Short synthesis of phenylpropanoid glycoside grayanoside-A and analogues

Article abstract of DOI:10.1016/j.carres.2016.11.010

A short synthesis of phenylethyl glycosides grayanoside-A 1, 2 and analogues 3–4 in high 43–65% overall yields is described. The main synthetic step involved regioselective O-6 acylation of unprotected 2-phenylethyl-β-D-glucoside 7 with cinnamoyl chlorides 8a-d using Me₂SnCl₂as catalyst. The acylation at O-6 is regioselective regardless of the type of cinnamoyl chloride used. Protection/deprotection steps of the glucoside core were not necessary. The synthetic route is generally applicable for the synthesis of phenylpropanoid glycoside class of compounds acylated at O-6.

Full text of DOI:10.1016/j.carres.2016.11.010

Carbohydrate Research 436 (2016) 50e53
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Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Short synthesis of phenylpropanoid glycoside grayanoside-A and
analogues
Duc Thinh Khong, Zaher M.A. Judeh*
School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, N1.2eB1-14, 637459, Singapore
a r t i c l e i n f o
a b s t r a c t
Article history:
A short synthesis of phenylethyl glycosides grayanoside-A 1, 2 and analogues 3e4 in high 43e65% overall
yields is described. The main synthetic step involved regioselective O-6 acylation of unprotected 2-
phenylethyl-b-D-glucoside 7 with cinnamoyl chlorides 8a-d using Me2SnCl2 as catalyst. The acylation
at O-6 is regioselective regardless of the type of cinnamoyl chloride used. Protection/deprotection steps
of the glucoside core were not necessary. The synthetic route is generally applicable for the synthesis of
phenylpropanoid glycoside class of compounds acylated at O-6.
Received 2 November 2016
Accepted 12 November 2016
Available online 14 November 2016
Keywords:
Phenylpropanoid glycosides
Grayanoside-A
© 2016 Elsevier Ltd. All rights reserved.
Regioselective acylation
Me2SnCl2
1. Introduction
deprotection strategies [2a]. The use of feruloyl, coumaroyl and
cinnamoyl acid chlorides/pyridine system for selective acylation of
Phenylpropanoid glycosides (PhGs) are natural compounds
distributed in plants and show antioxidation, antiproliferation,
antibacterial, antiviral, anti-inflammatory and hepatoprotection
primary hydroxyl groups of sucrose has been employed in our lab
for the synthesis of various phenylpropanoid sucrose esters [6]. It
usually resulted in unpredictable mixtures of acylated products
that were tedious to purify. Therefore, a general selective and more
predictable approach is needed to prepare the phenylpropanoid
glycoside class of compounds acylated at O-6.
Herein, we report a short synthetic route for grayanoside-A 1
and demonstrate its general applicability for the synthesis of O-6
acylated PhGs analogues 2e4. This route relies on direct O-6 acyl-
ation of unprotected glucoside core in high selectivity and yield
without protection/deprotection steps. The route is general for the
synthesis of phenylpropanoid glycosides class of compounds acyl-
ated at O-6.
activities [1]. PhGs have 2-phenylethyl-b-D-glucoside core acylated
with a (substituted) cinnamoyl moiety mainly at O-4 or O-6 and
may have additional one or two saccharide units bonded to the
glucoside core through glycosidic bonds (Fig. 1).
