A novel domino-click approach for the synthesis of sugar based unsymmetrical bis-1,2,3-triazoles

Article abstract of DOI:10.1016/j.carres.2007.10.021

Aryl or sugar azides were treated with allenylmagnesium bromide to generate 1,5-disubstituted-butynyl-N-aryl or N-glycosyl-1,2,3-bistriazoles in a domino fashion. Upon Cu(I) catalyzed 1,3-dipolar cycloaddition with sugar azides, these compounds afford nov

Full text of DOI:10.1016/j.carres.2007.10.021

Available online at www.sciencedirect.com
Carbohydrate Research 343 (2008) 139–144
Note
A novel domino-click approach for the synthesis of sugar
based unsymmetrical bis-1,2,3-triazoles
Bhupinder Singh Arora, Syed Shafi, Swarn Singh, Tabasum Ismail
and H. M. Sampath Kumar*
Synthetic Chemistry Division, Indian Institute of Integrative Medicine, Canal Road, Jammu-Tawi 180 001, India
Received 18 August 2007; received in revised form 22 October 2007; accepted 25 October 2007
Available online 30 October 2007
Abstract—Aryl or sugar azides were treated with allenylmagnesium bromide to generate 1,5-disubstituted-butynyl-N-aryl or
N-glycosyl-1,2,3-bistriazoles in a domino fashion. Upon Cu(I) catalyzed 1,3-dipolar cycloaddition with sugar azides, these
compounds afford novel unsymmetrical bis-1,2,3-triazoles in high yields.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Bistriazoles; Domino addition; Click chemistry; 1,3-Dipolar cycloaddition
Copper-catalyzed click chemistry involving azides and
terminal acetylenes has, in recent years, been the most
widely used method for the synthesis of libraries of bio-
logically active molecular frameworks, particularly for
the regioselective synthesis of 1,2,3-triazoles.1 The func-
tional group tolerance of the Cu(I)-catalyzed procedure
is exemplified in the synthesis of triazole-based ana-
logues of the neuraminidase inhibitor zanamavir2 and
in the preparation of functionalized a-trifluoromethyl-
substituted azahistidine analogues.3 Similarly, by apply-
ing the click chemistry approach, N-glycosyl-triazoles
based simple glycoside and oligosaccharide mimetics,
glyco-macrocycles, glycopeptides, glyco-clusters, and
carbohydrate arrays have been developed.4 Triazole-
substituted sugars have been explored as potential
monovalent and multivalent galectin ligands5a,b and also
for the investigation of substrate recognition6 by the
inhibition of glycosyltransferases.7 Synthesis of oligo-
mers with 1,2,3-triazole subunits is an emerging area
in macromolecular chemistry and glycobiology with
examples on the preparation of N-glycoside neo-
glycotrimers,8 pseudo-oligosaccharides,9 triazole linked
disaccharides,10 1,2,3-triazolecarbohybrids,11 glycocon-
jugates,12 and neoglycoconjugates.13
Bistriazole based size-specific mRNA hairpin loop
binding agents have been developed to target mRNAs
coding for proteins,14 which could be a promising
approach in drug discovery. Recent studies have
disclosed a series of 1,2,3-bistriazoles as potent HIV-1 pro-
tease inhibitors for the inhibition of viral replication.15
Being inspired by the wide range of pharmacological activ-
ities and applications of N-glycosyl-triazoles and bistri-
azole systems with particular emphasis on their HIV-1
protease inhibitory potential, we envisaged the design
and synthesis of a focused library of 1,5-disubstituted-
1,2,3-triazoles and bis-1,2,3-triazoles with tunable hydro-
philic lipophilic balance (HLB). An automated docking
procedure revealed that these carbohydrate-based bistri-
azoles molecules can be promising non-peptide HIV pro-
tease inhibitors, based on their active site binding affinity.
