5′-Uridyl derivatives of N-glycosyl allophanic acid and biuret

Article abstract of DOI:10.1016/j.carres.2009.08.038

(2′,3′-O-Isopropylidene-5′-uridyl) 4-(2,3,4,6-tetra-O-acetyl-β-d-glycopyranosyl)allophanates were obtained in the reactions of 2′,3′-O-isopropylidene-uridine and O-peracetylated β-d-gluco-, galacto- and xylopyranosylamines, and OCNCOCl. 2,3,4,6-Tetra-O-acetyl-β-d-glucopyranosyl isocyanate and N-(2′,3′-O-isopropylidene-5′-uridyl)urea gave 1-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-5-(2′,3′-O-isopropylidene-5′-uridyl)biuret. Deprotection of the β-d-gluco configured allophanate and biuret was carried out by standard methods.

Full text of DOI:10.1016/j.carres.2009.08.038

Carbohydrate Research 345 (2010) 163–167
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Note
50-Uridyl derivatives of N-glycosyl allophanic acid and biuret
*
Marietta Tóth, László Somsák
Department of Organic Chemistry, University of Debrecen, POB 20, H-4010 Debrecen, Hungary
a r t i c l e i n f o
a b s t r a c t
(20,30-O-Isopropylidene-50-uridyl) 4-(2,3,4,6-tetra-O-acetyl-b-
D
-glycopyranosyl)allophanates were obtained
-gluco-, galacto- and xylo
-glucopyranosyl isocyanate and N-(20,30-O-
-glucopyranosyl)-5-(20,30-O-isopropyli-
Article history:
Received 30 July 2009
Received in revised form 24 August 2009
Accepted 28 August 2009
Available online 2 September 2009
in the reactions of 20,30-O-isopropylidene-uridine and O-peracetylated b-
D
pyranosylamines, and OCNCOCl. 2,3,4,6-Tetra-O-acetyl-b-
D
isopropylidene-50-uridyl)urea gave 1-(2,3,4,6-tetra-O-acetyl-b-
D
dene-50-uridyl)biuret. Deprotection of the b-
D
-gluco configured allophanate and biuret was carried out
by standard methods.
Keywords:
Ó 2009 Elsevier Ltd. All rights reserved.
N-Glycosyl-allophanate
N-Glycosyl-biuret
50-Uridyl derivative
Nucleoside diphosphate (NDP) sugars (Chart 1) are natural sub-
strates for Leloir type glycosyltransferases.1 A large variety of
molecular structures have been designed, synthesized and tested
as inhibitors of these enzymes,2–4 fuelled by the need of suitable
means to elucidate the mechanism of action of such catalysts.5 Effi-
cient inhibitors also have the potential to be further developed to
drug candidates.6 Because of some similarities between allophanic
acid and biuret derivatives and the pyrophosphate moiety (cf. tar-
get compounds in Chart 1), we have carried out some reactions to
glycosylamines 712 and 813,14 to give 70% and 68% yields of the cor-
responding allophanates 10 and 11, respectively.
For the preparation of biurets an analogous route was envisaged
by using 50-amino-50-deoxy-uridine derivative 5 and glycosylam-
ines 6–8 with OCNCOCl. To this end, 1 was transformed into azide
4,15,16 via a 7:3 mixture of tosylate 216 and chloride 317 obtained on
tosylation of 1, according to published protocols. For the reduction
of 4 to 5, contradictory reports can be found in the literature:
hydrogenation15 with Pd–C in CH3OH was reported to be succes-
study the possibility of attaching b-
D-glycosyl residues and uridine
via these linkers. The experiences of these model studies can then
be applied to prepare similar
NDP sugars.
a-D-glycosyl derivatives to mimic
O
Gly
OH OH
HO
A simpleway to assemble allophanates is the reaction of the com-
mercially available bielectrophilic reagent chlorocarbonyl isocya-
nate7 (OCNCOCl) with the corresponding nucleophiles. Thus, the
O
O
O
Nucleobase
O
P
P
O
O
reaction of isopropylidene uridine 18 and b-
D-glucopyranosylamine
HO OH
69 with OCNCOCl was investigated first (Scheme 1 and Table 1). The
expectedly less nucleophilic alcohol 1 was reacted with OCNCOCl in
the first step in order to possibly avoid the formation of symmetric
products10 like 12. However, under slow addition of 1 to OCNCOCl
in THF (Table 1, entries 1 and 2) followed by 6, this was not achieved,
and in addition to the desired allophanate 9, iminodicarboxylate 12
and carbamate 1411 were also obtained. Appearance of 14 could be
due to the presence of traces of water in the reaction mixture. Addi-
tion of OCNCOCl in one portion to 1 and keeping the mixture at a low
temperature (Table 1, entry 3) allowed the avoidance of the forma-
tion of by-products 12 and 14 in significant amounts, and 9 was iso-
latedin 81%yield. Underthesameconditions 1 wasalso reactedwith
NDP sugars
H
H
O
Gly
N
N
X
U
O
OH
O
O
HO OH
O
NH
O
U =
X = O, NH
N
Target compounds
* Corresponding author. Tel.: +36 52512900x22348; fax: +36 52453836.
E-mail address: somsak@tigris.unideb.hu (L. Somsák).
Chart 1.
0008-6215/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2009.08.038