Total synthesis of PhGs has attracted significant interests due to
their diverse bioactivities. The conventional approach for their
synthesis has mainly relied on tedious, low-yielding and multistep
protection-deprotection strategies [2]. Our group has been inter-
ested in developing short and convenient synthesis of PhGs that
eliminate unnecessary protection/deprotection steps. To this end,
we focused our attention at synthesizing PhG class of compounds
acylated at O-6 since they represent the vast majority of the re-
ported PhGs. We recently communicated the synthesis of
calceolarioside-B and eutigoside-A [3]. It was natural for us to
extend our synthetic efforts to grayanoside-A 1, [4] PhG 2 [5] (no
name was given to this reported PhG) and test the general appli-
cability of the approach by synthesizing PhGs analogues 3e4 hav-
ing cinnamoyl moieties at O-6 (Fig. 1). The reported synthesis of
grayanoside-A 1 involved acylation of the glucoside core at O-6
with feruloyl acid chloride in pyridine [2g] or protection-
2. Results and discussion
Our synthesis of grayanoside-A 1, PhG 2 and analogues 3e4 is
depicted in Scheme 1. Direct 1,2-tran-b-glycosylation between
excess peracetate D-glucose 5 and 2-(4-allyloxyphenyl)ethanol 6
followed by deacetylation using NaOMe/MeOH gave 2-(4-
allyloxyphenyl)ethyl-b-D-glucopyranoside 7 in 82% yield [3]. We
noted that the use of excess rather than stoichiometric amount of
peracetate D-glucose 5 was beneficial as it gave higher yield of
glucopyranoside 7 [2a]. The glycosylation reaction proceeded
through neighboring group participation mechanism [7].
* Corresponding author.
E-mail address: zaher@ntu.edu.sg (Z.M.A. Judeh).
Next, direct regioselective O-6 acylation of 2-(4-allyloxyphenyl)
http://dx.doi.org/10.1016/j.carres.2016.11.010
0008-6215/© 2016 Elsevier Ltd. All rights reserved.

D.T. Khong, Z.M.A. Judeh / Carbohydrate Research 436 (2016) 50e53
51
O
No migration and/or hydrolysis of the cinnamoyl moieties were
observed at any stage. Because of convenience and high yields, this
work serves as a model for the direct synthesis of phenylpropanoid
glycoside class of compounds acylated at O-6.
R1
R2
O
4
6
O
HO
O
HO
2
OH
OH
4. Experimental
R1 = OMe, R2 = OH grayanoside-A 1
1 = R2 = OH
2
R
R1 = R2 = H
4.1. General procedures
3
R
1 = R2 = OMe 4
Chemical reagents were purchased from Sigma-Aldrich or Alfa
Aesar and used as received without further purification. 1H NMR
spectra were recorded at 300 MHz on a Bruker Avance DPX 300.
Unless stated otherwise, data refer to solutions in CDCl3 with TMS
as an internal reference. 13C NMR spectra were recorded at
75.47 MHz on a Bruker Avance DPX 300. HRMS were recorded on
Qstar XL MS/MS system. FTIR spectra were recorded on Perkin
Elmer FTIR system Spectrum BX. Analytical TLC was performed
using Merck 60 F254 precoated silica gel plates (0.2 mm thickness)
and visualized using UV radiation (254 nm). Flash chromatography
was performed using Merck silica gel 60 (230e400 mesh).
Fig. 1. Structures of grayanoside-A 1, PhG 2 and analogues 3e4.
ethyl-
b
-D-glucopyranoside 7 with acid chlorides 8a-d [8] using
catalytic amount of Me2SnCl2 [9] gave the desired O-6 acylated
glucosides 9a-d in 79e86% yield (Scheme 1). The preferential
acylation of cinnamoyl chloride at O-6 is due to the higher intrinsic
reactivity of 6-OH [10] and the increased acidity of 6-OH after
complexation with Me2SnCl2 [9].
Finally, removal of the allyl groups of the acylated glucosides 9a,
c-d using Pd/C proceeded smoothly to give grayanoside-A 1 in 74%
yield and analogues 3 and 4 in 92% and 89% yields, respectively.
Removal of the tert-butyldimethylsilyl (TBS) groups of acylated
glucoside 9b using tetra-n-butylammonium fluoride (TBAF) fol-
lowed by removal of the allyl group using Pd/C gave PhG 2 in 67%
yield. In all cases, no migration and/or hydrolysis [2g,h] of the
cinnamoyl moieties occurred as the allyl and TBS groups were
removed selectively. The structures of grayanoside-A 1 and PhG 2
were confirmed by 1H NMR and 13C NMR and matched with the
reported data [2a,g,5].
