Friedel-Crafts reactions of 2-naphthol with α-amido sulfones and conversion of the products with nucleophiles

Article abstract of DOI:10.1055/s-0030-1258218

2-Naphthol underwent Friedel-Crafts reaction with N-benzyloxycarbonylamino sulfones in the presence of InCl₃ at room temperature to form the corresponding sulfonyl derivatives in high yields. The products were subsequently reacted with nucleoph

Full text of DOI:10.1055/s-0030-1258218

PAPER
3731
Friedel–Crafts Reactions of 2-Naphthol with a-Amido Sulfones and
Conversion of the Products with Nucleophiles1
Biswanath Das,* Cheruku Ravindra Reddy, Chava Sindhu, Chithaluri Sudhakar, Siddavatam Nagendra
Organic Chemistry Division-1, Indian Institute of Chemical Technology, Hyderabad 500 007, India
Fax +91(40)27193198; E-mail: biswanathdas@yahoo.com
Received 6 July 2010; revised 13 July 2010
Table 1 Evaluation of Catalytic Activity of Different Catalysts for
the Preparation of Sulfone Derivative 3aa
Abstract: 2-Naphthol underwent Friedel–Crafts reaction with N-
benzyloxycarbonylamino sulfones in the presence of InCl3 at room
temperature to form the corresponding sulfonyl derivatives in high
yields. The products were subsequently reacted with nucleophiles
such as allyltributyltin and anisole to replace the sulfonyl group.
Entry
Catalyst
InCl3
Yield (%)b
Time (h)
1
2
3
4
5
6
7
8
9
93
91
87
84
85
81
86
83
81
5
5.5
8
Key words: 2-naphthol, a-amido sulfone, InCl3, Friedel–Crafts re-
action, nucleophile
BF3·OEt2
FeCl3
ZnCl2
10
9
2-Naphthol derivatives exhibit various important biologi-
cal properties including hypotensive and bradycardiac ef-
fects.2 Many of these compounds have recently been
prepared by us3 as well as by others.2,4 In continuation of
our work5 on the development of useful synthetic method-
ologies applying an a-amido sulfone we have observed
that 2-naphthol can easily undergo Fridel–Crafts reaction
with this reagent in the presence of catalytic amount of
InCl3 at room temperature (Scheme 1). The products (sul-
fone derivatives 3) were formed in high yields (81–93%).
ZrCl4
I2
12
10
11
16
Cu(OTf)2
Sc(OTf)3
Ba(NO3)2
a Reaction conditions: N-benzyloxycarbonylamino sulfone 2a
(R = Ph, 1 mmol), 2-naphthol (1; 1 mmol) and catalyst (10 mol%)
were stirred at r.t.
b Isolated yields after purification.
InCl3 (10 mol%)
Cbz
CH2Cl2
HN
+
OH
r.t., 4–9 h
mained intact. The structures of the products were estab-
lished from their spectral (IR, 1H and 13C NMR, ESI-MS,
and HR-ESI-MS) and analytical data.
R
SO2Tol
OH
R
SO2Tol
1
2
3
R = alkyl or aryl
81–93%
It is known7 that a-amido sulfones are converted into the
corresponding protected imines (N-acyliminium ions) on
treatment with a Lewis acid (Scheme 2). These imine de-
rivatives are highly suitable for nucleophilic addition. 2-
Naphthol (1) reacts first with these ions and next the
amine moiety of the resulting intermediate is displaced by
a sulfonyl group in the presence of the catalyst to form the
products 3.
Scheme 1
N-Benzyloxycarbonylamino sulfones 2 used in the
present conversion can be conveniently prepared6 from al-
dehydes and are generally stable. Both the aromatic and
aliphatic aldehydes were employed to prepare these sul-
fone derivatives. The aromatic aldehydes contained elec-
tron-donating as well as electron-withdrawing groups. N-
Benzyloxycarbonylamino sulfones were used6 earlier by
us in the presence of InCl3 in various synthetic work. In
the present conversion, initially we treated 2-naphthol
with the sulfone 2a (R = Ph) using different Lewis acids
(Table 1). Considering the reaction time and yield, InCl3
was found to be most efficient. Thus, subsequently it was
used to prepare a series of sulfonyl derivatives 3 from N-
benzyloxycarbonylamino sulfones 2 (Table 2). Different
functionalities such as halogen, ether, and nitro groups re-
The sulfone derivatives of type 3 were subsequently treat-
ed with the nucleophiles such as allyltributyltin and ani-
sole in the presence of BF3·OEt2 at –10 °C (Scheme 3).