A cascade reaction or tandem reaction or domino
reaction is a consecutive series of intramolecular organic
reactions, which often proceed via highly reactive inter-
mediates. It allows the organic synthesis of complex
multinuclear molecules from a single acyclic precursor
in an ecologically and economically favorable way. We
have earlier reported regiospecific domino addition of
aromatic, as well as aliphatic, azides with metalated
allenes, which results in the formation of 1,5-disubsti-
tuted triazoles in moderate to good yields.16 The same
strategy has been applied here for the synthesis of
*
Corresponding author. Tel.: +91 191 2572002x292; fax: +91 191
2569333; e-mail: hmskumar@yahoo.com
0008-6215/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2007.10.021

140
B. S. Arora et al. / Carbohydrate Research 343 (2008) 139–144
1,2,3-triazoles via addition of resonance-stabilized alle-
nylmagnesium bromide to sugar azides, which resulted
in the formation of novel 5-butynylated triazoles in
good yields. These molecules, upon Cu(I) catalyzed
1,3-dipolar cycloaddition with sugar azides, generated
novel unsymmetrical bis-1,2,3-triazoles (Scheme 1).
The formation of 1,5-disubstituted triazoles was
unequivocallyestablishedthroughthecharacteristicchem-
ical shift value of triazolyl proton (5-CH) at d = 7.70–
7.75 ppm in non-sugar cases in contrast to the appearance
of 4-CH signal at d = 8.30–8.38 in the case of 1,4-disubsti-
tuted triazoles.17 In the case of sugar based-triazoles, the
triazolyl proton (5-CH) was observed at d = 7.55 ppm.
A similar reaction involving azides and metalated
alkynes is known to give the 1,5-disubstituted triazole
regioisomers. Sharpless and co-workers reported the syn-
thesis of 1,5-disubstituted triazoles through the addition
of bromomagnesium acetylides to aryl azides18 and pro-
posed a mechanism beginning with the nucleophilic at-
tack of the acetylide on the terminal nitrogen atom of
the azide followed by spontaneous closure of the linear
intermediate to the 4-metallotriazole species. The reac-
tion of the bromomagnesium acetylides with azides gave,
after hydrolysis, preferentially the 1,5-disubstituted tria-
zoles; however, the yields were low. A plausible mecha-
nism for the formation of unusual product in case of
allenylmagnesium bromide can also be explained through
a similar pathway involving nucleophilic attack of alle-
nylmagnesium bromide species on the terminal nitrogen
of the azide followed by concomitant ring closure
through N–C heterocyclization driven by the excess of re-
agent. Subsequent attack by a second equivalent of alle-
nylmagnesium species, probably through Shlenk19 type
of equilibrium, generates the final product (Scheme 2).
Sugar based bistriazoles (Table 1), were designed
based on automatic docking studies, with an aim to
_
+
N N N
R'
N
_
Dry THF
rt
N
N
+
R
N
N
N N N
R
+
R'
N
N
N
R
CuSO4.5H2O
MgBr
Sod. Ascorbate
t BuOH : H2O (1:1)
N
1
3
4
2
(38-70%)
>90%
O
O
O
R
=
=
O
O
,
MeO
,
O2N
,
,
H3C
,
O
O
O
O
O
O
OAc
OAc
R'
O
O
AcO
,
,
NO2
OAc
Scheme 1. Domino-click approach to novel bistriazoles.
O
O
O
O
O
O
+
O
O
O
MgBr
N N
_
+
_
N
N
N N
N
N
N
O
O
O
O
O
O
+
1
BrMg
MgBr
2
N
O
N
O
N
O
O
O
MgBr
N
N
N
O
O
O
O
Br
O
Mg
Mg
Br
3
Scheme 2. Plausible mechanism for the synthesis of 1,5-substituted triazoles.

B. S. Arora et al. / Carbohydrate Research 343 (2008) 139–144
141
Table 1. Bistriazoles
Entry
Triazolea
3
Azide 1
Bistriazolea
4
Bistriazole yields (%)
N
N
N3
O
O
O
O
N
N
N
N
N
O
O
O
N
N
O
O
a
94
O
O
O
O
O
O
O
O
O
O
O
N
N
N
N
N
N
O
N
O
OAc
N3
OAc
OAc
N
N
O
O
O
b
c
d
96
92
93
OAc
AcO
O
AcO
OAc
O
OAc
O
O
O
O
O
N
N
N
N
N
O
N
N
N3
N
N
O
O
O
O
O
O
O
O
O
O
O
O
O
NO2
N
N
N
N
N
N
N
N3
N
N
O
O
O
NO2
O
O
O
O
O
O
O
N
N
N
N
N
O
N
O
N3
N
OAc
OAc
OAc
N
N
e
94
OAc
AcO
AcO
OAc
OAc
CH3
N
CH3
N
N3
O
O
O
N
N
N
N
N
O
O
O
N
N
O
O
f
92
94
O
O
CH3
N
CH3
N
N3
O
O
O
O
N
N
N
N
O
O
O
N
N
N
N
N
O
O
g
O
NO2
N
NO2
N
N
N
N
N
N
O
O
N3
OAc
OAc
OAc
OAc
N
h
95
AcO
AcO
OAc
OAc
NO2
N
NO2
N
N
N
N
N
N
N
O
O
N3
OAc
OAc
OAc
OAc
i
j
94
92
AcO
AcO
OAc
OAc
OMe
N
OMe
N
O
N3
N
N
N
OAc
OAc
N
N
O
N
OAc
OAc
N
AcO
AcO
OAc
OAc
a All products were characterized by IR, 1H NMR, 13C NMR, DEPT spectroscopy, and mass spectrometry.

