Synthesis of anomeric sulfonamides and their behaviour under radical-mediated bromination conditions

Article abstract of DOI:10.1016/j.carres.2008.11.002

O-Peracetylated methyl 3-(d-glycopyranosylthio)propanoates of β-d-gluco, and α- and β-d-galacto configurations were oxidized to the corresponding S,S-dioxides (sulfones) by Oxone or MCPBA. Oxidation of the β-d-gluco derivative with H₂O₂/Na₂WO₄ gave the corresponding S-oxide (sulfoxide). DBU-induced elimination of methyl acrylate from the β-d-gluco and β-d-galacto configured S,S-dioxides (sulfones) gave O-peracetylated β-d-glycopyranosyl-1-C-sulfinates which, on treatment with H₂NOSO₃H, furnished the corresponding β-d-glycopyranosyl-1-C-sulfonamides. Radical-mediated bromination of the protected methyl 3-(β-d-glycopyranosylthio)propanoate S,S-dioxides gave mixtures of 1-C- and 5-C-bromoglycosyl compounds. Similar brominations of the O-peracetylated β-d-glycopyranosyl-1-C-sulfonamides resulted in the formation of α-d-glycopyranosyl bromides and 1-C- and 5-C-bromoglycosyl sulfonamides. A rationale for these observations was proposed. Methyl 3-(β-d-glucopyranosylthio)propanoate, its S,S-dioxide, and β-d-glucopyranosyl-1-C-sulfonamide proved inefficient when tested as inhibitors of rabbit muscle glycogen phosphorylase b.

Full text of DOI:10.1016/j.carres.2008.11.002

Carbohydrate Research 344 (2009) 269–277
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Synthesis of anomeric sulfonamides and their behaviour
under radical-mediated bromination conditions
*
Katalin Czifrák, László Somsák
Department of Organic Chemistry, University of Debrecen, PO Box 20, H-4010 Debrecen, Hungary
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 10 October 2008
Received in revised form 5 November 2008
Accepted 5 November 2008
Available online 12 November 2008
O-Peracetylated methyl 3-(D-glycopyranosylthio)propanoates of b-D-gluco, and a- and b-D-galacto config-
urations were oxidized to the corresponding S,S-dioxides (sulfones) by OxoneÒ or MCPBA. Oxidation of
the b-
elimination of methyl acrylate from the b-
O-peracetylated b- -glycopyranosyl-1-C-sulfinates which, on treatment with H2NOSO3H, furnished the
corresponding b- -glycopyranosyl-1-C-sulfonamides. Radical-mediated bromination of the protected
methyl 3-(b- -glycopyranosylthio)propanoate S,S-dioxides gave mixtures of 1-C- and 5-C-bromoglycosyl
compounds. Similar brominations of the O-peracetylated b- -glycopyranosyl-1-C-sulfonamides resulted
in the formation of -glycopyranosyl bromides and 1-C- and 5-C-bromoglycosyl sulfonamides. A ratio-
nale for these observations was proposed. Methyl 3-(b-
and b-
glycogen phosphorylase b.
D-gluco derivative with H2O2/Na2WO4 gave the corresponding S-oxide (sulfoxide). DBU-induced
D
-gluco and b- -galacto configured S,S-dioxides (sulfones) gave
D
D
D
Keywords:
D
Sulfonamide
Glycopyranosyl
Bromination
Radical
D
a
-D
D
-glucopyranosylthio)propanoate, its S,S-dioxide,
D
-glucopyranosyl-1-C-sulfonamide proved inefficient when tested as inhibitors of rabbit muscle
Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
forts are devoted to finding new inhibitors (GPIs).7,8 To this end,
among others, computational chemistry is in the forefront of GPI
design.8 By using 4D-QSAR methods, it was predicted that com-
pound D, a sulfonyl analogue of C, might be a very efficient GPI
with an inhibition constant in the nanomolar range.9 Therefore,
we envisaged to prepare D from B in a way analogous to the chem-
istry2 applied to obtain A and its further transformations to C.
To the best of our knowledge, the necessary starting materials
to get A, that is N-unsubstituted anomeric sulfonamides, have
not yet been described. The only analogous compound is the
As part of an ongoing project to design and synthesize glycoen-
zyme inhibitors, we have prepared several compounds1–4 with
glycogen phosphorylase (GP) inhibitory activity5,6 from (3,4,5,7-
tetra-O-acyl-a-D-glycohept-2-ulopyranosyl bromide)onamides (A,
Chart 1). Among them, compound C was shown to have moderate
inhibition against rabbit muscle GPb (RMGPb).4 Since GP is a vali-
dated target for the treatment of type 2 diabetes mellitus, many ef-
N,N-diethylsulfonamide in the
a-anomeric position of N-acetyl-D-
O CONH2
O SO2NH2
glucosamine obtained by substituting Et2NH in the corresponding
glycosylsulfenyl chloride or bromide and subsequent oxidation.10
In this paper we disclose our experiences in the preparation of
glycopyranosyl sulfonamides and their reactivity under radical-
mediated bromination conditions.
Br
OPG
Br
OPG
(PGO)n
(PGO)n
PG = Ac, Bz
A
B
OH
OH
2. Results and discussion
O
O
HO
HO
HO
HO
NHCOCH3
CONH2
NHCOCH3
SO2NH2
HO
HO
A generally used method for the preparation of sulfonamides is
the ammonolysis of the corresponding sulfonylchlorides. At the
commencement of our work, glycosyl sulfonyl chlorides (e.g., 9)
were not known, therefore chlorination of sugar sulfonate salt 4
was envisaged. Several sulfonic acids and their salts attached to a
sugar skeleton were described.11–13, The general method for
C
D
measured4 Ki = 310 μM
predicted9 Ki = 0.59 μM
Chart 1.
obtaining such compounds was
a nucleophilic displacement
* Corresponding author. Tel.: +36 52 512 900/22348; fax: +36 52 453 836.
E-mail address: somsak@tigris.unideb.hu (L. Somsák).
For a more detailed list of citations see Ref. 23 in a paper by Knapp et al.10
0008-6215/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2008.11.002

270
K. Czifrák, L. Somsák / Carbohydrate Research 344 (2009) 269–277
OAc
OAc
O
OAc
O
O
a
93%
b
AcO
AcO
AcO
AcO
AcO
AcO
SR
OAc
SO3Na
70% from 2
87% from 3
OAc
OAc
OAc
1
2 R = Ac
3 R = H
4
e
c
43%
e
d
from 8
see ref. 10
OR
OAc
O
OAc
O
O
RO
RO
AcO
AcO
AcO
S
SO2Cl
AcO
CO2Me
-SO2
OR
AcO
OAc
X
f
96%
9
7 X = Cl
8 X = Br
5 R = Ac
6 R = H
g
39%
O
S
OAc
OAc
O
b
h
70% or
72%
AcO
AcO
CO2Me
10
OR
OR
OAc
O
O
S
O
O
k
O
j
O
RO
RO
RO
RO
i
AcO
AcO
S
SO2NH2
O-
CO2Me
81% from 11
OR
OR
39%
OAc
39%
l
11 R = Ac
12 R = H
13
14 R = Ac
15 R = H
Scheme 1. Reagents and conditions: (a) AcSH, BF3ꢁOEt2, dry CH2Cl2, 0–20 °C; (b) OxoneÒ, NaOAc, AcOH, rt; (c) HSCH2CH2CO2Me, BF3ꢁOEt2, CH2Cl2, 0–20 °C; (d) (1) H2NCSNH2,
dry acetone, reflux; (2) NaHSO3, CHCl3–H2O, reflux; (e) SOCl2, or PCl5, dry THF or dry Et2O, reflux; (f) NaOMe, dry MeOH, rt; (g) Na2WO4, H2O2, MeOH, rt; (h) mCPBA, NaHCO3,
CH2Cl2, 0–20 °C; (i) DBU, CHCl3, rt; (j) H2NOSO3H, water, rt; (k) AcCl, dry MeOH rt; (l) NH4OH, MeOH, rt.
by AcSK in the corresponding sugar derivative followed by oxida-
tion,13 and it was also extended to the anomeric position.14 Thus, to
desired sulfonamide 14 after chromatographic purification in 81%
yield for the two steps.
get sodium sulfonate
4
(Scheme 1), either O-peracetylated
For the preparation of the
(Scheme 2), the corresponding thioglycoside had to be prepared
first. BF3 catalyzed reaction of 1,2,3,4,6-penta-O-acetyl-b- -galac-
topyranose (16) with methyl 3-sulfanylpropanoate gave the -thi-
D-galacto configurated derivative 23
1-S-acetyl-1-thio-b-D-glucopyranose15 (2) prepared from 1,2,3,4,
6-penta-O-acetyl-b-D-glucopyranose (1) and thiolacetic acid16 or
O-peracetylated 1-thio-b-D-glucopyranose (3) obtained by the con-
ventional literature method17,18 from 8 was oxidized by OxoneÒ.14
The corresponding triethylammonium salt10 was made from 2 by
DMDO oxidation followed by chromatography in the presence of
Et3N. Reactions of 4 under usual chlorination conditions (neat
SOCl2, reflux; THF, SOCl2; THF–Et2O, PCl5) gave several compounds
which were not separated. Experiments to add nucleophiles to the
crude chlorination mixtures with the hope of trapping any sulfonyl
chloride formed were unsuccessful. Knapp et al. isolated the corre-
sponding glycosyl chloride 7 (70%) from the chlorination mixture of
their triethylammonium sulfonate,10 and accounted for the forma-
tion of 7 by SO2 extrusion from the unstable intermediate sulfonyl
chloride 9. For these reasons other possibilities were sought for the
preparation of the target sulfonamides.
