The formation of a cyclic diacetal of methyl α-D-mannopyranoside with a 16-membered macrocyclic loop

Article abstract of DOI:10.1039/b202273g

The X-ray structure of a diacetal with a 16-membered macrocyclic loop, which was obtained as a product of the condensation of methyl α-D-mannopyranoside and 1,4-bis(2-formylphenoxy)butane is presented together with polymeric compounds resulting from polyc

Full text of DOI:10.1039/b202273g

The formation of a cyclic diacetal of methyl a- -mannopyranoside with a
D
16-membered macrocyclic loop
Jolanta Maslinska-Solich,*a Nikodem Kuznik,b Maciej Kubickic and Sylwia Kukowkaa
a Institute of Physico-Chemistry and Polymer Technology, Silesian University of Technology, Strzody 9,
44-101 Gliwice, Poland. E-mail: jms1acet@zeus.polsl.gliwice.pl
b Institute of Inorganic Chemistry, Technology and Electrochemistry, Silesian University of Technology,
Krzywoustego 6, 44-101 Gliwice, Poland. E-mail: nikodem@zeus.polsl.gliwice.pl
c
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland
Received (in Cambridge, UK) 4th March 2002, Accepted 21st March 2002
First published as an Advance Article on the web 5th April 2002
The X-ray structure of a diacetal with a 16-membered
macrocyclic loop, which was obtained as a product of the
condensation of methyl a- -mannopyranoside and
D
1,4-bis(2-formylphenoxy)butane is presented together with
polymeric compounds resulting from polycondensation; a
similar polymer was formed in the reaction of methyl
2,3:4,6-di-O-salicylidene-a-
1,4-dibromobutane.
D-mannopyranoside
with
Over the past two decades numerous macrocycles have been
synthesized, with much attention focused on the systems
derived from carbohydrates.1 The sources of chiral crowns2 and
cryptands3,4 are monosaccharide derivatives, frequently methyl
Scheme 2 Alternative synthetic path of polycondensation.
sulfonic acid. If the molar ratio of co-monomers was 1+1, the
major product12 was cyclic diacetal 5 (57% yield) and polymer
6. Evidence for the cyclic diacetal compound 5 is demonstrated
in the NMR spectra. The characteristic signals due to methoxy
protons at 3.41 ppm, acetal protons in the region of 5.89 and
6.54 ppm and aromatic protons at 6.55–7.02, 7.2–7.50 and
7.50–7.52 ppm, which exist in the ratio 3+2+8 respectively,
confirmed that the condensation product 5 consists of two cyclic
acetal rings bridged by a di-O-[2,2A(1,4-butoxy)]phenylidene
unit. Although the spectral and analytical data were generally
consistent with compound 5, its structure could be determined
unambiguously by X-ray crystallographic analysis. These X-ray
studies of 5 are to our knowledge, the first analysis report of a
4,6-O-benzylidene-a-gluco-, a-
D
-galacto- and a- -mannopyr-
D
anosides. Chiral crown ethers and cryptands originating from
derivatives of the methyl hexopyranoside residue were found to
show chiral recognition of primary amine5,6 and aminoester
salts.7-9 Kakuchi et al.10 described syntheses of chiral poly-
(crown ether)s via cyclopolymerization of divinyl ethers
containing altro- galacto-, gluco- and mannopyranoside moie-
ties. The enantioselective transport of methyl esters of phenyl-
glycine and phenylalanine through bulk and solution of chiral
polymers10 was examined.
Recently, our investigations have been focused on poly-
acetals derived from methyl a- -mannopyranoside 1 and
D
cyclic diacetal of methyl a- -mannopyranoside with a 16-mem-
D
dialdehyde.11 The polycondensation of 1 with terephthaldehyde
under selected reaction conditions gave polymers with molec-
ular weights ranging from 1000 to 7000 g mol21. It has been
confirmed that the polymer chain is constructed of cyclic (5-
and 6-membered) acetal rings of dialdehyde and 1. Their
transformation into polyesters was achieved in the oxidation
reaction with N-bromosuccinimide.11
bered macrocyclic loop.
The asymmetric part of the unit cell contains two symmetry-
independent molecules; one of them is slightly disordered in the
alkyl chain, refined in two positions. As is depicted in Fig. 1,
compound 5†‡ adopts a trans-decaline-like conformation
which places the phenoxy group attached to the 1,3-dioxane
ring in an equatorial orientation. The conformation of the five-
membered 1,3-dioxolane rings is different in the two symmetry-
independent molecules: in one of the molecules it is close to an
envelope, while in the other—to a distorted half-chair. Both
In this paper we report the synthesis, structure and spectro-
scopic data of the products formed in the acetalation of 1 with
salicyldehyde 2 or 1,4-bis(2-formylphenoxy)butane 3. The
condensation or polycondensation of 1 with 3 was performed in
solution in the presence of a catalytic amount of toluene-p-
Fig. 1 Molecular structure of one of the two independent molecules of 5
(40% displacement ellipsoids).
Scheme 1 Synthesis of macrocyclic and polymeric compounds.
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CHEM. COMMUN., 2002, 984–985
This journal is © The Royal Society of Chemistry 2002