The conversion of 3 with allyltributyltin required one hour
while with anisole the reaction time was 45 minutes. The
products 4 and 5 were formed by replacement of the sul-
fonyl group of 3 by the nucleophiles (Table 3) in high
yields (81–89%). Thus, the present method has been uti-
lized for the preparation of 4,4-diarylbut-1-ene and tri-
arylmethanes starting from 2-naphthol (1). The interesting
point is that the conversions of 3 into 4 and 5 did not pro-
ceed in the presence of InCl3.
SYNTHESIS 2010, No. 21, pp 3731–3735
Advanced online publication: 18.08.2010
x
x.
x
x
.
2
0
1
0
DOI: 10.1055/s-0030-1258218; Art ID: Z17310SS
© Georg Thieme Verlag Stuttgart · New York

3732
B. Das et al.
PAPER
Table 3 Synthesis of 4 and 5 from Sulfone Derivativesa
Table 2 Synthesis of Sulfone Derivatives 3a
Sulfone
3a
R
Time (h) Productb Yield (%)c
Sulfone 2
R
Time (h) Productb Yield (%)c
Ph
1
4ad
5ae
4bd
5be
89
83
88
81
2a
2b
2c
2d
2e
2f
Ph
5
3a
3b
3c
3d
3e
3f
93
91
92
90
89
83
86
81
82
88
85
89
3a
Ph
0.75
1
4-MeC6H4
4-i-PrC6H4
3-FC6H4
4
3b
4-MeC6H4
4-i-PrC6H4
4.5
7
3c
0.75
a Reaction conditions: sulfone derivative 3a–c (1 mmol), nucleophile
(1.5 mmol), and BF3×OEt2 (20 mol%), –10 °C, N2 atmosphere.
b The structures of the products were established from their spectral
(IR, 1H, 13C NMR and ESI-MS) and analytical data.
c Isolated yields after purification.
4-ClC6H4
2-Cl-4-FC6H3
3,4-(OCH2O)C6H3
3,4,5-(MeO)3C6H2
4-O2NC6H4
2-naphthyl
n-Pr
6
8.5
6
2g
2h
2i
3g
3h
3i
d Derived from allyltributyltin.
8.5
9
e Derived from anisole.
In conclusion, we have demonstrated the synthesis of var-
ious 2-naphthol derivatives 3 by Friedel–Crafts reaction
of 2-naphthol (1) with N-benzyloxylcarbonylamino sul-
fones 2 in the presence of InCl3 and by subsequent treat-
ment of the products with nucleophiles using BF3·OEt2 as
a catalyst.
2j
6.5
9
3j
2k
3k
2l
i-Pr
8
3l
a Reaction conditions: N-benzyloxycarbonylamino sulfone 2 (1
mmol), 2-naphthol (1; 1 mmol), and InCl3 (10 mol%), r.t.
b The structures of the products were established from their spectral
(IR,1H and 13C NMR, ESI-MS, and HR-ESI-MS) and analytical data.
c Isolated yields after purification.
The spectra were recorded with the following instruments; IR:
PerkinElmer RX1 FT-IR spectrophotometer; NMR: Varian Gemini
200 MHz (1H) and 50 MHz (13C) spectrometer; ESI-MS: VG-Au-
tospec micromass and HR-ESI-MS: QSTAR XL, Hybrid MS sys-
tem. Column chromatography was carried out with silica gel (BDH
100–200 mesh) and TLC with silica gel GF254 precoated plates.