142
B. S. Arora et al. / Carbohydrate Research 343 (2008) 139–144
screen them both in their protected form (as lipophilic
ligands) and as unprotected sugars (hydrophilic ligands)
against wild HIV-1 protease to evaluate their inhibitory
potential. The design of binuclear hybrid structures of
this type encompassing sugar units attached to both
the heterocyclic moieties, separated by a flexible two car-
bon methylene spacer, would possibly provide a ligand
capable of effective target binding with tunable hydro-
philic lipophilic balance. Thus, the combination of dom-
ino addition and click approach provides a unique
method for achieving structural diversity to generate no-
vel unsymmetrical bisheterocyclic molecular frame-
works, which may find utility in pharmaceutical and
material science research. Currently, efforts are under-
way to screen this library against wild type HIV-1 pro-
tease to establish their inhibitory potential.
ride is generally required to promote formation of the
Grignard reagent and a small grain of iodine is added
as indicator for the formation of reagent). The mixture
was stirred at rt for 30 min to give a cloudy light-green
solution. Then the galactose azide solution in dry THF
(Table 1, entry 1a) (0.5 g, 1.75 mmol) was added drop-
wise to the above generated allenylmagnesium bromide.
The reaction mixture was stirred at rt for 6 h. The reac-
tion mixture was quenched with saturated aqueous
ammonium chloride solution (10 mL) and diluted with
EtOAc (50 mL). The organic layer was separated and
the aqueous layer extracted with EtOAc (2 · 20 mL).
The combined organic layers were dried over anhydrous
sodium sulfate and evaporated under reduced pressure
to afford the crude product, which was subjected to col-
umn chromatography (basic alumina, elution; n-hex-
ane–EtOAc gradient) to afford the pure triazole (Table
1, entry 3a) as a white solid (0.19 g, 38%); mp 134–
136 ꢁC; IR (KBr, cmꢀ1): 2984.2, 2920.8, 2867.9,
2371.3, 1802.3, 1763.0, 1735.4, 1718.4, 1595.6, 1508.4,
1465.9, 1438.4, 1387.5, 1352.6, 1244.2, 1213.4, 1168.3,
1110.5, 1070.1, 999.9, 920.8, 886.3, 862.1, 753.9, 670.0,
In conclusion, we have developed an unprece-
dented, convenient strategy for the synthesis of novel,
biologically important unsymmetrical bis-1,2,3-triazoles
employing a domino reaction followed by the copper
catalyzed click protocol.
1
546.6 and 526.6; H NMR (200 MHz, CDCl3): d 1.27
1. Experimental
1.1. General
(s, 3H), 1.35 (s, 3H), 1.51 (s, 3H), 1.65 (s, 3H), 2.02
(t, 1H, J = 2.6 Hz), 2.51–2.59 (m, 2H), 2.95 (t, 2H,
J = 7.4 Hz), 4.18 (dd, 1H, J = 6.66, 1.2 Hz), 4.28–4.32
(m, 3H), 4.37–4.50 (m, 1H), 4.63 (dd, 1H, J = 5.4,
2.5 Hz), 5.45 (d, 1H, J = 4.9 Hz), 7.54 (s, 1H); 13C
NMR (500 MHz, CDCl3): d 19.3, 23.8, 25.8, 26.3,
27.3, 27.4, 49.1, 69.2, 71.2, 71.8, 72.2, 72.4, 83.6, 97.5,
110.5, 111.1, 133.4, 138.1; ESI-MS: 364.1 [M+1], 386.1
[M+Na]+. Anal. Calcd for C18H25N3O5: C, 59.49; H,
6.93; N, 11.56. Found: C, 59.54; H, 6.98, N, 11.52.