D
a
ogalactoside 18 in moderate yield. To get the b-anomer, 2,3,4,
6-tetra-O-acetyl-1-thio-b-
D
-galactopyranose25,26 (17) was reacted
AcO
OAc
AcO
OAc
O
O
OAc
SH
AcO
AcO
OAc
OAc
16
17
b
to 20
a
85
%
to 18
18 R1 = S(CH2)2CO2Me,
R2 = H
35%
c
90%
19 R1 = SO2(CH2)2CO2Me,
AcO
AcO
Various sulfonamides were prepared by reaction of sulfinate
salts with electrophilic nitrogen sources such as hydroxylamine-
O-sulfonic acid19,20 or bis(2,2,2-trichloroethyl)azodicarboxylate.21
The preparation of the required anomeric sulfinate 13 was effected
by base-induced b-elimination from sulfone 11 which was ob-
tained by oxidation of thioglucoside 522,23 by either OxoneÒ or
mCPBA. Application of H2O2/Na2WO420,21 to oxidize 5 gave sulfox-
ides 10 (two TLC spots of very similar mobility) from which one
isomer could be isolated in pure state in moderate yield. As an
alternative route to sulfinates, the reductive cleavage of benzo-
thiazolyl sulfones was proposed;21 however, practically no change
OAc
O
2 = H
R2
R
20 R1 = H,
R2 = S(CH2)2CO2Me
21 R1 = H,
R2 = SO2(CH2)2CO2Me
AcO
R1
c
70%
d
from 21
AcO
AcO
OAc
OAc
O
O
S
e
O
SO2NH2
O- 79%
AcO
AcO
OAc
OAc
22
23
could be observed in the reaction of O-peracetylated b-D-glucopyr-
anosyl benzothiazol-2-yl sulfone24 with NaBH4 in THF/MeOH for
ꢀone week even at elevated temperature. Sulfinate 13, without
being purified, was treated with H2NOSO3H in water to give the
Scheme 2. Reagents and conditions: (a) HSCH2CH2CO2Me, BF3ꢁOEt2, CH2Cl2, 0–
20 °C; (b) BrCH2CH2CO2Me, Et3N, CH2Cl2, rt; (c) OxoneÒ, NaOAc, AcOH, rt; (d) DBU,
CHCl3, rt; (e) H2NSO3H, water, rt.

K. Czifrák, L. Somsák / Carbohydrate Research 344 (2009) 269–277
271
Table 1
Radical-mediated bromination of sulfonyl derivatives
R2
R2
R2
R2
OAc
O
OAc
O
OAc
O
bromination
conditions
a-c
OAc
O
R1
R1
R1
R3
R1
R3
+
+
R3
AcO
AcO
AcO
AcO
AcO
AcO
OAc
OAc
Br
Br
Br
R1
R2
Isolated yields (product ratios) (%)
11
21
14
R
R
3 = SO2(CH2)2CO2Me
3 = SO2NH2
OAc
H
OAc
H
OAc
H
a1
a2
b3
b4
c5
b6
24 21
26 43
28 11 (22)
(45)
28 12
30 (12)
25 30
—
—
27 27
29 12 (17)
(36)
29 11
31 (6)
8 24 (26)
(6)
8 19
23
H
OAc
32 (59)
Bromination conditions:
(a) Br2, CCl4, K2CO3, h
(b) Br2, CHCl3, K2CO3, h
m
, reflux.27
m
, reflux.2
(c) Br2, PhCF3, K2CO3, h
m
, reflux.30
1
Reaction time 3 h.
Reaction time 2 h.
Conversion 65% after 8 h with 0.6 g starting material.
2
3
4
5
6
Conversion 87% after 4 h with 0.1 g starting material. Product ratio calculated from the 1H NMR spectrum of the crude mixture.
Conversion 81% after 4 h.
Conversion 77% after 4 h. Product ratio calculated from the 1H NMR spectrum of the crude mixture.
with methyl 3-bromopropanoate in the presence of Et3N, and the
required compound 20 was obtained in good yield. The anomeric
configuration of these derivatives was clearly indicated by the vic-
These observations can be correlated with the relative radical
stabilization (RRS) factors of substituents (Table 2) as in earlier
explanations for the regioselectivity of radical-mediated bromina-
tion of sugar derivatives.27 As shown in Figure 1a, the radical sta-
bilization is highest in position 1 of the sugar ring (RRS = 8.3; for
positions 2–4, the OAc substituent is characterized by an RRS value
of 0.931). Although the radical in position next to the CO2Me group
seems to be better stabilized than C-5 (RRS 7.9 vs 6.5), the ob-
served higher reactivity of position 5 might be attributed to its ter-
tiary character (as compared to the secondary carbon in the
aglycon) which is not taken into consideration in the calculation
of the RRS value. However, bromination in the methylene groups
of the aglycon cannot be excluded, as very minor bromine-contain-
ing spots were observed by TLC in the reaction mixtures. Com-
pounds with a carbon substituent at position one (for the present
particular comparison a carboxamido group, but also other anhy-
dro-aldonic acid derivatives) showed an exclusive selectivity for
that position2,32,33 as it can be concluded from the RRS values27
(Fig. 1b). In the bromination of sulfonamides the relative reactivity
of positions 1 and 5 was similar to those of the sulfones (Fig. 1a).
However, the formation of glycosyl bromides needs further consid-
erations. We propose that in the bromination of sulfonamides
(Fig. 1c) the bromine radical may also abstract a hydrogen from
the SO2NH2 moiety as illustrated in I. Further b-fragmentation of
the intermediate sulfonamidyl radical II might give glycosyl radi-
cal34 III which, on bromine abstraction from the reagent, could give
the glycosyl bromide IV with high stereoselectivity. The prepon-
derance of this pathway may be attributed to the relatively free ac-
3
3
inal coupling constants: J1,2 = 5.3 Hz for 18 and J1,2 = 9.2 Hz for
20. Oxidation of thiogalactosides 18 and 20 by OxoneÒ afforded
the corresponding sulfones 19 and 21, respectively, in good yields
3
(3J1,2 = 2.6 Hz for 19 and J1,2 = 9.2 Hz for 21). Treatment of the b-
anomeric sulfone 21 with DBU followed by reaction of the non-iso-
lated sulfinate 22 with H2NOSO3H gave the expected sulfonamide
23 in 79% overall yield for the two steps. Similar base-induced
reaction of the a-anomer 19 resulted in a mixture from which no
discrete product could be isolated.
Radical-mediated bromination of various carbohydrate deriva-
tives proved a useful tool to produce versatile compounds for fur-
ther functionalization.27 Several pyranoid monosaccharide
substrates showed excellent regio- and stereoselectivities under
the bromination conditions to give either 1-C-bromo- or 5-C-bro-
mo derivatives of pyranoid rings with the bromine substituents
in axial positions. On the other hand, a study on bromination of
phenyl 2,3,4,6-tetra-O-acetyl-b-D-glucopyranosyl sulfone demon-
strated similar reactivities for the 1- and 5-positions (C-1 bromide
48%, C-5 bromide 38%).28
With these preliminaries in mind, it was to be expected that
bromination (Table 1) of the gluco (11) and galacto (21) sulfones
would give isomeric axial bromides 24 and 25, as well as 26 and
27, respectively. Bromination of sulfonamides 14 and 23 under dif-
ferent conditions gave varying proportions of the corresponding
D
a-
-glycopyranosyl bromidesà 8 and 32, respectively, the ratio also
being dependent on the scale of the reaction. The ring brominated
derivatives 28 and 29, as well as 30 and 31, respectively, were
formed as minor products when the reaction was performed on a
larger scale. Compounds 28 and 29 were isolated by chromatogra-
phy; however, the very similar chromatographic behaviour of 30
and 31 did not allow these derivatives to be prepared in pure state.
The position of the bromine substitution in the sugar ring followed
clearly from the coupling pattern of the 1H NMR spectra of these
compounds.
