Unusual functionalization of the lower rim of thiacalix[4]arene: Competition of alkylation and transalkylation

Article abstract of DOI:10.1007/s11172-011-0076-0

Thiacalix[4]arenes mono-, 1,3-di-, tri-, and tetrasubstituted at the lower rim, including those containing different substituents, were synthesized by the method based on the ability of the phenacyl moiety to serve as the protecting group, as well as to b

Full text of DOI:10.1007/s11172-011-0076-0

Russian Chemical Bulletin, International Edition, Vol. 60, No. 3, pp. 486—498, March, 2011
486
Unusual functionalization of the lower rim
of thiacalix[4]arene: competition of alkylation and transalkylation
S. E. Solovieva, E. V. Popova, A. O. Omran, A. T. Gubaidullin, S. V. Kharlamov, Sh. K. Latypov,
I. S. Antipin, and A. I. Konovalov
A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Research Center of the Russian Academy of Sciences,
8 ul. Akad. Arbuzova, 420088 Kazan, Russian Federation.
Fax: +7 (843) 273 2253. Eꢀmail: svsol@iopc.knc.ru; iantipin@ksu.ru
Thiacalix[4]arenes monoꢀ, 1,3ꢀdiꢀ, triꢀ, and tetrasubstituted at the lower rim, including
those containing different substituents, were synthesized by the method based on the ability of
the phenacyl moiety to serve as the protecting group, as well as to be involved in transalkylation.
Key words: thiacalix[4]arenes, protecting groups, functionalization of the lower rim, transꢀ
alkylation, Xꢀray diffraction study.
Thiacalix[4]arenes 1 represent a group of macrocyclic
compounds with distinct molecular cavities1—6 and serve
as convenient molecular platforms for the design of preorꢀ
ganized structures and supramolecular ensembles due to
a considerable potential for modifications of the upper
and lower rims of the macrocycle. The efficiency and seꢀ
lectivity of guest—host interactions can be increased manꢀ
ifold by the selective functionalization with appropriate
heteroatomic groups as a result of the formation of recepꢀ
tor systems containing several spatially preorganized bindꢀ
ing sites. The existence of several stereoisomers of the
thiacalix[4]arene platform, such as cone, partial cone,
1,3ꢀ and 1,2ꢀalternates,1 provides additional possibilities
for the design of molecular receptors. In addition, the
presence of bridging sulfur atoms and an increase in the
size of the cavity of the macrocycle in thiacalix[4]arene 1
compared to calix[4]arene 2 results in new features in the
chemical behavior, including the complexing ability.4—6
Results and Discussion
It is known that the reactions of calix[4]arene 2 with
alkylating agents in the presence of alkali carbonates afꢀ
ford disubstituted derivatives in high yields, whereas tetraꢀ
substituted products are difficult to synthesize even with
the use of strong bases, for example, of sodium hydride.1—3
1: X = S, R = H
2: X = CH2, R = H
In the series of thiacalix[4]arenes, tetrasubstituted prodꢀ
ucts are formed even in the presence of alkali carbonates.
Hence, the development of approaches to the synthesis of
partially substituted derivatives is of great importance.
Such a different behavior of these metacyclophanes is
due to changes in the hydrogen bond energy7 and the acidꢀ
base properties of phenol groups8 at the lower rim of the
macrocycles. In our opinion, there are three fundamenꢀ
tally different approaches to the synthesis of partially subꢀ
stituted thiacalix[4]arenes. One approach is based on the
optimization of the reaction conditions, including most
often the use of stoichiometric amounts of the reagents
and a base and the choice of the solvent, in which the
intermediates of the reaction are removed from the reacꢀ
tion zone due to their low solubility. This approach was
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 476—488, March, 2011.
1066ꢀ5285/11/6003ꢀ486 © 2011 Springer Science+Business Media, Inc.

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Russ.Chem.Bull., Int.Ed., Vol. 60, No. 3, March, 2011
487
Scheme 1
used for the synthesis of 1,3ꢀdisubstituted (soꢀcalled disꢀ
tally substituted) derivatives 3—7 in 50—85% yields.9—11
R = Me (3), CH2COOEt (4), CH2COOH (5), CH2Ph (6),
CH2C6H4NO2 (7), (CH2)nY (8), CH2COPh (9)
Another approach is based on the creation of steric
hindrances at the reaction centers by using reagents with
bulky substituents. This approach was successfully used
for the synthesis of a series of distal thiacalix[4]arenes 8
having the cone conformation in yields from 29 to 89% by
the Mitsunobu reaction.12 This approach opens up possiꢀ
bilities for the synthesis of monoꢀ and bisꢀcrown derivaꢀ
tives13 and some other disubstituted products.14—17 The
third approach to the synthesis of disubstituted thiaꢀ
calix[4]arene derivatives is described in the present study
and is based on the thermodynamic stabilization of the
resulting partially substituted products due to the formaꢀ
tion of hydrogen bonds between free phenolic hydroxyls
and functional groups of the substituents.
i. PhC(O)CH2Br, CsOH, MeCN, 12 h, 82 °C. ii. 1) PhCH3
(PhH), heating, PhNH2 (C6H13NH2); 2) DMF, Na2CO3, heating.
αꢀBromoacetophenone, whose carbonyl group can
form hydrogen bonds with phenolic hydroxyl, is a suitable
reagent for the functionalization of the thiacalixarene platꢀ
form. Earlier, we have described18 the synthesis of distally
substituted product 9 in 15% yield by the reaction of thiaꢀ
calixarene 1 with αꢀbromoacetophenone in acetonitrile in
the presence of a sixfold excess of cesium carbonate and
αꢀbromoacetophenone.
arene. The signals of the phenyl substituents are observed
in the 1H NMR spectrum (Fig. 1) as a doublet of the
orthoꢀphenyl protons (оꢀPhH, δ 8.16) and two triplets
of the paraꢀ (pꢀPhH, δ 7.59) and metaꢀphenyl (mꢀPhH,
δ 7.48) protons.
In the present study, we developed a procedure for the
synthesis of compound 9 in high yield (Scheme 1). The reꢀ
action of thiacalixarene with αꢀbromoacetophenone in acꢀ
etonitrile using the reagent ratio 1 : BrCH2C(O)Ph : CsOH =
= 1 : 2 : 2 and cesium hydroxide as the base gave comꢀ
pound 9 in 81% yield. It should be noted that, as opposed
to most of the procedures for the preparation of lowerꢀrim
functionalized thiacalixarenes, compound 9 can be easily
purified by recrystallization from a chloroform—hexane
mixture. The structure of compound 9 was confirmed by
oneꢀ and twoꢀdimensional NMR spectroscopy, IR specꢀ
troscopy, MALDIꢀTOF mass spectrometry, and Xꢀray difꢀ
fraction study.
The 1H NMR spectrum of compound 9 shows signals
of the phenyl protons of the substituents, two singlets of
equal intensity for the aromatic protons of the calixarene
platform, a singlet of the methylene protons, and two sinꢀ
glets of the tertꢀbutyl protons. This spectral pattern correꢀ
sponds to the structure of distally substituted thiacalix[4]ꢀ
The threeꢀdimensional structure of macrocycle 9 in
solution (cone) was determined by 2D NOESY spectroꢀ
scopy. The spectrum shows crossꢀpeaks between the sigꢀ
nals for the protons of the hydroxy and methylene groups,
the protons of ArH, the substituted and unsubstituted
4ꢀtertꢀbutylphenyl fragments, as well as between the sigꢀ
nals of the orthoꢀphenyl protons and the protons of the
—OCH2CO— group.
The singleꢀcrystal Xꢀray diffraction data for compound
9, whose crystals were grown from a chloroform—acetoꢀ
nitrile mixture, confirm the stereoisomeric form cone
(Fig. 2) of compound 9 and indicate that the stability of
this structure is associated with the formation of intraꢀ
molecular hydrogen bonds.
According to the Xꢀray diffraction data, compound 9
forms monoclinic crystals containing one independent
calixarene molecule and solvent water molecules in a ratio
of 1 : 3. One of the tertꢀbutyl groups of molecule 9 is disorꢀ
dered over two positions with occupancies of 0.64 and

