A. Nejatie et al.
Bioorganic Chemistry 106 (2021) 104484
′
′
diluted with CH
2
Cl
2
(125 mL/mmol) and washed with H
2
O. The organic
MHz, CD
3
OD) δ
C
173.66 (C-1), 150.34 (1JC–F = 255.0, C-3 ,5 ), 141.88
1
′
′
′
2
layer was separated and dried over anhydrous sodium sulfate, filtered
and concentrated under reduced pressure. Purification by column
chromatography using an eluent of ethyl acetate/hexanes (1:1 v/v)
afforded an inseparable mixture of peracetylated thiosialoside 3a and
( JC–F = 247.1, C-2 ,6 ), 141.49 (m, C-4 ), 103.95 (t, JC–F = 22.0 Hz, C-
′
1 ), 90.31 (C-2), 77.83 (C-6), 73.73 (C-8), 72.56 (C-4), 71.43 (C-5),
9
1
69.60 (C-7), 64.43 (C-9), 62.72 (-OCH
(471 MHz, CD
3
), 42.04 (C-3). 1 F { H}NMR
3
OD) δ
F
–132.29 (dd, J = 24.1, 8.1 Hz, Ar-F), –160.38 (dd,
glycal 4. These solids were dissolved in dry MeOH (25 mL/mmol) that
J = 23.4, 7.9 Hz, Ar-F). ESI-HRMS m/z: [M+Li] Calcd for C16
H
18
F
4
O
9
SLi
◦
was cooled to 0 C and K
2
CO
3
(5 equiv.) was added and the mixture was
469.0768; found 469.0754.
+
2
stirred under N for 24 h. The resulting mixture was neutralized with H
resin, filtered, then concentrated under reduced pressure. Purification
by column chromatography using an eluent of ethyl acetate/methanol
4.1.4. 4-Nitrophenyl 3-deoxy-2-thio-D-glycero-
α
-D-galacto-non-2-
ulopyranosidonic acid (1c)
47% yield over 2 steps from compound 3c; mp = 184–185 C; 1
◦
H
(
10:1 v/v) afforded an inseparable mixture of methyl ester and the
glycal impurity. The crude mixture was dissolved in THF/H
2
O (40 mL/
NMR (400 MHz, CD
3
OD) δ 8.13 (d, J = 8.8 Hz, 2H, Ar-H), 7.85 (d, J =
H
◦
mmol, 10:1) and cooled to 0 C followed by the addition of LiOH (1.5
8.8 Hz, 2H, Ar-H), 3.89–3.73 (m, 3H, H-7, H-8, H-9a), 3.67–3.55 (m, 3H,
H-4, H-6, H-9b), 3.55–3.46 (m, 1H, H-5), 2.92 (dd, J3eq,3ax = 12.3, J3eq,4
◦
equiv.). The mixture stirred at rt for 3 h at 0 C and gradually warmed to
+
rt over 20 h. The resulting mixture was neutralized with H resin,
= 4.9 Hz, 1H, H-3 eq), 1.73 (dd, J3eq,3ax = 12.3, J3ax,4 = 11.2 Hz, 1H, H-
3ax). 13C { H}NMR (101 MHz, CD
1
filtered, then concentrated under reduced pressure followed by purifi-
cation using column chromatography (ethyl acetate/MeOH, 9:1) gave
the Kdn thioglycoside 1a as a hygroscopic solid. 2,3,4,5,6-Penta-
3 C
OD) δ 173.45 (C-1), 149.00 (Ar),
142.53 (Ar), 136.33 (Ar), 124.08 (Ar), 90.28 (C-2), 77.70 (C-5), 74.07
(C-6), 72.57(C-8), 71.50 (C-4), 69.88 (C-7), 64.73(C-9), 42.30(C-3). ESI-
+
fluorothiophenyl
anosidonic acid (1a); 69% yield over 2 steps from 3a; H NMR (500 MHz,
CD 3.77 (m, 2H, H-7, H9b), 3.69–3.56 (m, 3H, H4, H8, H9a),
OD) δ
.51 (m, 2H, H-6, H-7), 2.88 (dd, J3eq,3ax = 12.4, J3eq,4 4.3 Hz, 1H, H-
ax), 1.78–1.67 (m, 1H, H-3 eq). C { H}NMR (101 MHz, CD OD) δ
73.43 (C-1), 150.31 ( JC–F = 249.8, C-3 ,5 ), 143.95 ( JC–F = 246.1, C-
3-deoxy-2-thio-D-glycero-
α
-D-galacto-non-2-ulopyr-
HRMS m/z: [M+Na] Calcd for C15
H19NO10SNa 428.0627; found
1
428.0621.
