Synthesis of polyhydroxylated cyclohexenyl sulfides and sulfoxides. Evaluation of their inhibitory activity on α- and β-D-glucosidases

Article abstract of DOI:10.1016/S0008-6215(99)00137-8

Racemic polyhydroxylated sulfides and sulfoxides have been prepared as potential transition-state analogs of the glucoside hydrolysis reaction, through a reaction sequence involving transformations of a ketone group into thioacetal, followed by partial ox

Full text of DOI:10.1016/S0008-6215(99)00137-8

www.elsevier.nl/locate/carres
Carbohydrate Research 320 (1999) 49–60
Synthesis of polyhydroxylated cyclohexenyl sulfides and
sulfoxides. Evaluation of their inhibitory activity on a-
and b-D-glucosidases
Andre´ Lubineau *, Isabelle Billault
Laboratoire de Chimie Organique Multifonctionnelle, Institut de Chimie Mole´culaire d’Orsay, UMR CNRS 8614,
Uni6ersite´ de Paris-Sud, Bat. 420, F-91405 Orsay, France
Received 31 March 1999; revised 26 May 1999; accepted 27 May 1999
Abstract
Racemic polyhydroxylated sulfides and sulfoxides have been prepared as potential transition-state analogs of the
glucoside hydrolysis reaction, through a reaction sequence involving transformations of a ketone group into
thioacetal, followed by partial oxidation to sulfoxide then regioselective thermal elimination of the sulfoxide to vinyl
sulfide. These sulfides with two, three or four hydroxyl groups have been oxidized to the corresponding diastereoiso-
meric sulfoxides. All compounds, summarily tested as inhibitors of a- and b-glucosidases, were found to be very weak
inhibitors and thus their biological properties were not studied in depth. Curiously, however, their inhibitory
properties, which are in the 10 mM range, do not really depend upon the number of hydroxyl groups or upon the
presence of polar sulfoxide. In order to get more insights, 2-phenyl sulfoxide-3,4,5-trihydroxycyclohex-1-ene (9a) was
studied in more detail using Brewers yeast a-glucosidase and was shown to give a mixed-type inhibition with a high
Ki of 45 mM. © 1999 Elsevier Science Ltd. All rights reserved.
Keywords: Carbasugars; Cyclohexenyl sulfides and sulfoxides; Glycosidase inhibitors; Glycoside hydrolysis transition state
1. Introduction
charge development around the anomeric car-
bon atom in the transition state along the
hydrolysis pathway. As a result, many N-sub-
stituted derivatives of 1–3 and some of their
In connection with a program directed to-
ward antibody catalysis of glycosidic bond
hydrolysis, we were interested in carbasugar-
type inhibitors, some of them being reported
as good a- and b- -glucosidase inhibitors.
D
Thus, the valienamine 1, the validamine 2 and
the valiolamine 3 were shown to be strong
inhibitors of a- -glucosidases [1]. The in-
D
hibitory activity of these compounds rests on
their configuration, their basic character or
their conformation, which mimics in part the
flattened anomeric region and/or the partial
* Corresponding author. Tel.: +33-1-6915-7233; fax: +
33-1-6915-4715.
E-mail address: lubin@icmo.u-psud.fr (A. Lubineau)
0008-6215/99/$ - see front matter © 1999 Elsevier Science Ltd. All rights reserved.
PII: S0014-827X(99)00137-8

50
A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
epimers have been synthesized, giving rise to
numerous other glucosidase inhibitors [2,3].
More recently, the natural carbasugar cy-
clophellitol 4 [4] has been isolated and de-
racemic derivatives for rapid evaluation of
their biological behavior, bearing in mind that
the complete determination of the exact in-
hibitory power would require the pure enan-
tiomeric form. Indeed, their potential use as
hapten for monoclonal antibody preparation
does not require the pure enantiomer as each
isolated monoclonal antibody must recognize
only one enantiomeric form in the antigenic
racemic mixture.
scribed as a specific inhibitor of b-
cosidases [5]. The cyclophellitol 4 is a fully
oxygenated -gluco-configured cyclohexane,
D-glu-
D
which possesses a flattened conformation im-
posed by an epoxide [6] and acts as an inacti-
vator of b- -glucosidases. As reported by
D
The syntheses of vinyl sulfides 5–7 and
vinyl sulfoxides 8a/8b–10a/10b were per-
formed from the corresponding racemic cyclo-
hexanones 11–13 in five and six steps,
respectively. The key step in all the syntheses
was a regioselective sulfoxide elimination that
led to the substituted cyclohexene. We also
describe the inhibitory potencies of vinyl
sulfides 5–7 and vinyl sulfoxides 8a/8b–10a/
Withers and Umezawa, the epoxide 4 is first
protonated by the carboxylic acid residue in
the active site of the enzyme, then attacked by
the nucleophile carboxylate residue to form a
covalent derivative that inactives the ‘retain-
ing’ b- -glucosidase [7]. In order to provide
D
some additional information about the inter-
actions of such an epoxide with glucosidases,
the 1,6-epi-cyclophellitol [8] and some related
derivatives (aziridine [9] and thiirane [10]),
possessing various configurations, have also
been prepared. Thus, transposed in the area of
catalytic antibodies, the design of the hapten
could result from two different strategies: one
based on the half-chair transition-state
analogs and the other based on positively
charged compounds expected to induce func-
tional group in the antibody-combining site
that would stabilize the delocalized positive
charge of the transition state.
10b toward a-
D
-glucosidase (Brewers yeast)
and b- -glucosidase (sweet almonds).
D
We now describe, for evaluation of their
inhibition properties, the syntheses of the
polyhydroxylated cyclohexenyl sulfides 5–7
and sulfoxides 8a/8b–10a/10b as new carba-
sugar-type derivatives. Similarly to the cy-
clophellitol 4, these compounds are uncharged
derivatives; however, they possess a double
bond in a correct position corresponding to
that in the oxocarbenium ion, which should
impose a flattened half-chair conformation.
On the one hand, we were interested in the
comparison of the inhibition activities be-
tween both series, the vinyl sulfides 5–7 and
the more polarized vinyl sulfoxides 8a/8b–
10a/10b, which could induce some charge in-
teractions in spite of the lack of basic center as
found in valienamine-type inhibitors. At the
same time, we considered evaluating the con-
tribution of hydroxy groups in the inhibition
and prepared the corresponding unsubstituted
cyclohexene derivatives for comparison. We
chose in a first approach to prepare the
2. Results and discussion
Preparation of the starting ketones 11–13.—
The dihydroxyketone 11 was readily obtained
in two steps from the commercial cyclo-
hexenone according to a known procedure
[11]. The trihydroxyketone 12 was prepared in
four steps (Scheme 1) from the epoxide 14,
easily available from 1,4-benzoquinone and
cyclopentadiene (two steps) [12]. The
diastereo- and regioselective reduction of 14
with tetrabutylammonium borohydride [13] at
low temperature afforded a mixture of
diastereoisomers 15a/15b in an 85:15 ratio as
determined by 13C NMR and H NMR spec-
trometry. The diastereoisomers 15a/15b could
1

A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
51
Scheme 1.