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Solovieva et al.
HO
mꢀH—Ph
oꢀH—Ph
pꢀH—Ph
8.6
8.4
8.2
8.0
7.8
7.6
7.4
7.2
7.0
6.8
6.6
6.4
δ
Fig. 1. Fragment of the 1H NMR spectrum of compound 9 in the aromatic proton region (CDCl3, 25 °C).
0.36. Two solvent water molecules are also disordered over
two positions with equal occupancy.
the molecule are 135.5, 140.7, –68.8, and 107.6°. Apparꢀ
ently, this mutual arrangement is determined by steric
hindrance due to the presence of the bulky substituents at
the lower rim of the molecule. This is also evidenced by
the character of the mutual arrangement of two phenacyl
substituents, resulting in the H(52)...O(54) interaction. It
should be noted that there are a large number of intramoꢀ
lecular O—H...O, O—H...S, and C—H...O hydrogen
bonds in molecule 9. The parameters of these interactions
are given in Table 1.
In the crystal structure, the calixarene molecule loses
the symmetry C2 and adopts the distorted cone conformaꢀ
tion (see Fig. 2) because two opposite benzene rings are
bent not in the opposite directions, as it is observed in the
classical cone conformation,1,3 but in the same direction
and are almost parallel to each other (the dihedral angle
between the benzene rings is 4.0(1)°, and the dihedral
angle between the two other rings is 83.6(2)°).
If the plane passing through four bridging sulfur atoms
is taken as the main plane of the molecule, the angles
between this plane and the planes of four benzene rings of
Only a pair of C—H...O hydrogen bonds (see Table 1)
responsible for the formation of centrosymmetric dimers
(Fig. 3) belongs to intermolecular interactions. The
a
b
S(1)
S(22)
S(1)
O(28)
S(22)
O(7)
H(452)
H(451)
H(21)
H(7)
H(21)
O(54)
H(7)
H(452)
O(54)
H(52)
H(52)
Fig. 2. Two projections of the molecular structure of product 9 in the crystalline state. Only the hydrogen atoms that are involved in the
hydrogen bonding (dashed lines) are shown. The solvent water molecules are not shown. The disordered tertꢀbutyl groups are
presented in positions with the highest occupancy.

Thiacalixarene derivatives
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489
Table 1. Hydrogen bond parameters in the crystal structure of
compound 9
H(402)
D—H...A
d/Å
Angle
/deg
O(14)
O(7)
D—H
H...A
D...A
O(7)—H(7)...S(1)
0.82
0.82
0.82
0.82
0.82
0.97
0.97
0.93
2.57
2.28
2.43
2.57
2.22
2.53
2.57
2.57
2.48
3.072(3)
3.031(4)
2.980(5)
3.072(3)
2.907(4)
3.344(5)
3.413(5)
3.297(7)
121
152
125
121
142
141
146
135
O(21)
O(28)
O(7)—H(7)...O(28)
O(7)—H(7)...O(54)
O(21)—H(21)...S(22)
O(21)—H(21)...O(28)
C(45)—H(451)...O(7)
C(45)—H(452)...O(21)
C(52)—H(52)...O(54)
Fig. 3. Formation of a dimer in the crystal structure of comꢀ
pound 9. Only the hydrogen atoms that are involved in the hyꢀ
drogen bonding (dashed lines) are shown. The solvent water
molecules are not shown.
C(40)—H(402)...O(21)* 0.96
3.404(10) 160
* The symmetry operation –x, –y, 1 – z.
π—π interaction between the electronic systems of the
aromatic rings of two adjacent molecules (the distance
between the centers of the rings is 4.186(3) Å, the dihedral
angle is 0°, the distance between the planes of the rings is
3.89 Å) also makes a contribution. The closer contact
between the benzene rings is hindered by the tertꢀbutyl
groups. The water molecules that are present in the crystal are
apparently weakly bound to a particular functional group of
thiacalix[4]arene molecule 9, which is indirectly evidenced
by their disordered arrangement in the crystal structure.
The investigation of the reactivity of compound 9
showed that the phenacyl moiety can be easily and quantiꢀ
tatively removed from the thiacalixarene platform by either
heating in DMF in the presence of a base (sodium carbonꢀ
ate) or refluxing in toluene or benzene in the presence of
benzylamine or hexylamine (see Scheme 1). Consequently,
the phenacyl moiety in compound 9 can act as the effiꢀ
cient protecting group, which opens up new possibilities
for the synthesis of mixed and asymmetrically substituted
thiacalixarenes.
To realize these possibilities, we made an attempt to
perform the functionalization at the remaining free pheꢀ
nol groups of macrocycle 9 with the aim of obtaining tetraꢀ
substituted product 10 containing different substituents
(Scheme 2). However, the reaction of compound 9 with
1ꢀiodopropane in acetone in the presence of sodium carꢀ
bonate afforded unexpected disubstituted product 11, viz.,
the dipropoxy derivative, in 89% yield.
The structure of compound 11 was determined by
NMR spectroscopy and Xꢀray diffraction. Compound 11
crystallizes in the individual state and forms monoclinic
crystals with one independent calixarene molecule (Fig. 4).
In the crystal structure, two tertꢀbutyl groups and two proꢀ
pyl groups are disordered over two positions with occuꢀ
pancies of 0.64 and 0.36. The conformation of calixarene
molecule 11 in the crystal is analogous to that of comꢀ
pound 9. Thus, both molecules have a distorted cone conꢀ
formation (the dihedral angle between two opposite benꢀ
zene rings that are bent in the same direction is 2.9(1)°;
the dihedral angle between the other two rings is 62.8(2)°).
a
b
S(15)
S(8)
S(1)
O(6)
O(6)
S(22)
S(22)
S(15)
S(8)
H(6)
O(46)
S(1)
H(47B)
O(8)
O(8)
H(47A)
H(8)
O(33)
H(6)
H(47A)
H(47B)
H(8)
Fig. 4. Two projections of molecule 11 in the crystalline state. Only the hydrogen atoms that are involved in the hydrogen bonding
(dashed lines) are shown. The disordered tertꢀbutyl and propyl groups are presented in positions with the highest occupancy.

