Efficient one-pot synthesis of glycosyl disulfides

Article abstract of DOI:10.1016/j.tetlet.2007.08.106

Methodology for the efficient and facile synthesis of glycosyl disulfides is reported. A one-pot procedure employing mild conditions using diethyl azodicarboxylate is described to synthesise a series of glycosyl disulfides in excellent yields.

Full text of DOI:10.1016/j.tetlet.2007.08.106

Tetrahedron Letters 48 (2007) 7637–7641
Efficient one-pot synthesis of glycosyl disulfides
Goreti Ribeiro Morais and Robert A. Falconer*
Institute of Cancer Therapeutics, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
Received 31 May 2007; revised 17 August 2007; accepted 30 August 2007
Available online 4 September 2007
Abstract—Methodology for the efficient and facile synthesis of glycosyl disulfides is reported. A one-pot procedure employing mild
conditions using diethyl azodicarboxylate is described to synthesise a series of glycosyl disulfides in excellent yields.
Ó 2007 Elsevier Ltd. All rights reserved.
1. Introduction
symmetrical and non-symmetrical. There is one report
of the use of diethyl azodicarboxylate, in a two-stage
reaction for the synthesis of aryl disulfides.18 However,
the two-stage procedure (with intermediate isolation
and purification) had the disadvantage of prolonged
reaction times, extreme conditions and moderate yields.
Hummel recently used this two-stage process to produce
an ethyl glycosyl disulfide, for use in thioglycoside
synthesis.19
The surface of the mammalian cell is decorated by many
complex carbohydrates, with key roles in communica-
tion, migration and disease, particularly cancer.1 To
understand these processes better, there is a need for
molecular probes with stability in biological systems.
The disulfide bond plays an important role in the forma-
tion of higher order structures in peptides and proteins,
and recent work has also highlighted the potential of
glycosyl disulfides as useful tools in the study of glyco-
biology.2–4 Diglycosyl disulfides have been studied as
potential O-glycoside mimics, for example, in lectin
binding,3,5,6 and for the study of carbohydrate struc-
ture.7,8 Natural glycosyl disulfides are relatively rare,
however, but mixed glycosyl disulfides (and their synthe-
sis) have recently received attention due to their use as
donors in oligosaccharide synthesis9 in addition to their
biological application. Compounds with disulfide link-
ages have also been investigated as anti-cancer agents,10
including bioreductive prodrugs.11
The first use of a series of azo derivatives in a one-pot
synthesis of glycosyl disulfides under mild, neutral con-
ditions and with excellent yields is reported. A series of
commercially available azo compounds were initially
examined, using the reaction between per-O-acetyl-1-
thioglucose 1 and benzyl mercaptan as a model reaction
(Table 1). The sugar and the reacting thiol were sequen-
tially added to a stirred solution of the azo compound in
THF—the yellow solution became colourless as the
reaction proceeded. Clearly, DEAD and DIAD pro-
duced the highest yields (Table 1) with ADDP being
particularly ineffective (the combination of ADDP and
trimethylphosphine worked particularly well in the syn-
thesis of thioglycosides, in our previous work).16 The
significant by-product in each reaction was the symmet-
rical diglucosyl disulfide, meaning that optimisation of
these reaction conditions was necessary. DEAD was
used for the remainder of this study, although our
results indicate that DIAD is an equally effective
alternative. Interestingly, the polymer-supported DEAD
behaved extremely poorly in these reactions, with no
significant formation of the product using either THF
or DMF as a solvent. We assume the nature of the resin
and/or the reactivity of the immobilised agent to be the
cause.
Current methods to synthesise glycosyl disulfides include
the use of alkylsulfonate esters,7–9,12 selenylsulfides,4,13
benzyltriethylammonium tetrathiomolybdate,14 sulfenyl
bromides15 and other procedures involving multiple
steps under aqueous conditions.2,3 Our previous work
on the synthesis of thioglycosides using the Mitsunobu
reaction16,17 led us to investigate the use of azo
compounds in the synthesis of glycosyl disulfides, both
Keywords: Glycosyl disulfide; Glycoside; Thioglycoside.