4.2. General procedure for O-6 acylation of 2-(4-allyloxyphenyl)
ethyl b-D-glucopyranoside 7 with cinnamoyl chloride 8a-d
To a solution of glucopyranoside 7 (85 mg, 0.25 mmol) in THF
(2.5 mL) was added Me2SnCl2 (2.75 mg, 5 mol%), cinnamoyl chlo-
ride 8 (0.375 mmol), DIPEA (87 mL, 0.5 mmol) under strong stirring.
The reaction was stirred for ~18 h (TLC) before diluting with
deionized H2O (10 mL). The mixture was extracted with EtOAc
(10 mL x 3), the combined organic phases were washed with brine,
dried over MgSO4, filtered and evaporated. The crude residue was
purified by flash column chromatography to give the respective O-6
acylated products. The general method was used to prepare com-
pounds 9a-d.
3. Conclusion
We have developed a short synthesis of grayanoside-A 1 and
PhG 2 and analogues 3e4 in high 43e65% overall yields without
protection-deprotection steps. The first key step involved 1,2-tran-
4.2.1. 2-(4-Allyloxyphenyl)ethyl 6-O-(E)-(3-methoxy-4-allyloxy)
b
-glycosylation of peracetylated D-glucose
allyloxyphenyl)ethanol 6 to give 2-(4-allyloxyphenyl)ethyl-
glucopyranoside 7. The second key step involved regioselective O-6
acylation of unprotected 2-phenylethyl- -D-glucoside 7 with cin-
5
with 2-(4-
cinnamoyl b-D-glucopyranoside 9a
b-D-
The crude product was purified by flash column chromatog-
raphy (EtOAc: DCM ¼ 3: 1) to give 120 mg (85% yield) as amorphous
b
solid. ½a D
ꢀ
ꢁ 25o ðc 0:023; CH2Cl2Þ. 1H NMR (CDCl3)
d: 2.80 (t,
namoyl chlorides 8a-d using Me2SnCl2 as catalyst. Acylation at O-6
is regioselective regardless of the type of cinnamoyl chloride used.
J ¼ 7.2 Hz, 2H), 3.32e3.43 (m, 3H), 3.50e3.56 (m, 1H), 3.62 (q,
J ¼ 8.4 Hz, 1H), 3.79 (s, 3H), 4.00 (q, J ¼ 7.9 Hz, 1H), 4.25 (d,
HO
HO
AcO
O
O
a
OH
AcO
O
HO
OAc
AcO
O
OH
+
OAc
O
5
6
7 (82%)
O
R1
Cl
b
R2
8a
1
: R = OMe, R2 = OAll
8b: R1 = R2 = OTBS
8c: R1 = R2 = H
R1
R2
R1
R2
O
O
: R1 = R2 = OMe
8d
O
O
O
O
HO
HO
c
HO
HO
O
O
d
OH
OH
O
OH
1
R1 = OMe, R2 = H grayanoside-A (74%)
: R = OMe, R2 = OAll (85%)
1
9a
R
R
1 = R2 = OH PhG 2 (67%)
9b: R1 = R2 = OTBS (79%)
9c: R1 = R2 = H (86%)
: R1 = R2 = OMe (82%)
1 = R2 = H 3 (92%)
R1 = R2 = OMe (89%)
4
9d
Reagents and conditions: a) BF3.OEt2, CH2Cl2, MS 4Å, rt, 12 h then NaOMe, MeOH, rt, 1 h;
b) 8a-d, Me2SnCl2, THF, rt, 18 h; c) Pd/C, p-TsOH, MeOH-H2O, 80 °C, 16 h (for 9a, 9c-d)
9b
d) TBAF, THF, 0 °C - rt, 2 h then Pd/C, p-TsOH, MeOH-H2O, 80 °C, 16 h (for
)
Scheme 1. Synthesis of grayanoside-A 1, PhG 2 and analogues 3e4.