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Solovieva et al.
Scheme 2
i. PrI, Na2CO3, Me2CO, 48 h; ii. PrBr, Na2CO3, Me2CO, 24 h.
Intermolecular hydrogen bonds were not found in the
crystal structure of 11. The absence of essential interacꢀ
tions is indirectly evidenced also by the disorder of the
tertꢀbutyl and propyl groups of the molecules. The hydroꢀ
gen atoms of the hydroxy groups of compound 11 also
participate only in intramolecular hydrogen bonds. The
involvement of two αꢀH atoms of the propoxy group in the
hydrogen bonding with the oxygen atoms of the hydroxy
groups results in the formation of the cyclic hydrogen bond
at the lower rim of calixarene. There are also O—H...S
bonds. The intramolecular hydrogen bond parameters are
given in Table 2.
inconsistent with the results of our study of the reaction
of macrocycle 9 with less reactive bromopropane (see
Scheme 2). In this reaction we obtained asymmetrically
substituted thiacalixarene 12 as a result of the replacement
of one phenacyl group by the propyl group. Hence, the
most possible mechanism of the formation of compound
11 involves the transalkylation. The initially formed oxoꢀ
nium cation 14 is subjected to the nucleophilic attack at
the Cα atom of the phenacyl substituent because it is more
Table 2. Intramolecular hydrogen bond parameters in the crystal
structure of compound 11
The formation of product 11 can be attributed to the
following several processes: the removal of the phenacyl
groups resulting in the formation of the starting thiacalixꢀ
arene followed by the reaction with 1ꢀiodopropane, the
initial alkylation of two free phenol groups followed by the
removal of the phenacyl substituents, and the transalkylaꢀ
tion through the formation of oxonium cations.
The first pathway can be ruled out because the starting
thiacalixarene 1 does not react with iodopropane under
these conditions.19 The reaction by the second pathway is
D—H...A
d/Å
Angle
/deg
D—H
H...⋅A
D...A
O(6)—H(6)...S(8)
O(6)—H(6)...O(33)
O(8)—H(8)...S(1)
O(8)—H(8)...O(33)
C(47)—H(47A)...O(8)
C(47)—H(47B)...O(6)
0.82
0.82
0.82
0.82
0.97
0.97
2.60
2.11
2.53
2.10
2.46
2.52
3.072(4)
2.797(2)
3.026(4)
2.876(3)
3.290(4)
3.331(5)
118
141
120
159
144
142

Thiacalixarene derivatives
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 3, March, 2011
491
electrophilic (δ1+ > δ2+) compared to the Cα atom of the
alkyl group due to the electronꢀwithdrawing character of
the adjacent benzoyl substituent (Scheme 3).
Table 3. Intramolecular hydrogen bond parameters in the crystal
structure of compound 12
D—H...A
d/Å
Angle
/deg
D—H
H...A
D...A
Scheme 3
O(14)—H(14)...O(21)
O(28)—H(28)...O(21)
C(45)—H(451)...O(28)
0.82
0.82
0.97
2.28 2.987(6)
2.13 2.913(6)
2.39 3.328(8)
145
161
163
The hydrogen atoms of the hydroxy groups of comꢀ
pound 12 participate only in intramolecular hydrogen
bonds. As opposed to compound 11, the cyclic hydrogen
bond at the lower rim is not formed in molecule 12 beꢀ
cause the propyl substituent in the molecule is twisted in a
somewhat different way and only one of two hydrogen
atoms of the methylene group is involved in the hydrogen
bonding with the oxygen atom of the hydroxy group. The
hydrogen bond parameters are given in Table 3. In the
crystal structure, there are no essential intermolecular inꢀ
teractions, except for usual van der Waals interactions.
The 1H NMR spectrum shows signals of the aromatic
protons of thiacalix[4]arene 12 as two doublets (AB sysꢀ
tem) and two singlets (Fig. 6). Since different substituents
are present at the lower rim of the macrocycle, the specꢀ
trum of compound 12 shows signals of the protons of three
nonequivalent tertꢀbutyl groups with the intensity ratio of
1 : 1 : 2 at δ 0.38, 1.15, and 1.32, signals of the protons
of the propoxy group at δ 1.13, 2.17, and 4.22, and
a signal of the methylene protons of the benzoylmethyl
group at δ 6.47.
+
Compound 12 crystallizes in the individual state from
a dichlromethane—hexane mixture (1 : 9) and forms
orthorhombic crystals with one independent calixarene
molecule (Fig. 5). One of the tertꢀbutyl groups of the molꢀ
ecule is disordered over two positions with occupancies of
0.64 and 0.36. The conformation of calixarene 12 in the
crystal is similar to that of the aboveꢀconsidered two strucꢀ
tures. Thus, calixarene 12 has a distorted cone conformaꢀ
tion; the dihedral angle between two opposite benzene
rings that are bent in the same direction is 3.3(3)°; the
angle between the two other ring is 67.7(3)°.
The phenacyl group that remains intact in compound
12 can be easily removed by refluxing with benzylamine
a
b
S(15)
S(22)
O(28)
O(21)
S(22)
H(28)
H(14)
S(8)
O(28)
S(1)
S(15)
O(14)
O(14)
O(21)
O(7)
H(451)
S(1)
O(46)
S(8)
O(7)
O(46)
Fig. 5. Two projections of molecule 12 in the crystal structure. Only the hydrogen atoms that are involved in the hydrogen bonding
(dashed lines) are shown. The disordered tertꢀbutyl group is presented in the position with the highest occupancy.

