Exploiting enzymatic regioselectivity: A facile methodology for the synthesis of polyhydroxylated hybrid compounds

Article abstract of DOI:10.1039/c0ob00304b

Polyhydroxylated hybrid molecules have been synthesized using a protocol based on the regioselective acylation of the target compounds with activated dicarboxylic acids catalyzed by Novozym-435. The procedure implies that the mixed ester derivatives prepared and isolated from the first esterification step act as acylating agents in the second esterification step.

Full text of DOI:10.1039/c0ob00304b

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PAPER
www.rsc.org/obc | Organic & Biomolecular Chemistry
Exploiting enzymatic regioselectivity: a facile methodology for the synthesis
of polyhydroxylated hybrid compounds†
Pietro Magrone,a Francesco Cavallo,a Walter Panzeri,a Daniele Passarellab and Sergio Riva*a
Received 22nd June 2010, Accepted 2nd September 2010
DOI: 10.1039/c0ob00304b
Polyhydroxylated hybrid molecules have been synthesized using a protocol based on the regioselective
acylation of the target compounds with activated dicarboxylic acids catalyzed by Novozym-435. The
procedure implies that the mixed ester derivatives prepared and isolated from the first esterification step
act as acylating agents in the second esterification step.
donors. Specifically, in a pioneer work, Dordick and coworkers
showed that divinyl adipate could be used to link paclitaxel and
Introduction
glucose in a two-step thermolisin-catalyzed acylation.8 Similarly,
Lin and coworkers allowed simple polyhydroxylated bioactive
molecules or the nucleoside 5-fluorouridine to react with divinyl
dicarboxylates.9 The monovinyl esters obtained were then used
either as co-monomers in AIBN-catalyzed polymerizations or as
donors to acylate simple monosaccharides (galactose, glucose, or
other sugars) in order to increase the solubility in water solutions.
Herein, we show that lipases’ regioselectivity can be efficiently
exploited to link together any kind of natural molecule carrying a
nucleophilic group (obviously accessible by the enzyme active site)
via diesters bridges of different lengths and nature. Specifically,
for the first time, we show also that activated esters of dithio
dicarboxylic acids are well-accepted acyl donors, thus offering
a simple and efficient two-step synthetic approach to dynamic
libraries of bioactive compounds.
In recent years different authors have explored the biological
activity of hybrid compounds obtained by linking—via a suitable
dicarboxylic acid—naturally occurring bioactive molecules. The
rationale behind this approach is that these new hybrid molecules
might have additive activities, as in the case of the so-called “dual-
drug” strategy.1 This can impart enhanced properties or efficacy
relative to the equivalent physical combination and improve
the therapeutic index (for instance, by linking podophyllotoxin
and vinorelbine,2 both acting on microtubules but with different
mechanisms).3 The same methodology can be applied to convey a
drug to a given area of the body via conjugation with a molecule
recognized by a specific receptor (i.e., by linking the anticancer
paclitaxel to 3,17-b-estradiol,4 an estrogen that interacts with
receptors on breast cancer cells). It has also been shown that the
use of dicarboxylated linkers containing a disulfide bridge allows
the synthesis of dynamic libraries of dimeric hybrids based on
disulfide exchange reactions.5 For instance, reduced glutathione
in the cells could secure reduction of the disulfide bond, with
subsequent release of the chemotherapeutic agents by nucleophilic
attack of the thiol group (thiolate anion) at the ester function with
formation of a thiolactone.5b
Results and discussion
As shown in Scheme 1, five different divinyl esters (1–5) and two
different ditrifluoroethyl esters (6–7) were synthesized, following
classical procedures.10
Moreover, in a completely different research area, it has been
shown that polyhydroxylated molecules linked via a dicarboxylic
chain (like the vitamin C-based bolaamphiphiles6) are capable of
self-aggregation, giving origin to regular supramolecular struc-
tures.
All these compounds have been prepared using (sometimes trou-
blesome) chemical protocols that require protection/deprotection
steps and rigorous control of the reaction conditions. The
structural complexity and inherent “fragility” of these molecules
make them ideal substrates for a biocatalyzed approach, exploiting
the regioselectivity of lipases and proteases suspended in organic
solvents.7 Different authors have shown that activated dicarboxy-
lates (i.e., divinyl adipate) are accepted by these enzymes as acyl
aIstituto di Chimica del Riconoscimento Molecolare, C.N.R., Via Mario
Bianco 9, 20131 Milan, Italy. E-mail: sergio.riva@icrm.cnr.it; Fax: (+39)-
02-2890-1239; Tel: (+39)-02-2850-0032
Scheme 1 Synthesis of activated diesters.
bDipartimento di Chimica Organica e Industriale, Universita` degli Studi di
Milano, Via Venezian 21, Milan, Italy
R
Novozymꢀ435 (the well-known immobilized preparation of
the lipase B from Candida antarctica), one of the most popular
enzymes among organic chemists, was the biocatalyst of choice
for its well-known regioselectivity.11
† Electronic supplementary information (ESI) available: Additional exper-
imental details, spectroscopic data, 1H- and 13C NMR spectra of all new
compounds are provided. See DOI: 10.1039/c0ob00304b
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Phenyl b-D-glucopyranoside (8) and benzyl
a-D-
mannopyranoside (9, Fig. 1) were selected as model substrates
and the corresponding conjugate compounds 25–29 (Fig. 3)
were prepared using the general two-step protocol reported in
Scheme 2 (where R1OH and R2OH take the place of the selected
polyhydroxylated substrates).
Scheme 2 General two-steps synthetic protocol.
conjugated compounds 25–29 were not dependent on the choice
of the first glycoside to be attached (8 or 9).
Compounds 25–34 were isolated in good to moderate yields
as summarized in Table 1 (reactions were performed under
similar conditions and not optimized for all the substrates) and
fully characterized by mass spectrometry (thus confirming the
formation of the hybrid molecules) and NMR analysis, which
unambiguously showed the expected regioselective acylation at
the primary OH’s of the two sugar units (for details, see the ESI†).
In order to investigate the scope of the proposed proce-
dure, other glycosides (methyl a-D-glucopyranoside, 10; p-nitro-
phenyl-2-acetamido-2-deoxy-b-D-glucopyranoside, 11) and some
bioactive model compounds (cortisone, 12; colchicoside, 13;
thiocolchicoside, 14) were considered as substrates and subjected
to the same reaction protocol shown in Scheme 2.
Fig. 1 Polyhydroxylated substrates.