Corresponding author. Tel.: +44 1274 235842; fax: +44 1274
233234; e-mail: r.a.falconer1@bradford.ac.uk
*
0040-4039/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2007.08.106

7638
G. Ribeiro Morais, R. A. Falconer / Tetrahedron Letters 48 (2007) 7637–7641
Table 1. Comparison of azo-compounds in the synthesis of benzyl
glycosyl disulfide 2a
The conditions for this type of reaction were subse-
quently optimised, varying solvent, reaction time, pro-
portions of reactants and the order of their addition.
A twofold excess of DEAD over the thiosugar was
found to be optimum. Reactions were best in THF, with
dichloromethane and dimethylformamide producing
lower yields.
OAc
O
OAc
O
BnSH
THF
AcO
AcO
AcO
AcO
SH
S
S
AcO
1
AcO
2a
Entry
Reagent (1.2 equiv)
ADDP (azodicarbonyldipiperidine)
DIAD (diisopropyl azodicarboxylate)
DTAD (di-tert-butyl azodicarboxylate)
DEAD (diethyl azodicarboxylate)
DEADa
Yield (%)
1
2
3
4
5
16
61
44
68
ndb
The study was then extended to include the synthesis of
a series of non-symmetrical disulfides, including aro-
matic and heterocyclic moieties (Table 2, entries 1–4
and 8–14), and by incorporating per-O-acetylated 1-thio-
sugars of galactose, mannose and rhamnose, in addi-
tion to glucose. Interestingly, using the same order of
addition of reagents, non-symmetrical alkyl disulfides
Conditions: 1 (1 equiv); benzyl mercaptan (1.2 equiv); 3 h; rt.
a Polymer-supported DEAD.
b Not determined.
Table 2. Synthesis of glycosyl disulfides
R1–SH + R2–SH ! R1–S–S–R2
Entry
1
R1
R2
Conditions
Product
Yield (%)
95
Reference
15
OAc
O
AcO
AcO
A
2a
AcO
OAc
O
AcO
AcO
2
3
A
A
2b
2c
94
15
20
AcO
OAc
O
N
N
78a
AcO
AcO
AcO
OAc
O
N
S
AcO
AcO
4
5
A
B
2d
2e
2f
2g
2h
2i
95
46
43
85
88
72
66
21
22
5
AcO
OAc
O
AcO
AcO
AcO
OAc
O
AcO
AcO
6
B
AcO
OAc
O
AcO
AcO
7
C
A
A
A
23
15
15
24
AcO
AcO
AcO
OAc
O
8
AcO
AcO
OAc
O
9
AcO
AcO
AcO
OAc
O
N
N
10
2j
AcO
AcO
H
3C
AcO
AcO
O
11
12
A
A
2k
2l
87
80
25
26
OAc
H3C
AcO
AcO
O
OAc

G. Ribeiro Morais, R. A. Falconer / Tetrahedron Letters 48 (2007) 7637–7641
7639
Table 2 (continued)
Entry
R1
R2
Conditions
A
Product
Yield (%)
95
Reference
OAc
O
AcO
AcO
AcO
13
2m
15
OAc
O
AcO
AcO
AcO
N
O
14
15
16
17
18
A
D
E
2n
2o
2p
2q
2r
93
95
79
72
86
27
OAc
O
OAc
O
AcO
AcO
AcO
AcO
7,8
7,8
28
AcO
AcO
AcO
OAc
O
OAc
O
AcO
AcO
AcO
AcO
AcO
OAc
O
H
AcO
3C
O
AcO
AcO
E
AcO
OAc
AcO
AcO
AcO
AcO
OAc
O
OAc
O
D
29
AcO
AcO
AcO
Conditions: (A) R1SH (1 equiv), R2SH (2 equiv), DEAD (2 equiv), THF, 3 h, rt; (B) R1SH (1 equiv), R2SH (6 equiv), DEAD (2 equiv), THF, 24 h,
reflux; (C) R2SH (2 equiv), DEAD (2 equiv), THF, 12 h, rt, followed by R1SH (1 equiv), 3 h, rt; (D) R1SH (2 equiv), DEAD (1 equiv), THF, 3 h, rt;
(E) R1SH (1 equiv), R2SH (1.1 equiv), DEAD (2 equiv), THF, 1 h, rt.
a DIAD used in place of DEAD.