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Solovieva et al.
ArH
mꢀPhH
ArH
ArH
ArH
CH2CO
oꢀPh
OH
pꢀPhH
8.0
7.8
7.6
7.4
7.2
7.0
6.8
6.6
6.4
δ
Fig. 6. Fragment of the 1H NMR spectrum of compound 11 (CDCl3, 25 °C).
(see Scheme 2) with the resulting formation of monosubꢀ
stituted product 13 in high yield (82%). The 1H NMR
spectrum of 13 shows signals of the protons of three nonꢀ
equivalent tertꢀbutyl groups with the intensity ratio of
2 : 1 : 1 and signals of the protons of the propyl group. The
aromatic protons appear as two singlets and two doublets
(AB system). The protons of the hydroxy groups appear as
two singlets with the intensity ratio of 1 : 2. The 2D ROESY
spectrum of compound 13 shows a crossꢀpeak between
the protons of the tertꢀbutyl groups and the aromatic proꢀ
tons of calixarene and a crossꢀpeak between the protons of
the propyl substituent and the protons of the OH groups.
This indicates that macrocycle 13 retains the stereoꢀ
isomeric cone conformation.
hydroxy groups as the main pathway giving isomeric tetraꢀ
substituted calixarenes 10 and 15, which differ in the threeꢀ
dimensional structure of the macrocyclic platform. The
MALDIꢀTOF mass spectra of these compounds have inꢀ
tense molecular ion peaks at m/z 1041 [M + H]+, 1064
[M + Na]+, and 1080 [M + K]+.
1
The H NMR spectra of compounds 10 and 15 have
the same number of signals with the same multiplicity.
The spectra of these compound differ only in the positions
of the signals. The spectra show multiplets of the protons
of the phenyl rings, two singlets of the aromatic protons
with equal intensity, a singlet of the methylene protons of
the O—CH2—C(O)Ph groups, two singlets of the tertꢀ
butyl protons, and signals of the protons of the propoxy
1
The replacement of acetone (see Scheme 2) by more
polar and higherꢀboiling acetonitrile (Scheme 4) led to
a sharp decrease (to 10%) in the yield of the transalkylaꢀ
tion product, viz., compound 12. The reaction of macroꢀ
cycle 9 with 1ꢀiodopropane involves the alkylation of free
groups. These H NMR spectra correspond to the strucꢀ
ture of symmetrically tetrasubstituted thiacalix[4]arene
containing different substituents. To determine the threeꢀ
dimensional structures of compounds 10 and 15, we perꢀ
formed 2D ROESY experiments. The 2D ROESY specꢀ
Scheme 4
coneꢀ10 (50%)
1,3ꢀalternateꢀ15 (10%)

Thiacalixarene derivatives
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 3, March, 2011
493
trum of compound 10 shows three crossꢀpeaks indicative
of the cone conformation: a crossꢀpeak between the proꢀ
tons of the tertꢀbutyl groups and the aromatic protons of
the calixarene platform and crossꢀpeaks between the orthoꢀ
phenyl protons of the substituent and the protons of the
—OCH2CO— fragment and the propyl group. The predomꢀ
inant formation of the stereoisomeric cone conformation
(compound 10) is associated with the template effect of
the sodium cation.5,6,18
Compound 15 is characterized by the nuclear Overꢀ
hauser effects (NOE) between the protons of the tertꢀbutyl
groups and the orthoꢀphenyl protons of the substituent,
between the protons of the tertꢀbutyl groups and the aroꢀ
matic protons of calixarene, and between the protons of
the propyl substituent and the aromatic protons of calixꢀ
arene. These interactions can occur only in the 1,3ꢀalterꢀ
nate conformation.
The structure of compound 15 was confirmed by the
Xꢀray diffraction data. Compound 15 crystallizes in the
individual state. In the crystal structure, molecule 15 has
a symmetrical structure and occupies a special position on
a twofold axis. Hence, there is oneꢀhalf of molecule 15 per
asymmetric unit. The molecular structure of compound
15 is shown in Fig. 7. One of two independent tertꢀbutyl
groups is disordered over two positions with occupancies
of 0.6 : 0.4. There are no essential intermolecular and inꢀ
tramolecular interactions in the crystal.
Therefore, the reaction of bisꢀphenacyl derivative 9
with haloalkanes occurs via two competitive pathways,
viz., the alkylation of free phenol groups OH and the transꢀ
alkylation of the phenacyl moiety (see Schemes 2 and 4),
the ratio between these processes being determined by the
reaction conditions. We found the following two factors
that have a substantial effect on the ratio of the alkylation
to transalkylation products: the nature of the cation in
alkali carbonate that is used as the base and the solvating
ability of the solvent.
The influence of the alkali metal cation was studied by
an example of the reaction of compound 9 with 1ꢀiodoꢀ
propane. The use of potassium or cesium carbonate inꢀ
stead of sodium carbonate in acetone leads to a sharp
change in the reaction pathway. In this case, the alkylaꢀ
tion of the free phenol groups OH giving product 15 is the
major reaction (Scheme 5). In addition, compounds
16—18 were also isolated from the reaction mixture by
chromatography. The latter compounds are formed due to
the fact that both reactions proceed simultaneously.
The conformation of compound 16, viz., the partial
cone, was determined by the 2D ROESY method. Comꢀ
1
pound 18 was identified based on the results of H NMR
spectroscopy and MALDIꢀTOF mass spectrometry and
the data published in the literature.19
1
In the H NMR spectrum of macrocycle 17 (Fig. 8),
there are several overlapping multiplets in the aromatic
(δ 7—8) and aliphatic (δ 0.5—1.5) regions, as well as
a series of signals at δ 3.5—6.5.
The multiplet at δ 5.26 (AB system, J = 28.2 Hz)
corresponds to the protons C(4)H2 (δ) (the atomic numꢀ
bering scheme is shown in Fig. 9), because the HMBC
spectrum shows a crossꢀpeak between this proton and the
carbonyl C atom (δ 198). The HMBC spectrum also shows
a crossꢀpeak between this C atom and the protons H(3)
(δ 7.79). The presence of NOE between the protons
C(4)H2 (δ) and H(3) (δ) additionally supports the above
Scheme 5
Reagents
Yield (%)
15
50
47
40
13
16
25
30
<5
70
17
<5
<5
43
—
18
<5
<5
—
K2CO3, Me2CO
Cs2CO3, Me2CO
K2CO3, MeCN
Cs2CO3, MeCN
—

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Solovieva et al.
a
b
S(8)
O(36)
O(25)
O(22)
O(36)
S(1)
S(8)
O(22)
O(25)
Fig. 7. Two projections of molecule 15 in the crystal structure. The disordered tertꢀbutyl group is presented in the position with the
highest occupancy.
conclusions (see Fig. 9). In addition, there are overlapꢀ
ping multiplets for the protons C(3)H2 (4 H) of the α and
β fragments (see Fig. 9) (δ ∼3.84) of compound 17. Four
AB systems (J = 2.7 Hz, the identification based on the
1D TOCSY spectra) in the aromatic region (see Fig. 8) of
the protons at the rim of calixarene are indicative of the
asymmetric structure.
To determine the conformation of compound 17, we
performed a series of NOE experiments (see Fig. 9). Upon
excitation of H(3) (δ fragment, see Fig. 9) (δ 7.79), NOE
was observed on C(4)H2 (δ fragment) (δ 5.26) and on two
multiplets in the aromatic region corresponding to the
protons H(1) and H(2) of the δ fragment (δ 7.20, 7.41)
and a signal at δ 1.26 assigned to the protons of one of the
tertꢀbutyl groups. In turn, the absence of NOE on the
signals of the aliphatic protons (H(1), H(2), and H(3)) of
the α and β fragments indicates that these fragments are
spatially distant from the phenylcarbonyl substituent δ.
Upon excitation of the protons C(3)H2 (α and β) (δ 3.84,
see Fig. 9), NOE was observed on four doublets of the AB
systems belonging to the protons of the rim and the proꢀ
tons C(2)H2/C(1)H3 (α and β fragments). In addition,
there is NOE between C(4)H2 (δ fragment) (δ 5.26) and
two doublets of two AB systems (see Fig. 9). Therefore,
AB
H(3)(δ)
7.8
7.7
7.6
7.5
7.4
1.0
7.3
7.2
δ
1.6
1.5
1.4
1.3
1.2
1.1
0.9 0.8
0.7
δ
H(3)(δ)
C(4)H2(δ)
C(3)H2(α, β)
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
δ
Fig. 8. 1H NMR spectrum of compound 16 (CDCl3, T = 30 °C); the signals of the AB spin systems of the protons H(5) and H(5´) are
labeled (AB).