This procedure implies that the monoester intermediates (i.e.,
15–24, Fig. 2) prepared and isolated from the first esterification
step might act as acylating agents in the second esterification step,
the lipase showing in both cases high regioselective control in the
formation of the desired hybrid molecules. This was indeed the
case, and, additionally, as expected, the isolated yield of the final
Fig. 3 summarizes the various conjugate products obtained. All
1
the structures were deduced by H-, 13C-NMR and MS analysis,
thus confirming the flexibility and simplicity of this two-steps
enzymatic strategy. Specifically, the hybrid compounds 33 and 34
Fig. 2 Intermediate activated monoesters obtained from the first esterification step.
5584 | Org. Biomol. Chem., 2010, 8, 5583–5590 This journal is The Royal Society of Chemistry 2010
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Table 1 Reaction yields for the hybrid compounds 25–34
Conclusions
Isolated yield (%):
first step (15–24)
Isolated yield (%):
second step
In summary, the present protocol describes a general and efficient
two-step access to novel polyhydroxylated conjugated compounds
based on enzymatic regioselective acylation of natural molecules
with activated dicarboxylates, including activated esters of dithio
dicarboxylic acids.
Compound
25
26
27
28
29
30
31
32
33
34
33a
68a
72a
47a
37a
96b
83b
89c
72d
54e
61
48
70
42
63
35
57
32
63
31
Experimental
General information
All chemicals were obtained from commercial sources (Aldrich)
and used without further purification. All solvents were of
a Relative to reaction with substrate 8. b Relative to reaction with substrate
11. c Relative to reaction with substrate 10. d Relative to reaction with
substrate 14. e Relative to reaction with substrate 12.
R
reagent grade or HPLC grade. Novozymꢀ 435 (immobilized
lipase from Candida antarctica) was a gift from Novozymes Inc.
Thin-Layer Chromatography (TLC) analysis were performed on
precoated silica gel 60 F254 plates (Merck) and treated with the
molybdate reagent ((NH4)6MoO24·4H2O, 42 g; Ce(SO4)2, 2 g;
H2SO4 concentrated 62 mL; made up to 1 L with deionized water)
or KMnO4 (0.5 g in 100 mL of NaOH 1M) or UV light (254
and 366 nm). Flash chromatography was performed using silica
˚
gel 60 (70–230 mesh, Merck). Molecular sieves (4 A, beads, 8–12
◦
1
mesh) were preactivated at ca. 150 C for 3 days. The H NMR
and 13C NMR spectra were recorded at the specified field strength
and in the solvent indicated using standard pulse techniques on
Bruker 300, 400, or 500 MHz and Varian Mercury 300 MHz
spectrometers at ambient temperatures. Chemical shifts (d) were
expressed in parts per million (ppm) and were referenced to TMS
or the residual solvent peak. Coupling constants (J) are quoted
to the nearest 0.1 Hertz (Hz). Assignments of signals were made
using COSY, DEPT, APT, HMQC and HMBC experiments where
necessary. EI and FAB mass spectra were recorded at an ionizing
voltage of 6 keV on a VG 70–70 EQ instrument.
General procedure for the synthesis of divinyl esters (1–5)10
A solution of the suitable dicarboxylic acid (0.1 mol) and
Hg(OAc)2 (0.8 g) in vinyl acetate (75 mL) was stirred under
nitrogen flow at r.t. and fuming H2SO4 (50 mL) was carefully
added dropwise. The reaction mixture was then heated under
reflux for 4 h. After cooling to r.t., NaOAc·3H2O (0.3 g) was
added portionwise and the mixture was then concentrated under
reduced pressure. The crude product was purified by distillation
or silica gel column chromatography.
General procedure for the synthesis of ditrifluoroethyl esters (6–7)
Fig. 3 Novel hybrid compounds.
A solution of the suitable dithiodicarboxylic acid (0.1 mol) in
thionyl chloride (75 mL) was stirred under nitrogen at r.t for
20 h. After evaporation under reduced pressure, the residue was
immediately added dropwise to a solution of TEA (0.22 mol),
DMAP (75 mg) and 2,2,2-trifluoroethanol (0.24 mol) in CH2Cl2
(127 mL) at -78 C. The reaction mixture was stirred at -78 C
for 1 h, then was kept at r.t. for 2.5 h. The precipitate was filtered
off and the filtrate was washed with water (1 ¥ 30 mL), NaHCO3
sat. solution (1 ¥ 30 mL), and water (1 ¥ 30 mL). The organic
phase was dried over anhydrous Na2SO4 and concentrated under
reduced pressure. The crude product was then purified by silica
gel column chromatography.
were designed to combine into a single structure two molecules
associated with a potent anti-inflammatory activity.
Work is in progress to evaluate the self-aggregation properties
of compounds 25–32 as well as the possibility of using them
as substrates (acting both as donors and acceptors) for the
glycosidases-catalyzed formation of intramolecular glycosidic
bonds. Finally, the approach described here for the preparation
of dynamic libraries of hybrid bioactive molecules (i.e., 33–34)
is being applied to the design and synthesis of novel releasable
compounds as potential anticancer and anti-angiogenesis agents.
The results will be reported in due course.
◦
◦
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Ditrifluoroethyl dithiodiglycolate (6)
(95 : 5 : 1)] (TLC detection by UV light and molybdate reagent).
1H NMR (300 MHz, CD3OD) dH: 2.66 (4H, s, CH2) 3.35 (1H,
m, CH) 3.46 (2H, m, CH) 3.59–3.67 (2H, m, CH) 3.69–3.76 (2H,
m, CH) 3.82 (1H, dd, J = 1.7, 3.0 Hz, CH) 4.19 (1H, dd, J = 3.0,
6.3 Hz, CH2) 4.22 (1H, dd, J = 3.0, 6.3 Hz, CH2) 4.40–4.51 (2H, m,
CH2) 4.46 (1H, d, J = 11.8 Hz, CH2Bn) 4.67 (1H, d, J = 11.8 Hz,
CH2Bn) 4.79 (1H, d, J = 1.4 Hz, CH) 4.87–4.92 (1H, m, CH) 6.97–
7.07 (3H, m, ArH) 7.22–7.34 (7H, m, ArH). 13C NMR (75 MHz,
CD3OD) dC: 28.79, 63.81, 64.25, 67.53, 68.89, 70.45, 70.86, 71.16,
71.37, 73.65, 74.12, 76.64, 99.56, 100.91, 116.62, 122.34, 127.66,
127.99, 128.27, 129.27, 137.70, 157.78, 172.63, 172.85. FAB+-MS
(m/z): 631 [M+Na]+.
Yellow oil (79% yield). Rf 0.38 [PetEt/EtOAc (95 : 5)] (TLC
detection by KMnO4). 1H NMR (300 MHz, CDCl3) dH: 3.67
(4H, s, CH2S) 4.76 (4H, q, J = 8.5 Hz, CH2O). 13C NMR (75 MHz,
CD3OD) dC: 41.38 (CH2S) 61.95 (q, J = 35.3 Hz, CH2O) 124.56
(q, J = 275.0 Hz, CF3) 169.57 (C O). EI+-MS (m/z) 346 [M]+.