(entries 5–7) required longer reaction times, producing
products in moderate yields only. However, reversal of
the order of addition of the reagents, that is, the sugar
thiol being added after complex formation between the
alkyl thiol and DEAD, significantly increased the reac-
tion yield from a modest 24% to 85% (entry 7), as com-
pared to ethyl thioglycoside, using the original
conditions (entry 6). Symmetrical and non-symmetrical
diglycosyl disulfides were also synthesised, all in excel-
lent yields (entries 15–18).
O
O
O
O
H
EtO C N N C OEt
EtO C N N C OEt
OAc
OAc
AcO
AcO
O
AcO
AcO
O
SH
S
HS R
AcO
AcO
3
OAc
AcO
AcO
O
S S R
AcO
A closer analysis of these reactions revealed that the
thiosugar reacts very quickly with DEAD to form inter-
mediate 330 (Scheme 1). The reacting thiol then acts as a
nucleophile, forming the disulfide and leaving the satu-
rated DEAD by-product (and conversely the thiosugar
reacted with the thiol–DEAD complex in the reverse
order of addition). A twofold excess of DEAD was
required to prevent the thiosugar reacting with the rap-
idly formed sugar–DEAD intermediate (which also
occurs rapidly) in place of the reacting thiol. In addition,
the thiosugar was added to the DEAD solution, as
opposed to the reverse, to further minimise this. In the
case of symmetrical diglycosyl disulfide synthesis, this
was not necessary: a twofold excess of the sugar over
DEAD allowed smooth conversion to the product in
excellent yields (entries 15 and 18). The high reactivity
of thiosugars towards a DEAD–sugar intermediate also
means that large excesses were not required for the syn-
thesis of non-symmetrical compounds (entries 16 and
17). Entry 3 confirms that DIAD is of equal effectiveness
as DEAD using these conditions—the yield using
DEAD was 76%, that is, lower than that of DIAD.
Scheme 1.
In summary we have described a convenient one-pot
synthesis of glycosyl disulfides, using mild and neutral
conditions, and in excellent yields. We are currently
investigating the application of these compounds to bio-
logical systems.
2. Typical experimental procedure
2,3,4,6-Tetra-O-acetyl-1-thio-b-D-glucopyranose 1 (50 mg,
0.138 mmol, 1.0 equiv) in THF (1 mL) and benzyl
mercaptan (0.275 mmol, 33 lL, 2 equiv) were sequen-
tially added to a solution of DEAD (0.275 mmol,
44 lL, 2.0 equiv) in THF (2 mL) under an inert atmo-
sphere. The reaction was stirred at room temperature
for 3 h. The reaction mixture was subsequently evapo-
rated and purified by flash chromatography (petroleum
ether–ethyl acetate 1:1) to give 2a (64 mg, 95%).

7640
G. Ribeiro Morais, R. A. Falconer / Tetrahedron Letters 48 (2007) 7637–7641
4OAc), 3.78 (m, 1H, H-5), 4.07 (m, 2H, H-6 and H-60),
Acknowledgements
4.74 (d, 1H, H-1, J1,2 = 9.3 Hz), 5.08 (dd, 1H, H-4,
J3,4 = J4,5 = 9.3 Hz), 5.24 (m, 2H, H-2 and H-3), 7.33 (t,
1H, 3J = 8.1 Hz), 7.42 (t, 1H, 3J = 8.1 Hz), 7.77 (d, 1H,
3J = 8.1 Hz), 7.86 (d, 1H, 3J = 8.1 Hz); 13C NMR
(150 MHz, CDCl3) d 20.35, 20.63, 20.68, 20.76, 61.70,
67.90, 69.51, 73.59, 76.21, 87.47, 121.13, 122.38, 125.05,
126.41, 136.11, 154.34, 169.35, 169.37, 170.22, 170.54; ES+
MS C21H23NO9S3 (529) m/z (%) 530 [M+H]+ (60). HRMS
(ESI): [M+H]+ calcd for C21H24O9NS3, 530.0608; found,
530.0608.
This work was supported by EPSRC funding (GRM)
and Yorkshire Cancer Research (RAF). We thank
Andrew Healey for running low resolution mass spectra
and the EPSRC National Mass Spectrometry Service
Centre, University of Wales Swansea for high resolution
accurate mass measurements.