Preparation of 6inyl sulfides (5–7) and 6inyl
sulfoxides (8–10) (Scheme 2).—The dihydroxy
ketone 11 was used as a model for the synthe-
sis of polyhydroxylated cyclohexenyl sulfides
5–7 and sulfoxides 8a/8b–10a/10b. Treatment
of 11 with thiophenol in concd aq hydrochlo-
ric acid [18] followed by acetylation gave the
acetylated dithioacetal 18 in 65% yield. Then,
18 was treated with mercuric acetate [19] and
regioselectively gave the cyclohexenyl sulfide
19 but only in low yield (40%). So, an alterna-
tive route has been developed. First the
dithioacetal 18 was selectively oxidized to a
diastereomeric mixture of sulfoxides using 1
equiv of m-chloroperoxybenzoic acid2 at −
30 °C. Then, the sulfoxide mixture was di-
rectly heated at 80 °C in the presence of
calcium carbonate [20] to provide the unique
vinylic sulfide 19 in 90% yield (two steps).
Then, deacetylation (MeOH, NaOMe) gave
the expected dihydroxy cyclohexenyl sulfide 5
in 95% yield. Using 1 equiv of m-chloroper-
oxybenzoic acid, the oxidation of 19 to get the
diastereomeric sulfoxides 20a/20b was not se-
lective, and further oxidation to the sulfone3
21 (35%) was observed. The sulfoxides 20a/
20b (ratio 60:40) and the sulfone 21 were
obtained in a 65:35 ratio and could not be
separated by flash chromatography at this
stage. Pure samples of 8a and 8b were ob-
tained after deacetylation of the mixture
(MeOH, NaOMe).
not be separated from each other by flash
chromatography; the configuration assign-
ment was therefore performed on the
diastereoisomeric mixture. Analysis of the
multiplicity and coupling constants associated
with H-3 of 15a/15b showed that the major
isomer 15a had a trans configuration (15a: dd,
J 4.5 and 3.5 Hz; 15b: d, J 4.5 Hz). This
assignment was later confirmed after acetyla-
tion of 15a/15b followed by separation of
both diastereoisomers by flash chromatogra-
phy (data not shown).
Fortunately the mixture 15a/15b, when sub-
mitted to a retro Diels–Alder reaction (di-
ethylphthalate, 190 °C), led to a mixture of
both epoxides 15b and 16 [14] from which the
epoxide 16 could be isolated in 80% yield.
Heating epoxide 16 in water at 80 °C for 4
days led to the trihydroxycyclohexenone 17
[15] in 41% yield1. According to the coupling
1
constants determined by H NMR (J4,5 8.0
Hz, J5,6 10.5 Hz), the hydroxy groups pos-
sessed a trans relative configuration. Epoxide
16, when treated in acidic conditions, also
gave the trihydroxycyclohexenone 17 but in a
lower yield (ca. 30%). Alkaline conditions to
open such an epoxide could not be used here
since aromatization might occur [16]. The cy-
clohexenone 17 was further reduced under
catalytic hydrogenation in the presence of
Pd–C to give 12 in 80% yield. The tetrahy-
droxylated ketone 13 was prepared in 11 steps
from furan and acrylic acid using a method
developed by Ogawa and co-workers [17]
(data not shown).
A similar strategy was used to prepare the
vinylic sulfides 6 and 7 and the vinylic sulfox-
ides 9a/9b and 10a/10b from either ketone 12
1 After heating the epoxide 16 in water at 80 °C for 4 days,
hydrolysis was not complete. The crude product also con-
tained the starting material (ca. 39%) and the product result-
ing of the 1,4-addition of water on the double bond of 17 (ca.
17%). Increasing temperature or reaction time did not im-
prove the yield.
2 Titration of the m-chloroperoxybenzoic acid solution was
performed (KI, NaHCO3, AcOH–water, then titration with
sodium thiosulfate) before use.
3 Formation of the sulfone 17 as by-product was observed
at low temperature, even before the complete conversion of 15
in the expected sulfoxides 16a/16b.

52
A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
Scheme 2.
or 13 (Scheme 2). Reaction of the ketones 12
or 13 with thiophenol and concd aq HCl
followed by acetylation gave acetylated dithio-
phenylacetal 23 or 24 but only in low yield
(ca. 30%). In fact, activation of 12 or 13 with
borontrifluoride etherate [21] in the presence
of thiophenol in dichloromethane at low tem-
perature (−5 °C) gave the best results, result-
ing in 23 (85%) and 24 (66%) after acetylation.
As expected, the cyclohexenyl sulfides 25 and
26 were the major regioisomers formed in the
course of the sulfoxide elimination step. The
vinylic sulfides 25 and 26 were obtained in 80
and 75% yields, respectively, although a small
amount (4%) of the others regioisomers 27
and 28 was formed. Deacetylation of 25 and
26 (MeOH, NaOMe) yielded the tri- and te-
trahydroxylated vinylic sulfides 6 (84%) and 7
(95%), respectively. Direct oxidation of both
vinylic sulfides 2 and 3 with an excess of
samples of the trihydroxylated vinylic sulfox-
ides 9a and 9b were obtained after flash chro-
matography, while only partial separation of
the tetrahydroxylated vinylic sulfoxides 10a/
10b (ca. 9:1, 1:1 and 1:4) was obtained.
Biological e6aluations.—The cyclohexenyl
sulfides 5–7 and sulfoxides 8a/8b–10a/10b are
very weak inhibitors of Brewers yeast a-
cosidase (EC 3.2.1.20) and sweet-almond b-
glucosidase (EC 3.2.1.21). The IC50 (50%
inhibition) was observed against yeast a-
D
-glu-
D-
D-
glucosidase at 10 mM for the cyclohexenyl
sulfides 6 and 7, at 8 mM for the cyclohexenyl
sulfoxide 9a, and at 2.5 mM for the cyclohex-
enyl sulfides 5, while the Km values of yeast
a-
D
-glucosidase and sweet-almonds b- -glu-
D
cosidase for their corresponding substrate4
were 0.16 and 2.4 mM, respectively. For all
the other derivatives and with both glucosi-
dases, the IC50 was not reached at 10 mM.
The number of hydroxy groups in either
sulfide or sulfoxide derivatives does not have
the expected effect on the inhibition. Thus, the
t-butylhydroperoxide at 60 °C gave
a
diastereomeric mixture (ratio 1:1) of vinylic
sulfoxides 9a/9b (84%) and 10a/10b (78%),
respectively. It is worth pointing out that fur-
ther oxidation to the sulfones using t-butylhy-
droperoxide as oxidant instead of m-chloro-
peroxybenzoic acid was not observed. Pure
4 The substrates used for the b-
monds) and for the a-D-glucosidase (Brewers yeast) were
p-nitrophenyl-b- and a- -glucopyranosides, respectively.
D-glucosidase (sweet al-
D

A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
53
3. Experimental
tetrahydroxylated vinylic sulfide 7 or the te-
trahydroxylated vinylic sulfoxides 10a/10b do
General methods.—1H (200 and 250 MHz)
not inhibit the a- or the b- -glucosidase better
D
13
and C (50 and 63 MHz) NMR spectra were
than the corresponding di- or trihydroxylated
derivatives 5, 8a/8b or 6, 9a/9b did. From
these preliminary inhibition studies, it appears
that neither the polyhydroxylated cyclohex-
enyl sulfides 5–7 nor the polyhydroxylated
cyclohexenyl sulfoxides 8a/8b–10a/10b pos-
sess the complete structural requirement to
interact efficiently as inhibitors with the car-
boxylic acid residue in the active side of the
tested glucosidases. While Khiar et al. [22]
reported that only one diastereoisomer (S iso-
recorded with Bruker AC 200 and 250 spec-
trometers. Chemical shifts were given relative
to Me4Si in CDCl3; for NMR spectra in
CD3OD, l 3.16 ppm was used as reference.