Table 2
Selected relative radical stabilization factors31 of substituents (RRSX) and their
combined values (RRSO,X) at positions 1 and 5 of the pyranoid ring
X
RRSX
RRSO,X
6.5
CH3 (= CH2OAc)
OMe (= O-ring)
SO2Ph
COOMe
CN
2.3
4.5
4.5
7.9
8.6
10.2
8.3
11.3
11.9
13.2
COMe
à
X represents the substituent in position 1 or 5 of the pyranoid ring while O stands
for the ring oxygen (its numerical value equated with that of OMe). The combined
effects were calculated by using the expression:31 0.03 ꢂ RRSO,X = 1 ꢃ (1 ꢃ 0.03
ꢂ RRSOMe)(1 ꢃ 0.03 ꢂ RRSX).
In the literature there are some examples with a similar outcome to the present
one: the corresponding
a-D-glycosyl bromides were formed on radical mediated
bromination of O-peracetylated phenyl b-D-glucopyranosyl sulfoxide,28 cellobiosyl
pyperidine29 and b-D-glucopyranosyl isothiocyanate.29

272
K. Czifrák, L. Somsák / Carbohydrate Research 344 (2009) 269–277
Table 3
7.9
4.5
a
Inhibition of RMGPb by selected 1-thio derivatives of D-glucose
OAc
5
Entry Compound
Ki (mM)
O 1
SO2
CO2Me
(AcO)n
(AcO)n
OH
137
O
HO
HO
1
6.5
SH
S
8.3
OH
OH
OAc
O
b
c
HO
HO
5
OCH3
O 1
2
3
n.i.
CONH2 (CO2Me, CN)
OH
O
6
6.5
~11-12
OH
O
O
n.i.37
O
HO
HO
S
S
OCH2CH3
OH
OAc
O
SO2 NH
SO2NH
OH
NO2
(AcO)n
H
N
HBr
O
HO
HO
4
5
0.6537
N
H
II
OH
NO2
OH
O
O
O
HO
HO
OAc
O
S
S
OCH3
OAc
n.i.
5
O
OH
1
SO2NH
Br
H
O
(AcO)n
(AcO)n
H
12
OH
H
III
O
O
O
I
HO
HO
6
7
n.i.
NH2
OH
Br2
15
OH
O
C
OAc
O
0.4437
O
HO
HO
NH2
(AcO)n
OH
Br
IV
Figure 1. (a) Relative radical stabilization factors taken from Table 2 for glucopyr-
anosyl sulfones and (b) anhydro-aldonic acid derivatives; (c) proposed reactivity
pattern for the radical-mediated bromination of anomeric sulfonamides.
chlorides. Further functionalization at C-1 of these sulfonamides
by radical-mediated bromination, although possible, has proven
limited because of formation of the corresponding glycosyl bro-
mides and 5-C-bromides as accompanying products. 1-Bromogly-
cosyl sulfones and sulfonamides seem to be unreactive in
nucleophilic substitutions. Appending the tetrahedral sulfonyl
cess to the NH2 as compared to the ring positions, but radical sta-
bilization factors may also play a role.
moiety to the anomeric centre of D-glucose results in a loss of activ-
ity against RMGPb.
In 1-bromoglucopyranosyl sulfonamide 28 as well as sulfone 24
some nucleophilic substitutions, reactions analogous to those car-
ried out easily1–3,35,36 with O-peracyl derivatives of (
D-glyco-hept-
2-ulopyranosyl bromide)onamides (Chart 1, A) were attempted.
Contrary to these transformations, reactions either with azide or
thiocyanate ions failed: either no change (28 and AgSCN or
NH4SCN, CH3NO2, 80 °C, Ar atm; 28 and NaN3, DMF, rt; 24 and
NaN3, acetone, LiN3, DMF, or acetone, each at rt) or decomposition
(24 and NaN3, DMF, rt; AgOTF, TMSN3, CH2Cl2, rt) of the starting
material could be observed.
3. Experimental
3.1. General methods
Melting points were measured in open capillary tubes or on a
Kofler hot-stage and are uncorrected. Optical rotations were deter-
mined on a Perkin–Elmer 241 polarimeter at room temperature.
NMR spectra were recorded with Bruker WP 360 SY (360/90 MHz
for 1H/13C) and Varian UNITYINOVA 400 WB (400/100 MHz for
1H/13C) spectrometers. Chemical shifts are referenced to Me4Si as
the internal reference (1H) or to the residual solvent signal (13C).
ESIMS were recorded with a Bruker micrOTOF-Q instrument.
Thin-layer chromatography (TLC) was carried out on aluminium
sheets coated with Silica Gel 60 F254 (Merck). TLC plates were in-
spected by UV light (k = 254 nm) and after gentle heating. Bromi-
nated compounds were visualized on TLC plates by spraying first
a 0.1% w/v fluorescein soln in absolute MeOH, then a 1:1 mixture
of H2O2 (30% in water) and AcOH. Upon gentle heating, bromo-
compounds gave pink-coloured spots. Silica gel column chroma-
The prepared 1-thioglucoside 5 and glucosyl sulfonyl deriva-
tives 11 and 14 were deprotected as shown in Scheme 1 to give
compounds 6, 12 and 15, respectively. These compounds were
tested as inhibitors of RMGPb (Table 3) in the way described ear-
lier.3 While 1-thio-b-
D-glucopyranose (entry 1) is a moderate
inhibitor, its glycosides are either non-inhibitory (entries 2 and
3) or only slightly more efficient (entry 4). The latter effect may
be due to interactions of the bulky aglycon in the so called b-chan-
nel of the enzyme.7,8 Sulfone 12 (entry 5) and sulfonamide 15 (en-
try 6) were inactive. Comparing the latter result to the effect of the
2,6-anhydro-aldonamide in entry 7 shows that introduction of the
tetrahedral sulfonyl moiety in the b-anomeric position of D-glucose
is not a useful modification with respect to inhibition of RMGPb.
tography was performed with Silica Gel Si 60 (40–63 lm) pur-
In conclusion, a synthetic sequence has been elaborated for the
chased from Merck (Darmstadt, Germany). Organic solutions
were dried over anhydrous MgSO4, and concentrated at diminished
pressure at 40–50 °C (water bath).
preparation of N-unsubstituted b-
D-glycopyranosyl-1-C-sulfona-
mides, which circumvents the unavailability of anomeric sulfonyl

K. Czifrák, L. Somsák / Carbohydrate Research 344 (2009) 269–277
273
3.2. 2,3,4,6-Tetra-O-acetyl-1-S-acetyl-1-thio-b-
D
-glucopyranose
(ppm) 171.9 (COOCH3), 170.5, 169.9, 169.2 (2) (CO), 83.7 (C-1),
75.7, 73.6, 69.5, 68.1 (C-2 to C-5), 61.9 (C-6), 51.6 (OCH3), 35.1,
25.2 (CH2), 20.5, 20.4 (2), 20.3 (CH3). Anal. Calcd for C18H26O11S1
(450.47): C, 47.99; H, 5.82. Found: C, 47.86; H, 5.66.
(adapted from14) (2)
1,2,3,4,6-Penta-O-acetyl-b-D-glucopyranose (1, 1.00 g, 2.56 mmol)
was dissolved in dry CH2Cl2 (10 mL). To the soln, thioacetic acid
(0.28 mL, 3.84 mmol) and BF3ꢁOEt2 (0.54 mL, 5.12 mmol) were
added at 0 °C. The mixture was then stirred at rt for 1 d, and after
completion of the reaction (TLC, 95:5 CH2Cl2–acetone) it was diluted
with CH2Cl2 (10 mL), washed with satd NaHCO3 (2 ꢂ 10 mL) and
water (1 ꢂ 10 mL). After drying, the solvent was removed under
diminished pressure. The crude product was crystallized from EtOH
to give 0.97 g (93%) of 2 as a white crystalline product. Mp: 119–
3.5. Methyl 3-(b-D-glucopyranosylthio)propanoate (6)
Thioglucoside 5 (0.18 g, 0.41 mmol) was dissolved in dry MeOH
(5 mL), and NaOMe (ꢀ1 M in MeOH) was added. The reaction mix-
ture was kept at rt until completion of the transformation (TLC, 1:1
CHCl3–MeOH). Amberlyst 15 (H+ form) was then added to remove
sodium ions, the resin was filtered off, and the solvent was evapo-
rated to give 0.11 g (96%) of 6 as a colourless oil. Rf = 0.73 (1:1
120 °C, (lit.15 mp: 118 °C); [ +29 (c 0.38, CHCl3), (lit.15
a] [a] +11
D D
(c 1.49, CHCl3)); 1H NMR (CDCl3, 360 MHz): d (ppm) 5.27, 5.12,
5.10 (pseudo t, 3H, J ꢀ 9.2 Hz in each, H-2, H-3, H-4), 5.26 (d, 1H,
CHCl3–MeOH); [
a
]
ꢃ74 (c 0.19, H2O); 1H NMR (D2O, 360 MHz):
D
0
0
d (ppm) 4.51 (dd, 1H, J6,6 13.2, J5,6 4.0 Hz, H-6), 3.85 (dd, 1H, J6,6
J1,2 9.2 Hz, H-1), 4.24 (dd, 1H, J6,6 11.9, J5,6 4.0 Hz, H-6), 4.10 (dd,
13.2, J5,6 1.2 Hz, H-60), 3.68 (s, 3H, OCH3), 3.64 (d, 1H, J1,2 9.2 Hz,
H-1), 3.44–3.23 (m, 3H, H-2, H-3, H-4), 3.26 (ddd, 1H, J4,5 9.2, J5,6
0
0
1H, J6,6 11.9, J5,6 2.6 Hz, H-60), 3.86 (ddd, 1H, J4,5 9.2, J5,6 4.0, J5,6
0
0
0
0
2.6 Hz, H-5), 2.39 (s, 3H, SCOCH3), 2.08, 2.03, 2.02, 2.01 (12H, 4s,
4 ꢂ OCOCH3); 13C NMR (CDCl3, 90 MHz): d (ppm) 191.8 (SCOCH3),
170.5, 169.2, 169.3 (2) (CO), 80.1 (C-1), 76.3, 73.8, 68.9, 67.8 (C-2
to C-5), 61.6 (C-6), 30.7 (SCOCH3) 20.6, 20.5 (3) (CH3).