All commercially available reagents were used as re-
ceived. Air- and moisture-sensitive reactions were per-
formed under nitrogen atmosphere. The progress of all
reactions was monitored by TLC on a 2 · 5 cm pre-
coated silica gel 60 F254 plates of thickness 0.25 mm
(Merck). Melting points were determined on a Buchi
¨
capillary apparatus and are uncorrected. Optical rota-
tions were recorded using a Perkin–Elmer 241 polarim-
eter. IR spectra were recorded on Bruker Vector 22
instrument. NMR spectra were recorded on a Bruker
DPX 200 instrument in CDCl3 with (CH3)4Si as an
1.3. Preparation of bistriazole—Typical procedure
Galactose-butynyl triazole (Table 1, entry 3a) (0.020 g,
0.055 mmol) was stirred in tertiary butanol and water
(1:1 mixture, 5 mL). Copper sulfate (0.066 mmol) and
sodium ascorbate (0.28 mmol) were added to the reac-
tion mixture. After 15 min, galactose azide (Table 1, en-
try 1a) (0.0157 g, 0.055 mmol) was added to the above
mixture and the reaction mixture was allowed to stir
for 8 h. The mixture was diluted with water and EtOAc
was added. The organic layer was separated and the
aqueous layer was extracted with EtOAc (2 · 20 mL).
The combined organic layers were dried over anhydrous
sodium sulfate and evaporated under reduced pressure to
afford the crude product, which was precipitated using
n-hexane–EtOAc affording pure 1,5-disubstituted-butyn-
yl-N-glycosyl-1,2,3-bistriazole (Table 1, entry 4a) as a
light brown colored viscous mass (0.019 g, 94%).
1
internal standard for H NMR spectra and solvent sig-
nals as internal standard for 13C NMR spectra. 1H
NMR chemical shifts and coupling constants J are given
in ppm (relative to (CH3)4Si) and Hz, respectively.
Mass spectra were recorded on EIMS (Shimadzu)
instrument and mass-spectrometric (MS) data are
reported in m/z.
1.2. Preparation of 5-but-3-ynyl-1-(2,2,7,7-tetramethyl–
tetrahydro-bis[1,3]dioxolo[4,5-b;40,50-d]pyran-5-ylmethyl)-
1H-[1,2,3]triazole (Table 1, entry 3a); typical procedure
To a suspension of magnesium turnings (0.631 g,
26.31 mmol) in dried THF with mercury(II) chloride
(6 mg, 2% w/w of propargyl bromide) was added prop-
argyl bromide (2.35 mL of 80 wt%, solution in toluene,
26.31 mmol) in small portions while stirring the reaction
mixture at rt (Note: a catalytic amount of mercuric chlo-
1.3.1. Bistriazole (Table 1, entry 4a). Light brown col-
28
ored viscous compound; ½aꢁD ꢀ11.6 (c 0.0014, CH2Cl2);
IR (CHCl3, cmꢀ1): 2920.8, 2857.4, 2730.6, 2371.3,

B. S. Arora et al. / Carbohydrate Research 343 (2008) 139–144
143
1846.2, 1751.6, 1595.1, 1508.5, 1458.3, 1338.8, 1353.1,
1259.2, 1214.5, 1166.2, 1110.7, 1070.3, 1005.9, 919.3,
902.9, 856.0, 735.2, 647.3, 599.8 and 513.0; H NMR
(500 MHz, CDCl3): d 22.4, 24.0, 24.3, 24.8, 25.9,
26.0, 29.6, 48.0, 68.1, 70.3, 70.6, 71.2, 95.9, 109.1,
109.8, 123.0, 125.4, 127.8, 130.5, 130.6, 133.7; ESI-MS:
528.1 [M+1]. Anal. Calcd for C24H29N7O7: C,
54.64; H, 5.54; N, 18.59. Found: C, 54.68; H, 5.58; N,
18.63.