Ditrifluoroethyl dithiodibutyrate (7)
Orange oil (84% yield). Rf 0.41 [PetEt/EtOAc (95 : 5)] (TLC
detection by KMnO4). 1H NMR (300 MHz, CDCl3) dH: 2.04–2.08
(4H, m) 2.56 (4H, t, J = 7.3 Hz) 2.72 (4H, J = 7.0 Hz) 4.47 (4H, q,
J = 8.5 Hz, CH2O). 13C NMR (75 MHz, CD3OD) dC: 25.43 (CH2)
32.98 (CH2) 38.51 (CH2S) 61.41 (q, J = 35.3 Hz, CH2O) 124.94 (q,
J = 276.7 Hz, CF3) 173.10 (C O). EI+-MS (m/z) 402 [M]+.
6-O-(Phenyl b-D-glucopyranosyl) vinylglutarate (16)
The general procedure outlined above was followed, starting
from phenyl b-D-glucopyranoside (1.00 g, 3.90 mmol) and divinyl
glutarate 2 (3.59 g, 19.5 mmol), obtaining pure 16 (1.05 g) in
68% yield after purification by silica gel column chromatography
[eluent: EtOAc–MeOH (98 : 2)]. Rf 0.51 [EtOAc–MeOH (95 : 5)]
General two-step procedure for the synthesis of compounds (15–34)
To a solution of substrate R1OH (1 mmol) and activated diester
˚
(5 mmol) in pure acetone (20 mL), molecular sieves (beads, 4 A,
R
8–12 mesh, 1 g) and Novozymꢀ435 (150 mg) were added. The
1
suspension was kept at 45 ◦C and shaken at 250 rpm for 12 h. The
reaction was monitored by TLC and terminated by filtering off the
enzyme. The filtrate was concentrated under reduced pressure and
the product was isolated by silica gel column chromatography. The
monoester and the second substrate R2OH were then subjected to
the same reaction conditions (using a 1 : 1 molar ratio of the two
reagents) to give the final product.
(TLC detection by UV light and molybdate reagent). H NMR
(500 MHz, CDCl3) dH: 1.97–2.00 (2H, m, CH2) 2.45 (4H, t, J =
7.3 Hz, CH2) 3.52–3.56 (1H, m, CH) 3.61–3.65 (1H, m, CH) 3.69–
3.71 (2H, m, CH) 4.37 (1H, dd, J = 2.2, 12.1 Hz, CH2) 4.44
(1H, dd, J = 5.3, 12.1 Hz, CH2) 4.57 (1H, dd, J = 1.6, 6.3 Hz,
CH2vin) 4.88 (1H, dd, J = 1.6, 14.0 Hz, CH2vin) 4.90 (1H, d,
J = 6.4 Hz, CH) 7.04–7.08 (3H, m, ArH) 7.24 (1H, dd, J = 6.3,
14.0 Hz, CHvin) 7.24–7.31 (2H, m, ArH). 13C NMR (100 MHz,
CDCl3) dC: 20.03 (CH2) 33.16, 33.33 (CH2) 63.57 (CH2) 70.26
(CH) 73.77 (CH) 74.30 (CH) 76.36 (CH) 98.28 (CH2) 101.10 (CH)
117.21 (CH, Ar) 123.43 (CH, Ar) 129.86 (CH, Ar) 141.36 (CH)
157.30 (CH, Ar) 170.52 (C–O) 173.58 (C–O). FAB+-MS (m/z): 419
[M+Na]+.
6-O-(Phenyl b-D-glucopyranosyl) vinylsuccinate (15)
The general procedure outlined above was followed, starting from
phenyl b-D-glucopyranoside (196 mg, 0.764 mmol) and divinyl
succinate 1 (650 mg, 3.82 mmol), obtaining pure 15 (95 mg) in
33% yield after purification by silica gel column chromatography
(eluent: EtOAc). The TLC of the crude reaction showed a complete
conversion of the starting material and the formation of a mixture
of at least two byproducts that were not isolated. Rf 0.62 [EtOAc–
MeOH (95 : 5)] (TLC detection by UV light and molybdate
6-O-(Phenyl-b-D-glucopyranosyl)-6¢-O-(benzyl-a-D-
mannopyranosyl) glutarate (26)
The general procedure outlined above was followed, starting from
16 (250 mg, 0.630 mmol) and benzyl a-D-mannopyranoside 9
(170 mg, 0.630 mmol) obtaining pure 26 (190 mg) in 48% yield
after purification by silica gel column chromatography [eluent:
EtOAc–MeOH (95 : 5)]. The moderate isolated yield was mainly
due to the presence of minor byproducts possessing very similar
chromatographic behaviour that could be separated from the
desired product only by repeated purification steps. Rf 0.25
[EtOAc–MeOH–H2O (95 : 5 : 1)] (TLC detection by UV light and
molybdate reagent). 1H NMR (300 MHz, CD3OD) dH: 1.88 (2H,
t, J = 7.1 Hz, CH2) 2.40 (4H, t, J = 7.1 Hz, CH2) 3.35–3.38 (1H, m,
CH) 3.42–3.47 (2H, m, CH) 3.59–3.66 (2H, m, CH) 3.69–3.79 (2H,
m, CH) 3.82 (1H, dd, J = 1.7, 3.3 Hz, CH) 4.18 (1H, dd, J = 3.3,
6.5 Hz, CH2) 4.22 (1H, dd, J = 3.3, 6.5 Hz, CH2) 4.39–4.49 (2H, m,
CH2) 4.46 (1H, d, J = 11.8 Hz, CH2Bn) 4.66 (1H, d, J = 11.8 Hz,
CH2Bn) 4.79 (1H, d, J = 1.4 Hz, CH) 4.87–4.89 (1H, m, CH) 6.94–
7.08 (3H, m, ArH) 7.21–7.35 (7H, m, ArH). 13C NMR (75 MHz,
CD3OD) dC: 20.11, 32.86, 63.49, 63.91, 67.52, 68.87, 70.49, 70.84,
71.18, 71.38, 73.65, 74.12, 76.63, 99.56, 100.94, 116.65, 122.37,
127.68, 127.99, 128.28, 129.25, 137.66, 157.79, 173.28, 173.50.
FAB+-MS (m/z): 645 [M+Na]+.