52
D.T. Khong, Z.M.A. Judeh / Carbohydrate Research 436 (2016) 50e53
J ¼ 3.75 Hz, 1H), 4.32e3.38 (m, 3H), 4.51e4.55 (m, 3H), 5.16e5.37
(m, 4H), 5.88e6.04 (m, 2H), 6.27 (d, J ¼ 16.0 Hz, 1H), 6.69e6.76 (m,
4.3.1. 2-(4-Hydroxyphenyl)ethyl 6-O-(E)-(3-methoxy-4-hydroxy)
cinnamoyl -D-glucopyranoside (grayanoside-A) 1
The crude mixture was purified by flash column chromatog-
raphy to give 35 mg (74% yield) as amorphous solid.
b
3H), 6.92e7.02 (m, 4H), 7.56 (d, J ¼ 16.0 Hz, 1H). 13C NMR (CDCl3)
d:
35.2, 55.93, 63.3, 68.8, 69.7,70.0, 71.2, 73.6, 74.2, 75.9, 102.9, 110.1,
112.7, 114.7, 115.0, 117.6, 118.5, 122.8, 127.3, 129.8, 130.3, 132.7, 133.3,
145.9, 149.5, 150.3, 157.2, 168.0. HRMS (ESIþ): m/z [MþH]þ calcd for
½
a D
ꢀ
ꢁ 15o ðc 0:032; MeOHÞ. 1H NMR (MeOD)
: 2.75 (t, J ¼ 7.35 Hz,
d
2H), 3.12 (t, J ¼ 8.55 Hz, 1H), 3.25e3.29 (m, 2H), 3.41e3.43 (m, 1H),
3.57e3.66 (m, 1H), 3.75 (s, 3H), 3.71e3.88 (m, 2H), 4.21e4.27 (m,
2H), 4.38e4.42 (m, 1H), 6.27 (d, J ¼ 15.9 Hz, 1H), 6.51e6.57 (m, 2H),
6.70 (d, J ¼ 8.1 Hz, 1H), 6.89e6.94 (m, 3H), 7.04 (d, J ¼ 1.8 Hz, 1H),
C
30H37O10: 577.3952; found: 577.3948.
4.2.2. 2-(4-Allyloxyphenyl)ethyl 6-O-(E)-3,4-bis(tert-
butyldimethylsilyloxy)caffeoyl -D-glucopyranoside 9b
b
7.52 (d, J ¼ 15.9 Hz, 1H). 13C NMR (MeOD)
d: 38.0, 57.9, 66.2, 73.3,
The crude product was purified by flash column chromatog-
raphy (EtOAc: DCM ¼ 3: 1) to give 144 mg (79% yield) as amorphous
74.0, 76.6, 76.9, 79.4, 106.1, 113.1, 116.8, 117.7, 118.0, 125.8, 129.2,
132.1, 132.4, 148.6, 150.9, 152.1, 158.3, 170.6. HRMS (ESIþ): m/z
[MþH]þ calcd for C24H29O10: 477.1761; found: 477.1760. 1H NMR
and 13C NMR are in agreement with the reported values [2g].
solid. ½a D
ꢀ
ꢁ 66o ðc 0:030; CH2Cl2Þ. 1H NMR (CDCl3)
: ꢁ0.01 (s, 6H),
d
0.00 (s, 6H), 0.768 (s, 9H), 0.772 (s, 9H), 2.67 (t, J ¼ 7.05 Hz, 2H),
3.25e3.53 (m, 5H), 3.87 (q, J ¼ 9.3 Hz, 1H), 4.10 (d, J ¼ 7.8 Hz, 1H),
4.18e4.25 (m, 3H), 4.37e4.42 (m, 1H), 5.03 (dd, J ¼ 1.2, 10.5 Hz, 1H),
5.16 (dd, J ¼ 1.5, 17.4 Hz, 1H), 5.74e5.83 (m, 1H), 6.07 (d, J ¼ 15.9 Hz,
1H), 6.57e6.60 (m, 3H), 6.75e6.90 (m, 4H), 7.40 (d, J ¼ 15.9 Hz, 1H).