1
(200 MHz, CDCl3): d 1.27 (s, 3H), 1.29 (s, 3H), 1.35
(s, 3H), 1.36 (s, 3H), 1.38 (s, 3H), 1.42 (s, 3H), 1.48 (s,
3H), 1.50 (s, 3H), 2.97 (s, 4H), 4.16–4.64 (m, 12H),
5.43–5.51 (m, 2H), 7.27 (s, 1H), 7.40 (s, 1H); 13C
NMR (500 MHz, CDCl3): d 20.6, 22.7, 24.3, 24.4,
24.9, 24.9, 25.9, 26.0, 26.1, 29.7, 31.9, 47.7, 50.4, 67.2,
67.9, 70.2, 70.4, 70.7, 70.7, 71.0, 71.1, 96.1, 96.2, 109.0,
109.1, 109.7, 109.8, 122.5, 145.5; ESI-MS: 671.4
[M+Na]+. Anal. Calcd for C30H44N6O10: C, 55.55; H,
6.84; N, 12.95. Found: C, 55.58; H, 6.88; N, 12.92.
1.3.5. Bistriazole (Table 1, entry 4e). Light brown col-
28
ored viscous compound; ½aꢁD ꢀ17.57 (c 0.0057, CHCl3);
IR (CHCl3, cmꢀ1): 3419.3, 2925.2, 2854.0, 2360.8,
2340.9, 1753.4, 1652.5, 1558.5, 1518.6, 1431.2, 1369.9,
1324.6, 1225.8, 1094.9, 1040.4, 924.8, 823.9, 756.7 and
669.1; 1H NMR (200 MHz, CDCl3): d 1.25 (s, 3H),
2.03–2.08 (m, 9H), 2.45 (s, 3H), 3.02–3.09 (m, 4H),
3.97–4.32 (m, 3H), 5.22–5.42 (m, 3H), 5.82 (d, 1H,
J = 8.08 Hz), 7.27–7.32 (m, 4H), 7.46 (s, 1H), 7.56 (s,
1H); 13C NMR (500 MHz, CDCl3): d 18.5, 18.9, 19.1,
19.6, 21.5, 22.6, 59.9, 66.0, 66.6, 68.4, 71.0, 73.5, 74.1,
84.0, 117.9, 123.5, 124.2, 128.6, 129.2, 132.5, 138.3,
144.6, 167.4, 167.8, 168.3, 168.9; ESI-MS: 585.2
[M+1], 607.2 [M+Na]+. Anal. Calcd for C27H32N6O9:
C, 55.47; H, 5.52; N, 14.37. Found: C, 55.45; H, 5.57;
N, 14.34.
1.3.2. Bistriazole (Table 1, entry 4b). Light brown col-
28
ored viscous compound; ½aꢁD ꢀ18.8 (c 0.037, CHCl3);
IR (CHCl3, cmꢀ1): 3399.9, 2988.9, 2937.3, 2360.6,
2341.6, 2120.1, 1756.2, 1647.5, 1557.9, 1456.5, 1435.6,
1375.0, 1219.9, 1166.5, 1067.0, 1042.2, 1006.7, 920.4,
904.1, 857.1, 756.1, 668.8 and 600.5; 1H NMR
(200 MHz, CDCl3): d 1.27–1.50 (m, 12H), 1.85 (s, 3H),
2.01–2.09 (m, 9H), 3.12 (s, 4H), 4.12–4.48 (m 10H),
5.38–5.49 (m, 3H), 5.82 (d, 1H, J = 8.76 Hz), 7.29 (d,
1H, J = 6.03 Hz), 7.47 (s, 1H); 13C NMR (200 MHz,
CDCl3): d 20.5, 20.9, 21.1, 22.8, 24.5, 25.3, 26.4, 48.2,
61.9, 62.1, 68.1, 68.3, 68.5, 70.6, 70.8, 71.2, 71.6, 73.1,
75.4, 88.3, 96.5, 106.8, 109.6, 110.2, 120.3, 132.5,
137.4, 146.9, 169.3, 169.8, 170.3, 171.0; ESI-MS: 737.2
[M+1]. Anal. Calcd for C32H44N6O14: C, 52.17; H,
6.02; N, 11.41. Found: C, 52.22; H, 5.98; N, 11.38.