164
M. Tóth, L. Somsák / Carbohydrate Research 345 (2010) 163–167
R2
R1
6, 9 R = R3 = OAc,
1 = CH2OAc, R2 = H (81%)
7, 10 R = R2 = OAc,
R1 = CH2OAc, R3 = H (70%)
8, 11 R = R3 = OAc,
H
N
H
R3
O
X
N
O
1. a from 1
U
U
R
R
O
O
R
2. b R2
O
O
O
R1
R3
O
O O
NH2
O O
R
9-11
+
R
R
1 = R2 = H (68%)
6-8
O O
1 X = OH
2 X = OTs
3 X = Cl
O
O
c from 9
U
O
N
H
O
U
O
4 X = N3
5 X = NH2
O
NH
12
U =
O O
N
d from 4
+
O
H
OH
O
H2N
O
H2N
N
U
U
H
H
O
O
HO
HO
N
N
X
U
O
O
O
OH
O
O
O O
O O
14
13 (70%)
HO OH
15 X = O (70%)
16 X = NH (60%)
OAc
O
f
e
AcO
AcO
NCO
OAc
17
OAc
O
AcO
NH
NH
AcO
OAc
O
OAc
O
OAc
H
H
H
N
H
H
N
O
AcO
AcO
AcO
N
N
N
U
U
OAc
O
AcO
O
O
+
+
OAc
OAc
AcO
AcO
O
O
O
OAc
O O
O O
20
18 (63%)
19
Scheme 1. Reagents and conditions: (a) THF soln of 1 equiv of OCNCOCl added in one portion to 1 in THF, ꢁ26 °C, 1 d; (b) THF soln of 1 equiv of 6–8 and 1 equiv of Et3N added
dropwise to the above-mentioned soln, 0 °C to rt; (c) AcCl, CH3OH, rt; (d) PPh3, NH3, CO2, EtOAc, rt; (e) 17, toluene, reflux, 1 d; (f) (1) cat. NaOCH3, CH3OH, rt, (2) CF3COOH
(90%), rt.
Table 1
Reactions of 20,30-isopropylidene uridine (1) and 2,3,4,6-tetra-O-acetyl-b-D-glucopyranosylamine (6) with OCNCOCl
Entry
Reaction conditionsa
Isolated yield (%)
9
12
14
1
2
3
1. THF soln of 1 added dropwise to OCNCOCl in THF, ꢁ20 to 0 °C, 2 h
2. THF soln of 6 and Et3N added dropwise to the above-mentioned soln, 0 °C to rt
1. THF soln of 1 added dropwise to OCNCOCl in THF, ꢁ26 °C, 1 d
45
10
23
10
81
24
14
2. THF soln of 6 and Et3N added dropwise to the above-mentioned soln, 0 °C
1. THF soln of OCNCOCl added in one portion to 1 in THF, ꢁ26 °C, 1 d
2. THF soln of 6 and Et3N added dropwise to the above-mentioned soln, 0 °C to rt
b
b
a
Two-step, one-pot procedures with added molecular sieves under N2 atm: step 1 is the reaction of 1 and OCNCOCl, step 2 is the reaction of the intermediate formed in
step 1 with 6.
b
Observed on TLC, but not isolated.
ful;16,18,19 however, in another report 4 was found to be ‘unreactive
to all reduction conditions tested, including Staudinger condi-
tions.20 In our experiments no discrete product could be isolated
under catalytic hydrogenation over Pd–C, and in Ph3P or (CH3)3P-
mediated reductions. Therefore, we have investigated another pos-
sibility to produce the desired biuret by reaction of 50-uridyl urea
13 and crystalline glucosyl isocyanate21 17. Urea 13 was prepared
from 4 by applying Staudinger-type conditions22 (PPh3, NH3, CO2).
In this way, 13 could be obtained in 70% yield, contrary to experi-
ments where commercial NH4OCONH2 was used in the presence of
either Ph3P or (CH3)3P which gave only ꢀ50% of 13. Equimolar
amounts of compounds 13 and 17 showed no reaction in EtOAc
at rt over one day. Boiling the mixture for two days resulted in
34% conversion of 13, and the expected biuret 18 was isolated in
81% yield together with urea 19 (11%). The conversion of 13 was
complete in one day in the presence of 2.2 equiv of 17 in boiling
toluene, and 18 (63%) and some 19 (4%) were isolated. The forma-
tion of 19 can be due to the presence of traces of water in the
reaction mixtures. In each of the above-mentioned reactions,
bis-glucopyranosyl urea 20 was also isolated in various amounts
that could be attributed to some traces of water present in the
mixtures.23
Deprotected derivatives were obtained by treating allophanate
9 with AcCl in CH3OH to give 15 (70%), and biuret 18 with a cata-
lytic amount of NaOCH3 in CH3OH in the first step and CF3COOH
(90%) in the second step to furnish 16 (60%).