4.0, J5,6 1.2 Hz, H-5), 2.99 (quintet, 1H, J 7.9, J 6.6 Hz, CH2), 2.93
(quintet, 1H, J 7.9, J 6.6 Hz, CH2), 2.76–2.74 (m, 2H, CH2); 13C
NMR (D2O, 90 MHz). d (ppm) 175.7 (COOCH3), 86.5 (C-1), 80.4,
77.4, 72.7, 70.0, (C-2 to C-5), 61.5 (C-6), 53.5 (OCH3), 35.5, 25.7
(CH2). Anal. Calcd for C10H18O7S1 (282.31): C, 42.55; H, 6.43. Found:
C, 42.50; H, 6.48.
3.3. Sodium 2,3,4,6-tetra-O-acetyl-b-D-glucopyranosyl-1-C-
sulfonate (adapted from14) (4)
3.6. Methyl 3-(2,3,4,6-tetra-O-acetyl-b-D-
(a) Compound 2 (0.50 g, 1.23 mmol) was suspended in glacial
acetic acid (10 mL), and OxoneÒ (1.89 g, 3.07 mmol) and NaOAc
(1.34 g, 12.3 mmol) were added. The mixture was stirred at rt until
TLC (4:1 CH2Cl2–MeOH) showed complete transformation of the
starting material. After filtration, the solvent was removed under
diminished pressure. The obtained crude product was purified by
column chromatography (eluent, 4:1 CHCl3–MeOH) to give 0.42 g
glucopyranosylthio)propanoate S-oxide (10)
Thioglucoside 5 (0.1 g, 0.22 mmol) was dissolved in MeOH
(3 mL). To this soln Na2WO4 (6.5 mg, 0.02 mmol) and H2O2
(0.1 mL, 3.30 mmol) were added in small portions. The mixture
was stirred at rt until completion of the transformation (TLC, 1:1
EtOAc–hexane). After filtration the solvent was removed under
diminished pressure. The obtained oil was purified by column
chromatography (2:1 EtOAc–hexane) to give 0.04 g (39%) of 10 as
(70%) of 4 as a white crystalline product. Mp: 218–220 °C; [a]
D
ꢃ59 (c 0.23, H2O) ; 1H NMR (D2O, 360 MHz): d (ppm) 5.43, 5.37,
5.17 (pseudo t, 3H, J ꢀ 9.4 Hz in each, H-2, H-3, H-4), 4.57 (d, 1H,
a white powder. Mp: 115–117 °C; [
NMR (CDCl3, 360 MHz): d (ppm) 5.34, 5.26, 5.11 (pseudo t, 3H,
a
]
ꢃ128 (c 0.22, CHCl3); 1H
D
0
J1,2 9.4 Hz, H-1), 4.43 (dd, 1H, J6,6 11.7, J5,6 2.1 Hz, H-6), 4.27 (dd,
1H, J6,6 11.7, J5,6 1.0 Hz, H-60), 4.14 (ddd, 1H, J4,5 9.4, J5,6 2.1, J5,6
J ꢀ 9.2 Hz in each, H-2, H-3, H-4), 4.37 (d, 1H, J1,2 9.2 Hz, H-1),
0
0
0
1.0 Hz, H-5), 2.15, 2.12, 2.11, 2.09 (12H, 4s, 4 ꢂ OCOCH3); 13C
NMR (D2O, 90 MHz): d (ppm) 174.2, 173.6, 173.2, 172.8 (CO),
85.5 (C-1), 75.7, 74.7, 69.5, 68.5 (C-2 to C-5), 62.5 (C-6), 21.9,
20.8, 20.7, 20.6 (CH3); ESI MS calcd for C14H19O12SNa 434.354,
found 457.018 (M+Na).
4.29 (dd, 1H, J6,6 13.2, J5,6 5.3 Hz, H-6), 4.21 (dd, 1H, J6,6 13.2, J5,6
0
0
0
2.6 Hz, H-60), 3.82 (ddd, 1H, J4,5 9.2, J5,6 5.3, J5,6 2.6 Hz, H-5), 3.73
0
(s, 3H, OCH3), 3.22–3.20 (m, 2H, CH2), 2.85 (m, 2H, CH2), 2.09,
2.07, 2.05, 2.03 (12H, 4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3,
90 MHz): d (ppm) 171.5 (COOCH3), 170.4, 169.9, 169.5, 169.2
(CO), 90.1 (C-1), 76.8, 73.0, 68.3, 67.5 (C-2 to C-5), 61.3 (C-6),
52.2 (OCH3), 42.0, 26.1 (CH2), 20.5 (2), 20.4 (2) (CH3). Anal. Calcd
for C18H26O12S1 (466.46): C, 46.35; H, 5.62. Found: C, 46.15; H,
5.55.
(b) Also prepared from 2,3,4,6-tetra-O-acetyl-1-thio-b-D-gluco-
pyranose17 (3, 0.50 g, 1.31 mmol) by using the same procedure.
Yield: 0.52 g (87%).
3.4. Methyl 3-(2,3,4,6-tetra-O-acetyl-b-D-
glucopyranosylthio)propanoate (5)
3.7. Methyl 3-(2,3,4,6-tetra-O-acetyl-b-D-
glucopyranosylthio)propanoate S,S-dioxide (11)
Compound 1 (5.00 g, 12.8 mmol) was dissolved in dry CH2Cl2
(30 mL), then methyl 3-sulfanylpropanoate (2.1 mL, 19.2 mmol)
and BF3ꢁOEt2 (2.7 mL, 25.6 mmol) were added at 0 °C. The soln
was stirred overnight (ꢀ16 h) at rt, (TLC, 1:2 EtOAc–hexane). After
complete transformation of the starting material, the mixture was
diluted with CH2Cl2 and washed with satd NaHCO3 (2 ꢂ 15 mL)
and water (1 ꢂ 15 mL), and then dried. The solvent was removed
under diminished pressure and the crude product crystallized from
EtOH to give 2.50 g (43%) of 5 as white needles. Mp: 86–87 °C (lit.22
(a) Thioglucoside 5 (0.1 g, 0.22 mmol) was dissolved in glacial
acetic acid (3 mL). To this soln, OxoneÒ (0.19 g, 0.33 mmol) and
NaOAc (0.14 g, 2.20 mmol) were added. The mixture was stirred
at rt until complete transformation of the starting material (TLC,
1:1 EtOAc–hexane). After filtration it was diluted with water
(10 mL) and washed with CH2Cl2 (3 ꢂ 5 mL). The organic phase
was washed with satd NaHCO3 (2 ꢂ 5 mL) and water (1 ꢂ 5 mL),
dried, and the solvent removed under diminished pressure. The
crude product was recrystallized from Et2O to give 0.07 g (70%)
of 11.