1
reagent). H NMR (500 MHz, CD3OD) dH: 2.67 (4H, s, CH2)
3.38 (1H, m, CH) 3.45–3.48 (2H, m, CH) 3.61–3.67 (1H, m,
CH) 4.20 (1H, dd, J = 6.9, 11.8 Hz, CH2) 4.44 (1H, dd, J =
2.2, 11.8 Hz, CH2) 4.57 (1H, dd, J = 1.4, 6.3 Hz, CH2vin) 4.88
(1H, dd, J = 1.4, 14.0 Hz, CH2vin) 4.90 (1H, d, J = 6.4 Hz,
CH) 6.90–7.10 (3H, m, ArH) 7.22–7.32 (3H, m, ArH, CHvin).
13C NMR (75 MHz, CD3OD) dC: 28.41 (CH2) 63.89 (CH2) 70.48
(CH) 73.65 (CH) 74.13 (CH) 76.66 (CH) 97.01 (CH2) 100.95 (CH)
116.64 (CH, Ar) 122.32 (CH, Ar) 129.25 (CH, Ar) 141.21 (CH)
157.79 (CH, Ar) 170.00 (C–O) 172.43 (C–O). FAB+-MS (m/z): 405
[M+Na]+.
6-O-(Phenyl-b-D-glucopyranosyl)-6¢-O-(benzyl-a-D-
mannopyranosyl) succinate (25)
The general procedure outlined above was followed, starting
from 6-O-(phenyl b-D-glucopyranosyl)-vinyl succinate 15 (90 mg,
0.235 mmol) and benzyl a-D-mannopyranoside 9 (64 mg,
0.235 mmol), obtaining the pure compound 25 (205 mg) in
61% yield after purification by silica gel column chromatography
[eluent: EtOAc–MeOH (95 : 5)]. Rf 0.25 [EtOAc–MeOH–H2O
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6-O-(Phenyl b-D-glucopyranosyl) vinyladipate (17)
6-O-(Phenyl-b-D-glucopyranosyl)-6¢-O-(benzyl-a-D-
mannopyranosyl) dithiodiglycolate (28)
The general procedure outlined above was followed, starting from
phenyl b-D-glucopyranoside 8 (500 mg, 1.95 mmol) and divinyl
adipate 3 (1.93 g, 9.76 mmol) obtaining pure 17 (575 mg) in
72% yield after purification by silica gel column chromatography
[eluent: EtOAc–MeOH (97 : 3)]. Rf 0.62 [EtOAc–MeOH (95 : 5)]
The general procedure outlined above was followed, starting
from 18 (170 mg, 0.336 mmol) and benzyl a-D-mannopyranoside
9 (91 mg, 0.336 mmol) obtaining pure 28 (95 mg) in 42%
yield after purification by silica gel column chromatography
[eluent: EtOAc–MeOH (95 : 5)]. The TLC of the crude reaction
showed the presence both of unreacted starting material and of
a mixture of unidentified byproducts that were not isolated. Rf
0.35 [EtOAc–MeOH–H2O (95 : 5 : 1)] (TLC detection by UV light
and molybdate reagent). 1H NMR (500 MHz, CD3OD) dH: 3.39–
3.42 (1H, m, CH) 3.48–3.50 (2H, m, CH) 3.60–3.61 (1H, m, CH)
3.66 (4H, s, CH2) 3.67–3.76 (2H, m, CH) 3.78–3.85 (2H, m, CH)
4.24–4.33 (2H, m, CH2) 4.47–4.55 (2H, m, CH2) 4.50 (1H, d, J =
11.8 Hz, CH2Bn) 4.73 (1H, d, J = 11.8 Hz, CH2Bn) 4.82 (1H, d, J =
1.7 Hz, CH) 4.89–4.91 (1H, m, CH) 6.99–7.08 (3H, m, ArH) 7.27–
7.30 (3H, m, ArH) 7.32–7.37 (4H, m, ArH). 13C NMR (100 MHz,
CD3OD) dC: 41.06, 41.16, 64.71, 65.16, 67.67, 69.05, 70.52, 70.97,
71.23, 71.53, 73.77, 74.21, 76.76, 99.63, 101.17, 116.88, 122.49,
127.75, 128.11, 128.37, 129.41, 137.81, 157.90, 169.95, 170.09.
FAB+-MS (m/z): 695 [M+Na]+.
1
(TLC detection by UV light and molybdate reagent). H NMR
(500 MHz, CD3OD) dH: 1.63–1.67 (4H, m, CH2) 2.34–2.40 (4H,
m, CH2) 3.35–3.39 (1H, m, CH) 3.44–3.49 (2H, m, CH) 3.65 (1H,
ddd, J = 2.3, 6.7, 9.2 Hz, CH) 4.25 (1H, dd, J = 6.7, 11.8 Hz, CH2)
4.45 (1H, dd, J = 2.2, 11.8 Hz, CH2) 4.58 (1H, dd, J = 1.5, 6.3 Hz,
CH2vin) 4.87 (1H, dd, J = 1.5, 14.0 Hz, CH2vin) 4.88–4.93 (1H, m,
CH) 7.02–7.10 (3H, m, ArH) 7.25–7.28 (3H, m, ArH, CHvin). 13
C
NMR (100 MHz, CD3OD) dC: 27.57, 27.81, 36.69, 37.13, 67.27,
74.31, 77.42, 77.91, 80.44, 100.57, 104.77, 120.49, 126.11, 132.94,
145.17, 161.52, 174.51, 177.36. FAB+-MS (m/z): 433 [M+Na]+.
6-O-(Phenyl-b-D-glucopyranosyl)-6¢-O-(benzyl-a-D-
mannopyranosyl) adipate (27)
The general procedure outlined above was followed, starting from
17 (350 mg, 0.853 mmol) and benzyl a-D-mannopyranoside 9
(208 mg, 0.768 mmol) obtaining pure 27 (345 mg) in 70% yield
after purification by silica gel column chromatography [eluent:
EtOAc–MeOH (95 : 5)]. Rf 0.37 [EtOAc–MeOH–H2O (90 : 10 : 1)]
6-O-(Phenyl-b-D-glucopyranosyl)-trifluoroethyl dithiodibutyrate
(19)
The general procedure outlined above was followed, starting
from phenyl b-D-glucopyranoside 8 (400 mg, 1.56 mmol) and
ditrifluoroethyl dithiodibutyrate 7 (1.84 g, 6.24 mmol), obtaining
pure 19 (320 mg) in 37% yield after purification by silica gel column
chromatography (eluent: EtOAc). The TLC of the crude reaction
showed a complete conversion of the starting material and the
formation of a mixture of at least two byproducts that were not
isolated. Rf 0.60 [EtOAc (100%)] (TLC detection by UV light and
molybdate reagent). 1H NMR (300 MHz, CD3OD) dH: 1.95–2.04
(4H, m, CH2) 2.40–2.49 (2H, m, CH2) 2.50–2.58 (2H, m, CH2)
2.69–2.73 (4H, m, CH2) 3.35–3.40 (1H, m, CH) 3.46–3.48 (2H, m,
CH) 3.64–3.65 (1H, m, CH) 4.22–4.27 (1H, dd, J = 6.7, 11.8 Hz,
CH2) 4.45 (1H, d, J = 11.6 Hz, CH2) 4.57 (2H, q, J = 8.7 Hz,
CH2CF3) 4.87–4.89 (1H, m, CH) 6.99–7.10 (3H, m, ArH) 7.27–
7.30 (2H, m, ArH). 13C NMR (75 MHz, CD3OD) dC: 23.91, 24.16,
31.48, 32.20, 36.99, 37.38, 59.68, 63.58, 70.52, 73.66, 74.15, 76.64,
100.95, 116.62, 122.36, 125.18, 129.29, 157.80, 171.61, 173.29.