Cbz
Cbz
HN
HN
InCl3
–
TolSO2InCl3
+
R
SO2Tol
R
2
Reaction of 2-Naphthol (1) with N-Benzyloxycarbonylamino
Sulfones 2; General Procedure
InCl3 (10 mol%) was added to a solution of an a-amido sulfone 2 (1
mmol) and 2-naphthol (1; 144 mg, 1 mmol) in CH2Cl2 (5 mL) under
N2. The mixture was stirred at r.t. and the reaction was monitored
by TLC. After completion, the reaction mixture was concentrated
and H2O (10 mL) and EtOAc (10 mL) were added. The organic lay-
er was separated and concentrated. The residue was subjected to
column chromatography (silica gel, hexane–EtOAc) to obtain the
pure product.
OH
1
–
TolSO2InCl3
H+
OH
OH
R
R
NHCbz
SO2Tol
3
1-[(Phenyl)(p-tosyl)methyl]-2-naphthol (3a)
Yellow oil.
Scheme 2
IR (KBr): 3377, 1624, 1598, 1442, 1280 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.74 (1 H, br s), 7.60–7.51 (7 H,
m), 7.32–7.11 (6 H, m), 7.01 (2 H, d, J = 8.0 Hz), 6.41 (1 H, s), 2.22
(3 H, s).
13C NMR (50 MHz, CDCl3): d = 156.4, 144.8, 135.1, 131.9, 130.6,
129.8, 129.5, 129.2, 129.0, 127.3, 123.5, 121.2, 120.8, 70.2, 21.3.
SnBu3
BF3•OEt2
OH
CH2Cl2, –10 °C
1 h
R
4
ESI-MS: m/z = 389 [M + H]+.
88–89%
OMe
HR-ESI-MS: m/z [M + Na]+ calcd for C24H20O3S + Na: 411.1030;
OH
found: 411.1013.
BF3•OEt2
R
SO2Tol
OH
CH2Cl2, –10 °C
45 min
3
1-[(p-Tolyl)(p-tosyl)methyl]-2-naphthol (3b)
Yellow oil.
R
OMe
IR (KBr): 3320, 1595, 1512, 1403, 1248 cm–1.
5
1H NMR (200 MHz, CDCl3): d = 8.79 (1 H, br s), 7.68–7.55 (5 H,
m), 7.54 (2 H, d, J = 8.0 Hz), 7.30–7.07 (5 H, m), 7.01 (2 H, d,
J = 8.0 MHz), 6.39 (1 H, s), 2.31 (3 H, s), 2.20 (3 H, s).
81–83%
Scheme 3
Synthesis 2010, No. 21, 3731–3735 © Thieme Stuttgart · New York

PAPER
Friedel–Crafts Reactions of 2-Naphthol with a-Amido Sulfones
IR (KBr): 3382, 1625, 1598, 1491, 1250 cm–1.
3733
13C NMR (50 MHz, CDCl3): d = 154.8, 145.1, 136.1, 131.8, 130.0,
129.9, 129.7, 129.5, 129.0, 127.9, 127.1, 123.5, 121.4, 120.2, 70.0,
21.5, 21.1.
1H NMR (200 MHz, CDCl3): d = 8.85 (1 H, br s), 7.68–7.52 (3 H,
m), 7.35–7.11 (6 H, m), 7.09–7.00 (3 H, m), 6.72 (1 H, d, J = 8.0
Hz), 6.31 (1 H, s), 5.08 (2 H, s), 2.22 (3 H, s).
ES-IMS: m/z = 425 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C27H26O6S + Na: 501.1187;
found: 425.1169.
13C NMR (50 MHz, CDCl3): d = 154.8, 152.3, 148.1, 144.6, 136.7,
133.2, 131.9, 129.8, 129.7, 129.5, 128.9, 127.1, 124.2, 123.2, 119.8,
119.2, 111.0, 67.6, 21.8.
1-[(4-Isopropylphenyl)(p-tosyl)methyl]-2-naphthol (3c)
Yellow oil.
IR (KBr): 3369, 1624, 1592, 1513, 1281 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.86 (1 H, br s), 7.70–7.51 (7 H,
m), 7.29–7.11 (5 H, m), 6.99 (2 H, d, J = 8.0 Hz), 6.36 (1 H, s), 2.84
(1 H, m), 2.20 (3 H, s), 1.20 (6 H, d, J = 7.0 Hz).