(b) Thioglucoside 5 (0.1 g, 0.22 mmol) was suspended in CH2Cl2
(3 mL), and NaHCO3 (0.19 g, 2.20 mmol) and mCPBA (0.22 g,
15.8 mmol, ꢀ70%) were added in five portions at 0 °C. The mixture
was stirred at rt until complete transformation of the starting
material (TLC, 1:1 EtOAc–hexane). After filtration it was diluted
with water (10 mL) and washed with CH2Cl2 (2 ꢂ 5 mL). The
mp: 88–89 °C); [
a
]
ꢃ64 (c 0.26, CHCl3 (lit.22
[
a
]
ꢃ32 (c 1.00,
D
D
CHCl3)); 1H NMR (CDCl3, 360 MHz): d (ppm) 5.23, 5.03, 5.01 (pseu-
do t, 3H, J ꢀ 9.2 Hz in each, H-2, H-3, H-4), 4.56 (d, 1H, J1,2 10.6 Hz,
0
0
H-1), 4.23 (dd, 1H, J6,6 11.9, J5,6 5.3 Hz, H-6), 4.14 (dd, 1H, J6,6 11.9,
J5,6 2.6 Hz, H-60), 3.74 (ddd, 1H, J4,5 9.2, J5,6 5.3, J5,6 2.6 Hz, H-5),
3.69 (s, 3H, OCH3), 2. 99 (dt, 1H, J 7.9, J 6.6 Hz, CH2), 2.88 (dt, 1H,
J 7.9, J 6.6 Hz, CH2), 2.69 (t, 2H, J 7.9, J 6.6 Hz, CH2), 2.09, 2.06,
2.03, 2.01 (12H, 4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3, 90 MHz): d
0
0

274
K. Czifrák, L. Somsák / Carbohydrate Research 344 (2009) 269–277
organic phase was washed with NaCl (1 ꢂ 5 mL), satd NaHCO3
(2 ꢂ 5 mL) and water (1 ꢂ 5 mL), dried, and the solvent removed
under diminished pressure. The crude product was recrystallized
from Et2O to yield 0.08 g (72%) of 11 as white crystalline product.
It was crystallized slowly to give 0.07 g (81%, from the sulfone,
0.1 g) of 14 as a white crystalline product. Mp: 201–204 °C; [a]
D
ꢃ20 (c 0.2, CHCl3); 1H NMR (CDCl3, 360 MHz): d (ppm) 5.39,
5.31, 5.14 (pseudo t, 3H, J ꢀ 9.3 Hz in each, H-2, H-3, H-4), 4.56
Mp: 146–147 °C; [
a]
D
ꢃ36 (c 0.22, CHCl3); 1H NMR (CDCl3,
(d, 1H, J1,2 9.2 Hz, H-1), 4.36 (dd, 1H, J6,6 13.2, J5,6 5.3 Hz, H-6),
0
4.46 (dd, 1H, J6,6 13.2, J5,6 1.0 Hz, H-60), 3.93–3.86 (m, 3H, H-5,
NH2), 2.11, 2.08, 2.06, 2.04 (12H, 4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3,
90 MHz): d (ppm) 170.9, 170.4, 170.1, 169.5 (CO), 87.0 (C-1), 75.9,
72.9, 67.8, 67.5 (C-2 to C-5), 61.3 (C-6), 20.2 (2), 20.1 (2) (CH3).
Anal. Calcd for C14H21O11NS (411.39): C, 40.88; H, 5.15. Found: C,
40.82; H, 5.05. Ms: [M+Na]+ 434.081. Repeated from 1.5 sulfone.
Yield: 1.03 g (81%).
0
0
360 MHz): d (ppm) 5.52, 5.33, 5.14 (pseudo t, 3H, J ꢀ 9.3 Hz in
each, H-2, H-3, H-4), 4.56 (d, 1H, J1,2 9.2 Hz, H-1), 4.28 (dd, 1H,
J6,6 11.9, J5,6 5.3 Hz, H-6), 4.21 (dd, 1H, J6,6 11.9, J5,6 2.6 Hz, H-60),
0
0
0
3.88 (ddd, 1H, J4,5 9.3, J5,6 5.3, J5,6 2.6 Hz, H-5), 3.75 (s, 3H,
OCH3), 3.60 (dt, 1H, J 7.9, 6.6 Hz, CH2), 3.41 (dt, 1H, J 7.9, 6.6 Hz,
CH2), 2.89 (m, 2H, CH2), 2.10, 2.05 (2), 2.03 (12H, 4s, 4 ꢂ OCOCH3);
13C NMR (CDCl3, 90 MHz): d (ppm) 170.5 (COOCH3), 170.3, 169.9,
169.2, 169.1 (CO), 87.9 (C-1), 76.6, 72.9, 67.2, 66.2 (C-2 to C-5),
61.2 (C-6), 52.3 (OCH3), 45.3, 26.2 (CH2), 20.4 (2), 20.3 (2) (CH3).
Anal. Calcd for C18H26O13S1 (482.46): C, 44.81; H, 5.43. Found: C,
44.78; H, 5.40.
3.11. b-D-Glucopyranosyl-1-C-sulfonamide (15)
Sulfonamide 14 (0.1 g, 0.24 mmol) was suspended in dry MeOH
(3 mL). A few drops of NH4OH were added and the mixture was
kept at rt until completion of the transformation (TLC, 4:1
CHCl3–MeOH). Amberlyst 15 (H+ form) was then added to remove
sodium ions, the resin was filtered off and the solvent removed un-
der diminished pressure. The crude oil was purified by column
chromatography (4:1 CHCl3–MeOH) to give 0.05 g (85%) of 15 as
3.8. Methyl 3-(b-D-glucopyranosylthio)propanoate S,S-dioxide
(12)
Sulfone 11 (0.1 g, 0.21 mmol) was suspended in a mixture of
dry MeOH (3 mL) and dry CHCl3 (2 mL). To this soln two drops
of AcCl were added. The mixture was kept at rt until completion
of the transformation (ꢀone week, TLC, 4:1 CHCl3–MeOH). It
was then neutralized with solid NaHCO3 and the solvent evapo-
rated after filtration. The crude oil was purified by column chro-
matography (4:1 CHCl3–MeOH) to give 0.05 g (75%) of 12 as a
a colourless oil. Rf = 0.59 (1:1 CHCl3–MeOH); [
a]
ꢃ34 (c 0.24,
D
H2O); 1H NMR (D2O, 360 MHz): d (ppm) 4.46 (d, 1H, J1,2 9.2 Hz,
0
H-1), 3.91 (dd, 1H, J6,6 11.9, J5,6 5.3 Hz, H-6), 3.74–3.54 (m, 4H,
H-2, H-3 or H-4, H-5, H-60) 3.43 (t,1H, J 9.2, J 9.2 Hz, H-4 or H-3);
13C NMR (D2O, 90 MHz): d (ppm) 90.5 (C-1), 80.9, 77.1, 70.8,
69.5, (C-2 to C-5), 61.2 (C-6); Anal. Calcd for C6H13O7S1 (243.24):
C, 29.60; H, 5.39. Found: C, 29.65; H, 5.36.
colourless oil. Rf = 0.37 (4:1 CHCl3–MeOH); [
a
]
ꢃ53 (c 0.26,
D
H2O); 1H NMR (D2O, 360 MHz): d (ppm) 4.68 (d, 1H, J1,2 9.2 Hz,
0
H-1), 3.90 (dd, 1H, J6,6 13.2, J5,6 5.3 Hz, H-6), 3.85 (s, 3H, OCH3),
3.83 (dd, 1H, J6,6 13.2, J5,6 2.6 Hz, H-60), 3.78–3.36 (m, 6H, H-2,
H-3, H-4, H-5, CH2), 2.98–2.92 (m, 2H, CH2); 13C NMR
(D2O, 90 MHz): d (ppm) 173.8 (COOCH3), 90.0 (C-1), 81.3, 77.2,
69.2, 69.1, (C-2 to C-5), 61.0 (C-6), 53.4 (OCH3), 47.1, 27.1 (CH2).
Anal. Calcd for C10H18O9S1 (314.31): C, 38.21; H, 5.77. Found: C,
38.25; H, 5.80.