20
22. Compound 2e: ½aꢀD ꢁ110.0 2 (c 0.09, CHCl3); 1H NMR
References and notes
(600 MHz, CDCl3) d 1.28 (m, 8H), 1.76 (m, 2H), 2.00,
2.02, 2.03, 2.07 (4s, 12H, 4OAc), 2.84 (m, 1H), 3.72 (m,
1H, H-5), 4.13 (dd, 1H, H-6, J6,5 = 2.0 Hz,
1. Sell, S. Hum. Pathol. 1990, 21, 1003–1019.
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H. J. Bioorg. Med. Chem. 2006, 14, 6314–6326.
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J.; Fairbanks, A. J.; Davis, B. G. Angew. Chem., Int. Ed.
2004, 43, 828–833.
5. Pei, Z. C.; Aastrup, T.; Anderson, H.; Ramstrom, O.
Bioorg. Med. Chem. Lett. 2005, 15, 2707–2710.
6. Pei, Z. C.; Larsson, R.; Aastrup, T.; Anderson, H.; Lehn,
J. M.; Ramstrom, O. Biosens. Bioelectron. 2006, 22, 42–
48.
7. Szilagyi, L.; Illyes, T. Z.; Herczegh, P. Tetrahedron Lett.
2001, 42, 3901–3903.
8. Brito, I.; Lopez-Rodriguez, M.; Benyei, A.; Szilagyi, L.
Carbohydr. Res. 2006, 341, 2967–2972.
9. Grayson, E. J.; Ward, S. J.; Hall, A. L.; Rendle, P. M.;
Gamblin, D. P.; Batsanov, A. S.; Davis, B. G. J. Org.
Chem. 2005, 70, 9740–9754.
10. Bittman, R.; Li, Z.; Samadder, P.; Arthur, G. Cancer Lett.
2007, 251, 53–58.
11. Vrudhula, V. M.; MacMaster, J. F.; Li, Z.; Kerr, D. E.;
Senter, P. D. Bioorg. Med. Chem. Lett. 2002, 12, 3591–
3594.
12. Davis, B. G.; Ward, S. J.; Rendle, P. M. Chem. Commun.
2001, 189–190.
13. Hotchkiss, T.; Kramer, H. B.; Doores, K. J.; Gamblin, D.
P.; Oldham, N. J.; Davis, B. G. Chem. Commun. 2005,
4264–4266.
14. Sivapriya, K.; Suguna, P.; Shubashree, S.; Sridhar, P. R.;
Chandrasekaran, S. Carbohydr. Res. 2007, 342, 1151–
1158.
15. Bell, R. H.; Horton, D.; Miller, M. J. Carbohydr. Res.
1969, 9, 201–214.
16. Falconer, R. A.; Jablonkai, I.; Toth, I. Tetrahedron Lett.
1999, 40, 8663–8666.
17. Malkinson, J. P.; Falconer, R. A. Tetrahedron Lett. 2002,
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56, 5907–5908.
J6,6 = 12.3 Hz), 4.23 (dd, 1H, H-60, J6 ,5
=
4.8 Hz,
0
0
0
J6 ,6 = 12.3 Hz), 4.46 (d, 1H, H-1, J1,2 = 9.6 Hz), 5.09
(dd, 1H, H-4, J4,3 = J4,5 = 9.6 Hz), 5.22 (m, 2H, H-2 and
H-3); 13C NMR (150 MHz, CDCl3) d 20.69, 20.73, 20.79
(2C), 25.69, 26.00, 26.06, 32.62, 32.73, 50.34, 62.10, 68.06,
69.37, 73.99, 76.01, 88.21, 169.27, 169.50, 170.37, 170.66;
ES+ MS C20H30NO9S2 (478) m/z (%) 501 [M+Na]+ (100).
HRMS (ESI): [M+NH4]+ calcd for C20H34O9NS2,
496.1669; found, 496.1670.