Flash chromatography was performed with
Silica Gel 60A CC 6–35 mm (SDS). Melting
points were measured on a Reichert apparatus
and were uncorrected. Optical rotations were
measured on an Electronic Digital Jasco DIP-
370 Polarimeter. IR spectra were recorded on
a FT-IR Bruker IFS 66 spectrometer. Mass
spectra were realized in EI mode on a Finni-
gan Mat 95S. Dry DME was distillated from
sodium and benzophenone, and dry CH2Cl2
from CaH2. Enzymes (Brewers yeast a-glu-
cosidase (EC 3.2.1.20) and sweet almond b-
glucosidase (EC 3.2.1.21)) were purchased
from Sigma Chemical Co and used without
further purification. Elemental analyses were
performed at the Service Central de Micro-
analyses du CNRS (Gif sur Yvette, France)
4-Hydroxy-5,8-methylene-10-oxa-tricyclo-
[4-4-04a,8a-4-1-02,3]-undeca-6-ene-1-one (15a/
15b).—A solution of 14 (1.5 g, 7.9 mmol) in
1:1 CH2Cl2–MeOH (80 mL) at −78 °C was
treated with tetrabutylammonium borohy-
dride (1.0 g, 3.95 mmol) over 2 h. The temper-
ature was slowly warmed up to 0 °C (2.5 h),
then the mixture was diluted with CH2Cl2 and
treated with a satd NH4Cl soln (100 mL). The
combined organic phases, filtered through a
phase separator filter, were concentrated.
Flash chromatography (7:3 hexane–EtOAc)
of the residue gave 15a/15b (85:15, 1.2 g, 81%)
as a white amorphous solid (ratio determined
mer) from a phenyl sulfoxide b-
noside diastereomeric mixture could be
hydrolyzed by a b- -galactosidase (E. coli ),
D
-galactopyra-
D
no significant discrimination has been ob-
served during the inhibition assay using the
sulfoxides 8a, 9a or 10a as compared with the
diastereoisomeric derivatives 8b, 9b or 10b. To
get more insights into the biochemical behav-
ior of vinyl sulfoxides, 2-phenysulfoxide-3,4,5-
trihydroxycyclohex-1-ene (9a) was studied in
more detail using Brewers yeast a-glucosi-
dases. The Lineweaver–Burke plots of a-glu-
cosidase inhibition by 9a showed a mixed-type
inhibition, which could indicate the participa-
tion of covalent linkage between the enzyme
and 9a, which could behave as a Michael
acceptor. Then, Km(app)/Vmax was plotted
against the 9a concentration to give Ki (45
mM).
Although the cyclohexenyl sulfoxides 8a/
8b–10a/10b possess a flattened conformation
with a planar pseudo anomeric center, the
sulfoxide group may not be basic enough, and
also not at the optimal distance from the
carboxylic acid residue in the active site, to
interact by forming a strong hydrogen bond
with the latter [23,24].
In conclusion, we have shown that the in-
hibitory properties of vinyl sulfides and sul-
foxides do not depend upon the number of
hydroxyl groups in the cyclohexenyl moiety
and that the polar vinyl sulfoxide functionality
does not bring any additional interaction with
the active sites of the tested enzymes. In par-
ticular, among all the tested compound, the
simplest vinyl sulfide 5 with only two hydroxyl
groups behaves as the best inhibitor.
13
by C NMR). IR 15a/15b (KBr) cm−1: 3378
(OH), 3058 and 2989 (CH double bond), 1710
1
(CO). Data for 15a: H NMR (CDCl3) l: 6.21
(m, 2 H, H-6 and H-7), 4.66 (ddd, 1 H, J 9.0
Hz, J4a,4 5.0 Hz, J4,3 3.5 Hz, H-4), 3.59 (dd, 1
H, J3,2 4.5 Hz, H-3), 3.30 (d, 1 H, H-2), 3.17
(dd, 1 H, J8a,4a 11.0 Hz, J8a,8 3.5 Hz, H-8a),
3.03, 3.09 (2 br s, 2 H, H-5 and H-8), 2.96
(ddd, 1 H, J4a,5 3.0 Hz, H-4a), 1.41 (br, 1 H, d,
J9a,9b 8.5 Hz, H-9a), 1.31 (br d, 1 H, H-9b).
13C NMR (CDCl3) l: 208.1 (C-1), 135.6, 135.3
(C-7, C-6), 66.94 (C-4), 59.4 and 54.6 (C-2,

54
A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
amorphous solid and a last fraction that con-
tained the product resulting from the 1,4-addi-
tion of water on 17. The epoxide 17 was
recrystallized in EtOH, mp 158–160 °C (Lit.
[15] 156–158 °C). IR (KBr) cm−1: 3434 (OH),
C-3), 51.2, 49.4, 44.9, 44.8, 42.5 (C-8, C-8a,
C-5, C-4a, C-9). Data for 15b: H NMR
1
(CDCl3) l: 6.18 (m, 1 H, H-6 or H-7), 6.02
(dd, 1 H, J6,7 6.0 Hz, J 3.0 Hz, H-6 or H-7),
3.52 (d, 1 H, J2,3 4.5 Hz, H-3), 3.28 (d, 1 H,
H-2), 2.64 (ddd, 1 H, J4a,8a 11.0 Hz, J4a,4 9.0
Hz, J4a,5 3.5 Hz, H-4a), 1.53 (dt, 1 H, J9a,9b 8.5
Hz, J9a,8 =J9a,5 2.0 Hz, H-9a), 1.45 (dt, 1 H,
1
2889 (CH double bond), 1684 (CO). H NMR
(CD3OD) l: 6.80 (dd, 1 H, J3,2 10.0 Hz, J3,4
2.0 Hz, H-3), 5.91 (dd, 1 H, J2,4 2.0 Hz, H-2),
4.24 (dt, 1 H, J 3.5 Hz, J4,5 8.0 Hz, H-4), 3.90
(d, 1 H, J6,5 10.5 Hz, H-6), 3.45 (dd, 1 H,
H-5). 13C NMR (D2O) l: 211.3 (C-1),
163.2(C-2), 137.3 (C-3), 88.3, 86.9, 82.1 (C-4,
C-5, C-6). Anal. Calcd for C6H8O4: C, 49.99;
H, 5.60, O, 44.42. Found C, 49.75; H, 5.67; O,
44.52.
J9b,5 =J9a,8 2.0 Hz, H-9b). lC (CDCl3): 138.6,
134.5 (C-7, C-6), 70.7 (C-4), 61.5, 55.4 (C-2,
C-3), 49.7, 47.5, 44.5, 43.8, 42.8 (C-8, C-8a,
C-5, C-4a, C-9). Anal. Calcd for C11H12O3: C,
68.72; H, 6.29; O, 24.97. Found: C, 68.69; H,
6.25; O, 24.92.
5-Hydroxy-7-oxabicyclo-[4-1-01,6]-hept-3-
ene-2-one (16).—A solution of 15a/15b
(85:15, 2.0 g, 10 mmol) in diethylphthalate (30
mL) was stirred at room temperature (rt) un-
der nitrogen bubbling for 30 min, then
warmed (still under bubbling) at 190 °C for
2.5 h. The reaction mixture was then cooled to
rt and filtered through Silica Gel (70–200
mm). Diethylphthalate was eluted with 9:1“
4:1 hexane–EtOAc and the crude product
with 3:2 hexane–EtOAc. After evaporation of
the solvents, flash chromatography (99:1“
19:1 CH2Cl2–MeOH, 1% gradient) of the
residue gave 16 (1.02 g, 80%) as white crystals,
mp 56–57 °C (Lit. [14] 56–58.5 °C). 15b did
not react under those conditions. IR (KBr)
cm−1: 3375 (OH), 2929 (CH double bond),
2,3,4-Trihydroxycyclohexanone
(12).—A
solution of 17 (0.38 g, 2.92 mmol) in MeOH
(9 mL) was stirred for 2 h under hydrogen (1
atm) in the presence of Pd–C 10% (35 mg).