1.3.6. Bistriazole (Table 1, entry 4f). Light brown col-
28
ored viscous compound; ½aꢁD ꢀ20.00 (c 0.0085, CHCl3);
IR (CHCl3, cmꢀ1): 3422.9, 2924.1, 2853.4, 2361.4,
2340.2, 1752.6, 1654.8, 1612.1, 1598.7, 1526.6, 1501.3,
1458.9, 1383.6, 1345.1, 1253.9, 1214.0, 1067.9, 1048.0,
1
1019.5, 920.3, 903.5, 856.2, 753.6, 691.6 and 669.7; H
NMR (200 MHz, CDCl3): d 1.27 (s, 3H), 1.34 (s, 6H),
1.46 (s, 3H), 2.42 (s, 3H), 2.99–3.08 (m, 4H), 4.14–4.63
(m, 6H), 5.48 (d, 1H, J = 4.85 Hz), 7.26–7.42 (m, 6H);
13C NMR (500 MHz, CDCl3): d 20.7, 21.2, 22.2, 23.1,
23.9, 24.4, 24.9, 25.4, 25.5, 26.0, 31.1, 50.1, 66.7, 69.7,
69.8, 70.2, 70.7, 95.7, 108.6, 109.4, 124.6, 124.7, 129.7,
139.4; ESI-MS: 519.2 [M+Na]+. Anal. Calcd for
C25H32N6O5: C, 60.47; H, 6.50; N, 16.92. Found: C,
60.52; H, 6.48; N, 16.95.
1.3.3. Bistriazole (Table 1, entry 4c). Light yellow col-
28
ored viscous compound; ½aꢁD ꢀ4.8 (c 0.0028, CHCl3);
IR (CHCl3, cmꢀ1): 2920.7, 2339.6, 2107.1, 1720.7,
1630.9, 1590.0, 1509.4, 1382.6, 1350.9, 1282.3, 1097.3,
1
1039.2, 743.4 and 601.9; H NMR (200 MHz, CDCl3):
d 1.26–1.59 (m, 22H), 3.13 (s, 2H), 3.50 (s, 2H), 3.74
(d, 2H, J = 5.62 Hz), 4.08 (s, 1H), 4.22–4.64 (m, 8H),
5.45 (d, 1H, J = 4.8 Hz), 7.37 (d, 2H, J = 3.46 Hz);
13C NMR (200 MHz, CDCl3): d 21.7, 22.7, 22.9, 23.5,
24.1, 24.4, 24.7, 24.8, 25.4, 26.4, 30.1, 35.1, 36.9, 48.2,
52.8, 65.6, 67.2, 69.7, 70.2, 73.5, 88.4, 94.2, 106.1,
122.9, 132.3; ESI-MS: 561.3 [M+1], 583.3 [M+Na]+.
Anal. Calcd for C27H40N6O7: C, 57.84; H, 7.19; N,
14.99. Found: C, 57.86; H, 7.24; N, 14.96.
1.3.7. Bistriazole (Table 1, entry 4g). Light yellow col-
28
ored viscous compound; ½aꢁD ꢀ22.86 (c 0.0028, CHCl3);
IR (CHCl3, cmꢀ1): 3378.4, 2986.6, 2925.8, 2955.2,
2360.1, 1733.8, 1653.1, 1518.3, 1456.4, 1383.2, 1307.3,
1255.1, 1212.5, 1166.0, 1111.1, 1068.8, 1005.9, 978.1,
1
919.5, 902.8, 858.0, 822.3, 755.7 and 667.6; H NMR
1.3.4. Bistriazole (Table 1, entry 4d). Light brown col-
(200 MHz, CDCl3): d 1.24 (s, 3H), 1.29 (s, 3H), 1.36
(s, 3H), 1.48 (s, 3H), 3.03–3.24 (m, 4H), 4.12–4.20 (m,
2H), 4.31–4.42 (m, 2H), 4.54–4.66 (m, 2H), 5.49 (d,
1H, J = 4.9 Hz), 7.44 (s, 1H), 7.63–7.71 (m, 3H), 8.42
(d, 2H, J = 8.9 Hz); 13C NMR (500 MHz, CDCl3): d
23.6, 24.4, 24.9, 25.9, 26.0, 29.7, 50.6, 67.2, 70.2, 70.7,
71.2, 96.2, 109.1, 109.9, 122.6, 125.1, 125.7, 133.3,
137.3, 141.2, 144.6, 147.9; ESI-MS: 528.2 [M+1]. Anal.