ESI-MS: m/z = 455 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C24H20O3S + Na: 455.0929;
found: 455.0927.
1-[(p-Tosyl)(3,4,5-trimethoxyphenyl)methyl]-2-naphthol (3h)
Yellow oil.
13C NMR (50 MHz, CDCl3): d = 154.4, 149.1, 144.7, 134.8, 133.1,
131.9, 130.0, 129.2, 129.1, 128.7, 127.0, 126.9, 123.1, 121.0, 120.5,
96.3, 69.9, 33.7, 23.5, 21.2.
IR (KBr): 3377, 1592, 1509, 1460, 1253 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.90 (1 H, br s), 7.75–7.52 (5 H,
m), 7.32–7.11 (3 H, m), 7.02 (2 H, d, J = 8.0 Hz), 6.86 (2 H, s), 6.32
(1 H, s), 3.82 (3 H, s), 3.80 (6 H, s), 2.21 (3 H, s).
ESI-MS: m/z = 453 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C27H26O3S + Na: 453.1500;
found: 453.1512.
13C NMR (50 MHz, CDCl3): d = 154.9, 153.5, 144.8, 133.1, 132.0,
129.4, 129.2, 128.6, 127.1, 123.2, 121.1, 120.9, 70.4, 61.0, 56.1,
21.5.
1-[(3-Fluorophenyl)(p-tosyl)methyl]-2-naphthol (3d)
Yellow oil.
IR (KBr): 3375, 1591, 1485, 1441, 1250 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.69 (1 H, br s), 7.69–7.59 (2 H,
m), 7.51 (2 H, d, J = 8.0 Hz), 7.41–7.06 (7 H, m), 7.01–6.90 (3 H,
m), 6.40 (1 H, s), 2.12 (3 H, s).
ESI-MS: m/z = 479 [M + H]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C27H26O6S + Na: 501.1347;
found: 501.1334.
1-[(4-Nitrophenyl)(p-tosyl)methyl]-2-naphthol (3i)
Yellow oil.
13C NMR (50 MHz, CDCl3): d = 164.6, 154.4, 145.4, 136.1, 132.0,
130.0, 129.1, 129.0, 128.7, 127.2, 125.8, 123.2, 116.8 (d, J = 10
Hz), 115.2 (d, J = 8.0 Hz), 69.8, 21.6.
IR (KBr): 3414, 1690, 1598, 1516, 1345, 1275 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.60 (1 H, br s), 7.89–7.80 (3 H,
m), 7.75–7.62 (2 H, m), 7.58 (1 H, m), 7.38 (1 H, m), 7.31–7.20 (4
H, m), 7.05–6.92 (3 H, m), 6.46 (1 H, s), 2.22 (3 H, s).
ESI-MS: m/z = 429 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C24H19ClO3S + Na: 429.0936;
found: 429.0922.
13C NMR (50 MHz, CDCl3): d = 156.1, 146.3, 144.0, 136.0, 131.8,
131.2, 129.8, 128.2, 127.9, 127.8, 126.0, 122.9, 121.1, 118.0, 117.3,
66.5, 21.1.
1-[(4-Chlorophenyl)(p-tosyl)methyl]-2-naphthol (3e)
Yellow oil.
IR (KBr): 3378, 1624, 1590, 1490, 1261 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.72 (1 H, br s), 7.74–7.47 (7 H,
m), 7.39–7.08 (5 H, m), 6.99 (2 H, d, J = 8.0 Hz), 6.35 (1 H, br s),
2.22 (3 H, s).
ESI-MS: m/z = 456 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C24H19NO5S + Na: 456.0876;
found: 456.0873.
1-[(Naphthalene-2-yl)(p-tosyl)methyl]-2-naphthol (3j)
Yellow oil.
13C NMR (50 MHz, CDCl3): d = 154.8, 144.9, 133.0, 131.8, 131.2,
IR (KBr): 3418, 1689, 1609, 1445, 1341 cm–1.
129.1, 128.9, 128.2, 127.0, 123.2, 121.0, 120.2, 69.1, 21.2.