4.3.2. 2-(4-Hydroxyphenyl)ethyl 6-O-(E)-cinnamoyl b-D-
glucopyranoside 3
The crude mixture was purified by flash column chromatog-
raphy to give 40 mg (92% yield) as amorphous solid.
13C NMR (CDCl3)
d: ꢁ5.44, ꢁ5.41, 17.06, 17.12, 24.51, 24.54, 33.9,
62.0, 67.4, 68.6, 69.8, 72.2, 72.9,103.0,113.4,113.5,116.2,119.2,119.8,
121.2, 126.4, 128.5, 129.0, 132.0, 144.7, 145.8, 148.3, 155.8, 166.8.
HRMS (ESIþ): m/z [MþH]þ calcd for C38H59O10Si2: 731.3647; found:
731.3643.
½
a D
ꢀ
ꢁ 28o ðc 0:030; MeOHÞ. 1H NMR (MeOD)
: 2.73 (t, J ¼ 7.35 Hz,
d
2H), 3.11 (t, J ¼ 7.8 Hz,1H), 3.25e3.27 (m, 3H), 3.44 (t, J ¼ 7.8 Hz,1H),
3.62 (q, J ¼ 8.7 Hz, 1H), 3.84 (q, J ¼ 9.3 Hz, 1H), 4.22e4.28 (m, 2H),
4.41e4.45 (m, 1H), 6.44 (d, J ¼ 16.2 Hz, 1H), 6.54 (d, J ¼ 7.8 Hz, 2H),
6.93 (d, J ¼ 7.8 Hz, 2H), 7.22e7.31 (m, 3H), 7.40e7.46 (m, 2H), 7.59
4.2.3. 2-(4-Allyloxyphenyl)ethyl 6-O-(E)-cinnamoyl
b
-D-
(d, J ¼ 15.6 Hz, 1H). 13C NMR (MeOD)
d: 38.0. 66.4, 73.3, 74.0, 76.6,
glucopyranoside 9c
76.9, 79.5, 106.1, 117.6, 117.7, 120.2, 130.7, 131.5, 132.1, 132.4, 133.1,
The crude product was purified by flash column chromatog-
raphy (EtOAc: DCM ¼ 3: 1) to give 101 mg (86% yield) as amorphous
137.2, 148.0, 158.3, 169.9. HRMS (ESIþ): m/z [MþH]þ calcd for
C
23H27O8: 431.1706; found: 431.1712.
solid. ½a D
ꢀ
ꢁ 63o ðc 0:022; CH2Cl2Þ. 1H NMR (CDCl3)
d: 2.81 (t,
J ¼ 8.1 Hz, 2H), 3.32e3.67 (m, 5H), 4.01 (q, J ¼ 8.0 Hz, 1H), 4.25 (d,
J ¼ 7.5 Hz, 1H), 4.34e4.39 (m, 3H), 4.51e4.56 (m, 1H), 5.22 (dd,
J ¼ 1.5, 10.5 Hz, 1H), 5.31 (dd, J ¼ 1.5, 17.1, 1H), 5.88e6.01 (m, 1H),
6.40 (d, J ¼ 15.9 Hz, 1H), 6.71 (d, J ¼ 8.7 Hz, 2H), 7.02 (d, J ¼ 8.7 Hz,
2H), 7.26e7.30 (m, 3H), 7.39e7.42 (m, 2H), 7.63 (d, J ¼ 15.9 Hz, 1H).
