Synthesis and extraction properties of oxathiacrown compounds containing benzyl groups

Article abstract of DOI:10.1007/s10593-006-0074-6

8-Benzyl-1.4-dioxa-7,10-dithiacyclododecane and 11-benzyl-1,4,7-trioxa-10, 13-dithiacyclopentadecane were obtained by the interaction of (2,3-dibromo-1-propyl)benzene with 1,8-dimercapto-3,6-dioxaoctane and 1,11-dimercapto-3,6,9-trioxaundecane. The extrac

Full text of DOI:10.1007/s10593-006-0074-6

Chemistry of Heterocyclic Compounds, Vol. 42, No. 2, 2006
SYNTHESIS AND EXTRACTION PROPERTIES
OF OXATHIACROWN COMPOUNDS
CONTAINING BENZYL GROUPS
N. A. Rezekina, E. V. Rakhmanov, E. V. Lukovskaya, A. A. Bobylyova, A. A. Abramov,
V. A. Chertkov, A. V. Khoroshutin, and A. V. Anisimov
8-Benzyl-1.4-dioxa-7,10-dithiacyclododecane and 11-benzyl-1,4,7-trioxa-10,13-dithiacyclopentadecane
were obtained by the interaction of (2,3-dibromo-1-propyl)benzene with 1,8-dimercapto-3,6-dioxaoctane
and 1,11-dimercapto-3,6,9-trioxaundecane. The extracting ability of the obtained compounds has been
studied in relation to Sr2+ and Pb2+ ions from aqueous solutions in the presence of anions of various
degrees of hardness with determination of the metal content by a radiometric method.
Keywords: dithia-12(15)-crown-4(5) ethers, Sr2+ and Pb2+ ions, complex-formation, extraction.
The ability of thiacrown ethers to form complexes with the ions of heavy and transition metals
stimulated the search for new efficient and selective ligands of this class [1]. In recent years oxathiacrown ethers
containing various substituents have been studied intensively [2-9]. However the extracting ability of similar
compounds is practically unstudied. The present work is devoted to the development of a method of synthesis of
new oxathiacrown compounds linked with aromatic fragments through a methylene bridge, and to the study of
their extracting properties. Benzooxathia and other annelated crown ethers are not considered. The essence of the
method consists of electrophilic addition of bromine at the double bond of an allyl group with subsequent
macrocyclization of the compounds obtained with various dithiols.
Since one of the most convenient methods of obtaining thiacrowns is the interaction of the appropriate
dihalides or ditosylates with dithiols [10, 11], allylbenzene (1), was selected as the starting material, and was
converted into (2,3-dibromo-1-propyl)benzene (2) [12]. 1,8-Dimercapto-3,6-dioxaoctane (3) and
1,11-dimercapto-3,6,9-trioxaundecane (4), synthesized by the method of [13], were used as nucleophiles.
n
O
SH
O
HS
S
Br2 / CHCl3
Br
3, 4
S
O
Br
M2CO3/EtOH/H2O
O
n
2
1
5, 6
3, 5 n = 1; 4, 6 n = 2; M = Li, Cs
__________________________________________________________________________________________
M. V. Lomonosov Moscow State University, Moscow 119899, Russia; e-mail:
anis@petrol.chem.msu.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 244-249,
February, 2006. Original article submitted November 29, 2004.
216
0009-3122/06/4202-0216©2006 Springer Science+Business Media, Inc.

8-Benzyl-1,4-dioxa-7,10-dithiacyclododecane (5) and 11-benzyl-1,4,7-trioxa-10,13-dithiacyclopenta-
decane (6) were obtained under high dilution conditions in the presence of template reagents Li2CO3 and Cs2CO3
by the method of [14]. A detailed study of the NMR spectra of compounds 5 and 6 was of particular interest
13
since this is important for subsequent conformational investigations. In the C NMR spectra of macrocycles 5
and 6 the number of signals in the aliphatic region was 9 and 11, which clearly confirms the proposed structures.