Water was then added, and the mixture was
filtered through a Celite pad and eluted with
1:1 MeOH–water and the resulting aq soln
was concentrated. The residue was adsorbed
on Silica Gel (70–200 mm) and deposited on a
Silica Gel column. Elution (49:1“22:3,
CH2Cl2–MeOH, 2% gradient) gave 12 (0.31 g,
80%) as a white amorphous solid. IR (KBr)
cm−1: 3418 (OH), 2967, 2929, 2883 (CH),
1
1708 (CO). H NMR (CD3OD) l: 3.90 (dd, 1
H, J2,3 9.5 Hz, J2,6a 1.5 Hz, H-2), 3.68 (ddd, 1
H, J4,5a 11.5 Hz, J4,3 9.0 Hz, J4,5b 4.5 Hz, H-4),
3.13 (dd, 1 H, H-3), 2.41 (tdd, 1 H, J6a,5a 14.5
Hz, J6a,5b 6.0 Hz, H-6a), 2.21 (ddd, 1 H, J6b,5b
4.5 Hz, J6b,5a 2.5 Hz, H-6b), 1.98 (dddd, 1 H,
J5b,5a 12.5 Hz, J5b,4 4.5 Hz, H-5b), 1.35 (m, 1
1
1676 (CO). H NMR (CDCl3) l: 6.71 (ddd, 1
H, J4,3 10.5 Hz, J4,5 4.0 Hz, J4,6 2.5 Hz, H-4),
6.00 (dt, 1 H, J3,5=J3,1 1.5 Hz, H-3), 4.69 (br
dd, 1 H, J5,OH 8.0 Hz, J5,4 4.0 Hz, J5,6 1.0 Hz,
H-5), 3.81 (ddd, 1 H, J6,1 3.5 Hz, H-6), 3.46
(m, 1 H, H-1), 2.87 (d, 1 H, OH). lC (CDCl3)
:194.2 (C-1), 144.5 (C-4), 126.7 (C-3), 62.8,
57.7, 53.2 (C-2, C-5 and C-6). Anal. Calcd for
C6H6O3: C, 57.14; H, 4.80; O, 38.06. Found:
C, 57.93; H, 4.94; O, 36.99.
13
H, H-5a). C NMR (CD3OD) l: 153.0 (C-1),
80.9, 79.4, 72.5 (C-2, C-3, C-4), 36.5, 29.9
(C-5, C-6). Anal. Calcd for C6H10O4: C, 49.31;
H, 6.90, O, 43.79. Found C, 49.15; H, 6.95; O,
43.75.
1,1%-Bis(phenylthio) - 2,3 - diacetoxycyclohex-
ane (2h, 3i)/(2i, 3h) (18).—A solution of 11
(1.0 g, 7.7 mmol) in PhSH (15 mL) was
treated with a concd HCl soln (36%, 0.13 mL)
for 60 h. The mixture was then neutralized
with Et3N, diluted by Et2O (100 mL), and
treated with a NaOH soln (10%, 100 mL). The
combined organic phases were dried (MgSO4)
and concentrated. The crude product was
crystallized in hexane–AcOEt to give the di-
hydroxy dithioacetal intermediate (1.67 g) as
white crystals, mp 92 °C. The mother liquor
4,5,6 - Trihydroxycyclohex - 2 - ene - 1 - one
(17).—A solution of 16 (0.53 g, 4.2 mmol) in
water (21 mL) was kept at 80 °C for 4 days.
Water was then co-evaporated with MeCN
and the residue adsorbed on Silica Gel (70–
200 mm) and deposited on a Silica Gel
column. Elution (19:1“4:1 CH2Cl2–MeOH)
gave a first fraction (210 mg, 39%) containing
the starting material 16 principally, a second
one containing 17 (249 mg, 41%) as brown

A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
55
was concentrated and flash chromatography
(7:3 hexane–EtOAc) of the residue gave an
additional crop (152 mg). Total yield: 1.83 g,
72%. IR (KBr) cm−1: 3453 (OH), 2953 and
(19:1, CH2Cl2–MeOH). After evaporation
and drying in vacuo, pyridine (7 mL), Ac2O (1
mL) and 2,4-dimethylaminopyridine (13 mg,
0.11 mmol) were added and the mixture was
stirred overnight. After evaporation, CH2Cl2
(25 mL) was added and the solution was
washed with water (25 mL), filtered on a
phase separator filter and concentrated. Flash
chromatography (9:1 hexane–EtOAc) of the
residue gave 23 (0.29 g, 85%) as a white solid.
IR (KBr) cm−1: 3061, 2946 (CH Ar), 1752
1
2922 (CH Ar). H NMR (CDCl3) l: 7.75 (m,
2 H, H Ar), 7.20–7.65 (m, 8 H, H Ar), 4.21
(ddd, 1 H, J3,4a 11.0 Hz, J3,2 9.0 Hz, J3,4b 4.0
Hz, H-3), 3.62 (br s, 1 H, OH), 3.43 (d, 1 H,
H-2), 2.94 (br s, 1 H, OH), 1.55–2.07, 0.94–
1.46 (2 m, 6 H, CH2). 13C NMR (CDCl3) l:
137.5, 137.1 (CH Ar), 130.0 (Cq Ar), 129.7,
129.3, 129.0, 128.6 (CH Ar), 78.1, 70.5 (C-2,
C-3), 70.9 (C-1), 33.5, 31.6, 19.7 (C-4, C-5,
C-6). Anal. Calcd for C18H20O2S2: C, 64.63;
H, 6.63; O, 9.57. Found: C, 64.63; H, 6.41; O,
9.44.
1
(CO). H NMR (CDCl3) l: 7.82 (m, 2 H, CH
Ar), 7.54 (m, 2 H, CH Ar), 7.37 (m, 6 H, CH
Ar), 5.67 (t, 1 H, J3,2=J3,4 9.5 Hz, H-3), 5.22
(d, 1 H, H-2), 4.58 (ddd, 1 H, J4,5a 11.5 Hz,
J4,5b 5.0 Hz, H-4), 2.16 (s, 3 H, OAc), 2.00 (br
s, 6 H, OAc), 1.96 (m, 1 H, H-6a), 1.70 (m, 2
A solution of the dihydroxy dithioacetal
(0.75 g, 2.26 mmol) in pyridine (6 mL) was
treated with Ac2O (1.27 mL), 2,4-dimethy-
laminopyridine (70 mg, 0.6 mmol) and kept at
rt overnight. After co-evaporation with
toluene several times, flash chromatography
(9:1“9:2 hexane–EtOAc) of the residue gave
18 (0.85 g, 90%) as white crystals, mp 142–
144 °C. IR (KBr) cm−1: 3065, 2937, 2863 (CH
13
H, H-6b and H-5a), 1.26 (m, 1 H, H-5b). C
NMR (CDCl3) l: 170.1, 169.8 (OCOCH3),
137.5, 136.9, 130.1, 129.9, 129.6, 129.0, 128.7
(CH Ar and Cq Ar), 75.4, 72.7, 72.1 (C-2,
C-3, C-4), 66.4 (C-1), 29.8, 24.9 (C-5, C-6),
20.8, 20.6 (OCOCH3). Anal. Calcd for
C24H26O6S2: C, 60.74; H, 5.52; O, 20.23.