3
H
3
3
1
4
6
4.1.5. 4-Methylumbelliferyl 3-deoxy-2-thio-D-glycero-
ulopyranosidonic acid (1d)
α-D-galacto-non-2-
1
3
1
3
C
1
′
′
1
63% yield over 2 steps from compound 3d; mp = 158–160 C; 1
◦
H
′
1
′
′
′
), 138.80 ( JC–F = 256.1, C-2 ,6 ), 106.71 (C-1 ), 90.01 (C-2), 78.09 (C-
), 73.75 (C-8), 72.42 (C-4), 71.32 (C-5), 69.46 (C-7), 64.30 (C-9), 41.80
NMR (400 MHz, D
2
O) δ 7.62 (d, J = 8.2 Hz, 1H, Ar-H), 7.48–7.32 (m,
H
2H, Ar-H), 6.30 (s, 1H, Ar-H), 3.80–3.67 (m, 3H, H-7, H-8, H-9a),
3.60–3.45 (m, 3H, H-4, H-6, H-9b), 3.41–3.34 (m, 1H, H-5), 2.77 (dd,
1
9
1
(
C-3). F { H}NMR (471 MHz, CD
F), –153.70 (t, J = 20.1 Hz, Ar-F), –165.06 (t, J = 19.0 Hz, Ar-F). ESI-
SNa 473.0305; found
3
OD) δ
F
–129.89 (d, J = 22.7 Hz, Ar-
J
3ax,3eq = 12.6, J3eq,4 = 3.9 Hz, 1H, H-3eq), 1.76 (t, J3ax,4 = 11.8 Hz, 1H,
HRMS m/z: [M+Na] Calcd for
C
15
H
15
F
5
O
8
H-3ax). The NMR data are in agreement with those reported in the
literature [29].
4
73.0302.
4
.1.2. General syntheses of S-aryl
α
-Kdn substrates (1b–g)
4.1.6. 4-Chlorophenyl 3-deoxy-2-thio-D-glycero-
α
-D-galacto-non-2-
Sodium aryl thiolate salts were prepared by adding an aqueous
NaOH solution (1.0 M, 1.1 eq) to a solution of aryl thiol in methanol
100 mL) with the mixture being stirred at rt for 30 min. This mixture
ulopyranosidonic acid (1e)
80% over 2 steps from compound 3e; mp = 208–210 C; 1H NMR
◦
(
(400 MHz, CD
3
OD) δ 7.59 (d, J = 8.5 Hz, 2H, Ar-H), 7.29 (d, J = 8.5 Hz,
H
was then concentrated under reduced pressure to dryness, and the
resultant aryl thiolate salt was dissolved in water, and this solution was
lyophilized to give the thiolate salts as white solids. The known pro-
tected 3-deoxy-D-glycero-D-galacto-non-2-ulopyranosonyl chloride 2 [3]
and a thiolate salt (1.2 eq., for the synthesis of the 2,3,5,6-tetrafluoro-4-
methoxythiophenyl glycoside 2,3,4,5,6-pentafluorothiophenolate was
the thiol used for coupling) were dissolved in dry DMF (15 mL/mmol)
and the mixture was stirred at room temperature under Ar for 16–20 h.
2H, Ar-H), 3.86–3.69 (m, 3H, H-7, H8, H9a), 3.65–3.53 (m, 2H, H-4, H-
6, H-9b), 3.49–3.43 (m, 1H, H-5), 2.86 (dd, J3eq,3ax = 12.4, J3eq,4 = 4.9
Hz, 1H, H-3 eq), 1.67 (dd, J3ax,3eq = 12.4, J3ax,4 = 11.2 Hz, 1H, H-3ax).
1
3
1
C { H}NMR (101 MHz, D
2
C
O) δ 173.09 (Ar), 137.47 (Ar), 128.86 (C-
1), 88.33 (C-2), 75.90 (C-5), 72.45 (C-6), 70.67 (C-8), 69.68 (C-14),
+
67.73 (C-7), 62.57 (C-9), 40.03 (C-3). ESI-HRMS m/z: [M+Na] Calcd
8
for C15H19ClO SNa 417.0387; found 417.0383.