Thiacalixarene derivatives
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 3, March, 2011
495
Fig. 9. Main 1H—13C HMBC correlations (dashed lines) and NOE (solid arrows) and main HMBC correlations in fragments α—δ
(solid lines).
the observed NOE provide evidence that compound 17
adopts the stereoisomeric 1,3ꢀalternate conformation
(Fig. 10). Compound 17 is a new internal chiral asymmetꢀ
rically substituted thiacalix[4]arene derivative containing
three different achiral fragments.
tives, in particular, derivatives 16 and 17, in high yields
due to the fine tuning of the experimental conditions.
Evidently, the alkylation of free phenol groups OH
occurs through their deprotonation and the formation of
ion pairs, whose structure and reactivity strongly depend
on the nature of the cation and the solvating ability of the
solvent. Since the smaller alkali metal cation forms stronꢀ
ger ion pairs and leads to a decrease in the reactivity of the
anion,20—22 the transalkylation is the main reaction pathꢀ
way in acetone in the case of sodium cations. The replaceꢀ
ment of the sodium cation by potassium or cesium cations
leads to an increase in the reaction rate of alkylation and
an increase in the content of the corresponding product in
the reaction mixture. The use of the stronger solvating
higherꢀboiling solvent, viz., acetonitrile, has a similar efꢀ
fect, the influence of the nature of the cation being subꢀ
stantially weaker.
When acetonitrile is used as the solvent, the nature of
the alkali metal cation does not have a substantial effect
on the ratio of the alkylation to transalkylation reactions
(see Scheme 5) as opposed to the processes in acetone.
The total yield of the substitution products changes only
slightly. In the presence of Na2CO3 (see Scheme 4), the
yield is 60% (10 and 15); in the presence of K2CO3, the
yield is 88% (15—17); in the presence of Cs2CO3, the
yield is 83% (15 and 16) (see Scheme 5). However, in the
presence of potassium or cesium carbonate, as in the case
of acetone, the content of the products of both reactions
increases. Consequently, the rates of these reactions are
comparable, which opens up the possibility of synthesizꢀ
ing asymmetrically substituted thiacalix[4]arene derivaꢀ
To sum up, we showed that the phenacyl substituent
has a unique ability to act as the protecting group for
phenolic hydroxyls in the chemistry of thiacalixarenes and as
the good leaving group in the transalkylation, which opens
up wide possibilities for the synthesis of partially and asymꢀ
metrically substituted thiacalix[4]arene derivatives.
Experimental
The solvents were purified before use according to known
procedures.23 The 1H and 13C NMR spectra were recorded
on Bruker MSLꢀ400 and Bruker DRXꢀ500 spectrometers
(1H, 500.13 MHz; 13C, 125.77 MHz). The 1D and 2D NMR
experiments (DEPT, NOESY, 2D COSY, 2D HSQC, 2D
HMBC) were performed in CDCl3 on a Bruker Avanceꢀ600
spectrometer (1H, 600.13 MHz; 13C, 150.92 MHz) using signals
of the deuterated solvents CHCl3 (δH 7.26) and CDCl3 (δC 77.16)
as the internal standard.24 The IR spectra were recorded on
a Bruker Vector 22 Fourierꢀtransform infrared spectrometer in
KBr pellets at 1ꢀcm–1 resolution with accumulation of 64 scans
in the wavenumber range of 400—4000 cm–1 at 20 °C. The moꢀ
lecular mass spectra were obtained on a MALDIꢀTOF Dynamo
Fig. 10. Conformation of compound 17 in solution, 1,3ꢀalternate.

