bhuyan, Tetrahedron Lett., 2004, 45, 8625.
11 S.H. Mashraqui, M.B. Pati!, H.D. Mistry, S. Ghadigaonkar and
A. Meetsma, Chem. Lett., 2004,33, 1058.
12 A. Chetia, C.J. Saikia, K.C. Lekhok and R.C. Boruah, Tetrahedron Lett.,
2004,45,2649.
3m: Colourless crystals; m.p. 164°C; IR (KEr) cm-': 3439,3230,
3145, 1600, 1541, 1514, 1438, 1351, 1267, 1211, 1145,813,732;
'H
NMR (500 MHz, DMSO-d ):1) 9.97 (s, lH), 8.39-8.37 (ss, lH), 8.15
6
(s, br, lH), 7.82 (d,J= 8.0 Hz, lH), 7.78 (d,J= 9 Hz, lH), 7.71-7.69
(ss, lH), 7.47 (br, 3H), 7.30 (t, J= 7.5 Hz, lH), 7.21 (d, J= 9.0 Hz,
lH), 6.98 (d, J= 8.0 Hz, lH), 6.92 (s, lH), 6.83 (d, J= 7.5 Hz, lH),
13 J. Zhu and H. Bicnaymc, Multicomponent
reactions, Wilcy-VCH,
Weinheim, Germany, 2005.
14 A. Diimling and 1. Ugi, Angew. Chem. Int. Ed., 2000, 39,3168.
15 N.K. Paul, L. Dietrich andA. Jha, Synth. Commun., 2007, 37,877.
2.13 (s, 3H), 2.10 (s, 3H); l3C NMR (125 MHz, DMSO-d6):
153.6, 140.8, 135.8, 134.3, 133.1, 129.6, 129.5, 128.6, 127.3, 127.1,
123.8, 123.3, 123.0, 120.0, 119.1,54.1,20.1, 19.4; MS (EI) m/z (%):
302 (M-34, 3), 259 (19), 245 (100), 202 (5), 144 (100) 115 (41);
1) 183.5,
16 A. Jha, N.K. Paul, S. Trikha and T.S. Cameron, Can.
J Chem., 2006,
84,843.
17 M. Periasamy, M.N. Reddy and S. Anwar, Tetrahedron: Asymmetry, 2004,
15,1809.
18 M.R. Saidi, N. Azizi and M.R. Naimi-Jamal, Tetrahedron Lett., 2001, 42,
8111.
Anal. Calcd for C2oH20NpS:
C, 71.40; H, 5.99; N, 8.33. Found: C,
71.51; H, 6.05; N, 8.32%.
19 M.R. Saidi and N. Azizi, Tetrahedron: Asymmetry, 2003, 14, 389.
20 M. Dabiri, A.S. Delbari and A. Bazgir, Heterocycles, 2007, 71, 543.
21 M.M. Khodaei, A.R. Khosropour and H. Moghanian, Synlett., 2006,916.
22 S.B. Pati!, P.R. Singh, M.P. Surpur and S.D. Samant, Synth. Commun.,
2007,37, 1659.
Received 17 November 2008; accepted 19 January 2009
Paper 08/0298 doi: 10.3184/030823409X416910
Published online: 6 April 2009
23 S. Kantevari, S.Y.N. Yuppalapati and L. Nagarapu, Catal. Commun.,
2007,8, 1857.
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