3.12. Methyl 3-(2,3,4,6-tetra-O-acetyl-
galactopyranosylthio)propanoate (18)
a-D-
0
0
1,2,3,4,6-Penta-O-acetyl-b-D-galactopyranose(16, 5.0 g, 12.8 mmol)
was dissolved in dry CH2Cl2 (30 mL), and methyl 3-sulfanylpro-
panoate (2.1 mL, 19.2 mmol) and BF3ꢁOEt2 (2.7 mL, 25.6 mmol)
were added at 0 °C. The soln was stirred overnight (ꢀ16 h) at rt
(TLC, 1:2 EtOAc–hexane). After complete transformation of the
starting material, the mixture was diluted with CH2Cl2 and
washed with satd NaHCO3 (2 ꢂ 15 mL) and water (1 ꢂ 15 mL),
dried, and the solvent removed under diminished pressure. The
crude product was purified by silica gel column chromatography
(1:2 EtOAc–hexane) EtOH to give 2.00 g (35%) of 18 as a colourless
3.9. Mixed salt of 2,3,4,6-tetra-O-acetyl-b-D-glucopyranosyl-1-C-
sulfinic acid (13)
Sulfone 11 (0.1 g, 0.21 mmol) was dissolved in freshly distilled
dry CHCl3 (10 mL), and DBU (30 L, 0.21 mmol) was added. The
l
mixture was stirred at rt until complete transformation of the
starting material (TLC, 7:3 CHCl3–MeOH). The solvent was evapo-
rated and the crude oil was purified by column chromatography
(7:3 CHCl3–MeOH) to give 0.06 g of 13 as a white crystalline prod-
uct. 1H NMR (D2O, 360 MHz): d (ppm) 5.36, 5.29, 5.08 (pseudo t,
3H, J ꢀ 9.2 Hz in each, H-2, H-3, H-4), 4.38 (dd, 1H, J6,6 11.9, J5,6
oil. Rf = 0.16 (1:2 EtOAc–hexane), [
a
]
D
+496 (c 0.34, CHCl3); 1H
NMR (CDCl3, 360 MHz): d (ppm) 5.76 (d, 1H, J1,2 5.3 Hz, H-1),
5.45 (dd, 1H, J3,4 2.6, J4,5 1.0 Hz, H-4), 5.26 (dd, 1H, J2,3 10.6, J1,2
5.3 Hz, H-2), 5.18 (dd, 1H, J2,3 10.6, J3,4 2.6 Hz, H-3), 4.58 (t, 1H,
J5,6 6.6, J5,6 5.8 Hz, H-5), 4.15–4.09 (m, 2H, H-6, H-60), 3.71 (s,
0
2.6 Hz, H-6), 4.27 (dd, 1H, J6,6 11.9, J5,6 1.0 Hz, H-60), 4.00 (ddd,
3H, OCH3), 2.88 (dt, 1H, J 7.9, J 6.6 Hz, CH2), 2.78 (dt, 1H, J 7.9, J
0
0
0
1H, J4,5 9.2, J5,6 2.6, J5,6 1.0 Hz, H-5), 3.66 (d, 1H, J1,2 9.2 Hz, H-1),
6.6 Hz, CH2), 2.68–2.64 (m, 2H, CH2), 2.15, 2.06 (2), 1.96 (12H,
2.10, 2.05, 2.04 (2) (12H, 3s, 4 ꢂ OCOCH3); 13C NMR (D2O,
90 MHz): d (ppm) 174.3, 173.9, 173.3 (2) (CO), 92.8 (C-1), 75.8,
75.2, 68.7, 68.5 (C-2 to C-5), 62.5 (C-6), 20.9, 20.7, 20.6 (2) (CH3);
Ms: [M+Na]+ 419.059, [M+K]+ 435.035. Repeated from 1.5 g sul-
fone. Yield: 1.35 g (ꢀ100%). For further preparative purposes, the
crude product obtained after solvent removal was used without
purification.
3s, 4 ꢂ OCOCH3); 13C NMR (CDCl3, 90 MHz):
d (ppm) 171.8
(COOCH3), 170.3, 170.1 (2), 169.7 (CO), 89.9 (C-1), 67.9, 67.8,
67.7, 66.6 (C-2 to C-5), 61.8 (C-6), 51.7 (OCH3), 34.4, 25.1 (CH2),
20.6, 20.5 (3) (CH3); Anal. Calcd for C18H26O11S1 (450.47): C,
47.99; H, 5.82. Found: C, 47.89; H, 5.76.
3.13. Methyl 3-(2,3,4,6-tetra-O-acetyl-a-D-
galactopyranosylthio)propanoate S,S-dioxide (19)
3.10. 2,3,4,6-Tetra-O-acetyl-b-D-glucopyranosyl-1-C-
sulfonamide (14)
Thiogalactoside 18 (0.5 g, 1.10 mmol) was dissolved in glacial
acetic acid (15 mL). To this soln, OxoneÒ (0.95 g, 1.65 mmol) and
NaOAc (0.60 g, 11.0 mmol) were added. The mixture was stirred
at rt until complete transformation of the starting material (TLC,
1:1 EtOAc–hexane). After filtration, it was diluted with water
(15 mL) and extracted with CH2Cl2 (3 ꢂ 15 mL). The organic phase
was washed with satd NaHCO3 (2 ꢂ 15 mL) and water (1 ꢂ 15 mL),
Sulfinate 13 (0.1 g) was suspended in water (5 mL). To this soln,
H2NOSO3H (0.08 g, 0.71 mmol) and NaOAc (0.06 g, 0.73 mmol)
were added and the mixture was stirred at rt for 2 h. After extrac-
tion with EtOAc, (5 ꢂ 5 mL) the organic phase was washed with
satd NaHCO3 (2 ꢂ 5 mL) and water (5 mL), dried and evaporated.

K. Czifrák, L. Somsák / Carbohydrate Research 344 (2009) 269–277
275
dried, and the solvent removed under diminished pressure. The
crude product was purified by column chromatography (1:1
3.16. Mixed salt of 2,3,4,6-tetra-O-acetyl-b-
1-C-sulfinic acid (22)
D-galactopyranosyl-
EtOAc–hexane) to give 0.48 g (90%) of 19 as a colourless oil.
Rf = 0.36 (1:1 EtOAc–hexane), [
a
]
+33 (c 0.25, CHCl3); 1H NMR
Sulfone 21 (0.5 g, 1.05 mmol) was dissolved in freshly distilled
dry CHCl3 (15 mL) and DBU (150 L, 1.05 mmol) was added. The
D
(CDCl3, 360 MHz): d (ppm) 5.79 (dd, 1H, J2,3 10.6, J3,4 2.6 Hz, H-
3), 5.56 (dd, 1H, J3,4 2.6, J4,5 1.0 Hz, H-4), 5.47 (dd, 1H, J2,3 10.6,
J1,2 2.6 Hz, H-2), 5.36 (d, 1H, J1,2 2.6 Hz, H-1), 4.81 (t, 1H, J5.6 6.6,
l
mixture was stirred at rt until complete transformation of the
starting material (TLC, 7:3 CHCl3–MeOH). The solvent was evapo-
rated and the crude oil was purified by column chromatography
(7:3 CHCl3–MeOH) to give 0.35 g of 22 as a yellowish oil. 1H
NMR (D2O, 360 MHz): d (ppm) 5.47 (dd, 1H, J3,4 4.0, J4,5 1.0 Hz,
H-4), 5.43 (t, 1H, J1,2 10.6, J2,3 10.6 Hz, H-2), 5.26 (dd, 1H, J2,3
10.6, J3,4 4.0 Hz, H-3), 3.64 (d, 1H, J1,2 10.6 Hz, H-1), 3.55–3.45
J5,6 5.8 Hz, H-5), 4.19–4.06 (m, 2H, H-6, H-60), 3.62 (s, 3H, OCH3),
0
3.49–3.44 (m, 2H, CH2), 2.93–2.85 (m, 2H, CH2), 2.16, 2.13, 2.09,
2.01 (12H, 4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3, 90 MHz): d (ppm)
170.6 (COOCH3), 170.3, 170.0, 169.5, 169.2 (CO), 84.8 (C-1), 71.3,
66.9, 66.7, 65.7 (C-2 to C-5), 62.2 (C-6), 52.3 (OCH3), 46.5, 25.8
(CH2), 20.4, 20.2 (3) (CH3); Anal. Calcd for C18H26O13S1 (482.46):
C, 44.81; H, 5.43. Found: C, 44.86; H, 5.38.
(m, 2H, H-6, H-60), 3.29 (pseudo t, 1H, J5,6 6.6, J5,6 6.6 Hz, H-5),
0
2.21, 2.06 (2), 2.00 (12H, 3s, 4 ꢂ OCOCH3); 13C NMR (D2O,
90 MHz): d (ppm) 173.6, 173.4, 173.0, 172.9 (CO), 92.8 (C-1),
74.4, 72.4, 68.3, 65.4 (C-2 to C-5), 62.1 (C-6), 20.4, 20.2, 20.1,
20.0 (CH3). For further preparative purposes, the crude product ob-
tained after solvent removal was used without purification.
3.14. Methyl 3-(2,3,4,6-tetra-O-acetyl-b-D-
galactopyranosylthio)propanoate (20)
2,3,4,6-tetra-O-acetyl-1-thio-b-D
-galactopyranose25,26 (17, 3.0 g,
7.86 mmol) was dissolved in dry CH2Cl2 (50 mL). To this soln
methyl 3-bromopropanoate (1.11 mL, 9.43 mmol) and Et3N
(1.05 mL, 9.43 mmol) were added. The mixture was stirred at rt
for 3 days (TLC, 1:2 EtOAc–hexane). It was then diluted with
CH2Cl2 and washed with satd NaHCO3 (2 ꢂ 50 mL) and water
(1 ꢂ 50 mL), dried, and the solvent evaporated. The crude product
was purified by column chromatography (1:2 EtOAc–hexane) to
give 2.10 g (85%) of 20 (conversion is 65%) as a yellowish oil.
3.17. 2,3,4,6-Tetra-O-acetyl-b-D-galactopyranosyl-1-C-
sulfonamide (23)
Sulfinate salt 22 (ꢀ0.35 g) was suspended in water (5 mL).