The reaction mixture was diluted with CH
2
Cl
2
(125 mL/mmol) and
4.1.7. Phenyl 3-deoxy-2-thio-D-glycero-
ulopyranosidonic acid (1f)
α
-D-galacto-non-2-
washed with H O. The organic layer was separated and dried over
2
86% yield over 2 steps from compound 3f; mp = 166–167 C; 1
◦
H
anhydrous sodium sulfate, filtered and concentrated under reduced
pressure. Purification by silica gel flash chromatography using an eluent
of ethyl acetate/hexanes (1:1 v/v) afforded an inseparable mixture of
peracetylated thiosialoside 3a,c–g and glycal 4. These solids were dis-
NMR (400 MHz, CD
3
OD) δ 7.64 (d, J = 7.9 Hz, 2H, Ar-H), 7.37–7.26
H
(m, 3H, Ar-H), 3.87–3.81 (m, 2H, H-7, H-9a), 3.78 (dd, J = 8.8,1.9 Hz,
1H, H-8), 3.63 (dd, J = 11.9, 6.5 Hz, 1H, H-9b), 3.61–3.53 (m, 2H, H-4,
H-5), 3.51–3.44 (m, 1H, H-6), 2.86 (dd, J3eq,3ax = 12.5, J3eq,4 = 4.9 Hz,
◦
solved in dry MeOH (25 mL/mmol) that was cooled to 0 C and a so-
1
3
lution of 1 M NaOMe (5 equiv.) was added and the mixture was stirred
under Ar for 60 min. The resulting mixture was concentrated under
reduced pressure before being dissolved in THF (40 mL/mmol) to which
an aqueous solution of 1 M LiOH (3 equiv.) was added and the mixture
stirred at rt for 3–5 h. Removal of solvent by evaporation under reduced
pressure followed purification by silica gel flash chromatography (ethyl
acetate/MeOH, 9:1) gave the Kdn thioglycoside 1b as a hygroscopic
solid and the glycosides 1c–g as colorless amorphous solids.
1H, H-3eq), 1.70 (dd, J3ax,3eq = 12.5, J3ax,4 = 11.3 Hz, 1H, H-3aq).
C
1
{ H}NMR (101 MHz, CD
3 C
OD) δ 137.22, 132.45, 129.90, 129.42 (Ar),
89.78 (C-2), 77.51 (C-5), 74.00 (C-7), 72.67 (C-4), 71.59 (C-6), 70.07 (C-
ꢀ
8), 64.87 (C-9), 42.14 (C-3). ESI-HRMS m/z: [Mꢀ H] Calcd for
15 19 8
C H O S 359.0806; found 359.0789.
4.1.8. 3,5-Dimethylphenyl 3-deoxy-2-thio-D-glycero-
α
-D-galacto-non-2-
ulopyranosidonic acid (1g)
0% yield over 2 steps from compound 3g; mp = 176–180 C; 1
◦
H
6
4
.1.3. 2,3,5,6-Tetrafluoro-4-methoxythiophenyl 3-deoxy-2-thio-D-glycero-
NMR (400 MHz, CD
3
OD) δ
H
7.25 (s, 2H, Ar-H), 6.94 (s, 1H, Ar-H),
α
-D-galacto-non-2-ulopyranosidonic acid (1b)
3.90–3.81 (m, 2H, H-7, H-9a), 3.77 (dd, J = 9.0, 1.9 Hz, 1H, H-8),
3.64 (dd, J = 11.3, 5.7 Hz, 1H, H-9b), 3.60–3.53 (m, 2H, H-4, H-6),
3.51–3.45 (m, 1H, H-5), 2.83 (dd, J3eq,3ax = 12.5, J3eq,4 = 4.7 Hz, 1H, H-
3
7% yield over 2 steps from compound 3a; 1H NMR (400 MHz,
CD
3
OD) δ
H
4.11 (s, 3H, –OCH ), 3.81–3.74 (m, 2H, H-7, H-9b), 3.69
3
(
ddd, J = 8.9, 6.4, 2.6 Hz, 1H, H-4) 3.65–3.54 (m, 2H, H-8, H-9a),
.50–3.41 (m, 2H, H-6, H-7), 2.91 (dd, J3eq,3ax = 12.2, J3eq,4 4.9 Hz, 1H,
3 eq), 2.27 (s, 6H, 2 × CH ), 1.69 (dd, J3eq,3ax = 12.4, J3ax,4 = 11.3 Hz,
3
1H, H-3aq).13C { H}NMR (101 MHz, CD
1
OD) δ
3
3
C
139.04, 134.64, 131.54
1
3
1
H-3 eq), 1.78–1.67 (t, J3eq,3ax = 11.6 Hz 1H, H-3aq). C { H}NMR (101
(Ar), 77.55 (C-5), 74.07 (C-7), 72.64 (C-4), 71.61 (C-6), 70.11 (C-8),
5