Found: C, 60.58, H, 5.61; O, 20.19.
1
Ar) and 1758 (CO). H NMR (CDCl3) l: 7.85
1,1% - Bis(phenylthio) - 2,3,4 - triacetoxy - 5-
acetoxymethylcyclohexane (2h, 3i, 4h, 5i)/
(2i, 3h, 4i, 5i) (24).—Tetrahydroxylated ke-
tone 13 (0.15 g, 0.85 mmol) was treated at
0 °C with BF3·Et2O (0.315 mL, 2.55 mmol)
and PhSH (1.75 mL) for 48 h as described for
the preparation of 23. After workup, pyridine
(7 mL), Ac2O (1.6 mL) and 2,4-dimethyl-
aminopyridine (15 mg, 0.13 mmol) were
added to the residue and the mixture was
stirred for 12 h. After workup, flash chro-
matography (9:1, hexane–EtOAc) gave 24
(0.30 mg, 66%) as a white amorphous solid.
(m, 2 H, H Ar), 7.57 (m, 2 H, H Ar), 7.26–
7.44 (m, 6 H, H Ar), 5.41 (ddd, 1 H, J3,4a 11.0
Hz, J3,2 9.5 Hz, J3,4b 5.0 Hz, H-3), 5.20 (d, 1
H, H-2), 2.16 (s, 3 H, AcO), 2.01 (s, 3 H,
AcO), 2.08, 1.85, 1.59, 1.34 and 1.15 (4 m, 6
H, CH2). 13C NMR (CDCl3) l: 170.3, 170.2
(OCOCH3), 137.6, 137.0 (CH Ar), 130.8 (Cq
Ar), 129.6, 129.4, 128.8, 128.6 (CH Ar), 72.3,
72.1 (C-2, C-3), 67.9 (C-1), 33.9, 29.9, 19.2
(C-4, C-5, C-6), 21.03, 20.86 (OCOCH3).
Anal. Calcd for C22H24O4S2: C, 63.44; H, 5.81;
O, 15.36; S, 15.39. Found: C, 63.74; H, 5.52;
O, 15.34; S, 15.44.
1,1%-Bis(phenylthio) - 2,3,4 - triacetoxycyclo-
hexane (2h, 3i, 4h)/(2i, 3h, 4i) (23).—A
solution of 12 (0.105 g, 0.72 mmol) in CH2Cl2
(5 mmol) at −5 °C was treated with PhSH
(1.5 mL, 14.4 mmol) and BF3·Et2O (0.266 mL,
2.16 mL) for 4 h. Et3N (0.62 mL) was then
added and CH2Cl2 was evaporated under ni-
trogen flushing. The crude product was
washed with hexane (3×15 mL) then 5:1
hexane–Et2O (2×15 mL). The resulting white
solid was dissolved in MeOH (20 mL), ad-
sorbed on Silica Gel (70–200 mm), deposited
at the top of a Silica Gel column and eluted
1
IR (KBr) cm−1: 2931 (CH Ar), 1754 (CO). H
NMR (CDCl3) l: 7.55 and 7.86 (2 br d, 2 H,
CH Ar), 7.30–7.50 (m, 8 H, CH Ar), 5.65 (t,
1 H, J3,4 =J3,2 9.5 Hz, H-3), 5.26 (d, 1 H,
H-2), 4.72 (dd, 1 H, J4,5 10.5 Hz, H-4), 3.50 (d,
2 H, J7,5 4.0 Hz, H-7a and H-7b), 2.52 (m, 1
H, H-5), 2.16 (s, 3 H, AcO), 2.02 (s, 3 H,
AcO), 1.98 (3 H, AcO), 1.78 (s, 3 H, AcO),
1.65 (dd, 1 H, J6a,6b 15.0, J6a,5 3.0 Hz, H-6a),
13
1.21 (dd, 1 H, J6b,5 12.0 Hz, H-6b). C NMR
(CDCl3) l: 170.4, 169.9, 169.8, 169.7 (4
OCOCH3), 137.6, 136.8, 129.9, 129.7, 129.0,
128.8 (CH, Cq Ar), 74.9, 73.2, 71.2 (C-2, C-3,

56
A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
1
C-4), 65.3 (C-1), 62.6 (C-7), 35.4, 33.6 (C-5,
C-6), 20.6, 20.5, 20.4 (OCOCH3). Anal. Calcd
for C27H30O8S2: C, 59.32; H, 5.53; S, 11.73.
Found: C, 59.32; H, 5.68; S, 11.06.
bond), 1730, 1752 (CO). H NMR (CDCl3):
7.20–7.40 (m, 5 H, CH Ar), 6.61 (ddd, 1 H,
J1,6a 5.5 Hz, J1,6b 3.0 Hz, J1,3 1.5 Hz, H-1), 5.61
(ddd, 1 H, J3,4 7.0 Hz, J3,6a 3.0 Hz, J3,6b 1.5
Hz, H-3), 5.35 (dd, 1 H, J4,5 9.5 Hz, H-4), 5.13
(ddd, 1 H, J5,6b 8.5 Hz, J5,6a 5.5 Hz, H-5), 2.73
(dt d, 1 H, J6a,6b 17.5 Hz, H-6a), 2.36 (ddt, 1
H, H-6b), 2.05 (s, 3 H, OAc), 2.02 (s, 3 H,
2 - Phenylthio - 3,4 - diacetoxycyclohex - 1 - ene
(3h, 4i)/(3i, 4h) (19).—A solution of 18 (0.75
g, 1.8 mmol) in CH2Cl2 (4 mL) at −30 °C
was treated with a 0.28 M m-chloroperoxy-
benzoic acid (mCPBA) soln in CH2Cl2 (7.04
mL, 1.97 mmol). The mixture was then slowly
warmed up to rt (1 h), diluted with CH2Cl2
(20 mL), washed with a phosphate buffer (0.2
M, pH 7.6, 20 mL), filtered through a phase
separator filter and concentrated. The residue
was taken up in DME (15 mL), treated with
CaCO3 (0.9 g, 9 mmol) and kept at 80 °C for
15 h. The solution was cooled to rt, diluted
with CH2Cl2 (50 mL), filtered, washed with
water (60 mL), dried (MgSO4), filtered and
concentrated. Flash chromatography (9:1 hex-
ane–EtOAc) of the residue gave 19 (0.5 g,
13
OAc), 1.89 (s, 3 H, OAc). C NMR (CDCl3)
l: 170.0, 169.8, 169.7 (OCOCH3), 133.8,
132.8, 131.7, 131.1, 131.0, 129.0, 127.5 (CH
Ar, Cq Ar, C-1, C-2), 128.3, 126.5 (CH Ar),
72.6, 71.8, 68.0 (C-3, C-4, C-5), 30.5 (C-6),
20.8, 20.6, 20.4 (OCOCH3). Anal. Calcd for
C18H20O6S: C, 59.33; H, 5.53. Found: C,
59.49; H, 5.76. Data for 27: 1H NMR (CDCl3)
l: 7.68–7.39 (m, 2 H, CH Ar), 7.38–7.28 (m,
3 H, CH Ar), 5.54 (br d, 1 H, J3,4 9.5 Hz,
H-3), 5.06 (ddd, 1 H, J4,5a 6.5 Hz, J4,5b 3.0 Hz,
H-4), 2.21 (m, 2 H, H-6a and H-6b), 2.17 (s, 3
H, OAc), 2.10 (s, 3 H, OAc), 2.09 (s, 3 H,
OAc) and 1.89 (m, 2 H, H-5a and H-5b).