H2NOSO3H (0.28 g, 2.5 mmol) and NaOAc (0.24 g, 2.92 mmol) were
added and the mixture was stirred at rt for 2 h. After extraction
with EtOAc (5 ꢂ 10 mL), the organic phase was washed with satd
NaHCO3 (2 ꢂ 10 mL) and water (10 mL), dried, and the solvent
evaporated to give 0.27 g (79%, from the sulfone, 0.4 g) of 23 as a
Rf = 0.18 (1:2 EtOAc–hexane); [a]
+169 (c 0.42, CHCl3); 1H NMR
D
(CDCl3, 360 MHz): d (ppm) 5.40 (dd, 1H, J3,4 2.6, J4,5 1.0 Hz, H-4)
5.23 (pseudo t, 1H, J2,3 10.6, J1,2 9.2 Hz, H-2), 5.05 (dd, 1H, J2,3
10.6, J3,4 2.6 Hz, H-3) 4.54 (d, 1H, J1,2 9.2 Hz, H-1), 4.16 (dd, 1H,
yellowish oil. Rf = 0.23 (1:1 EtOAc–hexane); [
a
]
+32 (c 0.22,
D
CHCl3); 1H NMR (CDCl3, 360 MHz): d (ppm) 5.51 (s, 1H, NH2),
5.48 (1H, dd, J3,4 4.0, J4,5 1.0 Hz, H-4), 5.29 (s, 1H, NH2), 5.26 (t,
1H, J1,2 10.6, J2,3 10.6 Hz, H-2), 5.17 (dd, 1H, J2,3 10.6, J3,4 2.3 Hz,
0
0
0
J6,6 11.9, J5,6 5.3 Hz, H-6), 4.12 (dd, 1H, J6,6 11.9, J5,6 2.6 Hz, H-
60), 3.95 (t, 1H, J5.6 6.6, J5,6 5.8 Hz, H-5), 3.70 (s, 3H, OCH3), 3.02
H-3), 4.41 (d, 1H, J1,2 10.6 Hz, H-1), 4.22 (t, 1H, J5,6 6.6, J5,6
0
0
(dt, 1H, J 7.9, J 6.6 Hz, CH2), 2.93 (dt, 1H, J 7.9, J 6.6 Hz, CH2),
2.72–2.68 (m, 2H, CH2), 2.16, 2.05 (2), 1.98 (12H, 3s, 4 OCOCH3);
13C NMR (CDCl3, 90 MHz): d (ppm) 172.0 (COOCH3), 170.3, 170.1,
169.9, 169.7 (CO), 84.5 (C-1), 74.4, 71.7, 67.1, 67.0 (C-2 to C-5),
61.4 (C-6), 51.7 (OCH3), 35.1, 25.4 (CH2), 20.6, 20.5 (2), 20.4
(CH3); Anal. Calcd for C18H26O11S1 (450.47): C, 47.99; H, 5.82.
Found: C, 47.85; H, 5.92.
6.6 Hz, H-5), 4.16–4.11 (m, 2H, H-6, H-60), 3.93–3.86 (m, 3H, H-5,
NH2), 2.17, 2.08, 2.05, 1.99 (12H, 4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3,
90 MHz): d (ppm) 171.1, 170.5, 170.0, 169.8 (CO), 87.8 (C-1), 75.2,
70.7, 66.9, 65.3 (C-2 to C-5), 60.9 (C-6), 20.8, 20.6 (2), 20.5 (CH3).
Anal. Calcd for C14H21O11NS (411.39): C, 40.88; H, 5.15. Found: C,
40.80; H, 5.21.
3.18. Bromination methods
3.15. Methyl 3-(2,3,4,6-tetra-O-acetyl-b-D-
galactopyranosylthio)propanoate S,S-dioxide (21)
(a) A methyl 3-(2,3,4,6-tetra-O-acetyl-b-
propanoate S,S-dioxide (11 or 21, 0.1 g, 0.21 mmol) was dissolved
in dry CCl4 (10 mL), and bromine (30 L, 0.73 mmol) and some
D-glycopyranosylthio)
Thiogalactoside 20 (1.0 g, 2.20 mmol) was dissolved in glacial
acetic acid (30 mL). To this soln, OxoneÒ (1.90 g, 3.30 mmol) and
NaOAc (1.20 g, 22.0 mmol) were added. The mixture was stirred
at rt until complete transformation of the starting material (TLC,
1:1 EtOAc–hexane). After filtration it was diluted with water
(30 mL) and extracted with CH2Cl2 (3 ꢂ 30 mL). The organic phase
was washed with satd NaHCO3 (2 ꢂ 30 mL) and water (1 ꢂ 30 mL),
dried, and the solvent was removed under diminished pressure.
The crude product was recrystallized from Et2O to give 0.74 g
l
K2CO3 were added. The mixture was placed in an Erlenmeyer flask
above a heat lamp (375 W, distance from the lamp ꢀ2–3 cm,
height of the soln 1–2 cm), and refluxed. It was monitored by
(TLC, 1:1 EtOAc–hexane). After 3 h CHCl3 (10 mL) was added, and
the mixture washed with 1 M aq Na2S2O3 (10 mL), satd NaHCO3
(2 ꢂ 10 mL) and water (10 mL). After drying, the solvent was re-
moved and the residue purified by column chromatography (1:1
EtOAc–hexane).
(70%) of 21 as a white crystalline product. Mp: 120–122 °C; [
a
]
(b)
amide (14 or 23, 0.1 g, 0.24 mmol) was dissolved in dry CHCl3
(10 mL), and bromine (30 L, 0.73 mmol) and some K2CO3 were
added. The mixture was placed in an Erlenmeyer flask above a heat
lamp (375 W, distance from the lamp ꢀ2–3 cm, height of the soln
1–2 cm), and refluxed. If the mixture decolourized, bromine
A
2,3,4,6-tetra-O-acetyl-b-D-glycopyranosyl-1-C-sulfon-
D
+6 (c 0.24, CHCl3); 1H NMR (CDCl3, 360 MHz): d (ppm) 5.68 (1H,
pseudo t, J2,3 10.6, J1,2 9.2 Hz, H-2), 5.47 (dd, 1H, J3,4 4.0, J4,5
2.6 Hz, H-4) 5.16 (dd, 1H, J2,3 10.6, J3,4 4.0 Hz, H-3), 4.52 (d, 1H,
l
0
J1,2 9.2 Hz, H-1), 4.23–4.16 (m, 2H, H-5, H-6), 4.11 (dd, 1H, J6,6
11.9, J5,6 5.3 Hz, H-60), 3.74 (s, 3H, OCH3), 3.55 (dt, 1H, J 7.9, J
0
6.6 Hz, CH2), 3.42 (dt, 1H, J 7.9, J 6.6 Hz, CH2), 2.92–2.87 (m, 2H,
CH2), 2.20, 2.07, 2.06, 1.98 (12H, 4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3,
90 MHz): d (ppm) 170.5 (COOCH3), 170.2, 169.9, 169.8, 169.2 (CO),
88.6 (C-1), 75.4, 71.1, 66.6, 63.3 (C-2 to C-5), 61.0 (C-6), 52.3
(OCH3), 45.1, 26.1 (CH2), 20.6, 20.5, 20.4, 20.3 (CH3); Anal. Calcd
for C18H26O13S1 (482.46): C, 44.81; H, 5.43. Found: C, 44.74; H,
5.46.
(10 lL) was added again. It was monitored by (TLC, 1:1 EtOAc–hex-
ane). After 8 h CHCl3 (10 mL) was added, and the mixture washed
with 1 M aq Na2S2O3 (10 mL), satd NaHCO3 (2 ꢂ 10 mL) and water
(10 mL). After drying, the solvent was removed and the residue
purified by column chromatography (1:1 EtOAc–hexane).
(c) 2,3,4,6-Tetra-O-acetyl-b-
D-glycopyranosyl-1-C-sulfonamide
(14, 0.1 g, 0.24 mmol) was dissolved in dry PhCF3 (10 mL), and bro-

276
K. Czifrák, L. Somsák / Carbohydrate Research 344 (2009) 269–277
mine (30
l
L, 0.73 mmol) and some K2CO3 were added. The mixture
5.63 (dd, 1H, J3,4 2.6, J4,5 1.0 Hz, H-4), 4.92 (d, 1H, J1,2 9.2 Hz. H-
1), 4.67 (d, 1H, J6,6 11.9 Hz, H-6), 4.40 (d, 1H, J6,6 11.9 Hz, H-60),
3.73 (3H, s, OCH3), 3.46–3.40 (2H, m, CH2), 2.89–2.82 (2H, m,
CH2), 2.15, 2.06 (2), 1.97 (12H, 3s, 4 ꢂ OCOCH3); 13C NMR (CDCl3,
90 MHz): d (ppm) 170.2 (COOCH3), 169.5 (2), 169.0 (2) (CO), 95.7
(C-5), 85.9 (C-1), 69.8, 68.5, 65.9, (C-2 to C-4), 60.3 (C-6), 52.5
(OCH3), 45.8, 26.0 (CH2), 20.9, 20.5, 20.4, 20.3 (CH3). Anal. Calcd
for C18H25O13S1 (561.36): C, 38.50; H, 4.49. Found: C, 38.59; H,
4.53.