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Solovieva et al.
Finnigan mass spectrometer in the concentration range of
10–3—10–5 mol L–1. 1,8,9ꢀTrihydroxyanthracene or pꢀnitroꢀ
aniline was used as the matrix. The purity of the compounds
was checked by TLC on Silufol UVꢀ254 plates with the use of
a VLꢀ6.LC ultraviolet lamp (6W, 254 nm); in some cases, the
spots were visualized with iodine vapor in an iodine chamber.
The compositions of the reaction products were confirmed by
elemental analysis on a Perkin—Elmer PE 2400 series 2 CHNS/O
analyzer. The melting points were measured on a Boetius micro
meltingꢀpoint apparatus equipped with a PHMK 05 visual atꢀ
tachment. Singleꢀcrystal Xꢀray diffraction studies of compounds
9—11 and 15 were carried out at the Department of Xꢀray Difꢀ
fraction Studies of the Center of Collaborative Research on the
basis of the Laboratory of Diffraction Research Methods of the
A. E. Arbuzov Institute of Organic and Physical Chemistry of
the Kazan Research Center, the Russian Academy of Sciences.
The Xꢀray diffraction data were collected on a CADꢀ4 Nonius
B.V. automated fourꢀcircle diffractometer at 20 °C (graphite
monochromator, ω/2θꢀscanning technique, variable scan rate,
1—16.4 grad min–1, θꢀscan mode). The preliminary data proꢀ
cessing was performed with the use of the MolEN program packꢀ
age25 on an AlphaStation 200. The intensities of three check
reflections showed no decrease in the course of Xꢀray data colꢀ
lection. Empirical absorption corrections were applied. All strucꢀ
tures were solved by direct methods with the use of the SIR
program26 and refined first isotropically and then anisotropically
using the SHELXLꢀ9727 and WinGX28 program packages. The
coordinates of the hydrogen atoms of the hydroxy groups in the
structures of 9, 11, and 12 were located in difference electron
density maps (the other hydrogen atoms in all compounds were
positioned geometrically) and refined using a riding model. The
crystallographic characteristics and the Xꢀray data collection
and structure refinement statistics are given in Table 4. The
figures were drawn and the intermolecular interactions were anꢀ
alyzed with the use of the PLATON program.29 The atomic
coordinates and displacement parameters for compounds 11,
15, 9, and 12 were deposited with the Cambridge Structural
Database (http://www.ccdc.cam.ac.uk; CCDC 710148, 710149,
710150, and 710151, respectively).
pꢀtertꢀButylthiacalix[4]arene 1 (see Ref. 5) and αꢀbromoꢀ
acetophenone30 were synthesized according to procedures deꢀ
scribed earlier.
25,27ꢀBis(benzoylmethoxy)ꢀ5,11,17,23ꢀtetraꢀtertꢀbutylꢀ26,28ꢀ
dihydroxyꢀ2,8,14,20ꢀtetrathiacalix[4]arene (9). αꢀBromoacetoꢀ
phenone (0.55 g, 2.76 mmol) and predried cesium hydroxide
(0.41 g, 2.73 mmol) were added to a suspension of thiacalixarene 1
(1 g, 1.39 mmol) in anhydrous acetonitrile (60 mL). The reacꢀ
tion mixture was refluxed with stirring for 16 h and then cooled
to ~20 °C. The precipitate was filtered off, water (20 mL) was
added to the precipitate, and then extraction with chloroform
Table 4. Crystallographic characteristics and the Xꢀray data collection and structure refinement statistics for compounds 9, 11, 12, and 15
Parameter
9
11
Colorless prismatic
12
15
Color, habit
Molecular formula
Molecular weight
Crystal system
Space group
C56H60O6S4•3 H2O
1011.33
Monoclinic
P21/n
C46H60O4S4
805.18
Monoclinic
C2/c
C51H60O5S4
881.23
Orthorhombic
Pna21
C62H72O6S4
1041.48
Monoclinic
P2/c
a/Å
b//Å
с/Å
13.311(7)
22.169(9)
20.121(8)
105.24(2)
5729(4)
22.893(6)
19.559(5)
22.630(10)
114.34(5)
9232(5)
8
16.924(4)
17.030(5)
17.905(5)
—
5160(2)
4
11.343(3)
13.165(2)
19.922(6)
93.59(3)
2969.1(13)
2
β/deg
Volume/Å3
Z
4
dcalc/g cm–3
1.173
19.34
1.159
2.45
1.134
2.26
1.165
2.08
Absorption coefficient/cm–1
Absorption correction
Radiation (λ/Å)
F(000)
psiꢀscan
CuꢀKα (1.54184)
2152
psiꢀscan
MoꢀKα (0.71073)
3456
psiꢀscan
MoꢀKα (0.71073)
1880
psiꢀscan
MoꢀKα (0.71073)
1112
Number of measured reflections
9943
4884
8028
9345
Rint
0.0794
0.0544
0.1819
0.0824
Number of observed independent
reflections with I > 2σ(I)
6667
2559
4229
1639
R factors based on reflections with I > 2σ(I)
R
Rw
0.0788
0.2192
0.0618
0.1545
0.0592
0.1338
0.0548
0.1028
Goodness of fit
Number of refined parameters
h, k, l ranges
1.084
627
–15 < h < 0,
0 < k < 26,
–22 < l < 23
0.775/–0.542
0.982
472
0 < h < 22,
–19 < k < 0,
–24 < l < 20
0.571/–0.294
0.999
491
–21 < h < 0,
–19 < k < 0,
–21 < l < 19
0.669/–0.346
0.945
334
–13 < h < 13,
–15 < k < 11,
–17 < l < 23
0.212/–0.170
Residual electron density/
е•Å–3, ρmax/ρ
min