Integration of the chemical shifts of signals was made on the basis of HETCOR and COSY two-dimensional
experiments. Systematic analysis of the structure of multiplets in the 1H NMR spectra together with information
on cross peaks in the correlation pictures enabled an unequivocal assignment to be made of all the signals in the
1
13C NMR and of the multiplets in the H NMR spectra (see EXPERIMENTAL). Key information for assigning
was the heteronuclear 13C-1H links in the SESE experiments (spin echo with selective excitation) [15]. The
starting point was the assignment of the benzylic CH2 group signals where the spin of the carbon atom is linked
with the ortho protons of the phenyl groups in both compounds 5 and 6 [16, 17]. The multiplets in the 1H NMR
spectra of compound 5 are well resolved with the exception of a single very broad multiplet for the remote H-2
and H-3 protons. The structures of the multiplets in the spectra of compound 6 are more complex. Nevertheless
the majority of the signals were assigned apart from the remote protons H-2, H-3, H-5, and H-6. The chemical
shifts of the protons of the cyclic CH2 groups linked to oxygen and sulfur lie at 3.50-3.86 and 2.40-3.36 ppm
respectively. The range of shielding of the remote protons was significantly less than for protons of CH2 groups
linked to sulfur, which is in good agreement with data previously obtained for 12-membered thiacrown ethers
[18]. It is remarkable that in both macrocycles shielding is observed for the pseudo-axial H-6 (compound 5) and
H-9 (compound 6) protons, which are subject to more or less the same anisotropic influence of the neighboring
phenyl substituents and sulfur, as our preliminary investigations showed (see, for example [19]). On the whole
our observations for compounds 5 and 6 showed that the greater the distance of the protons of the macrocyclic
ligand from a substituent then the less is its effect on their chemical shifts. This has been noted previously for
thiacrown [18], crown [19], and azacrown ethers [20].
Concerning the study of complex formation using dithia-12(15)-crown-4(5) ethers, it is known that an
unsubstituted 15-membered macrocyle forms stable complexes with Ag(I) [21] and with ions of metals of the
platinum group [22]. In the first case coordination of the metal ion is effected both with sulfur atoms and with
oxygen, and in the second, only with the sulfur atoms. It has also been reported [22] that a 12-membered
macrocycle immobilized on SiO2 through an ester group is an efficient complex-forming adsorbent for Ag(I),
Au(III), and Hg(II) ions [8]. The extracting ability of compounds 5 and 6 synthesized in the present work was
studied using the example of a soft cation Sr(II) and an intermediate cation Pb(II). Extraction was carried out
from solutions of nitric acid and lithium picrate (LiPi). As was shown previously in [23, 24], lithium does not
compete with strontium and lead under these conditions, but the use of salts and not picric acid is preferable,
since the salt is practically completely dissociated in aqueous solution, picrate anion acting as counter ion.
From the data obtained it is evident that the investigated oxathiacrown ethers 5 and 6 preferentially
extract lead cation from picrate solutions. This may indicate that the presence of sulfur atoms in the heterocycle
aids the extraction of intermediate and, probably, soft metal cations. This, to a first approximation, corresponds
to the concept of Pearson and the experimental data obtained previously in our laboratory [25, 26]. Another
interesting fact must be mentioned. A concentration dependence is observed for the distribution coefficients of
the metal cations in all the extraction systems investigated. This phenomenon is known in the literature [27, 28]
and is linked with dissociation in polar solvents, to which dichloroethane belongs, of the compounds being
extracted. The dissociation of complexes in the organic phase may lead to a mutual influence of metal cations
on the extraction of one another [27, 28], and then the selectivity of isolating a radionuclide will depend on
several factors, varying which will possibly determine the optimum conditions for separating radioactive
isotopes.