FAB+-MS (m/z): 581 [M+Na]+.
1
(TLC detection by UV light and molybdate reagent). H NMR
(300 MHz, CD3OD) dH: 1.61–1.66 (4H, m, CH2) 2.32–3.37 (4H,
m, CH2) 3.32–3.37 (1H, m, CH) 3.40–3.44 (2H, m, CH) 3.60–3.66
(2H, m, CH) 3.70–3.78 (2H, m, CH) 3.80–3.85 (1H, m, CH) 4.20
(2H, dd, J = 6.3, 11.8 Hz, CH2O) 4.36–4.41 (2H, m, CH2O) 4.48
(1H, d, J = 14.0 Hz, CH2Bn) 4.67 (1H, d, J = 14.0 Hz, CH2Bn) 4.79
(1H, d, J = 1.4 Hz, CH) 4.88–4.92 (1H, m, CH) 6.97–7.08 (3H, m,
ArH) 7.23–7.35 (7H, m, ArH). 13C NMR (75 MHz, CD3OD) dC:
24.19, 24.25, 33.42, 33.45, 63.46, 63.91, 67.54, 68.83, 70.49, 70.84,
71.21, 71.39, 73.65, 74.12, 76.64, 99.55, 100.92, 116.64, 122.37,
127.71, 127.98, 128.31, 129.24, 137.66, 157.79, 173.69, 173.89.
FAB+-MS (m/z): 659 [M+Na]+.
6-O-(Phenyl-b-D-glucopyranosyl)-trifluoroethyl dithiodiglycolate
(18)
The general procedure outlined above was followed, starting
from phenyl b-D-glucopyranoside (250 mg, 0.975 mmol) and
ditrifluoroethyl dithiodiglycolate 6 (1.35 g, 3.90 mmol) obtaining
pure 18 (230 mg) in 47% yield after purification by silica gel column
chromatography (eluent: EtOAc). The TLC of the crude reaction
showed a complete conversion of the starting material and the
formation of a mixture of unidentified byproducts that were not
isolated. Rf 0.65 [EtOAc–MeOH–H2O (95 : 5 : 1)] (TLC detection
by UV light and molybdate reagent). 1H NMR (300 MHz,
CD3OD) dH: 3.34–3.40 (1H, m, CH) 3.46–3.49 (2H, m, CH) 3.65
(2H, s, CH2) 3.67 (2H, s, CH2) 3.75–3.77 (1H, m, CH) 4.23 (1H,
dd, J = 6.6, 11.8 Hz, CH2) 4.52 (1H, dd, J = 2.2, 11.8 Hz, CH2)
4.57 (2H, q, J = 8.8 Hz, CH2CF3) 4.91–4.93 (1H, m, CH) 6.95–
7.10 (3H, m, ArH) 7.24–7.27 (2H, m, ArH). 13C NMR (75 MHz,
CD3OD) dC: 40.19, 40.99, 60.67 (q, J = 36.0 Hz), 64.63, 70.37,
73.74, 74.08, 76.62, 100.97, 116.68, 122.35, 129.32, 157.80, 168.42,
169.80, 183.20. FAB+-MS (m/z): 525 [M+Na]+.
6-O-(Phenyl-b-D-glucopyranosyl)-6¢-O-(benzyl-a-D-
mannopyranosyl) dithiodibutyrate (29)
The general procedure outlined above was followed, starting from
19 (250 mg, 0.449 mmol) and benzyl a-D-mannopyranoside 9
(121 mg, 0.449 mmol) obtaining pure 29 (204 mg) in 63% yield
after purification by silica gel column chromatography [eluent:
EtOAc–MeOH (97 : 3)]. Rf 0.75 [EtOAc–MeOH–H2O (90 : 10 : 1)]
1
(TLC detection by UV light and molybdate reagent). H NMR
(400 MHz, CD3OD) dH: 1.92–2.04 (4H, m, CH2) 2.38–2.53 (4H,
m, CH2) 2.66–2.73 (4H, m, CH2) 3.39–3.41 (1H, m, CH) 3.46 (2H,
m, CH) 3.58–3.61 (2H, m, CH) 3.64–3.66 (2H, m, CH) 3.71–3.80
(2H, m, CH) 3.82–3.84 (1H, m, CH) 4.21–4.26 (2H, dd, J = 6.7,
11. Hz, CH2) 4.43–4.47 (2H, m, CH2) 4.50 (1H, d, J = 11.8 Hz,
CH2) 4.70 (1H, d, J = 11.8 Hz, CH2) 4.82 (1H, bs, CH) 4.89 (1H,
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m, CH) 7.00–7.03 (1H, m, ArH) 7.06–7.10 (2H, m, Ar) 7.26–
7.28 (3H, m, ArH) 7.33–7.35 (4H, m, ArH). 13C NMR (75 MHz,
CD3OD) dC: 25.40, 33.46, 38.51, 62.57, 64.81, 65.28, 68.81, 70.10,
71.42, 71.75, 72.05, 72.40, 72.62, 74.88, 75.34, 77.87, 78.10, 100.76,
102.17, 117.86, 123.60, 128.91, 129.18, 129.51, 130.50, 138.83,
158.99, 174.51, 174.70. FAB+-MS (m/z): 751 [M+Na]+.
gel column chromatography [eluent: EtOAc–MeOH (97 : 3)]. Rf
0.38 [EtOAc–MeOH (95 : 5)] (TLC detection by UV light and
molybdate reagent). 1H NMR (300 MHz, CD3OD) dH: 1.60–1.62
(4H, m, CH2) 1.98 (3H, s, CH3) 2.34–2.36 (4H, m, CH2) 3.40 (1H,
dd, J = 8.8, 9.6 Hz, CH) 3.62 (1H, dd, J = 8.8, 10.2 Hz, CH)
3.70–3.72 (1H, m, CH) 3.92 (1H, dd, J = 8.5, 10.2 Hz, CH) 4.22
(1H, dd, J = 6.3, 11.8 Hz, CH2) 4.45 (1H, dd, J = 2.2, 12.1 Hz,
CH2) 4.53 (1H, dd, J = 1.6, 6.3 Hz, CH2vin) 4.81 (1H, dd, J =
1.6, 14.0 Hz, CH2vin) 5.22 (1H, d, J = 8.3 Hz, CH) 7.10 (2H,
d, J = 8.5 Hz, ArH) 7.19 (1H, dd, J = 6.3, 14.0 Hz, CHvin)
8.16 (2H, d, J = 8.5 Hz, ArH). 13C NMR (100 MHz, CD3OD)
dC: 22.23, 24.29, 24.56, 33.38, 33.84, 56.48, 63.82, 71.34, 74.72,
74.99, 97.29, 99.04, 116.99, 125.90, 141.67, 143.40, 162.76, 171.85,
173.17, 174.02. FAB+-MS (m/z): 519 [M+Na]+.