(Rint = 0.0288) Rf = 0.0402 [3570 data Fo > 4s(Fo)], wR(F2) = 0.0980,
S = 1.00. Largest residual density peak (0.32 e Å23) is located close to atom
C7B (1.33 Å). CCDC 166041. See http://www.rsc.org/suppdata/cc/b2/
b202273g/ for crystallographic files in .cif or other electronic format.
symmetry-independent molecules are H-endo isomers [at C(7)].
Similar isomers13 of benzylidene-, alkenylidene-acetals of 1
have been reported. The macrocyclic 16-membered ring can be
expected to accommodate small molecules. Its diagonals
(defined by the O…O distances) range from 4.646(4) to
4.847(4) Å. The macrocyclic 16-membered loop confines a bent
tetragon of shape close to a trapezium with the sides:
1 J. F. Stoddart, Chem. Soc. Rev., 1979, 8, 85; Top.Stereochem., 1987, 17,
207; J. M. Coterón, C. Vicent, C. Bosso and S. Penades, J. Am. Chem.
Soc., 1993, 115, 10066.
2 P. Bakó, L. Fenichel and L. Toke, Justus Liebigs Ann. Chem., 1981,
1163; P. Bakó, L. Fenichel and L. Toke, Acta Chim. Acad. Sci. Hung.,
1978, 98, 357; P. Bakó, L. Fenichel and L. Toke, Acta Chim. Acad. Sci.
Hung., 1982, 111, 297.
3 P. Bakó, E. Czinege, T. Bakó, M. Czugler and L. Toke, Tetrahedron:
Asymmetry, 1999, 10, 4539.
4 M. Pietraszkiewicz, P. Salacinski and J. Jurczak, J. Chem. Soc., Chem.
Commun., 1983, 1184; M. Pietraszkiewicz, P. Salacinski and J. Jurczak,
Tetrahedron, 1984, 40, 2967; M. Pietraszkiewicz, P. Salacinski and J.
Jurczak, Tetrahedron, 1984, 40, 2971; M. Pietraszkiewicz, P. Salacinski
and J. Jurczak, J. Carbohydr. Chem., 1985, 4, 429.
5 R. B. Pettman and J. F. Stoddart, Tetrahedron Lett., 1979, 451, 461.
6 D. A. Laidler, J. F. Stoddart and J. B. Wohlstenholme, Tetrahedron
Lett., 1979, 465.
7 M. Pietraszkiewicz and N. Spencer, J. Coord. Chem. B, 1992, 27,
115.
8 M. Pietraszkiewicz and M. Kozbial, J. Ind. Phenom., 1992, 14, 339.
9 M. Pietraszkiewicz, M. Kozbial and O. Pietraszkiewicz, J .Membrane
Sci., 1998, 138, 109 and references cited therein.
O(7a)…O(8a):
4.435(4);
O(4a)…O(3a):
3.057(4);
O(7a)…O(4a): 3.059(4); O(8a)…O(3a): 2.963(4) Å.
The oligomer and polymer fractions were obtained by two
alternative synthetic paths. The acetalation of 1 with salicy-
laldehyde 2 under acid-catalysed (PVP–TsOH) conditions
yields a mixture of diastereoisomers at the acetal position of
1,3-dioxolane rings (in approximately equal amounts).14 Alka-
line-catalysed condensation of methyl 2,3:4,6-di-O-salicyli-
dene-a-
-mannopyranoside14 4 with 1,4-dibromobutane under
D
standard conditions (K2CO3)15 in butyl acetate gave the
expected polycondensates in high yield (87%). A small amount
of 5 (5%) was also isolated after flash column chromatography
purification. The evidence for polymer 6 was confirmed by SEC
analysis (Mn = 800–2100 g mol21). The NMR data of polymer
6 have been used to establish the configuration of a five-
membered acetal ring at C(2) and C(3) of the methyl a- -
D
1
mannopyranoside units in the polymer chain. The H-NMR
spectrum of 6 consists of several sets of bands produced by
acetal protons at 5.4–5.6 and 5.8–6.0 ppm (1,3-dioxane),
6.1–6.2 ppm (H-2 exo 1,3-dioxolane) and 6.4–6.6 ppm (H-endo
1,3-dioxolane). The relative intensities of endo-H and exo-H (in
the 1,3-dioxolan-2yl ring) were 2+1. The characteristic signals
of methoxy, acetal and aromatic protons provide evidence that
the repeating units in the polymer chain consist of one molecule
of 1 and one of 3.
10 T. Kakuchi, O. Haba and K. Yokota, Makromol. Chem., 1991, 192,
1601.
11 J. Maslinska-Solich, Macromol. Biosci., 2001, 1, 312.
12 Synthesis of methyl 2,3(R);4,6(R)-di-O-[2,2(1,4-butoxy)]phenylidene-