20
23. Compound 2g: ½aꢀD ꢁ122.5 1 (c 1.18, CHCl3); 1H NMR
(600 MHz, CDCl3) d 0.86 (t, 3H, J = 7.2 Hz), 1.29 (m,
6H), 1.64 (m, 2H), 1.99, 2.01, 2.02, 2.06 (4s, 12H, 4OAc),
2.75 (m, 2H), 3.72 (m, 1H, H-5), 4.13 (dd, 1H, H-6,
J6,5 = 2.1 Hz, J6,6 = 12.3 Hz), 4.21 (dd, 1H, H-60,
0
0
0
J6 ,5 = 4.4 Hz, J6 ,6 = 12.3 Hz), 4.50 (d, 1H, H-1,
J1,2 = 9.6 Hz), 5.09 (dd, 1H, H-4, J4,5 = J4,3 = 9.6 Hz),
5.24 (m, 2H, H-2 and H-3); 13C NMR (150 MHz, CDCl3)
d 13.98, 20.56, 20.60, 20.68 (2C), 22.49, 28.09, 28.82, 31.33,
40.07, 62.01, 67.99, 69.08, 73.83, 75.99, 88.03, 169.15,
169.37, 170.23, 170.52; ES+ MS C20H32O9S2 (480) m/z (%)
503 [M+Na]+ (100). HRMS (ESI): [M+NH4]+ calcd for
C20H36O9NS2, 498.1826; found, 498.1825.
20
1
24. Compound 2j: ½aꢀD ꢁ91.5 1 (c 0.84, CHCl3); H NMR
(600 MHz, CDCl3) d 1.95, 1.97, 2.10, 2.13 (4s, 12H,
4OAc), 3.88 (t, 1H, H-5, J5,6 = 6.5 Hz), 3.95 (d, 2H,
J5,6 = 6.5 Hz), 4.66 (d, 1H, H-1, J1,2 = 9.9 Hz), 5.04 (dd,
1H, H-3, J3,4 = 3.2 Hz, J2,3 = 9.9 Hz), 5.37 (d, 1H, H-4,
J3,4 = 3.2 Hz), 5.41 (dd, 1H, H-2, J1,2 = J2,3 = 9.9 Hz),
7.10 (t, 1H, 3J = 4.8 Hz), 8.59 (d, 2H, 3J = 4.8 Hz); 13C
NMR (150 MHz, CDCl3) d 20.68, 20.72, 20.76, 20.94,
61.24, 67.06, 71.84, 74.72, 88.74, 118.34, 157.78 (2C),
169.63, 170.13, 170.35, 170.36, 170.84; ES+ MS
C18H22N2O9S2 (474.08) m/z (%) 497 [M+Na]+ (100).
HRMS (ESI): [M+H]+ calcd for C18H23O9N2S2, 475.0839;
found, 475.0842.
20
1
25. Compound 2k: ½aꢀD ꢁ76.3 1 (c 1.84, CHCl3); H NMR
(600 MHz, CDCl3) d 1.22 (d, 3H, J = 6.1 Hz), 1.97, 2.03,
2.11 (3s, 9H, 3OAc), 3.94 (d, 1H, J = 12.3 Hz), 3.98 (d,
1H, J = 12.3 Hz), 4.05 (m, 1H, H-5), 4.69 (s, 1H, H-1),
2
2
5.04 (dd, 1H, H-4, J3,4 = 9.9 Hz, J4,5 = 9.7 Hz), 5.13 (dd,
1H, H-3, J2,3 = 3.4 Hz, J3,4 = 9.9 Hz), 5.37 (dd, 1H, H-2,
J1,2 = 1.5 Hz, J2,3 = 3.4 Hz), 7.24–7.30 (m, 5H); 13C NMR
(150 MHz, CDCl3) d 17.45, 20.74, 20.88, 21.00, 43.81,
68.59, 69.16, 70.24, 70.86, 88.40, 127.71, 128.80 (2C),
129.44 (2C), 136.67, 169.83, 169.99 (2C); ES+ MS
C19H24O7S2 (428.10) m/z (%) 451 [M+Na]+ (100). HRMS
(ESI): [M+NH4]+ calcd for C19H28O7NS2, 446.1302;
found, 446.1297.
19. Hummel, G.; Hindsgaul, O. Angew. Chem., Int. Ed. 1999,
38, 1782–1784.