1H NMR (200 MHz, CDCl3): d = 8.78 (1 H, br s), 7.77–7.52 (6 H,
m), 7.40–7.12 (9 H, m), 6.98 (2 H, d, J = 8.0 Hz), 6.58 (1 H, s), 2.17
(3 H, s).
13C NMR (50 MHz, CDCl3): d = 153.3, 145.2, 136.1, 133.1, 131.8,
129.7, 129.2, 128.8, 128.5, 128.2, 127.5, 127.3, 127.1, 126.8, 125.0,
123.2, 123.0, 120.4, 70.0, 21.1.
ESI-MS: m/z = 445, 447 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C24H19ClO3S + Na: 445.0641;
445.0637.
1-[(2-Chloro-4-fluorophenyl)(p-tosyl)methyl]-2-naphthol (3f)
Yellow oil.
IR (KBr): 3385, 1600, 1490, 1279 cm–1.
1H NMR (200 MHz, CDCl3): d = 9.34 (1 H, s), 8.38 (1 H, m) 7.74–
7.58 (4 H, m), 7.33–7.02 (8 H, m), 6.72 (1 H, s), 2.38 (3 H, s).
ESI-MS: m/z = 461 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C28H22O3S + Na: 461.1182;
found: 461.1179.
1-[1-(p-Tosyl)butyl]-2-naphthol (3k)
Yellow oil.
IR (KBr): 3348, 1624, 1597, 1462, 1280 cm–1.
13C NMR (50 MHz, CDCl3): d = 164.5, 154.0, 145.6, 134.8, 133.7,
132.1, 130.0, 129.9, 127.3, 123.8, 122.1, 121.8, 117.9 (d, J = 10.0
Hz), 115.1 (d, J = 10.0 Hz), 67.0, 21.5.
ESI-MS: m/z = 463, 465 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C24H18ClO3S + Na: 463.0541;
1H NMR (200 MHz, CDCl3): d = 8.60 (1 H, s), 7.70–7.59 (2 H, m),
7.54 (2 H, d, J = 8.0 Hz), 7.34–7.22 (2 H, m), 7.20–7.13 (2 H, m),
7.02 (2 H, d, J = 8.0 Hz), 4.98 (1 H, dd, J = 7.0, 2.0 Hz), 2.70 (1 H,
m), 2.41 (1 H, m), 2.21 (3 H, s), 1.20–1.09 (2 H, m), 0.82 (3 H, t,
J = 7.0 Hz).
found: 463.0544.
1-[(1,3-Benzodioxo1-5-yl)(p-tosyl)methyl]-2-naphthol (3g)
Yellow oil.
Synthesis 2010, No. 21, 3731–3735 © Thieme Stuttgart · New York

3734
B. Das et al.
PAPER
13C NMR (50 MHz, CDCl3): d = 155.1, 144.6, 135.1, 131.5, 129.5,
129.1, 129.0, 126.9, 123.1, 121.3, 120.6, 64.7, 26.2, 21.1, 20.7,
13.9.
ESI-MS: m/z = 377 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C21H22O3S + Na: 377.1187;
1-(1-p-Tolylbut-3-enyl)-2-naphthol (4b)
Yellow oil.
IR (KBr): 3423, 1603, 1512, 1461, 1267 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.02 (1 H, d, J = 8.0 Hz), 7.75 (1
H, d, J = 8.0 Hz), 7.61 (1 H, d, J = 8.0 Hz), 7.40 (1 H, t, J = 8.0 Hz),
7.33–7.20 (3 H, m), 7.16–7.04 (2 H, m), 6.93 (1 H, d, J = 8.0 Hz),
5.70 (1 H, m), 5.12–4.99 (2 H, m), 4.88 (1 H, br d, J = 8.0 Hz), 3.12
(1 H, m), 2.95 (1 H, m), 2.29 (3 H, s).
found: 377.1186.
1-[2-Methyl-1-(p-tosyl)propyl]-2-naphthol (3l)
Yellow oil.
13C NMR (50 MHz, CDCl3): d = 152.5, 140.0, 137.2, 136.1, 133.4,
129.7, 128.9, 128.0, 126.8, 123.2, 122.3, 119.5, 116.6, 40.2, 35.9,
21.0.