2 - Phenylthio - 3,4,5 - triacetoxy - 6 - acetoxy-
methylcyclohex-1-ene (3h, 4i, 5h, 6i)/(3i, 4h,
5i, 6h) (26) and 1-phenylthio-2,3,4-triacetoxy-
5-acetoxymethylcyclohex-1-ene (3h, 4i, 5h)/
(3i, 4h, 5i) (28).—Compound 24 (0.163 g,
0.3 mmol) was treated, as described for the
preparation of 19, with a 0.16 M mCPBA soln
in CH2Cl2 (2.06 mL, 0.3 mmol) to give 168 mg
of the sulfoxide intermediate. This residue,
dissolved in DME, was treated with CaCO3
(0.21 g, 2.13 mmol) and kept at 85 °C
overnight. After workup, flash chromatogra-
phy (17:3 hexane–EtOAc) of the residue gave
26 (92 mg, 75%) and 28 (5 mg, 4%) as white
solids. Data for 26: IR (KBr) cm−1: 3059,
2957, 2935 (CH Ar and double bond), 1750
90%) as a colorless syrup. IR (NaCl) cm−1
:
2934 (CH Ar and double bond), 1743 (CO).
1H NMR (CDCl3) l: 7.25 (m, 5 H, CH Ar),
6.39 (t, 1 H, J1,6a =J1,6b 4.0 Hz, H-1), 5.33 (br
d, 1 H, J3,4 4.5 Hz, H-3), 5.04 (q, 1 H,
J4,5a =J4,5b 4.5 Hz), 2.32 (m, 2 H, H-6a and
H-6b), 2.04 (s, 3 H, AcO), 1.92 (s+m, 5 H,
AcO, H-5a and H-5b). 13C NMR (CDCl3) l:
169.9, 169.7 (OCOCH3), 134.5, 128.5 (Cq Ar,
C-2), 130.1, 128.9 (CH Ar), 139.4, 126.8 (CH
Ar, C-1), 70.7, 69.5 (C-3, C-4), 23.3, 22.7 (C-5,
C-6), 21.0, 20.6 (OCOCH3). Anal. Calcd for
C16H18O4S: C, 62.73; H, 5.92; O, 20.89; S,
10.46. Found: C, 62.65; H, 5.81; O, 20.72; S,
10.53.
2-Phenylthio-3,4,5-triacetoxycyclohex-1-ene
(3h, 4i, 5h)/(3i, 4h, 5i) (25) and 1-
phenylthio-2,3,4-triacetoxycyclohex-1-ene (3h,
4i)/(3i, 4h) (27).—Compound 23 (0.387 g,
0.81 mmol) was treated, as described for the
preparation of 19, with a 0.145 M mCPBA
soln in CH2Cl2 (6 mL, 0.87 mmol) at −40 °C,
yielding 392 mg of the intermediate sulfoxide.
The residue was dissolved in DME (7 mL),
treated with CaCO3 (0.57 g, 5.7 mmol), and
stirred overnight at 85 °C. After normal
workup, flash chromatography (17:3 hexane–
EtOAc) gave 25 (0.24 g, 80%) and 27 (5 mg,
4%), both as white solids. Data for 25: IR
(KBr) cm−1: 3069, 2946 (CH Ar and double
1
(CO). H NMR (CDCl3) l: 7.40–7.23 (m, 5
H, CH Ar), 5.84 (t, 1 H, J1,3 =J1,6 2.0 Hz,
H-1), 5.69 (ddd, 1 H, J3,4 7.0 Hz, J3,6 3.0 Hz,
H-3), 5.38 (dd, 1 H, J4,5 10.0 Hz, H-4), 5.26
(dd, 1 H, J5,6 9.0 Hz, H-5), 4.06 (dd, 1 H, J7a,7b
11.0 Hz, J7a,6 4.0 Hz, H-7a), 4.01 (dd, 1 H,
J7b,6 5.0 Hz, H-7b), 2.87 (m, 1 H, H-6), 2.06
(br s, 6 H, OAc), 2.00 (s, 3 H, OAc), 1.93 (s,
3 H, OAc). 13C NMR (CDCl3) l: 170.3, 170.6,
170.9, 169.8 (OCOCH3), 133.5, 131.7, 131.6,
129.3, 127.9 (CH Ar, Cq Ar, C-1, C-2), 73.4,
71.9, 68.4, 62.8 (C-3, C-4, C-5, C-7), 41.6
(C-6), 20.6, 20.5 (OCOCH3). Anal. Calcd

A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
57
for C21H24O8S: C, 57.79; H, 5.54; O, 29.32.
Found: C, 57.49; H, 5.56; O, 29.48. Data for
28: H NMR (CDCl3) l: 7.45–7.23 (m, 5 H,
1 H, H-1), 3.62 (m, 1 H, H-3), 3.52 (dt, 1 H,
J5,6a 5.5 Hz, J5,6b =J5,4 9.0 Hz, H-5), 3.36 (dd,
1 H, J4,3 7.0 Hz, H-4), 2.31 (dtd, 1 H, J6a,6b
17.5 Hz, J6a,1 1.5 Hz, J 5.5 Hz, H-6a) and 1.94
(ddt, 1 H, J6b,1 =J 3.0 Hz). 13C NMR
(CD3OD) l: 137.1, 135.3 (Cq, C-2), 133.0,
130.2, 128.4 (CH Ar, C-1), 78.9, 74.6, 70.1
(C-3, C-4, C-5) and 34.7 (C-6). Anal. Calcd
for C12H14O3S: C, 60.48; H, 5.92; O, 20.14.
Found: C, 60.44; H, 5.94; O, 20.41.
1
CH Ar), 5.68 (dt, 1 H, J3,4 6.0 Hz, J=J3,5 2.0
Hz, H-3), 5.24 (dd, 1 H, J4,5 9.0 Hz, H-4), 4.12
(dd, 1 H, J7a,7b 11.0 Hz, J7a,5 4.0 Hz, H-7a),
3.89 (dd, 1 H, J7b,5 4.0 Hz, H-7b), 2.23–2.41
(m, 3 H, H-6a, H-6b and H-5), 2.13 (s, 3 H,
OAc), 2.07 (s, 3 H, OAc), 2.05 (s, 3 H, OAc)
13
and 1.97 (s, 3 H, OAc). C NMR (CDCl3) l:
170.6, 170.3, 169.9, 168.1 (OCOCH3), 140.1,
131.2, 125.3 (Cq Ar, C-1, C-2), 132.7, 129.2,
128.1 (CH Ar), 71.3, 71.2, 62.6 (C-3, C-4,
C-7), 36.9, 29.3 (C-5, C-6), 20.8, 20.4
(OCOCH3).
2 - Phenylthio - 3,4,5 - trihydroxy - 6 - hydrox-
ymethylcyclohex-1-ene (3h, 4i, 5h, 6i)/(3i,
4h, 5i, 6h) (7).—Compound 26 (92 mg, 0.2
mmol) was treated as described for the prepa-
ration of 6 with NaOMe (6 mg, 0.135 mmol)
in MeOH (4.5 mL). Flash chromatography of
the crude reaction mixture (24:1“46:3
CH2Cl2–MeOH) gave 7 (54 mg, 95%) as a
white powder after filtration through a poly-
acrylamide gel and lyophilization. IR (KBr)
cm−1: 3395 (OH), 2889 (CH Ar and double
2-Phenylthio-3,4-dihydroxycyclohex-1-ene
(3h, 4i)/(3i, 4h) (5).—A solution of 19 (0.33
g, 1.08 mmol) in MeOH (5 mL) was treated at
rt with a 0.5 M NaOMe soln in MeOH (0.4
mL) for 1.5 h. The mixture was then neutral-
ized with AcOH and concentrated. Flash
chromatography (3:2 hexane–EtOAc) of the
residue gave 5 (226 mg, 95%) as a white foam.
