M. Makha, C. L. Raston / Tetrahedron Letters 42 (2001) 6215–6217
6217
was added dropwise at 80°C under a stream of nitrogen.
The reaction vessel was lowered into a 200°C preheated
heating mantle and kept at this temperature for 2.5 h.
After 1 min the reactants dissolved and after 15 min a
precipitate began to form. Tetralin was evaporated in
vacuo from the cooled reaction mixture and the residue
was stirred in 200 ml of warm chloroform containing 2 M
HCl (250 ml). The chloroform layer was separated,
filtered, washed with water and dried (MgSO4) to afford
a yellowish solid, after removal of the solvent. The yel-
lowish solid was triturated in refluxing methanol, filtra-
tion affords 3 g of a beige powder which consisted of a
mixture of p-phenylcalix[n]arenes (n=4, 5 and 6). The
beige solid was then heated in an acetone/methanol mix-
ture and upon standing 0.80 g (7.4%) of p-phenyl-
calix[6]arene precipitated: IR (KBr) 3173 cm−1 (OH
mixture was filtered and treated with activated charcoal
(×2) leaving a clear light greenish solution. Water was
evaporated affording a deliquiscent light green solid,
which was crystallized from acetone to afford the per-sul-
fonic acid of p-phenylcalix[8]arene. IR (KBr): w(OH)
2900; 3200 cm−1; wa(SO2) 1006–1068 cm−1; ws(SO2) 1176
cm−1 1H NMR (300 MHz, DMSO-d6, 25°C): l=7.56
.
(br-d, 16H; PhHAX), 7.42 (br-d, 16H; PhHAX), 7.30 (s,
16H; Ar-H), 6.25 (s. br; COH/SOH, shifts downfield with
increasing [H2SO4]), 3.95 (br, 16H; Ar-CH2-Ar). 13C
NMR (300 MHz, DMSO-d6, 25°C): l=32.03
(ArCH2Ar), 126.35 (Ar), 126.64 (Ar), 127.55 (Ar), 128.64
(Ar), 132.19 (Ar), 141.65 (Ar), 145.25 (Ar), 152.11 (Ar-
OH).
17. General procedure for n=4, 5 and 6: To a solution of
p-phenylcalix[5]arene (0.4 g, 0.51 mmol) dissolved in 20
ml of dry chloroform, 1 ml of chlorosulfonic acid was
added dropwise at 0°C under argon. The mixture was
stirred at room temperature for ca. 12 h to form a bright
rose biphasic mixture. The reaction mixture was poured
over ice, and the aqueous phase was separated and
treated with activated charcoal (×2) leaving a clear light
greenish solution. Water was then evaporated affording a
deliquiscent green solid and upon addition of acetone/
methanol mixture, a fine gray precipitate formed which
was filtered over Celite to afford sulfonic acid of p-
1
stretching); H NMR (300 MHz, CDCl3, 25°C): l=4.05
(s-br, 12H; ArCH2Ar), 7.22–7.49 (m, 42H; ArH), 10.57
(s, 6H; OH); 13C NMR (300 MHz, CDCl3, 25°C): l=
32.93 (ArCH2Ar), 127.00 (Ar), 127.15 (Ar), 127.74 (Ar),
128.63 (Ar), 128.84 (Ar), 135.56 (Ar), 140.88 (Ar), 149.35
(Ar-OH), MS (ESI−): m/z (%): 1091.6 (100) [M−H+],
1092.3 (68) [M], 1093.5 (33) [M+H+]; C78H60O6 (1092.43):
requires C, 85.68; H, 5.54; found: C, 85.40; H, 6.30. The
filtrate was then evaporated and the residue triturated in
acetone/methylene chloride, affording 0.5 g (5%) of a
crystalline solid shown to be p-phenylcalix[5]arene: IR
phenylcalix[5]arene. IR (KBr): w(OH) 2900; 3413 cm−1
wa(SO2) 1007–1068 cm−1; ws(SO2) 1174 cm−1 1H NMR
,
1
(KBr) 3282 cm−1 (OH stretching); H NMR (300 MHz,
.