217

TABLE 1. Conditions for Synthesizing Compounds 5 and 6
Volume
EtOH–H2O,
ml
Dithiol, g (mmol)
Crown
ether
Template reagent,
g (mmol)
Method
2, g (mmol)
3
4
5
1
2
Li2CO3, 0.19 (2.5)
Cs2CO3, 1.63 (5)
Cs2CO3, 1.63 (5)
0.14 (0.5)
0.28 (1)
1.4 (5)
0.1 (0.55)
0.2 (1.1)
200
400
400
1.2 (5.3)
TABLE 2. Distribution Coefficients of Sr(II) and Pb(II) on Extraction with a
1.5 × 10-2 M Solution of 8-Benzyl-1,4-dioxa-7,10-dithiacyclododecane in
Dichloroethane
Concentration of M(NO3)2, mol/l
Aqueous
10-2
5×10-3
2×10-3
10-3
10-4
phase
Sr2
Pb2+
Sr2
Pb2+
Sr2
Pb2+
Sr2
Pb2+
—
Sr2 Pb2+
H2O
0.12
0.2
—
0.15
0.4
—
0.2
—
0.26
0.3
—
3 mol/l
HNO3
4×10-3
4×10-3
0.8
6×10-3 0.5
1.2
8×10-3 0.55
9×10-3
0.6 0.01
0.3
0.8
1
1.6
1.2
1.8
1.5
2.2
mol/l LiPi
TABLE 3. Distribution Coefficients of Sr(II) and Pb(II) on Extraction with a
1.5 × 10-2 M solution of 11-Benzyl-1,4,7-trioxa-10,13-dithiacyclopenta-
decane in Dichloroethane
Concentrtion М(NO3)2, mol/l
Aqueous
phase
5×10-3
Pb2+
2×10-3
Pb2+
10-3
10-4
Sr2
Sr2
Sr2
Pb2+
—
Sr2
Pb2+
—
H2O
0.2
0.8
0.6
—
0.25
1.2
1
—
0.27
1.5
0.42
2.2
2
3 mol/l HNO3
4×10-3 mol/l
LiPi
6×10-3
0.45
7×10-3
0.68
9×10-3
0.95
15×10-3
1.35
1.5
EXPERIMENTAL
1
The H and 13C NMR spectra were recorded on a Varian XR 400 spectrometer (400 and 100 MHz
respectively). Solutions (25%) of samples in CDCl3 were used, internal standard was HMDS (δ 0.05 ppm) for
13
1H, and solutions (30-50%) in CDCl3 for C. The spectra of the oxathiacrown ethers were identified by COSY
and HETCOR methods. Mass spectra were obtained on a Finnigan MAT 112S instrument with direct insertion
of samples into the ion source, ionizing voltage was 70 eV. A check on the progress of reactions and the purity
of compounds was carried out by TLC on Silufol UV 254 plates in the systems ether–hexane, 1:1, and ethyl
acetate–petroleum ether, 1:1.
(2,3-Dibromo-1-propyl)benzene (2). Bromine (28 g, 0.175 mol) was added dropwise with stirring at
0-5°C to a solution of allylbenzene (20 g, 0.17 mol) in CHCl3 (125 ml). After distilling off the solvent, the
residue was distilled in vacuum. Compound 2 (44.2 g) was obtained; bp 126-128°C (4 mm Hg). Lit.
bp 137-138°C (8 mm Hg) [12]. Yield 94%. Mass spectrum: m/z (Irel, %): 278 (3) [M]+, 199 (12), 118 (11),
218

1
91 (100), 65 (3.5), 58 (2). H NMR spectrum, δ, ppm: 3.09 (1H, dd, J = 13.21, J = 5.43, CH2); 3.45 (1H, dd,
J = 13.23, J = 5.52, CH2); 3.58 (1H, dd, J = 11.44, J = 9.11, CH2Br); 3.77 (1H, dd, J = 11.44, J = 3.08, CH2Br);
4.31 (1H, m, CHBr); 7.25 (5H, m, C6H5).
1,11-Dimercapto-3,6,9-trioxaundecane (4). A mixture of 1,11-dibromo-trioxaundecane (17.9 g,
0.056 mol), thiourea (8.9 g, 0.12 mol), and EtOH (40 ml) was boiled for 12 h. The solution was cooled, and 20%
KOH solution (96 ml) was carefully added dropwise. The mixture was boiled for 4 h. At the end of the reaction
the mixture was acidified with dilute HCl to pH 2-3, then NaCl (25 g) was dissolved in it. An oily film was
formed. The substance was extracted with ether, and the ether extract dried over CaCl2. After distilling off the
solvent the residue was distilled in vacuum. A colorless liquid (4.5 g) was isolated; bp 142-143°C (2 mm Hg).
1
Yield 36%. Mass spectrum: m/z (Irel, %): 167 (2), 133 (1), 107 (34), 61 (100), 45 (30). H NMR spectrum,
δ, ppm (J, Hz): 1.60 (1H, t, J = 7.26, SH); 2.68 (4H, dd, J = 10.23, J = 7.26, CH2SH); 3.62 (12H, m, CH2O).
8-Benzyl-1,4-dioxa-7,10-dithiacyclododecane (5) and 11-Benzyl-1,4,7-trioxa-10,13-dithiacyclo-
pentadecane (6) (General Procedure). Solutions of dibromide 2 and dithiol 3 or 4 each in ethanol (10 ml)
were added simultaneously with stirring in a stream of argon to a boiling solution of Li2CO3 or Cs2CO3 in 1:1
aqueous alcohol. The quantities and molar ratios of reactants are given in Table 1. The reaction mixture was
boiled for 50 h, evaporated, and the residue extracted with hot ethyl acetate. The extract was dried over CaCl2.
The solvent was removed, and the residue chromatographed on silica gel in the system EtOAc–petroleum ether,
1:1.