IR (KBr) cm−1: 3381, 3056, 2926 (CH Ar and
1
bond). H NMR (CD3OD) l: 6.92–7.33 (m, 5
H, CH Ar), 5.57 (t, 1 H, J1,6 =J1,3 1.5 Hz,
H-1), 3.86 (m, 1 H, H-3), 3.63 (dd, 1 H, J7a,7b
10.5 Hz, J7a,6 4.0 Hz, H-7a), 3.45 (dd, 1 H,
J7b,6 6.0 Hz, H-7b), 3.28–3.43 (m, 2 H, H-4
and H-5), 2.16 (m, 1 H, H-6). 13C NMR
(CD3OD) l: 137.6, 135.6 (Cq Ar, C-2), 132.8,
131.3, 130.2, 128.3 (CH Ar, C-1), 79.1, 74.4,
71.4, 63.1 (C-3, C-4, C-5, C-7), and 48.0 (C-6).
Anal Calcd for C13H16O4S·0.25 H2O: C, 57.23;
H, 6.09; O, 24.92; S, 11.75. Found: C, 56.67;
H, 6.01; O, 24.12; S, 11.64.
1
double bond). H NMR (CDCl3) l: 7.39–7.15
(m, 5 H, CH Ar), 6.08 (t, 1 H, J1,6a =J1,6b 3.0
Hz, H-1), 3.98 (m, 1 H, H-3), 3.81 (ddd, 1 H,
J4,5a 11.0 Hz, J4,5b 3.0 Hz, J4,3 6.0 Hz, H-4),
3.40 (br s, 2 H, 2 OH), 2.26 (m, 2 H, H-6a and
H-6b), 1.95, 1.71 (2 m, 2 H, H-5a and H-5b).
13C NMR (CDCl3) l: 133.9, 132.6 (Cq Ar,
C-2), 130.2, 129.1 (CH Ar), 135.7, 126.9 (CH
Ar, C-1), 72.9, 72.5 (C-3, C-4), 27.1, 24.9 (C-5,
C-6). Anal. Calcd for C12H14O2S: C, 64.84; H,
6.35; O, 14.39. Found: C, 64.15; H, 6.36; O,
14.06.
2-Phenyl sulfoxide-3,4-diacetoxycyclohex-1-
ene (3h, 4i)/(3i, 4h) (20a/20b) and 2-phenyl
sulfone-3,4-diacetoxycyclohex-1-ene (3h, 4i)/
(3i, 4h) (21).—A solution of 19 (0.804 g, 0.26
mmol) in CH2Cl2 (20 mL) was treated at
−40 °C with a 0.102 M mCPBA soln in
CH2Cl2 (28.3 mL, 2.88 mmol). The solution
was slowly warmed to rt (2 h), diluted with
CH2Cl2 (50 mL), then washed with a phos-
phate buffer (0.1 M, pH 7.6, 70 mL). The
organic phase was filtered through a phase
separator filter then concentrated. Flash chro-
matography (3:2 hexane–EtOAc) of the
residue gave 3 fractions: 21 (50 mg), a mixture
(7:13) of 21 and 20a/20b (3:2, 593 mg), and
20a/20b (3:2, 50 mg) as colorless oils (overall
2-Phenylthio-3,4,5-trihydroxycyclohex-1-ene
(3h, 4i, 5h)/(3i, 4h, 5i) (6).—A solution of
25 (156 mg, 0.43 mmol) in MeOH (8.6 mL)
was treated at rt with NaOMe (11 mg, 0.21
mmol) for 30 min. The mixture was neutral-
ized with Dowex (AC50Wx8) (H+ form) and
filtered. The crude product was adsorbed on
Silica Gel (70–200 mm) and deposited at the
top of a Silica Gel column. Elution (49:1“
24:1 CH2Cl2–MeOH) gave 6 (86 mg, 84%) as
a white powder after filtration through a poly-
acrylamide gel and lyophilization. IR (KBr)
cm−1: 3202 (OH), 2890 (CH Ar and double
1
1
bond). H NMR (CD3OD) l : 7.77 (m, 1 H,
yield 82%). Data for 21: H NMR (CDCl3) l:
CH Ar), 7.41–7.04 (m, 4 H, CH Ar), 5.44 (m,
7.80–7.90 (m, 2 H, CH Ar), 7.48–7.49 (m, 4

58
A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
H, CH Ar and H-1), 5.59 (d, 1 H, J3,4 3.0 Hz,
H-3), 4.98 (m, 1 H, H-4), 2.47 (m, 2 H, H-6a
and H-6b), 1.93 (m and s, 4 H, H-5a and
OAc), 1.83 (m, 1 H, H-5b) and 1.72 (s, 3 H,
OAc). 13C NMR (CDCl3) l: 169.2, 168.5
(OCOCH3), 139.5, 135.6 (Cq Ar, C-2), 144.8,
133.1 (CH Ar, C-1), 128.8, 127.8 (CH Ar),
67.7, 62.7 (C-3, C-4), 21.4, 20.4, 20.1
(OCOCH3, C-5, C-6). 20a/20b were character-
ized after deacetylation and separation (see
below).
A solution of 6 (0.13 g, 0.54 mmol) in water
(2.5 mL) and MeOH (1 mL) was treated with
a 7.3 M t-BuOOH soln in water (3.7 mL) and
kept at 60 °C for 24 h. The reaction mixture
was concentrated, and two successive flash
chromatographies
(19:1“9:1
CH2Cl2–
MeOH) of the residue gave 9a and 9b in three
fractions after filtration through a polyacry-
lamide gel and lyophilization: 9a (49 mg),
9a/9b (3:7, 32 mg) and 9b (34 mg) as white
powders. Data for 9a: IR (KBr) cm−1: 3341
(OH), 2901 (CH Ar and CH double bond),
2-Phenyl sulfoxide-3,4-dihydroxycyclohex-
1-ene (3h, 4i)/(3i, 4h) (8a and 8b).—A solu-
tion of the mixture of 20a/20b and 21 (15:7,
0.2 g, 0.39 mmol of 20a/20b and 0.21 mmol of
21) in MeOH (10 mL) was treated at rt, with
a 0.5 M NaOMe soln in MeOH (0.43 mL,
0.215 mmol) for 5 h. The reaction mixture was
neutralized with AcOH (12 mL) and concen-
trated. Flash chromatography (CH2Cl2–
MeOH) of the residue gave four fractions: 22
(47 mg), 8a (16 mg), 8a/8b (28 mg) and 8b (38
mg) as white foams (overall yield 88%). IR
(KBr) cm−1 (mixture 8a/8b): 3400 (OH), 2930
(CH Ar and CH double bond), 1083 (SO).