CDCl3, 25°C): l=4.01 (s-br, 10H; ArCH2Ar), 7.25–7.49
(m, 35H; ArH), 9.11 (s, 5H; OH); 13C NMR (300 MHz,
CDCl3, 25°C): l=32.14 (ArCH2Ar), 127.00 (Ar), 127.08
(Ar), 127.20 (Ar), 128.36 (Ar), 128.86 (Ar), 135.30 (Ar),
140.88 (Ar), 149.87 (Ar-OH), MS (ESI+): m/z (%): 933.35
(100) [M+Na+]; C65H50O5 (910.36): requires C, 85.68; H,
5.54; found: C, 84.06; H, 5.24; mp >350°C [dec.]. After
evaporation of the filtrate, the residue obtained was
triturated with acetone affording 1 g (9%) of p-phenyl-
calix[4]arene: IR (KBr) 3200 cm−1 (OH stretching); 1H
NMR (300 MHz, CDCl3, 25°C): l=3.67 (d, 4H;
(300 MHz, DMSO-d6, 25°C): l=7.58 (br-d, 10H;
PhHAX), 7.46 (br-d, 10H; PhHAX), 7.40 (s, 10H; Ar-H),
6.27 (s. br; COH/SOH, shifts downfield with increasing
[H2SO4]), 3.91 (br, 10H; Ar-CH2-Ar). 13C NMR (300
MHz, DMSO-d6, 25°C): l=31.48 (ArCH2Ar), 126.42
(Ar), 126.66 (Ar), 127.82 (Ar), 128.75 (Ar), 132.40 (Ar),
141.55 (Ar), 145.52 (Ar), 151.75 (Ar-OH).
Sulfonic acid of p-phenylcalix[4]arene: IR (KBr): w(OH)
2900; 3421 cm−1, wa(SO2) 1004–1059 cm−1; ws(SO2) 1171
cm−1 1H NMR (300 MHz, DMSO-d6, 25°C): l=7.6
.
(br-d, 8H; PhHAX), 7.4 (br-d, 8H; PhHAX), 7.27 (s, 8H;
Ar-H), 5.74 (s; COH/SOH, shifts downfield with increas-
ing [H2SO4]), 4.01 (br-s, 8H; Ar-CH2-Ar). 13C NMR (300
MHz, DMSO-d6, 25°C): l=31.66 (ArCH2Ar), 125.92
(Ar), 126.70 (Ar), 127.48 (Ar), 128.73 (Ar), 131.90 (Ar),
141.34 (Ar), 146.40 (Ar), 152.80 (Ar-OH).
ArCH2Ar; JAB=13.5 Hz), 4.38 (d, 4H; ArCH2Ar; JAB
=
13.5 Hz) 7.20–7.49 (m, 28H; ArH), 10.43 (s, 4H; OH);
13C NMR (300 MHz, CDCl3, 25°C,): l=31.33
(ArCH2Ar), 127.08 (Ar), 127.12 (Ar), 128.26 (Ar), 128.64
(Ar), 128.90 (Ar), 135.99 (Ar), 140.96 (Ar), 148.69 (Ar-
OH), MS (ESI−): m/z (%): 727.4 (100) [M−H+]; C52H40O4
(728.29): requires C, 85.68; H, 5.54; found: C, 85.50; H,
6.06.
Chromatographic separation of p-phenylcalix[4,5,6]-
arenes can also be achieved on a silica gel column using
acetone/methylene chloride/hexane as eluents at ratios of
1:1:2 with Rf values of 0.23, 0.64 and 0.46, respectively.
The chloroform insoluble material (5.7 g) contaminated
with p-phenylphenol was triturated several times with hot
acetone/chloroform to give 4.1 g (38%) of a white solid
p-phenylcalix[8]arene.
Sulfonic acid of p-phenylcalix[6]arene: IR (KBr): w(OH)
2953; 3441 cm−1, wa(SO2) 1007–1067 cm−1; ws(SO2) 1173
1
cm−1. H NMR (300 MHz, DMSO-d6, 25°C): l=7.52 (d,
12H; PhHAX; JAX=6.3 Hz), 7.43 (d, 12H; PhHAX; JAX
=
6.3 Hz), 7.32 (s, 12H; Ar-H), 8.75 (s. br, COH/SOH,
shifts downfield with increasing [H2SO4]), 3.85 (br, 12H;
Ar-CH2-Ar). 13C NMR (300 MHz, DMSO-d6, 25°C):
l=31.68 (ArCH2Ar), 126.25 (Ar), 126.40 (Ar), 127.35
(Ar), 128.75 (Ar), 132.95 (Ar), 143.01 (Ar), 145.52 (Ar),
151.70 (Ar-OH).
18. Sodium sulfonates of p-phenylcalix[4]arene, IR (KBr):
15. Shinkai, S.; Mori, S.; Koreishi, H.; Tsubaki, T.; Manabe,
O. J. Am. Chem. Soc. 1986, 108, 2409.
16. 2 g of p-phenylcalix[8] arene was stirred at 80°C in 10 ml
of neat sulfuric acid for ca. 12 h whereupon cooling, the
reaction mixture was poured over ice, then the aqueous
w(OH) 3475 cm−1, wa(SO2) 1008–1042 cm−1; ws(SO2) 1126;
1452 cm−1 1H NMR (300 MHz, DMSO-d6, 25°C): l=
,
7.56 (d, 8H; PhHAX; JAX=7.2 Hz), 7.44 (d, 8H; PhHAX),
7.37 (s, 8H; Ar-H), 3.91 (br-s, 8H; Ar-CH2-Ar).
.