Calcd for C24H29N7O7: C, 54.64; H, 5.54; N, 18.59.
Found: C, 54.67; H, 5.58; N, 18.58.
28
ored viscous compound; ½aꢁD ꢀ20.74 (c 0.0054, CHCl3);
IR (CHCl3, cmꢀ1): 3385.7, 3142.8, 2987.7, 2926.2,
2854.3, 2630.3, 2341.2, 1588.3, 1538.1, 1455.9, 1383.8,
1357.9, 1305.8, 1255.4, 1212.7, 1165.9, 1110.8, 1068.4,
1044.5, 1006.1, 919.5, 902.7, 883.9, 853.2, 749.6 and
668.9; 1H NMR (200 MHz, CDCl3): d 1.20 (s, 3H),
1.25 (s, 3H), 1.35 (s, 3H), 1.51 (s, 3H), 3.23 (s, 4H),
4.23–4.66 (m, 6H), 5.42 (d, 1H, J = 4.83 Hz), 7.49–
7.77 (m, 5H), 8.06 (d, 1H, J = 7.9 Hz); 13C NMR

144
B. S. Arora et al. / Carbohydrate Research 343 (2008) 139–144
1.3.8. Bistriazole (Table 1, entry 4h). Light brown col-
C26H30N6O9: C, 54.73; H, 5.29; N, 14.73. Found: C,
54.78; H, 5.31; N, 14.69.
28
ored viscous compound; ½aꢁD ꢀ13.33 (c 0.0037, CHCl3);
IR (CHCl3, cmꢀ1): 3417.2, 2922.5, 2852.1, 2360.1,
2341.1, 2117.7, 1752.7, 1612.6, 1598.7, 1526.5, 1501.9,
1429.9, 1367.1, 1345.6, 1224.8, 1063.9, 1040.8, 978.7,
Acknowledgments
1
924.9, 856.1, 753.4, 691.9, 669.5 and 601.6; H NMR
(200 MHz, CDCl3): d 1.85 (s, 3H), 2.03–2.08 (m, 9H),
3.05–3.25 (m, 4H), 3.96–4.03 (m, 1H), 4.10–4.17 (m,
1H), 4.27–4.33 (m, 1H), 5.21–5.42 (m, 3H), 5.8 (d, 1H,
J = 8.9 Hz), 7.51 (s, 1H), 7.63 (s, 1H), 7.71 (d, 2H,
J = 8.9 Hz), 8.44 (d, 2H, J = 8.9 Hz); 13C NMR
(500 MHz, CDCl3): d 20.2, 20.5, 20.6, 20.7, 23.3, 24.2,
61.5, 67.6, 70.1, 72.5, 75.2, 85.7, 119.6, 125.2, 125.5,
125.8, 133.3, 136.5, 141.6, 145.7, 147.6, 169.2, 169.7,
170.2; ESI-MS: 638.1 [M+Na]+. Anal. Calcd for
C26H29N7O11: C, 50.73; H, 4.75; N, 15.93. Found: C,
50.76; H, 4.77; N, 15.95.
The authors thank CSIR and UGC, New Delhi, for the
award of fellowships to graduate students.
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28
ored viscous compound; ½aꢁD ꢀ12.07 (c 0.0027, CHCl3);
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2119.7, 1752.6, 1650.7, 1612.2, 1517.3, 1436.2, 1372.0,
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28
ored solid; mp 109–111 ꢁC; ½aꢁD ꢀ16.8 (c 0.0034,
´
13. Perez-Balderas, F.; Ortega-Munoz, M.; Morales-Sanfru-
˜
CH2Cl2); IR (KBr, cmꢀ1): 2920.8, 2846.8, 2360.8,
1752.5, 1630.9, 1596.7, 1498.9, 1456.6, 1377.4, 1229.4,
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2.02–2.08 (m, 6H), 2.17 (s, 3H), 3.08–3.15 (m, 4H),
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7.42–7.57 (m, 7H); 13C NMR (500 MHz, CDCl3): d
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69.5, 72.6, 75.2, 85.7, 119.4, 125.3, 129.6, 129.7, 132.6,
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571.2 [M+1], 593.2 [M+Na]+. Anal. Calcd for
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