0
0
was placed in an Erlenmeyer flask above a heat lamp (375 W, dis-
tance from the lamp ꢀ2–3 cm, height of the soln 1–2 cm), and re-
fluxed. It was monitored by (TLC, 1:1 EtOAc–hexane). After 4 h, the
mixture was washed with 1 M aq Na2S2O3 (10 mL), satd NaHCO3
(2 ꢂ 10 mL) and water (10 mL). After drying, the solvent was re-
moved under diminished pressure, and the residue purified by col-
umn chromatography (1:1 EtOAc–hexane).
3.19. Methyl (2,3,4,6-tetra-O-acetyl-1-C-bromo-b-
D-
glucopyranosylthio)propanoate S,S-dioxide (24)
3.23. 2,3,4,6-Tetra-O-acetyl-1-C-bromo-b-D-glucopyranosyl-1-C-
sulfonamide (28)
Isolated from the bromination mixture of 11 (1.0 g, 2.07 mmol)
obtained by method (a) as a white crystalline product (0.25 g, 21%)
Obtained by bromination of 14 (0.60 g, 1.45 mmol) by method
(b) 0.05 g (11%) and method (c) 0.058 g (12%) as a white crystalline
from hexane. Mp: 92–93 °C; [
a
]
D
+176 (c 0.28, CHCl3); 1H NMR
(CDCl3, 360 MHz.): d (ppm) 5.66 (d, 1H, J1,2 9.2 Hz, H-2), 5.49,
5.25 (pseudo t, 2H, J ꢀ 9.2 Hz in each, H-3, H-4), 4.36–4.18 (m,
3H, H-5, H-6, H-60), 3.75 (s, 3H, OCH3), 3.72–3.63 (m, 2H, CH2),
2.89–2.84 (m, 2H, CH2), 2.12, 2.09, 2.06, 2.02 (12H, 4s,
4 ꢂ OCOCH3); 13C NMR (CDCl3, 90 MHz): d (ppm) 170.3 (COOCH3),
170.2, 169.6, 168.9, 168.6 (CO), 106.8 (C-1), 75.4, 71.3, 66.9, 66.2
(C-2 to C-5), 60.2 (C-6), 52.4 (OCH3), 43.1, 26.3 (CH2), 20.4 (3)
20.3 (CH3). Anal. Calcd for C18H25O13S1 (561.36): C, 38.50; H,
4.49; S, 5.71. Found: C, 38.55; H, 4.42; S, 5.77.
product from hexane. Mp: 185–187 °C; [a] +235 (c 0.26, CHCl3);
D
1H NMR (CDCl3, 360 MHz): d (ppm) 5.56–5.45 (m, 2H, H-2, H-3
or H-4), 5.38–5.34 (m, 2H, NH2), 5.26 (t, 1H, J 9.2, J 9.2 Hz, H-4 or
H-3), 4.33–4.26 (m, 3H, H-5, H-6, H-60), 2.10 (2), 2.05, 2.01 (12H,
4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3, 90 MHz): d (ppm) 170.9,
169.8, 169.7, 169.3 (CO), 105.4 (C-1), 75.2, 71.5, 68.7, 66.6 (C-2 to
C-5), 60.4 (C-6), 20.7 (2), 20.5, 20.4 (CH3). Anal. Calcd for
C14H20O11BrNS (490.28): C, 34.30; H, 4.11. Found: C, 34.35; H, 4.01.
3.24. 2,3,4,6-Tetra-O-acetyl-5-C-bromo-b-D-glucopyranosyl-1-C-
3.20. Methyl (2,3,4,6-tetra-O-acetyl-5-C-bromo-b-
D
-
sulfonamide (29)
glucopyranosylthio)propanoate S,S-dioxide (25)
Obtained by bromination of 14 (0.60 g, 1.45 mmol) by method
Isolated from the bromination mixture of 11 (1.0 g, 2.07 mmol)
by method (a) as a colourless oil (0.35 g, 30%). Rf = 0.66 (1:1 EtOAc–
(b) 0.054 g (12%) and method (c) 0.056 g (12%) as a yellowish oil.
Rf = 0.59 (1:1 EtOAc–hexane); [
a
]
D
ꢃ284 (c 0.24, CHCl3); 1H NMR
hexane); [
a]
ꢃ252 (c 0.20, CHCl3); 1H NMR (CDCl3, 360 MHz): d
(CDCl3, 360 MHz): d (ppm) 5.58, 5.51 (pseudo t, 2H, J ꢀ 9.2 Hz in
each, H-2, H-3), 5.38–5.32 (m, 2H, NH2), 5.23 (d, 1H, J1,2 9.2, Hz,
H-1), 4.84 (d, 1H, J3,4 9.2 Hz, H-4), 4.90–4.56 (m, 2H, H-6, H-60),
2.11, 2.08 (2), 2.01 (12H, 3s, 4 ꢂ OCOCH3); 13C NMR (CDCl3,
90 MHz): d (ppm) 170.2 (2), 169.6, 169.0 (CO), 98.4 (C-5), 85.6
(C-1), 71.1, 68.2, 67.0 (C-2 to C-4), 65.5 (C-6), 20.6 (2), 20.4 (2)
(CH3). Anal. Calcd for C14H20O11BrNS (490.28): C, 34.30; H, 4.11.
Found: C, 34.28; H, 4.08.
D
(ppm) 5.66, 5.58 (pseudo t, 2H, J ꢀ 9.2 Hz in each, H-2, H-3), 5.26
(d, 1H, J1,2 10.6 Hz. H-1), 4.96 (d, 1H, J3,4 9.2 Hz, H-4), 4.58 (d, 1H,
J6,6 11.9 Hz, H-6), 4.46 (d, 1H, J6,6 11.9 Hz, H-60), 3.76 (s, 3H,
OCH3), 3.82–3.54 (m, 2H, CH2), 2.88–2.84 (m, 2H, CH2), 2.13,
2.10, 2.07, 2.03 (12H, 4s, 4 ꢂ OCOCH3); 13C NMR (CDCl3,
90 MHz): d (ppm) 170.1 (COOCH3), 169.6, 169.5, 168.9, 168.7
(CO), 98.3 (C-5), 85.5 (C-1), 71.2, 67.9, 66.9, (C-2 to C-4), 60.2 (C-
6), 52.4 (OCH3), 45.9, 26.1 (CH2), 20.4 (2) 20.3 (2) (CH3). Anal. Calcd
for C18H25O13S1 (561.36): C, 38.50; H, 4.49. Found: C, 38.48; H,
4.45.
0
0
Acknowledgements
Financial support for this work was provided by the Hungarian
Scientific Research Fund (Grants: OTKA 46081 and 61336). The
authors thank P. Gergely and T. Docsa for the glycogen phosphor-
ylase assays.
3.21. Methyl (2,3,4,6-tetra-O-acetyl-1-C-bromo-b-
galactopyranosylthio)propanoate S,S-dioxide (26)
D-
Isolated from the bromination mixture of 21 (0.20 g,
0.41 mmol) obtained by method (a) as a colourless oil (0.1 g,
References
43%). Rf = 0.55 (1:1 EtOAc–hexane); [a]
+154 (c 0.18, CHCl3); 1H
D
NMR (CDCl3, 360 MHz): d (ppm) 5.82 (d, 1H, J1,2 10.6 Hz, H-2),
5.55 (dd,1H, J3,4 2.6, J4,5 1.0 Hz, H-4), 5.32 (dd, 1H, J2,3 10.6, J3,4
1. Somsák, L.; Nagy, V.; Docsa, T.; Tóth, B.; Gergely, P. Tetrahedron: Asymmetry
2000, 11, 405–408.
2. Somsák, L.; Nagy, V. Tetrahedron: Asymmetry 2000, 11, 1719–1727.
Corrigendum 2247.
0
2.6 Hz, H-3), 4.52 (t, 1H, J5,6 6.6, J5,6 6.6 Hz, H-5), 4.26–4.22 (m,
2H, H-6, H-60), 3.75 (s, 3H, OCH3), 3.72–3.66 (m, 2H, CH2), 2.96–
2.92 (m, 2H, CH2), 2.12, 2.07, 2.05, 2.00 (12H, 4s, 4 ꢂ OCOCH3);
13C NMR (CDCl3) d (ppm): 170.2 (COOCH3), 172.0, 170.1, 169.7,
169.6 (CO), 108.1 (C-1), 74.8, 69.6, 66.1, 63.8 (C-2 to C-5), 60.3
(C-6), 52.4 (OCH3), 43.0, 26.3 (CH2), 20.9 20.4 (3) (CH3). Anal. Calcd
for C18H25O13S1 (561.36): C, 38.50; H, 4.49; S, 5.71. Found: C, 38.53;
H, 4.41; S, 5.77.
}
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D-
Isolated from the bromination mixture of 21 (0.20 g,
0.41 mmol) obtained by method (a) as a colourless oil (0.06 g,
27%). Rf = 0.50 (1:1 EtOAc–hexane); [
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]
ꢃ131 (c 0.18, CHCl3); 1H
D
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