20
20. Compound 2c: ½aꢀD ꢁ134.5 1 (c 0.59, CHCl3); 1H NMR
(600 MHz, CDCl3) d 1.92, 1.95, 1.96, 2.05 (4s, 12H,
4OAc), 3.65 (m, 1H, H-5), 4.04 (m, 2H, H-6 and H-60),
4.63 (d, 1H, H-1, J1,2 = 9.6 Hz), 5.04 (dd, 1H, H-4,
J4,3 = J4,5 = 9.6 Hz), 5.20 (m, 2H, H-2 and H-3), 7.07 (m,
1H), 8.55 (m, 2H); 13C NMR (150 MHz, CDCl3) d 20.62,
20.67, 20.70, 20.83, 61.79, 67.84, 69.50, 73.82, 76.04, 86.58,
118.28, 118.33, 157.77, 157.99, 169.34, 170.29, 170.50,
170.65; ES+ MS C18H22O9N2S2 (474) m/z (%) 497
[M+Na]+ (100). HRMS (ESI): [M+H]+ calcd for
C18H23O9N2S2, 475.0839; found, 475.0835.
20
1
26. Compound 2l: ½aꢀD ꢁ7.5 1 (c 2.01, CHCl3); H NMR
(600 MHz, CDCl3) d 0.95 (d, 3H, J = 6.1 Hz), 1.96, 2.02,
2.11 (3s, 9H, 3OAc), 3.85 (m, 1H, H-5), 5.05 (dd, 1H, H-4,
J3,4 = 9.9 Hz, J4,5 = 9.7 Hz), 5.16 (dd, 1H, H-3,
20
21. Compound 2d: ½aꢀD ꢁ252.5 1 (c 0.64, CHCl3); 1H NMR
J2,3 = 3.4 Hz, J3,4 = 9.9 Hz), 5.23 (d, 1H, H-1, J1,2
=
1.4 Hz), 5.40 (dd, 1H, H-2, J1,2 = 1.4 Hz, J2,3 = 3.4 Hz),
(600 MHz, CDCl3) d 1.75, 1.99, 2.00, 2.09 (4s, 12H,

G. Ribeiro Morais, R. A. Falconer / Tetrahedron Letters 48 (2007) 7637–7641
7641
3
3
7.26 (d, 1H, J = 7.3 Hz), 7.31 (dd, 2H, J = 7.3 Hz), 7.56
20.75, 62.28, 68.26, 68.95, 69.01, 69.16, 70.01, 70.85, 73.69,
76.60, 86.66, 87.87, 169.27, 169.36, 169.78, 169.90, 169.93,
169.98, 170.31; ES+ MS C26H36O16S2 (668) m/z (%) 691
[M+Na]+ (100). HRMS (ESI): [M+NH4]+ calcd for
C26H40O16NS2, 686.1783; found, 686.1784.
(d, 2H, 3J = 7.3 Hz); 13C NMR (150 MHz, CDCl3) d
16.96, 20.73, 20.85, 20.96, 68.67, 69.26, 70.26, 70.98, 88.49,
128.06, 129.17 (2C), 130.03 (2C), 136.43, 169.93, 169.95
(2C); ES+ MS C18H22O7S2 (414.08) m/z (%) 437 [M+Na]+
(100). HRMS (ESI): [M+NH4]+ calcd for C18H26O7NS2,
432.1145; found, 432.1149.
20
1
29. Compound 2r: ½aꢀD ꢁ32.1 1 (c 2.64, CHCl3); H NMR
(600 MHz, CDCl3) d 1.95, 2.01, 2.05, 2.14 (4s, 24 H,
8OAc), 4.00 (m, 2H, H-6), 4.08 (m, 2H, H-60), 4.20 (dd,
20
27. Compound 2n: ½aꢀD +22 1 (c 1.45, CHCl3); 1H NMR
0
(600 MHz, CDCl3) d 1.94, 2.00, 2.05, 2.16 (4s, 12H,
2H, H-5, J5,6 = 6.1 Hz, J5,6 = 10.9 Hz), 4.54 (d , 2H, H-1,
0
4OAc), 3.88 (dd, 1H, H-6, J5,6 = 2.0 Hz, J6,6 = 12.4 Hz),
J1,2 = 9.6 Hz), 5.05 (dd, 2H, H-3, J3,4 = 3.4 Hz,
J2,3 = 9.6 Hz), 5.32 (dd, 2H, H-2, J1,2 = J2,3 = 9.6 Hz),
5.41 (d, 2H, H-4, J3,4 = 3.4 Hz); 13C NMR (150 MHz,
CDCl3) d 20.64, 20.71, 20.75, 20.88, 60.77, 66.63, 67.69,
72.17, 74.77, 88.44, 169.46, 170.08, 170.24, 170.36.