Thiacalixarene derivatives
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 3, March, 2011
497
(2×50 mL) was performed. Chloroform was evaporated until the
volume was 3 mL, hexane (10 mL) was added, and the precipiꢀ
tate that formed (0.8 g) was filtered off. An additional amount
(0.27 g) of compound 9 was isolated from the filtrate. The total
yield was 81%, m.p. 241—242 °C. Trace amounts of tetrasubstiꢀ
tuted product 13 in the stereoisomeric 1,3ꢀalternate conformaꢀ
tion18 were detected in the filtrate. Found (%): C, 70.46; H, 6.13;
S, 10.22. C56H60O6S4. Calculated (%): C, 70.26; H, 6.32;
S, 10.02. 1H NMR (CDCl3), δ: 0.81 (s, 18 H, But); 1.32 (s, 18 H,
But); 6.17 (s, 4 H, OCH2); 6.95 (s, 4 H, ArH); 7.48 (t, 4 H,
mꢀArH, J = 7.9 Hz); 7.59 (t, 2 H, pꢀArH, J = 7.9 Hz); 7.67 (t, 4 H,
ArH); 8.16 (d, 4 H, oꢀArH, J = 7.9 Hz); 8.36 (s, 2 H, OH). IR,
ν/cm–1: 3395, 3366 (OH), 1699 (C=O). MALDI TOF MS, m/z:
957 [M + H]+, 980 [M + Na]+, 997 [M + K]+.
5,11,17,23ꢀTetraꢀtertꢀbutylꢀ25,27ꢀdipropoxyꢀ26,28ꢀdihydrꢀ
oxyꢀ2,8,14,20ꢀtetrathiacalix[4]arene (11). A mixture of comꢀ
pound 9 (0.2 g, 0.209 mmol), 1ꢀiodopropane (1.8 g, 10.58 mmol),
and molten sodium carbonate (0.22 g, 2.09 mmol) in acetone
(25 mL) was refluxed with stirring for 48 h. Acetone was reꢀ
moved, chloroform (40 mL) and dilute hydrochloric acid (10 mL)
were added to the residue, and the organic phase was separated,
washed with water, dried with calcium chloride, and concenꢀ
trated to 3 mL. Then acetonitrile was added. Compound 11 was
obtained in a yield of 150 mg (89%), m.p. 224—226 °C. Found (%):
C, 69.00; H, 7.66; S, 15.46. C46H60O4S4. Calculated (%):
C, 68.62; H, 7.52; S, 15.92. 1H NMR (CDCl3), δ: 0.80 (s, 18 H,
But); 1.15 (t, 3 H, CH3CH2, J = 7.4 Hz); 1.34 (s, 18 H, But); 2.04
(m, 2 H, CH2CH2CH3, J = 7.4 Hz); 4.46 (t, 2 H, OCH2,
J = 7.4 Hz); 6.96 (s, 4 H, ArH); 7.66 (s, 4 H, ArH); 7.99 (s, 2 H,
OH). IR, ν/cm–1: 3381 (OH). MALDI TOF MS, m/z: 805
[M + H]+, 828 [M + Na]+, 844 [M + K]+.
25ꢀBenzoylmethoxyꢀ5,11,17,23ꢀtetraꢀtertꢀbutylꢀ27ꢀpropꢀ
oxyꢀ26,28ꢀdihydroxyꢀ2,8,14,20ꢀtetrathiacalix[4]arene (12).
A mixture of compound 9 (0.2 g, 0.209 mmol), 1ꢀbromopropane
(1.29 g, 10.48 mmol), and molten sodium carbonate (0.22 g,
2.09 mmol) in acetone (25 mL) was refluxed with stirring for
24 h. Acetone was removed, chloroform (25 mL) and water
(10 mL) were added to the residue, and the organic phase was
washed, separated, and dried with CaCl2. Then chloroform was
removed, and the residue was chromatographed on a column
packed with silica gel using dichloromethane as the eluent. Comꢀ
pound 12 was obtained in a yield of 114 mg (74.7%), Rf = 0.55
(CH2Cl2), m.p. 223—224 °C. Found (%): C, 69.09; H, 7.22;
S, 14.46. C51H60O5S4. Calculated (%): C, 69.51; H, 6.86; S, 14.55.
1H NMR (CDCl3), δ: 0.38 (s, 9 H, But); 1.13 (t, 3 H, CH3CH2,
J = 7.3 Hz); 1.15 (s, 9 H, But); 1.32 (s, 18 H, But); 2.17 (m, 2 H,
CH2CH2CH3, J = 7.3 Hz); 4.22 (t, 2 H, OCH2, J = 7.3 Hz);
6.30 (s, 2 H, ArH); 6.47 (s, 2 H, CH2CO); 7.48 (t, 2 H, mꢀPhH,
J = 7.7 Hz); 7.51 (s, 2 H, ArH); 7.59 (t, 1 H, pꢀPhH, J = 7.7 Hz);
7.62 (d, 2 H, ArH, J = 2.5 Hz); 7.72 (d, ArH, J = 2.5 Hz); 8.07
phy using the dichloromethane—hexane mixture (2 : 1) as the
eluent, Rf = 0.63 (CH2Cl2—hexane (2 : 1)). Compound 13 was
obtained in a yield of 68 mg (82%), m.p. 247 °C. Found (%):
C, 70.16; H, 6.43; S, 14.40. C51H60O5S4. Calculated (%): C, 69.51;
H, 6.86; S, 14.55. 1H NMR (CDCl3), δ: 1.19 (s, 9 H, But); 1.21
(s, 9 H, But); 1.24 (s, 18 H, But); 1,25 (t, 3 H, Me, J = 7.30 Hz);
2.23 (m, 2 H, CH2, J = 7.30 Hz); 4.36 (t, 2 H, CH2O, J = 7.30 Hz);
7.59 (s, 2 H, ArH); 7.60 (d, 2 H, ArH, J = 2.37 Hz); 7.64 (s, 2 H,
ArH); 7.64 (d, 2 H, ArH, J = 2.37 Hz); 9.21 (s, 2 H, OH); 9.34
(s, 1 H, OH). IR, ν/cm–1: 3397 (OH), 2931, 2870 (тꢀBu).
MALDI TOF MS, m/z: 763 [M + H]+.
25,27ꢀBis(benzoylmethoxy)ꢀ5,11,17,23ꢀtetraꢀtertꢀbutylꢀ
26,28ꢀdipropoxyꢀ2,8,14,20ꢀtetrathiacalix[4]arene (10). A mixꢀ
ture of compound 9 (0.2 g, 0.209 mmol), 1ꢀiodopropane (0.642 g,
4.22 mmol), and molten sodium carbonate (0.13 g, 0.125 mmol)
in anhydrous acetonitrile (25 mL) was placed in a 100 mL roundꢀ
bottom flask equipped with a magnetic stirrer and a reflux conꢀ
denser and refluxed with stirring for 24 h. Then the solvent was
removed in vacuo, water (30 mL) and CHCl3 (50 mL) were
added to the residue, and the organic layer was separated and
dried over CаCl2. The drying agent was filtered off, and chloroꢀ
form was removed. The residue was chromatographed on a colꢀ
umn packed with silica gel using the hexane—dichloromethane
mixture (1 : 1) and then the dichloromethane—acetone mixture
(30 : 1) as the eluents. Compound 12 was isolated in a yield of
18.5 mg (10%); compound 10, in a yield of 110 mg (50%); comꢀ
pound 15, in a yield of 22 mg (10%).
Compound 10, Rf = 0.45 (CH2Cl2), m.p. 115—117 °C.
Found (%): C, 70.89; H, 6.62; S, 12.12. C62H72O6S4. Calculatꢀ
1
ed (%): C, 70.50; H, 6.97; S, 12.31. H NMR (CDCl3), δ: 0.89
(t, 6 H, —CH2CH3, J = 7.7 Hz); 0.96 (s, 18 H, But); 1.24 (s, 18 H,
But); 1.77 (m, 4 H, —CH2CH3, J = 6.7 Hz); 3.96 (t, 4 H,
—OCH2, J = 7.7 Hz); 6.10 (s, 4 H, OCH2CO); 7.10 (s, 4 H,
ArH); 7.39 (t, 2 H, mꢀPhH, J = 6.7 Hz); 7.48 (s, 4 H, ArH); 7.53
(t, 4 H, pꢀPhH, J = 6.7 Hz); 7.98 (d, 4 H, oꢀPhH, J = 6.7 Hz).
IR, ν/cm–1: 1706 (C=O). MALDI TOF MS, m/z: 1041 [M + H]+,
1064 [M + Na]+, 1080 [M + K]+.
Compound 15, Rf = 0.31 (CH2Cl2), m.p. 256—258 °C.
Found (%): C, 70.66; H, 7.13; S, 12.75. C62H72O6S4. Calculatꢀ
1
ed (%): C, 70.50; H, 6.97; S, 12.31. H NMR (CDCl3), δ: 0.60
(t, 6 H, —CH2CH3, J = 7.8 Hz); 0.96 (s, 18 H, But); 1.16 (m, 4 H,
—CH2CH3, J = 7.8 Hz); 1.27 (s, 18 H, But); 3.83 (t, 4 H,
—OCH2, J = 7.8 Hz); 5.33 (s, 4 H, OCH2CO); 7.19 (s, 4 H, ArH);
7.36 (s, 4 H, ArH), 7.39 (t, 2 H, mꢀPhH, J = 7.8 Hz); 7.51 (t, 4 H,
pꢀPhH, J = 6.8 Hz); 7.82 (d, 4 H, oꢀPhH, J = 7.8 Hz). IR,
ν/cm–1: 1699 (C=O). MALDI TOF MS, m/z: 1041 [M + H]+,
1064 [M + Na]+, 1080 [M + K]+.
25ꢀBenzoylmethoxyꢀ5,11,17,23ꢀtetraꢀtertꢀbutylꢀ26,27,28ꢀ
tripropoxyꢀ2,8,14,20ꢀtetrathiacalix[4]arene (16). A mixture of
compound 2 (0.2 g, 0.209 mmol), 1ꢀiodopropane (0.35 g,
2 mmol), and cesium carbonate (0.68 g, 2 mmol) in anhydrous
acetonitrile or acetone (25 mL) was placed in a 100 mL roundꢀ
bottom flask equipped with a magnetic stirrer and a reflux conꢀ
denser and refluxed with stirring for 24 h. The solvent was reꢀ
moved using a waterꢀjet vacuum pump, water (30 mL) and CHCl3
(50 mL) were added to the residue, the organic layer was sepaꢀ
rated and dried over CаCl2, and the drying agent was filtered off.
Then chloroform was removed, and the residue was chromatoꢀ
graphed on a column packed with silica gel using the hexane—
dichloromethane mixture (1 : 1) and then the dichloromethane—
acetone mixture (30 : 1) as the eluents. The reaction performed
(s, 2 H, OH); 8.12 (d, 2 H, oꢀPhH, J = 7.7 Hz). IR, ν/cm–1
:
3378 (OH), 1701 (C=O). MALDI TOF MS, m/z: 881 [M + H]+,
903 [M + Na]+, 920 [M + K]+.
5,11,17,23ꢀTetraꢀtertꢀbutylꢀ25ꢀpropoxyꢀ26,27,28ꢀtrihydrꢀ
oxyꢀ2,8,14,20ꢀtetrathiacalix[4]arene (13). A mixture of comꢀ
pound 11 (0.1 g, 0.114 mmol) and benzylamine (0.05 mL,
0.46 mmol) in toluene (15 mL) was stirred at 110 °C for 24 h.
Then chloroform (20 mL) and dilute (1 : 3) hydrochloric acid
(5 mL) were added. The organic layer was washed with water
(2×10 mL) and dried over calcium chloride. The solvent was
removed, and the residue was purified by column chromatograꢀ