IR (KBr): 3360, 1598, 1514, 1457, 1338, 1283 cm–1.
1H NMR (200 MHz, CDCl3): d = 8.92 (1 H, br s), 7.51 (2 H, d,
J = 8.0 Hz), 7.41–7.22 (6 H, m), 6.90 (2 H, d, J = 8.0 Hz), 5.41 (1
H, d, J = 7.0 Hz), 3.31 (1 H, m), 2.22 (3 H, s), 1.29 (6 H, d, J = 7.0
Hz).
13C NMR (50 MHz, CDCl3): d = 153.1, 143.0, 138.2, 133.2, 131.0,
130.5, 129.0, 128.7, 127.5, 126.5, 126.2, 125.2, 123.0, 122.8, 67.3,
27.5, 31.2, 14.4.
ESI-MS: m/z = 289 [M + H]+.
Anal. Calcd for C21H20O: C, 87.50; H, 6.94. Found: C, 87.63; H,
6.87.
1-[(4-Isopropylphenyl)(4-methoxyphenyl)methyl]-2-naphthol
(5b)
Yellow oil.
ESI-MS: m/z = 377 [M + Na]+.
HR-ESI-MS: m/z [M + Na]+ calcd for C21H22O3S + Na: 377.1187;
IR (KBr): 3483, 1615, 1509, 1462, 1250 cm–1.
found: 377.1189.
1H NMR (200 MHz, CDCl3): d = 7.92 (1 H, d, J = 8.0 Hz), 7.71 (1
H, d, J = 8.0 Hz), 7.65 (1 H, d, J = 8.0 Hz), 7.40–7.21 (2 H, m),
7.18–7.08 (6 H, m), 7.01 (1 H, d, J = 8.0 Hz), 6.81 (2 H, d, J = 8.0
Hz), 6.25 (1 H, s), 3.75 (3 H, s), 2.89 (1 H, m), 1.27 (6 H, d, J = 7.0
Hz).
13C NMR (50 MHz, CDCl3): d = 158.9, 153.2, 148.0, 139.5, 133.4,
130.0, 129.8, 128.9, 128.8, 127.5, 126.4, 123.0, 122.8, 120.1, 114.3,
55.6, 47.8, 30.0, 24.1.
Reaction of Sulfone Derivatives 3 with Nucleophiles; General
Procedure
To a stirred solution of the sulfonyl derivative 3 (1 mmol) in anhyd
CH2Cl2 (4 mL) kept under N2 at –10 °C were added allyltributyltin
or anisole (1.5 mmol) and BF3·Et2O (20 mol%) under stirring. The
reaction was monitored by TLC. After completion, the reaction
mixture was concentrated. H2O (10 mL) and EtOAc (10 mL) were
added. The organic layer was separated and concentrated. The resi-
due was subjected to column chromatography (silica gel; hexane–
EtOAc) to isolate the pure product.
ESI-MS: m/z = 405 [M + Na]+.
Anal. Calcd for C27H26O2: C, 84.82; H, 6.81. Found: C, 84.71; H,
6.87.
1-(1-Phenylbut-3-enyl)-2-naphthol (4a)
Yellow oil.
IR (KBr): 3423, 1603, 1512, 1461, 1267 cm–1.
Acknowledgment
The authors thank CSIR and UGC, New Delhi for financial assi-
stance.
1H NMR (200 MHz, CDCl3): d = 8.02 (1 H, d, J = 8.0 Hz), 7.72 (1
H, d, J = 8.0 Hz), 7.61 (1 H, d, J = 8.0 Hz), 7.40 (1 H, t, J = 8.0 Hz),
7.36–7.21 (3 H, m), 7.10 (2 H, d, J = 8.0 Hz), 6.95 (1 H, d, J = 8.0
Hz), 5.71 (1 H, m), 5.14–4.98 (2 H, m), 5.87 (1 H, d, J = 7.0 Hz),
3.12 (1 H, m), 2.95 (1 H, m), 2.27 (3 H, s).