Symmetrical disulfide; triplet seen in thio-monosaccha-
ride; ES+ MS C28H38NO18S2 (726) m/z (%) 749 [M+Na]+
(83). HRMS (ESI): [M+NH4]+ calcd for C28H42O18NS2,
744.1838; found, 744.1841.
4.30 (dd, 1H, H-60 J5,6 = 4.7 Hz, J6,6 = 12.4 Hz), 4.45 (m,
1H, H-5), 5.29 (dd, 1H, H-3, J2,3 = 3.4 Hz, J3,4 = 9.9 Hz),
5.36 (dd, 1H, H-4, J3,4 = J4,5 = 9.9 Hz), 5.54 (dd, 1H, H-2,
0
0
J1,2 = 1.5 Hz, J2,3 = 3.4 Hz), 5.57 (d, 1H, H-1, J1,2
=
1.5 Hz), 7.32 (m, 2H), 7.48 (m, 1H), 7.65 (m, 1H);
13C NMR (150 MHz, CDCl3) d 20.65, 20.68, 20.78,
20.92, 61.86, 65.79, 69.28, 69.49, 70.93, 87.98, 110.49,
119.57, 125.03, 125.28, 141.76, 152.52, 161.83, 169.64,
169.81, 169.85, 170.64; ES+ MS C21H23NO10S2
(513.54) m/z (%) 536.1 [M+Na]+ (100). HRMS (ESI):
[M+H]+ calcd for C21H24O10NS2, 514.0836; found,
514.0839.
20
1
30. Compound 3: ½aꢀD ꢁ25.0 1 (c 5.23, CHCl3); H NMR
(600 MHz, CDCl3) d 1.26 (m, 6H, 2CH3), 1.98, 2.01, 2.06,
2.08 (4s, 12H, 4OAc), 3.71 (m, 1H, H-5), 4.20 (m, 6H, H-6,
H-60 and 2CH2), 4.88 (d, 1H, H-1, J1,2 = 9.6 Hz), 4.96
(dd, 1H, H-4, J3,4 = J4,5 = 9.6 Hz), 5.07 (dd, 1H, H-3,
20
28. Compound 2q: ½aꢀD ꢁ200.5 1 (c 1.67, CHCl3); 1H NMR
(600 MHz, CDCl3) d 1.23 (d, 3H, J = 5.8 Hz, CH3rha),
1.98, 2.00, 2.00, 2.03, 2.03, 2.04, 2.11 (7s, 21 H, 7OAc),
3.75 (m, 1H, H-5glc), 4.00 (m, 1H, H-5rha), 4.09 (dd,
J2,3 = J3,4 = 9.6 Hz), 5.22 (dd, 1H, H-2, J1,2 = J2,3 =
9.6 Hz), 7.19 (br s, 1H, NH); 13C NMR (150 MHz,
CDCl3) d 14.34, 14.50, 20.64, 20.68, 20.70, 20.80, 61.97,
62.36, 64.61 (2C), 68.12, 68.32, 73.79, 75.99, 155.59 (CO),
156.05 (CO), 169.43, 169.76, 170.19, 170.87; ES+ MS
C20H30N2O13S (538) m/z (%) 539 [M+H]+ (30), 561
[M+Na]+ (30). HRMS (ESI): [M+NH4]+ calcd for
C20H34O13N3S, 556.1807; found, 556.1809.
0
1H, H-6glu, J6,5 = 1.3 Hz, J6,6 = 12.3 Hz), 4.20 (dd, 1H,
0 0
, J6 ,5 = 5.5 Hz, J6 ,6 = 12.3 Hz), 4.50 (d, 1H,
H-1glu, J1,2 = 9.2 Hz), 5.10 (m, 2H, H-4glu and H-4rha),
H-60
glu
5.24 (m, 4H, H-2glu, H-3glu, H-4rha and H-1rha), 5.50 (dd,
1H, H-2rha
(150 MHz, CDCl3) d 17.50, 20.71, 20.73 (3C), 20.74,
,
J1,2 = 1.6 Hz, J2,3 = 3.3 Hz); 13C NMR