Compound 5. Method 1: yield 15%. Method 2: yield <1%. Mass spectrum: m/z (Irel, %): 298 (47) [M]+,
265 (2), 238 (14), 207 (22), 176 (14), 148 (41), 117 (100), 91 (52), 61 (47), 45 (37). 1H NMR spectrum, δ, ppm
(J, Hz): 2.40 (1H, ddd, J = 15.17, J = 8.24, J = 3.24, H-6a); 2.61 (1H, dd, J = 13.50, J = 10.55, H-9cis); 2.64 [1H,
dd, J = 14.02, J = 9.04, CH2(a)C6H5]; 2.66 (1H, ddd, J = 15.19, J = 5.68, J = 2.95, H-6b); 2.71 (2H, m, H-11);
3.27 [1H, dd, J = 13.98, J = 4.07, CH2(b)C6H5]; 3.36 (1H, dd, J = 13.55, J = 4.17, H-9trans); 3.50-3.60 (6H, m,
H-2, H-3, H-5a, H-8); 3.70 (1H, dt, Jo = 10.55, Jm = 5.30, H-12a); 3.74 (1H, ddd, J = 10.48, J = 5.68, J = 3.27,
13
H-5b); 3.87 (1H, dt, J = 10.52, J = 4.76, H-12b); 7.20-7.28 (5H, m, C6H5). C NMR spectrum, δ, ppm: 31.11
(C(6)), 31.55 (C(11)), 38.13 (C(9)), 39.63 (CH2C6H5), 47.24 (C(8)), 70.27 and 70.47 (C(2), C(3)), 73.41 (C(12)), 73.51
(C(5)), 126.07 (p-C6H5), 127.95 (m-C6H5), 129.60 (o-C6H5), 139.34 (ipso-C6H5). Found, %: C 60.15; H 7.45.
C15H22O2S2. Calculated, %: C 60.36; H 7.43.
Compound 6. Yield 16%. Mass spectrum: m/z (Irel, %): 342 (52) [M]+, 282 (5), 251 (10), 225 (7), 176
(31), 148 (38), 117 (100), 91 (35), 45 (35). 1H NMR spectrum, δ, ppm (J, Hz): 2.53 (1H, d t, J = 14.47, J = 6.4,
H-9a); 2.63-2.82 [5H, m, H-9b, H-12trans, H-14, CH2(a)C6H5]; 3.11 (1H, dd, J = 13.68, J = 4.33, H-12cis); 3.24
[1H, dd, J = 15.04, J = 4.55, CH2(b)C6H5]; 3.27 (1H, m, H-11); 3.56-3.71 (10H, m, H-2, 3, 5, 6, 8); 3.74 (2H, t,
J = 6.30, H-15); 7.26 (5H, m, C6H5). 13C NMR spectrum, δ, ppm: 30.92 (C(9)), 32.11 (C(14)), 38.22 (C(12)), 39.34
(CH2C6H5), 47.20 (C(11)), 70.12 and 70.24 (C(2), C(6)), 71.05 and 71.06 (C(3), C(5)), 72.20 (C(8)), 72.26 (C(15)),
126.21 (p-C6H5), 128.01 (m-C6H5), 129.49 (o-C6H5), 139.01 (ipso-C6H5). Found, %: C 59.79; H 7.63.
C17H26O3S2. Calculated, %: C 59.61; H 7.63.
Extraction of Sr(II) and Pb(II) Cations. Determination of the distribution coefficients of Sr(II) and
Pb(II) was carried out radiometrically with a Canberra-Packard 2700 liquid scintillation counter, using the
isotopes 89Sr (T1/2 = 50.5 days, Eβ- max = 1.492 MeV) and 210Pb (T1/2 = 22.3 years, Eβ- max 0.063 MeV) [16]. Since
the maximum energy of the β particle from 210Pb is low, counting of it was carried out using its daughter element
210Bi (T1/2 = 5 days, Eβ- max = 1.16 MeV). To establish radioactive equilibrium between the mother 210Pb and
daughter 210Bi, samples for recording activity were stored for approximately 25 days from the time of
preparation to the beginning of counting.
The work was carried out with the financial support of a grant from the "INTAS" scientific program
(Grant 03-514696).
219

REFERENCES
1.
2.
3.
4.