4.3.3. 2-(4-Hydroxyphenyl)ethyl 6-O-(E)-3,4-dimethoxycinnamic
b-D-glucopyranoside 4
The crude mixture was purified by flash column chromatog-
raphy to give 43 mg (89% yield) as amorphous solid.
½
a D
ꢀ
ꢁ 28o ðc 0:030; MeOHÞ. 1H NMR (MeOD)
: 2.73 (t, J ¼ 7.2 Hz,
d
13C NMR (CDCl3)
d: 32.8, 61.4, 66.2, 67.9, 68.8, 70.1, 71.5, 73.8, 100.3,
2H), 3.11 (t, J ¼ 7.35 Hz, 1H), 3.20e3.30 (m, 2H), 3.34e3.48 (m, 1H),
3.62 (q, J ¼ 7.8 Hz, 1H), 3.74 (s, 3H), 3.77 (s, 3H), 3.77e3.88 (m, 1H),
4.22e4.26 (m, 2H), 4.40e4.44 (m, 1H), 6.32 (d, J ¼ 15.6 Hz, 1H), 6.53
(d, J ¼ 6.9 Hz, 2H), 6.84e6.98 (m 4H), 7.08 (s, 1H), 7.53 (d,
112.2, 115.0, 115.1, 125.8, 126.4, 127.4, 127.7, 127.9, 130.9, 131.7, 143.1,
154.6, 164.9. HRMS (ESIþ): m/z [MþH]þ calcd for C26H31O8:
471.2019; found: 471.2020.
J ¼ 15.3 Hz, 1H). 13C NMR (MeOD)
d: 36.6, 56.49, 56.55, 64.8, 72.0,
4.2.4. 2-(4-Allyloxyphenyl)ethyl 6-O-(E)-3,4-dimethoxycaffeoyl
b-
72.6, 75.1, 75.5, 78.1, 104.7, 111.4, 112.7, 116.2, 116.3, 124.3, 128.8,
130.6, 131.0, 146.8, 150.9, 153.0, 156.9, 169.0. HRMS (ESIþ): m/z
[MþH]þ calcd for C25H31O10: 491.1917; found: 491.1910.
D-glucopyranoside 9d
The crude product was purified by flash column chromatog-
raphy (EtOAc: DCM ¼ 3: 1) to give 108 mg (82% yield) as amorphous
solid. ½a D
ꢀ
ꢁ 34o ðc 0:023; CH2Cl2Þ. 1H NMR (CDCl3)
d
: 2.87 (t,
4.4. 2-(4-Hydroxyphenyl)ethyl 6-O-(E)-caffeoyl b-D-
glucopyranoside PhG 2
J ¼ 6.9 Hz, 2H), 3.43e3.71 (m, 5H þ OH), 3.90 (s, 6H), 4.06 (q,
J ¼ 7.8 Hz,1H), 4.32e4.34 (m, 2H), 4.38e4.44 (m, 2H), 4.57e4.60 (m,
1H), 5.27 (d, J ¼ 10.5 Hz, 1H), 5.39 (d, J ¼ 17.1 Hz, 1H), 5.96e6.01 (m,
1H), 6.37 (d, J ¼ 15.9 Hz, 1H), 6.82e6.88 (m, 3H), 7.05e7.14 (m, 4H),
A solution of TBAF (1M in THF, 0.4 mL) was added dropwise to an
ice-cold solution of glucoside 9b (73 mg, 0.1 mmol) in THF (6 mL).