Data for 8a: 1H NMR (CD3OD) l: 7.55 (m,
2 H, CH Ar), 7.43 (m, 3 H, CH Ar), 6.59 (t, 1
H, J1,6a =J1,6b 3.8 Hz, H-1), 3.91 (br d, 1 H,
J3,4 4.5 Hz, H-3), 3.63 (ddd, 1 H, J4,5a 6.8 Hz,
J4,5b 2.3 Hz, H-4), 2.23 (m, 2 H, H-6a and
H-6b), 1.81 (m, 1 H, H-5b), and 1.56 (br dt, 1
H, H-5a). 13C NMR (CD3OD) l: 143.3, 139.0,
132.3 (Cq Ar, CH Ar, C-1, C-2), 130.2, 126.5
(CH Ar), 71.3, 68.9 (C-4, C-3), 25.6, 23.7 (C-6,
C-5). Anal. Calcd for C12H14O3S·0.25 H2O: C,
59.36; H, 6.02; O, 21.41; S, 13.20. Found C,
58.62, H, 5.99; O, 20.36; S, 11.91.
1
1082 and 1023 (SO). H NMR (CD3OD) l:
7.56 (m, 2 H, CH Ar), 6.40 (m, 2 H, CH Ar),
6.31 (m, 1 H, H-1), 4.13 (m, 1 H, H-3), 3.51
(td, 1 H, J5,6a 5.0 Hz, J5,6b =J5,4 9.0 Hz, H-5),
3.36(dd, 1 H, J4,3 7.0 Hz, H-4), 2.53 (dtd, 1 H,
J6a,6b 18.0 Hz, J6a,3 7.0 Hz, H-6a) and 2.13
(ddt, 1 H, J6b,3 =J6b,1 3.0 Hz, H-6b). 13C
NMR (CD3OD) l: 144.8, 143.7 (CqAr, C-2),
133.2, 132.5 (CH Ar, C-1), 130.3, 126.8 (CH
Ar), 78.1, 72.5, 69.6 (C-3, C-4, C-5), 34.0
(C-6). Anal. Calcd for C12H14O4S·0.5 H2O: C,
54.74; H, 5.74. Found: C, 54.67; H, 5.68. Data
for 9b: IR (KBr) cm−1: 3355 (OH), 2897 (CH
1
Ar and double bond), 1082 and 1020 (SO). H
NMR (CD3OD) l: 7.60 (m, 2 H, CH Ar),
7.41 (m, 3 H, CH Ar), 6.31 (m, 1 H, H-1),
3.23–3.50 (m, 3 H, H-3, H-4, H-5), 2.66 (br
dt, 1 H, J6a,6b 19.0 Hz, J6a,5=J6a,1 5.0 Hz,
H-6a), 2.14 (m, 1 H, H-6b). 13C NMR
(CD3OD) l: 144.8, 142.9 (Cq Ar, C-2), 130.6,
127.1 (CH Ar), 133.1, 127.0 (CH Ar, C-1),
79.2, 79.3, 69.9 (C-3, C-4, C-5) and 34.1 (C-6).
Anal. Calcd for C12H14O4S·0.5 H2O: C, 54.74;
H, 5.74. Found: C, 54.91; H, 5.75.
Data for 8b: 1H NMR (CD3OD) l: 7.60 (m,
2 H, CH Ar), 7.44 (m, 3 H, CH Ar), 6.5 (br t,
1 H, J1,6a=J1,6b 3.0 Hz, H-1), 3.62 (ddd, 1 H,
J4,5a 10.0 Hz, J4,3 6.0 Hz, J4,5b 3.5 Hz, H-4),
3.36 (br d, 1 H, H-3), 2.31 (m, 2 H, H-6a and
H-6b), 1.82 (m, 1 H, H-5b), 1.47 (ddt, 1 H,
2-Phenyl sulfoxide-3,4,5-trihydroxy-6-hy-
droxymethylcyclohex-1-ene (3h, 4i, 5h, 6i)/
(3i, 4h, 5i, 5h) (10a/10b).—A solution of 7
(0.094 g, 0.35 mmol) in water (2 mL) was
treated with a 7.3 M t-BuOOH soln in water
(2 mL) as previously described for the prepa-
ration of 9a/9b. Flash chromatography
(19:1“9:1 CH2Cl2–MeOH) gave 10a and 10b
in three fractions after filtration through a
polyacrylamide gel and lyophilization, 10a/10b
(9:1, 23 mg), 10a/10b (1:1, 31 mg) and 10a/10b
(1:4, 24 mg) (overall yield 78%). Data for 10a:
IR (KBr) cm−1: 3397 (OH), 2888 (CH Ar and
13
J5a,5b 13.0 Hz, J5a,6a =J5a,6b 7.0 Hz, H-5a). C
NMR (CD3OD): l143.9, 143.1, 132.9, 131.4
(Cq Ar, CH Ar, C-1, C-2), 130.4, 127.1 (CH
Ar), 73.4, 70.8 (C-3, C-4), 28.7, 24.7 (C-5,
C-6). Anal. Calcd for C12H14O3S: C, 60.48; H,
5.92; O, 20.14. Found C, 60.39; H, 5.98; O,
19.92.
1
double bond), 1081 and 1029 (SO). H NMR
2-Phenyl
sulfoxide-3,4,5-trihydroxycyclo-
hex-1-ene (3h, 4i, 5h)/(3i, 4h, 5i) (9a/9b).—
(D2O) l: 7.76 (m, 2 H, CH Ar), 7.42 (m, 3 H,

A. Lubineau, I. Billault / Carbohydrate Research 320 (1999) 49–60
59
Acknowledgements
CH Ar), 6.53 (t, 1 H, J1,6=J1,3 2.0 Hz, H-1),
4.46 (m, 1 H, H-3), 3.94 (dd, 1 H, J7a,7b 11.0
Hz, J7a,6 4.0 Hz, H-7a), 3.81 (dd, 1 H, J7b,6 5.0
Hz, H-7b), 3.55–3.71 (m, 2 H, H-4 and H-5),
The University of Paris-Sud and the CNRS
are acknowledged for their financial support.
13
2.61 (m, 1 H, H-6). C NMR (D2O) l: 142.5,
140.9 (Cq Ar, C-2), 134.1, 132.8, 130.0, 126.5
(CH Ar, C-1), 76.8, 71.2, 69.3, 60.7 (C-3, C-4,
C-5, C-7), 46.1 (C-6). Anal Calcd for 10a/10b
(ca. 9:1) C13H16O5S·H2O: C, 51.64; H, 6.00.
Found: C, 51.44; H, 6.96. Data for 10b: IR
(KBr) cm−1: 3331 (OH), 2881 (CH Ar and
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double bond), 1080 and 1023 (SO). H NMR
(D2O) l: 7.78 (m, 2 H, CH Ar), 7.66 (m, 3 H,
CH Ar), 6.52 (m, 1 H, H-1), 4.00 (dd, 1 H,
J7a,7b 10.5 Hz, J7a,6 4.0 Hz, H-7a), 3.84 (dd, 1
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C13H16O5S·0.75 H2O: C, 52.43; H, 5.92; O,
30.89. Found: C, 52.03; H, 5.97; O, 31.19.
High-resolution EI-MS for 10a/10b (ca. 1:1)
M+ Calcd for C13H16O5S: 284.0718. Found:
284.0729.
Enzyme and acti6ity measurements.—En-
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phosphate buffer (50 mM, pH 6.8). Using
p-nitrophenyl a-
trophenyl b- -glucopyranoside as substrates,
the hydrolytic activity of a- -glucosidase
(Brewers yeast) and b- -glucosidase (sweet al-
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D
D
D
monds), respectively, was followed by measur-
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the a-
D
-glucosidase and 2.40 mM for the b- -
D
glucosidase.
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the following concentrations: 0.1, 1, 5 and 10
mM) was preincubated with the glucosidase at
37 °C for 15 min before the addition of the
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Ki of 9a towards Brewers yeast a-glucosidase
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60
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