6-O-(p-Nitrophenyl-2-acetamido-2-deoxy-b-D-glucopyranosyl)
vinylglutarate (20)
The general procedure outlined above was followed, starting
from p-nitrophenyl-2-acetamido-2-deoxy-b-D-glucopyranoside 11
(500 mg, 1.46 mmol) and divinyl glutarate 2 (1.34 g, 7.30 mmol),
obtaining pure 20 (675 mg) in 96% yield after purification by silica
gel column chromatography [eluent: EtOAc–MeOH (97 : 3)]. Rf
0.38 [EtOAc–MeOH–H2O (95 : 5 : 1)] (TLC detection by UV light
and molybdate reagent). 1H NMR (400 MHz, CD3OD) dH: 1.90
(2H, quint, J = 7.4 Hz, CH2) 1.97 (3H, s, CH3) 2.42–2.43 (4H,
m, CH2) 3.42 (1H, dd, J = 8.8, 9.7 Hz, CH) 3.62 (1H, dd, J =
8.8, 10.3 Hz, CH) 3.72 (1H, ddd, J = 2.2, 6.6, 9.7 Hz, CH) 3.93
(1H, dd, J = 8.4, 10.3 Hz, CH) 4.25 (1H, dd, J = 6.6, 11.9 Hz,
CH2) 4.47 (1H, dd, J = 2.2, 11.9 Hz, CH2) 4.55 (1H, dd, J = 1.6,
6.3 Hz, CH) 4.82 (1H, dd, J = 1.6, 14.0 Hz, CH) 5.23 (1H, d, J =
8.4 Hz, CH) 7.13 (2H, d, J = 9.3 Hz, ArH) 7.23 (1H, dd, J = 6.3,
14.0 Hz, CH) 8.19 (2H, d, J = 9.3 Hz, ArH). 13C NMR (75 MHz,
CD3OD) dC: 21.21, 23.25, 33.76, 34.16, 57.38, 64.88, 72.24, 75.71,
75.93, 98.30, 99.94, 117.88, 127.00, 144.35, 163.75, 171.94, 174.25,
174.60. FAB+-MS (m/z): 505 [M+Na]+.
6-O-(p-Nitrophenyl-2-acetamido-2-deoxy-b-D-glucopyranosyl)-6¢-
O-(methyl a-D-glucopyranosyl) adipate (31)
The general procedure outlined above was followed, starting from
21 (500 mg, 1.01 mmol) and methyl a-D-glucopyranoside 10
(214 mg, 1.01 mmol), obtaining pure 31 (350 mg) in 57% yield
after purification by silica gel column chromatography [eluent:
EtOAc–MeOH (96 : 4)]. Rf 0.25 [EtOAc–MeOH–H2O (95 : 5 : 1)]
1
(TLC detection by UV light and molybdate reagent). H NMR
(400 MHz, CD3OD) dH: 1.62–1.64 (4H, m, CH2) 1.97 (3H, s, CH3)
2.34–2.36 (4H, m, CH2) 3.26 (1H, dd, J = 8.9, 10.0 Hz, CH) 3.37
(3H, s, CH3) 3.38–3.43 (2H, m, CH) 3.56–3.58 (2H, m, CH) 3.65–
3.67 (2H, m, CH2) 3.93 (1H, dd, J = 8.4, 10.3 Hz, CH2) 4.16 (1H,
dd, J = 6.0, 11.8 Hz, CH2) 4.24 (1H, dd, J = 6.4, 12.0 Hz, CH2)
4.35 (1H, dd, J = 2.2, 11.8 Hz, CH2) 4.45 (1H, dd, J = 2.2, 11.9 Hz,
CH2) 4.61 (1H, d, J = 3.7 Hz, CH) 5.23 (1H, d, J = 8.4 Hz, CH)
7.14 (2H, d, J = 9.3 Hz, ArH) 8.19 (2H, d, J = 9.3 Hz, ArH).13C
NMR (75 MHz, CD3OD) dC: 22.95, 25.38, 34.59, 55.64, 57.14,
64.48, 64.77, 71.03, 71.94, 73.46, 75.06, 75.43, 75.68, 99.69, 101.26,
117.68, 126.65, 144.08, 163.49, 173.93, 174.77, 174.92. FAB+-MS
(m/z): 669 [M+Na]+.
6-O-(p-Nitrophenyl-2-acetamido-2-deoxy-b-D-glucopyranosyl)-6¢-
O-(methyl-a-D-glucopyranosyl) glutarate (30)
The general procedure outlined above was followed, starting
from 20 (670 mg, 1.40 mmol) and methyl a-D-glucopyranoside
10 (272 mg, 1.40 mmol), obtaining pure 30 (290 mg) in 35%
yield after purification by silica gel column chromatography
[eluent: EtOAc–MeOH (95 : 5)]. The TLC of the crude reaction
showed the presence both of unreacted starting material and of a
mixture of unidentified byproducts that were not isolated. Rf 0.25
[EtOAc–MeOH–H2O (90 : 10 : 1)] (TLC detection by UV light and
molybdate reagent). 1H NMR (400 MHz, CD3OD) dH: 1.90–1.92
(2H, m, CH2) 1.97 (3H, s, CH3) 2.36–2.37 (4H, m, CH2) 3.25 (1H,
dd, J = 8.9, 10.0 Hz, CH) 3.36 (3H, s, CH3) 3.38–3.45 (2H, m, CH)
3.57–3.59 (2H, m, CH) 3.65–3.75 (2H, m, CH2) 3.92 (1H, dd, J =
8.4, 10.3 Hz, CH2) 4.16 (1H, dd, J = 6.0, 11.8 Hz, CH2) 4.20 (1H,
dd, J = 6.5, 12.0 Hz, CH2) 4.37 (1H, dd, J = 2.2, 11.8 Hz, CH2) 4.47
(1H, dd, J = 2.2, 11.9 Hz, CH2) 4.60 (1H, d, J = 3.8 Hz, CH) 5.23
(1H, d, J = 8.4 Hz, CH) 7.14 (2H, d, J = 9.3 Hz, ArH) 8.20 (2H, d,
J = 9.3 Hz, ArH). 13C NMR (75 MHz, CD3OD) dC: 21.62, 21.86,
23.25, 29.83, 34.27, 55.94, 56.35, 57.38, 64.83, 65.08, 71.30, 72.19,
73.73, 75.31, 75.71, 75.93, 99.96, 101.54, 117.93, 127.05, 144.38,
163.78, 174.25, 174.66, 174.84. FAB+-MS (m/z): 655 [M+Na]+.