The reaction mixture was stirred for 2 h, evaporated to dryness, and
then dissolved in H2O (5 mL). The aqueous solution was extracted
with EtOAc (5 mL x 5), the combined organic extracts were dried
over MgSO4, filtered and evaporated to dryness. The crude mixture
obtained was redissolved in MeOH: H2O (1.8 mL: 0.2 mL). Pd/C
(10 wt%, 50 mg) and p-TsOH (2 mg) were then added to the solution
which was stirred at 80 ꢂC for 8 h. The reaction mixture was then
filtered through a pad of Celite®, and evaporated to dryness. The
residue was purified by flash column chromatography
(CH2Cl2eMeOH ¼ 15: 1) to afford 31 mg (67% yield after two steps)
7.68 (d, J ¼ 15.9 Hz, 1H). 13C NMR (CDCl3)
d: 35.0, 55.88, 55.94, 63.4,
68.7, 70.0, 71.2, 73.6, 74.2, 76.0, 102.9, 109.7, 111.0, 114.7, 114.9, 117.6,
123.0, 127.1, 129.8, 130.3, 133.3, 145.9, 149.2, 151.3, 157.2, 168.0.
HRMS (ESIþ): m/z [MþH]þ calcd for C28H35O10: 531.2230; found:
531.2234.
4.3. General procedure for deprotection of allyl groups
To a solution of O-Allyl protected glucopyranoside 9a, c-
d (0.1 mmol) in MeOH: H2O (20:1 v:v, 10 mL) was added p-TsOH
(1.72 mg), Pd/C (100 mg of Pd/C per 0.1 mmol of allyl group). The
reaction mixture was heated at 80 ꢂC for ~12 h whereby TLC
analysis showed complete consumption of starting material. The
reaction mixture was filtered through a pad of Celite® and the fil-
trates were evaporated to dryness. The crude residue was purified
by column chromatography using pure EtOAc as eluent to give PhGs
1, 3e4.
as amorphous solid. ½a D
ꢀ
ꢁ 28o ðc 0:020; MeOHÞ. 1H NMR (MeOD)
d:
2.73 (t, J ¼ 7.5 Hz, 2H), 3.14 (t, J ¼ 8.1 Hz, 1H), 3.24e3.28 (m, 1H),
3.40e3.44 (m, 1H), 3.58e3.66 (m, 1H), 3.73e3.89 (m, 2H),
4.20e4.28 (m, 2H), 4.37e4.41 (m, 1H), 6.28 (d, J ¼ 15.6 Hz, 1H),
6.49e58 (m, 2H), 6.62 (d, J ¼ 8.4 Hz, 1H), 6.78e6.81 (m, 1H),
6.85e6.92 (m, 3H), 7.58 (d, J ¼ 15.6 Hz,1H). 13C NMR (MeOD)
d:38.0,
66.1, 73.3, 73.9, 76.6, 76.9, 79.4, 106.1, 116.4, 116.5, 117.6, 118.0, 124.6,

D.T. Khong, Z.M.A. Judeh / Carbohydrate Research 436 (2016) 50e53
(1997) 281e285;
53
129.2, 132.1, 132.4, 148.3, 148.7, 151.1, 158.3, 170.7. HRMS (ESIþ): m/z
[MþH]þ calcd for C23H27O10: 463.1604; found: 463.1609. The
spectra was in agreement with the literature values [5].
h) S.-Q. Zhang, Z.-J. Li, A.-B. Wang, M.-S. Cai, R. Feng, Carbohydr. Res. 308
(1998) 281e285;
i) F.-Y. Zhou, J. She, Y.-G. Wang, Carbohydr. Res. 341 (2006) 2469e2477.
[3] K.D. Thinh, Z.M.A. Judeh, Short synthesis of phenylpropanoid glycosides
calceolarioside-B and eutigoside-A, Tetrahedron Lett. (2016) (submitted).
[4] a) H. Shimomura, Y. Sashida, T. Adachi, Phytochemistry 26 (1987) 2363e2366;
b) K. Hanhineva, P. Soininen, M.J. Anttonen, H. Kokko, I. Rogachev, A. Aharoni,
Appendix A. Supplementary data
€
R. Laatikainen, S. Karenlampi, Phytochem. Anal. 20 (2009) 353e364.
Supplementary data related to this article can be found at http://
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