M. G. Voronkov and V. I. Knutov, Sulfur Reports, 6, 13 (1986).
A. Anantanarayan, P. Dutton, T. Fyles, and M. J. Pitre, J. Org. Chem., 51, 752 (1986).
M. One, K. Akama, K. Kimura, K. Tanaka, and T. Shono, J. Chem. Soc., Perkin Trans. 1, 1675 (1989).
J. S. Bradshaw, K. E. Krakowiak, R. M. Izatt, L. Brus, and B. J. Tarbet, J. Heterocycl. Chem., 27, 347
(1990).
5.
6.
J. Buter, R. M. Kellog, and F. van Bolhuis, J. Chem. Soc., Chem. Commun., 910 (1991).
J. W. Sibert, S. J. Lange, D. J. Williams, A. G. M. Barrett, B. M. Hoffmann, and D. J. William, Inorg.
Chem., 34, 2300 (1995).
7.
8.
H.-J. Drexler, H. Reinke, and H.-J. Holdt, Chem. Ber., 129, 807 (1996).
E. I. Troyansky, M. S. Pogosyan, N. M. Samoshina, G. I. Nikishin, V. V. Samoshin, L. K. Shpigun,
N. E. Kopytova, and P. M, Kamilova, Mendeleev Commun., 9 (1996).
9.
10.
11.
12.
13.
14.
S. Karaböcek, I. Degirmencioglu, N. Karabocek, Trans. Metal Chem., 28, 529 (2003).
C. S. Pedersen, J. Am. Chem. Soc., 89, 7017 (1967).
C. S. Pedersen, J. Am. Chem. Soc., 92, 391 (1970).
D. Pressman and W. G. Young, J. Am. Chem. Soc., 66, 705 (1944).
B. C. Cossar, J. O. Fournier, D. L. Fields, and D. D. Reynolds, J. Org. Chem., 27, 93 (1962).
O. A. Fedorova, A. I. Vedernikov, O. V. Eshcheulova, P. V. Tsapenko, Yu. V. Pershina, and
S. P. Gromov, Izv. Akad. Nauk, Ser. Khim., 1881 (2000).
15.
V. A. Chertkov, E. K. Dobretsova, D. V. Gremyachinskii, S. S. Golotvin, N. A. Simonov, L. P. Vatlina,
and V. V. Samoshin, Khim. Geterotsikl. Soedin., 41 (1997).
16.
17.
18.
L. Ernst, V. Wray, V. A. Chertkov, and N. M. Sergeyev, J. Magn. Reson., 25, 125 (1977).
P. E. Hansen, Prog. NMR Spectroscopy, 14, 175 (1981).
V. V. Samoshin, E. I. Troyansky, D. V. Ditmchuk, R. F. Ismagilov, V. A. Chertkov, S. V. Lindeman,
V. N. Khrustalyov, and Y. T. Struchkov, J. Phys. Org. Chem., 11, 241 (1998).
M. Sirish, V. A. Chertkov, and H.-Y. Schneider, Chem,-Eur. J., 1181 (2002).
A. K. Shestakova, V. A. Chertkov, H.-J. Schneider, K. A. Lysenko, Org. Lett., 3, 325 (2001).
R. M. Izatt, R. E. Terry, L. D. Hansen, A. G. Avondet, Y. S. Bradshow, N. L. Daily, T. E. Jensen,
J. J. Christensen, and B. D. Haymore, Inorg. Chim. Acta, 30, 1 (1978).
19.
20.
21.
22.
23.
24.
A. J. Blake, G. Reid, and M. Schröder, J. Chem. Soc., Dalton Trans., 3839 (1990).
B. I. Fan, E. Kh. Ernandes, A. A. Abramov, and B. Z. Iofa, Vestn. Mosk. Univ., 32, Ser. 2, 475 (1991).
G. G. Talanova, N. S. A. Elkarim, R. E. Hanes, H. S. Hwang, R. D. Rogers, and R. A. Bartech, J. Anal.
Chem., 71, 672 (1999).
25.
26.
A. A. Abramov, A. V. Anisimov, and A. A. Bobyleva, Khim. Geterotsikl. Soedin., 243 (2002).
A. A. Kalmykov, A. V. Arhipov, A. A. Abramov, N. A. Ivanova, B. Z. Iofa, O. P. Pronina,
Y. A. Sapoznikov, and A. V. Anisimov, J. Radioanal. Chem., 228, 33 (1998).
A. A. Abramov, Vestn. Mosk. Univ., 41, Ser. 2, 3 (2000).
A. A. Abramov, S. V. Volkova, O. V. Dubovaya, B. Z. Iofa, and N. A. Rezekina, Zh. Neorg. Khim., 48,
865 (2003).
27.
28.
220