6-O-(Methyl-a-D-glucopyranosyl)-vinyldodecanedioate (22)
The general procedure outlined above was followed, starting from
methyl a-D-glucopyranoside 10 (300 mg, 1.54 mmol) and divinyl
dodecanedioate 4 (2.18 g, 7.72 mmol), obtaining pure 22 (594 mg)
in 89% yield after purification by silica gel column chromatography
[eluent: EtOAc–MeOH (97 : 3)]. Rf 0.40 [EtOAc–MeOH (95 : 5)]
1
(TLC detection by UV light and molybdate reagent). H NMR
(300 MHz, CD3OD) dH: 1.29–1.33 (12H, m, CH2) 1.61–1.65 (4H,
m, CH3) 2.32–2.35 (4H, m, CH2) 3.27–3.30 (2H, m, CH) 3.39
(3H, s, CH3) 3.60 (1H, t, J = 9.2 Hz, CH) 3.69–3.71 (1H, m, CH)
4.19 (1H, dd, J = 6.0, 11.8 Hz, CH2) 4.36 (1H, dd, J = 1.8, 11.8 Hz,
CH2) 4.55 (1H, dd, J = 1.4, 6.3 Hz, CH2vin) 4.63 (1H, d, J =
3.6 Hz, CH) 4.83 (1H, dd, J = 1.6, 14.0 Hz, CH2vin) 5.22 (1H, d,
J = 8.3 Hz, CH) 7.22 (1H, dd, J = 6.3, 14.0 Hz, CHvin). FAB+-MS
(m/z): 455 [M+Na]+.
6-O-(p-Nitrophenyl-2-acetamido-2-deoxy-b-D-glucopyranosyl)
vinyladipate (21)
6-O-(p-Nitrophenyl-2-acetamido-2-deoxy-b-D-glucopyranosyl)-6¢-
O-(methyl-a-D-glucopyranosyl) dodecanedioate (32)
The general procedure outlined above was followed, starting
from p-nitrophenyl-2-acetamido-2-deoxy-b-D-glucopyranoside 11
(500 mg, 1.46 mmol) and divinyl adipate 3 (1.44 g, 7.30 mmol),
obtaining pure 21 (600 mg) in 83% yield after purification by silica
The general procedure outlined above was followed, starting from
22 (189 mg, 0.438 mmol) and p-nitrophenyl-2-acetamido-2-deoxy-
b-D-glucopyranoside 11 (150 mg, 0.438 mmol), obtaining pure
5588 | Org. Biomol. Chem., 2010, 8, 5583–5590
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32 (102 mg) in 32% yield after purification by silica gel column
chromatography [eluent: EtOAc–MeOH (95 : 5)]. The TLC of the
crude reaction showed the presence both of unreacted starting
material and of a mixture of unidentified byproducts that were not
isolated. Rf 0.25 [EtOAc–MeOH–H2O (95 : 5 : 1)] (TLC detection
by UV light and molybdate reagent). 1H NMR (400 MHz,
CD3OD) dH: 1.20–1.28 (12H, m, CH2) 1.56–1.60 (4H, m, CH2)
1.97 (3H, s, CH3) 2.32–2.34 (4H, m, CH2) 3.25–3.27 (1H, m, CH)
3.37 (3H, s, CH3) 3.38–3.43 (2H, m, CH) 3.59–3.61 (2H, m, CH)
3.70–3.72 (2H, m, CH2) 3.93 (1H, dd, J = 8.4, 10.2 Hz, CH2)
4.16–4.26 (2H, m, CH2) 4.36 (1H, dd, J = 1.9, 11.8 Hz, CH2)
4.44 (1H, dd, J = 2.0, 11.8 Hz, CH2) 4.64 (1H, d, J = 3.6 Hz,
CH) 5.23 (1H, d, J = 8.4 Hz, CH) 7.15 (2H, d, J = 9.2 Hz, ArH)
8.18 (2H, d, J = 9.2 Hz, ArH).13C NMR (100 MHz, CD3OD) dC:
22.22, 25.30, 29.36, 29.43, 29.54, 29.69, 34.32, 54.87, 56.41, 63.82,
64.02, 70.37, 71.22, 71.38, 72.76, 74.34, 74.73, 74.95, 98.97, 100.53,
116.99, 125.89, 143.32, 162.80, 173.19, 174.50, 174.72. FAB+-MS
(m/z): 752 [M+Na]+.
65.18, 69.73, 71.95, 75.23, 75.98, 78.24, 90.02, 103.00, 113.83,
125.09, 129.08, 129.25, 136.17, 136.97, 140.09, 144.04, 152.70,
153.09, 153.56, 160.50, 172.98, 173.16, 174.74, 175.06, 184.07,
202.73, 207.46, 212.37. FAB+-MS (m/z): 1034 [M+H]+ 1056
[M+Na]+.
21-O-(Cortisone) trifluoroethyl dithiodibutyrate (24)
The general procedure outlined above was followed, starting
from cortisone 12 (500 mg, 1.39 mmol) and ditrifluoroethyl
dithiodibutyrate 7 (1.63 g, 5.55 mmol), obtaining pure 24 (501 mg)
in 54% yield after purification by silica gel column chromatography
[eluent: EtOAc/PetEt (7 : 3)]. The TLC of the crude reaction
showed the presence of a mixture of unidentified byproducts that
were not isolated. Rf 0.35 [EtOAc/PetEt (7 : 3)] (TLC detection by
1
UV light and molybdate reagent). H NMR (400 MHz, CDCl3)
dH: 0.68 (3H, s, CH3) 1.26–1.28 (1H, m) 1.40 (3H, s, CH3) 1.45–
1.47 (1H, m) 1.64–1.66 (2H, m) 1.92–2.17 (8H, m) 2.26–2.58 (10H,
m) 2.72–2.80 (6H, m) 2.86 (1H, d, J = 12.4 Hz) 4.46 (2H, q, J =
8.46 Hz, CH2CF3) 4.67 (1H, d, J = 17.4 Hz, CH2O) 5.08 (1H, d,
J = 17.4 Hz, CH2O) 5.73 (1H, s, CH C). 13C NMR (125 MHz,
CDCl3) dC: 15.72, 17.55, 23.54, 24.23, 24.52, 32.24, 32.49, 32.62,
33.99, 35.05, 35.17, 36.81, 37.77, 37.84, 37.91, 38.59, 50.12, 50.23,
51.56, 60.61 (q, J = 36.3 Hz), 62.86, 68.02, 89.12, 123.23 (q, J =
275.0 Hz), 124.75, 169.58, 171.66, 172.86, 200.45, 204.99, 209.35.
FAB+-MS (m/z): 663 [M+H]+.