498
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Solovieva et al.
in acetone afforded compound 15 in a yield of 0.1 g (47%) and
compound 16 in a yield of 60 mg (30%); the reaction performed
in acetonitrile gave compound 15 in a yield of 30 mg (13%) and
compound 16 in a yield of 140 mg (70%).
3. Calixarenes in Nanoworld, Eds J. Vicens, J. Harrofield,
Springer, Dordrecht, Netherlands, 2007, 396 pp.
4. H. Kumagai, M. Hasegawa, S. Miyanari, Y. Sugawa, Y. Sato,
T. Hori, S. Ueda, H. Kamiyama, S. Miyano, Tetrahedron
Lett., 1997, 38, 3971.
Compound 16, m.p. 270—272 °C. Found (%): C, 71.22;
H, 7.63; S, 13.02. C57H72O5S4. Calculated (%): C, 70.92; H, 7.52;
S, 13.28. 1H NMR (CDCl3), δ: 0.66 (m, 9 H, —CH2CH3);
0.9—1.15 (m, 6 H, —CH2CH3); 1.11 (s, 18 H, But); 1.26 (s, 9 H,
But); 1.28 (s, 9 H, But); 3.83 (m, 6 H, —OCH2); 5.17 (s, 2 H,
—OCH2C(O)); 7.12 (d, 2 H, ArH, J = 2.3 Hz); 7.32 (s, 2 H, ArH);
7.34 (d, 2 H, ArH, J = 2.3 Hz); 7.39 (s, 2 H, ArH); 7.41 (t, 2 H,
mꢀРhH, J = 7.1 Hz); 7.52 (t, 2 H, pꢀРhH, J = 7.1 Hz); 7.77
(d, 2 H, oꢀPhH, J = 7.1 Hz). IR, ν/cm–1: 1711 (C=O). MALDI
TOF MS, m/z: 965 [M + H]+, 988 [M + Na]+, 1005 [M + K]+.
25ꢀBenzoylmethoxyꢀ5,11,17,23ꢀtetraꢀtertꢀbutylꢀ28ꢀhydrꢀ
oxyꢀ26,27ꢀdipropoxyꢀ2,8,14,20ꢀtetrathiacalix[4]arene (17).
A mixture of compound 9 (0.2 g, 0.209 mmol), 1ꢀiodopropane
(0.35 g, 2 mmol), and K2CO3 (0.28 g, 2 mmol) in anhydrous
acetonitrile or acetone (25 mL) was placed in a 100 mL roundꢀ
bottom flask equipped with a magnetic stirrer and a reflux conꢀ
denser and refluxed with stirring for 24 h. The solvent was reꢀ
moved using a waterꢀjet vacuum pump, water (30 mL) and CHCl3
(50 mL) were added to the residue, the organic layer was sepaꢀ
rated and dried over CаCl2, and the drying agent was filtered off.
Then chloroform was removed, and the residue was chromatoꢀ
graphed on a column packed with silica gel using the hexane—diꢀ
chloromethane mixture (1 : 1) and then the dichloromethꢀ
ane—acetone mixture (30 : 1) as the eluents. The reaction perꢀ
formed in acetone afforded compound 15 in a yield of 108 mg
(50%) and compound 17 in a yield of 50 mg (25%); the reaction
performed in acetonitrile gave compound 15 in a yield of 80 mg
(40%) and compound 17 in a yield of 82 mg (43%).
Compound 17, m.p. 241 °C. Found (%): C, 70.04; H, 7.15;
S, 13.98. C54H66O5S4. Calculated (%): C, 70.24; H, 7.21;
S, 13.89. 1H NMR (CDCl3), δ: 0.64 (t, 3 H, CH2CH3, J = 7.5 Hz);
0.69 (t, 3 H, CH2CH3, J = 7.5 Hz); 0.86 (m, 2 H, CH2); 1.1
(m, 2 H, CH2); 1.14 (s, 9 H, But); 1.17 (s, 18 H, But); 1.26
(s, 9 H, But); 3.84 (m, 4 H, OCH2CH2); 5.26 (m, 2 H, OCH2CO,
J = 28.2 Hz); 7.05 (d, 1 H, ArH, J = 2.7 Hz); 7.16 (d, 1 H, ArH,
J = 2.7 Hz); 7.19 (d, 1 H, ArH, J = 2.7 Hz); 7.20 (t, 2 H, РhH,
J = 7.9 Hz); 7.25 (d, 1 H, ArH, J = 2.7 Hz); 7.34 (d, 1 H, ArH,
J = 2.7 Hz); 7.37 (d, 1 H, ArH, J = 2.7 Hz); 7.39 (d, 1 H, ArH,
J = 2.7 Hz); 7.41 (t, 1 H, PhH, J = 7.9 Hz); 7.57 (d, 1 H, ArH,
J = 2.7 Hz); 7.79 (d, 2 H, РhH, J = 7.9 Hz); 7.75 (s, 1 H, OH).
IR, ν/cm–1: 1711 (C=O). MALDI TOF MS, m/z: 923 [M + H]+,
946 [M + Na]+.
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This study was financially supported by the Russian
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Received May 17, 2010;
in revised form November 18, 2010