a- -mannopyranoside 5. A mixture of 1 (0.01 mol, 1.94 g) and 3 (0.01
D
mol 2.98 g) in benzene (50–100 ml), TsOH (0.05–0.1 g), was subjected
to azeotropic distillation (Dean-Stark). After 20 h the catalyst was
deactivated with CaO and the solvent was removed under reduced
pressure. The white powder of the products was filtered off (analyzed by
TLC, NMR). A mixture of compounds was fractionated on silica gel
(CHCl3:CH3OH 20:1). The solutions were concentrated and the residue
was subjected to low pressure at 80–100 °C/3 mmHg. Appropriate
crystals were obtained by crystallization from ethyl acetate+chloroform
(8+1) and by diffusion of heptane to the 1,4-dioxane solution, mp.229.6
The formation of the macrocycle 5 and polymer 6 can be
discussed on the basis of the dynamic chemistry.16,17 Direct
acid-catalysed acetalation of two bifunctional building blocks 1
and 3 is driven to macrocycle 5 (57% yield) and polymer 6.
Macrocycle formation was efficient under thermodynamic
conditions, whereas the polymer was formed under kinetically
controlled conditions which led to mixture of exo-H and endo-H
(in 1,3-dioxolane) units.
°C, [a]25
= 256.0° (c.1 CHCl3). The residue of polycondensation
546
products was purified by reprecipitation in THF–ethanol, SEC 800–
25
2100 g mol21; [a]546 = +16 to 225.0° (c.1 CHCl3).
Further investigations are in progress in order to confirm the
13 J. Gelas, Adv. Carbohydr. Chem. Biochem., 1981, 39, 71 and Z.
Jedlinski, J. Maslinska-Solich and A. Dworak, Carbohydr.Res., 1975,
42, 150.
binding selectivity of methyl a- -mannopyranoside with 1,w-
D
dialdehyde in the formation of macrocyclic diacetals and new
class of sugar polymers.
14 J. Maslinska-Solich, N. Kuznik, M. Sowa and S. Kukowka, Proc. III Int.
Symposium on Polymers, June 2001, Gliwice, Poland.
15 Polycondensation of methyl 2,3+4,6-di-O-salicylidene-a-D-mannopyr-
Notes and references
anoside 4 with 1,4-dibromobutane. A mixture of 4 (6.3 mmol, 2.55 g),
1,4-dibromobutane (6.3 mmol, 1.36 g) and 1.80 g of K2CO3 in 50 ml of
a mixture of DMF–butyl acetate (1+10) was heated at 80 to 100 °C.
After 20 h the mixture was filtered off and solvents were removed under
reduced pressure. The residue 6 was purified by flash chromatogra-
phy.1H NMR (CDCl3) of 6 d 1.80–2.10 (m, CH2), 3.36–3.43(m.,
OCH3), 3.80–4.85 (m, OCH, OCH2), 4.98–5.09(m., OCHO anom),
5.3–5.6 and 5.8–6.0(m OCHO, H-2 dioxan-2-yl), 6.10–6.24(m, OCHO,
H-2 dioxolan-2-yl, exo), 6.42–6.60(m, OCHO, H-2 dioxolan-2-yl, endo
), 6.89–7.04(m., Ar), 7.20–7.42(m, Ar), 7.43–7.72 (m, Ar), 7.80–7.82
(m, Ar), 10.49–10.5 (m, CHO).
† Spectral data of 5: 1H NMR (CDCl3, 300 MHz, SiMe4) d 1.9–2.2 (m, 4H),
3.4 (s, 3H), 3.8–3.83 (m, 2H), 3.91–4.03 (m, 3H), 4.05–4.15 (m, 3H),
4.24–4.22 (d, J 5.7Hz, 1H), 4.59–4.54 (dd, J5.7 and 8.2 Hz, 1H), 5.07 (s,
1H), 5.89 (s, 1H), 6.54 (s, 1H), 6.86–6.96 (m, 4H), 7.27–7.3 (m, 2H),
7.59–7.52 (dd, 2H) 13C NMR(CDCl3, 75 MHz) d 27.52, 55.09, 59.89,
69.74, 69.87, 75.25, 75.86, 76.34, 98..43, 98.75, 99.29, 113.49, 120.64,
120.94, 125.56, 125.89, 130.24, 157.50, 157.80; satisfactory elemental
analysis obtained.
‡ Crystal data for compound 5: C25 H28 O8, M = 456.47, monoclinic, space
group P21, a = 11.955(2), b = 16.560(3), c = 12.578(3) Å, b =
113.83(3)°, U = 2277.8(8) Å3, Z = 4, T = 293(2) K, m(Cu-Ka) = 0.825
mm21, Dc = 1.331, 3997 reflections measured, of which 3791 independent
16 J. K. M. Sanders, Pure Appl. Chem., 2000, 72, 2265.
17 L. M. Greig and D. Philp, Chem.Soc.Rev., 2001, 30, 287.
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