6-O-(Thiocolchicoside) vinyladipate (23)
The general procedure outlined above was followed, starting from
thiocolchicoside 14 (400 mg, 0.710 mmol) and divinyl adipate 3
(563 mg, 2.84 mmol), obtaining pure 23 (365 mg) in 72% yield
after purification by silica gel column chromatography [eluent:
EtOAc–MeOH (95 : 5)]. Rf 0.55 [EtOAc–MeOH–H2O (90 : 10 : 1)]
1
(TLC detection by UV light and molybdate reagent). H NMR
6-O-(Colchicoside)-21¢-O-(cortisone) dithiodibutyrate (34)
(400 MHz, CD3OD) dH: 1.62–1.66 (4H, m, CH2) 1.90 (1H, m,
CH2) 1.98 (3H, s, NHCOCH3) 2.12–2.22 (1H, m, CH2) 2.34–2.40
(5H, m, CH2) 2.47 (3H, s, SCH3) 2.58–2.63 (1H, dd, J = 6.3,
13.4 Hz, CH2) 3.37–3.55 (3H, m, CH) 3.63 (3H, s, OCH3) 3.64–
3.67 (1H, m, CH) 3.94 (3H, s, OCH3) 4.20–4.24 (1H, dd, J = 6.3,
11.9 Hz, CH) 4.49–4.56 (3H, m, CH, CH2vin) 4.82–4.86 (1H, d, J =
14.0 Hz, CH2vin) 4.98 (1H, d, J = 7.4 Hz, CH) 6.87 (1H, s, ArH)
7.18 (1H, s, ArH) 7.21–7.26 (1H, dd, J = 6.3, 14.0 Hz, CHvin)
7.34 (2H, s, ArH).13C NMR (75 MHz, CD3OD) dC: 15.39, 22.78,
25.32, 25.60, 30.87, 34.44, 34.86, 37.46, 53.92, 62.35, 62.53, 64.95,
71.81, 75.23, 75.85, 78.18, 98.29, 102.90, 113.76, 129.09, 136.12,
136.99, 140.05, 142.12, 143.51, 152.70, 153.02, 153.57, 160.55,
171.87, 172.96, 174.99, 184.07. FAB+-MS (m/z): 718 [M+H]+ 740
[M+Na]+.
The general procedure outlined above was followed, starting
from 24 (230 mg, 0.347 mmol) and colchicoside 13 (190 mg,
0.347 mmol), obtaining pure 34 (119 mg) in 31% yield after
purification by silica gel column chromatography [eluent: EtOAc–
MeOH (85 : 15)]. The TLC of the crude reaction showed the
presence of unreacted starting material. Rf 0.20 [EtOAc–MeOH
(85 : 15)] (TLC detection by UV light and molybdate reagent). 1H
NMR (400 MHz, CD3OD) dH: 0.61 (3H, s, CH3) 1.23 (1H, m)
1.42 (3H, s, CH3) 1.43–2.77 (31H, m) 2.01 (3H, s, NHCOCH3)
2.96 (1H, d, J = 12.4 Hz) 3.39–3.57 (3H, m) 3.63 (3H, s, OCH3)
3.66–3.68 (1H, m) 3.96 (3H, s, OCH3) 4.01 (3H, s, OCH3) 4.21
(1H, dd, J = 6.7, 11.9 Hz) 4.51–4.53 (2H, m) 4.88 (2H, 2d, J =
17.7 Hz) 4.97 (1H, m) 5.71 (1H, s, CH ) 6.90 (1H, s, ArH) 7.19
(1H, d, J = 11.0 Hz, ArH) 7.39 (1H, s, ArH) 7.40 (1H, d, J =
11.0 Hz, ArH). 13C NMR-DEPT (100 MHz, CD3OD) dC: 15.56,
17.50, 22.31, 23.85, 25.10, 25.23, 30.39, 32.85, 33.14, 33.20, 33.35,
34.23, 35.03, 35.45, 37.06, 37.61, 38.13, 38.30, 50.74, 50.90, 53.52,
56.83, 61.72, 62.01, 63.29, 64.60, 69.22, 71.38, 74.73, 75.37, 77.71,
102.66, 113.49, 114.75, 124.52, 130.97, 137.46. FAB+-MS (m/z):
1110 [M+H]+ 1122 [M+Na]+.
6-O-(Thiocolchicoside)-21¢-O-(cortisone) adipate (33)
The general procedure outlined above was followed, starting from
23 (200 mg, 0.278 mmol) and cortisone 12 (100 mg, 0.278 mmol),
obtaining pure 33 (180 mg) in 63% yield after purification by silica
gel column chromatography [eluent: EtOAc–MeOH (95 : 5)]. Rf
0.15 [EtOAc–MeOH (95 : 5)] (TLC detection by UV light and
molybdate reagent). 1H NMR (400 MHz, CD3OD) dH: 0.70
(3H, s, CH3) 1.25–2.73 (28H, m) 1.41 (3H, s, CH3) 1.99 (3H, s,
NHCOCH3) 2.47 (3H, s, SCH3) 2.94 (1H, d, J = 12.2 Hz) 3.33–
3.56 (3H, m) 3.63 (3H, s, OCH3) 3.66–3.67 (1H, m) 3.95 (3H, s,
OCH3) 4.15–4.20 (1H, dd, J = 7.0, 11.8 Hz) 4.49–4.56 (2H, m)
4.83 (1H, d, J = 17.3 Hz) 4.92 (1H, d, J = 17.3 Hz) 4.96 (1H,
d, J = 7.0 Hz) 5.71 (1H, s) 6.89 (1H, s) 7.18 (1H, s) 7.34 (2H,
s). 13C NMR (75 MHz, CD3OD) dC: 15.45, 16.17, 18.05, 22.89,
24.39, 25.65, 30.98, 33.77, 33.87, 34.50, 34.80, 34.97, 35.60, 35.96,
37.52, 38.11, 39.89, 51.27, 51.44, 52.76, 53.97, 62.39, 62.58, 63.79,
Acknowledgements
We thank COST (action CM0701 “CASCAT”) and C.N.R. (target
project “FUSINT”) for financial support.
Notes and references
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