13C NMR (50 MHz, CDCl3): d = 152.2, 139.6, 136.9, 135.0, 133.4,
129.6, 128.8, 127.5, 126.3, 123.2, 122.4, 119.1, 116.4, 40.5, 36.2,
21.1.
References
(1) Part 209 in the series ‘Studies on Novel Synthetic
Methodologies’.
(2) Shen, A. Y.; Tsai, C. T.; Chen, C. L. Eur. J. Med Chem.
1999, 34, 877.
(3) (a) Das, B.; Laxminarayana, K.; Ravikanth, B.; Rao, B. R.
J. Mol. Catal. A: Chem. 2007, 261, 180. (b) Das, B.;
Veeranjaneyulu, B.; Krishnaiah, M.; Balasubramanyam, P.
Synth. Commun. 2009, 39, 1929.
ESI-MS: m/z = 289 [M + H]+.
Anal. Calcd for C21H20O: C, 87.50; H, 6.94. Found: C, 87.61; H,
6.98.
(4) (a) Khodaei, M. M.; Khosropour, A. R.; Moghanian, H.
Synlett 2006, 916. (b) Selvam, N. P.; Perumal, P. T.
Tetrahedron Lett. 2006, 47, 7481. (c) Srihari, G.; Nagaraju,
M.; Murthy, M. M. Helv. Chim. Acta 2007, 90, 1497.
(d) Shaterian, H. R.; Amirzadeh, A.; Khorami, E.;
Ghashang, M. Synth. Commun. 2008, 38, 2983.
(e) Mahdavinia, G. H.; Bigdeli, M. A. Chin. Chem. Lett.
2009, 20, 383.
(5) (a) Das, B.; Damodar, K.; Saritha, D.; Chowdhury, N.;
Krishnaiah, M. Tetrahedron Lett. 2007, 48, 7930. (b) Das,
B.; Damodar, K.; Shashi Kanth, B.; Srinivas, Y.; Kalavathi,
I. Synlett 2008, 3133. (c) Das, B.; Damodar, K.; Bhunia, N.
J. Org. Chem. 2009, 74, 5607.
1-[(4-Methoxyphenyl)(phenyl)methyl]-2-naphthol (5a)
Yellow oil.
IR (KBr): 3481, 1610, 1508, 1460, 1249 cm–1.
1H NMR (200 MHz, CDCl3): d = 7.91 (2 H, d, J = 8.0 Hz), 7.75–
7.68 (2 H, m), 7.40–7.20 (7 H, m), 7.11 (2 H, d, J = 8.0 Hz), 7.02 (1
H, d, J = 8.0 Hz), 6.81 (2 H, d, J = 8.0 Hz), 6.30 (1 H, s), 5.11 (1 H,
br s), 3.73 (3 H, s).
13C NMR (50 MHz, CDCl3): d = 159.5, 153.2, 141.8, 133.6, 133.5,
130.0, 129.8, 129.2, 129.0, 127.3, 127.0, 123.1, 122.8, 120.2, 114.8,
55.0, 48.2.
ESI-MS: m/z = 329 [M + H]+.
(6) (a) Pearson, W. H.; Lindbeck, A. C.; Kampf, J. W. J. Am.
Chem. Soc. 1933, 115, 2622. (b) Mecozzi, T.; Petrini, M.
J. Org. Chem. 1999, 64, 8970.
Anal. Calcd for C23H20O2: C, 84.15; H, 6.10. Found: C, 84.22; H,
6.07.
Synthesis 2010, No. 21, 3731–3735 © Thieme Stuttgart · New York

PAPER
Friedel–Crafts Reactions of 2-Naphthol with a-Amido Sulfones
3735
(7) (a) Petrini, M. Chem. Rev. 2005, 105, 3949. (b) Petrini, M.;
Baumann, T.; Dabmen, S.; Bräse, S. Adv. Synth. Catal. 2009,
351, 1019.
Torregiani, E. Synthesis 2007, 159. (c) Thirupathi, P.; Kim,
S. S. J. Org. Chem. 2009, 74, 7755. (d) Reingruber, R.;
Synthesis 2010, No. 21, 3731–3735 © Thieme Stuttgart · New York