M. Tóth, L. Somsák / Carbohydrate Research 345 (2010) 163–167
165
With the availability of 50-uridyl-carbamate 1411,24 and the pro-
(C-5-U, C-6-Glc), 27.0, 25.4 (CH3-isopropylidene), 20.6, 20.4
(COCH3); Anal. Calcd for C28H36N4O17 (700.62): C, 48.00; H, 5.18;
N, 8.00. Found: C, 48.09; H, 5.27; N, 7.93.
pensity of carbamates to react with isocyanates25, an alternative
pathway opens for allophanates of types 9–11. Since
a-D-glyco-
syl-isocyanates23 can be synthesized in a stereoselective manner,
the reactions of urea 13 and carbamate 14 can expectedly be ex-
tended to those isocyanate derivatives as well to obtain mimics
of UDP sugars.
1.4. (20,30-O-Isopropylidene-50-uridyl) 4-(2,3,4,6-tetra-O-acetyl-
b-D
-galactopyranosyl)allophanate (10)
Prepared by the general procedure (Section 1.2) from 20,30-O-iso-
propylidene-uridine 1 (100 mg, 0.35 mmol) to give 171 mg (70%) of
1. Experimental
10 as a colourless syrup. Rf = 0.36 (10:1 EtOAc-hexane); [a D
]
ꢁ7 (c
0.9, CHCl3); 1H NMR (DMSO-d6): d (ppm) 11.41 (br s, 1H, NH), 10.45
(br s, 1H, NH), 8.21 (d, 1H, J1-Gal, NH = 9.6 Hz, NH), 7.65 (d, 1H,
J = 8.1 Hz, CH-uracyl), 5.80 (d, 1H, J1,2-U = 2.3 Hz, H-1-U), 5.59 (d, 1H,
J = 8.1 Hz, CH-uracyl), 5.34 (dd, 1H, J3,4-Gal = 3.5 Hz, H-3-Gal), 5.33
(pseudo t, 1H, J1,2 = 10.0 Hz, H-1-Gal), 5.28 (pseudo d, 1H, H-4-Gal),
5.07 (dd, 1H, J2,3-U = 6.3 Hz, H-2-U), 4.98 (pseudo t, 1H, J2,3-Gal = 9.8 Hz,
1.1. General methods
Optical rotations were determined with a Perkin–Elmer 241
polarimeter at rt. NMR spectra were recorded with Bruker 360
(360/90 MHz for 1H/13C) or Avance DRX 500 (500/125 MHz for
1H/13C) spectrometers. Chemical shifts are referenced to internal
(CH3)4Si (1H), or to the residual solvent signals (13C). 1H NMR
assignments were established on the basis of gradient-enhanced
DQF-COSY spectra.26 Proton chemical shifts and scalar coupling
constants were extracted from the resolution-enhanced 1D proton
spectra. COSY spectra were recorded with 512 ꢂ 2 k data points,
spectral widths 4000 Hz, number of transients 4 and recycle delay
of 1.8 s. TLC was performed on DC-Alurolle Kieselgel 60 F254
(Merck), and the plates were visualized under UV light and by gen-
tle heating. For column chromatography Kieselgel 60 (Merck, parti-
cle size 0.063–0.200 mm) was used. Flasks were flame-dried before
performing the reactions. Organic solutions were dried over anhy-
drous MgSO4 and concentrated under diminished pressure at 40–
50 °C (water bath). OCNCOCl was purchased from Sigma–Aldrich.
H-2-Gal), 4.80 (dd, 1H, J = 2.8 Hz, H-3-U), 4.34–4.25 (m, 4H, H-4-U,
3,4-U
H-5a-U, H-5b-U, H-5-Gal), 4.02 (dd, 1H, J5,6a-Gal = 6.2, J6a,6b-
Gal = 11.3 Hz, H-6a-Gal), 3.98 (dd, 1H, J5,6b-Gal = 6.8 Hz, H-6b-Gal),
2.13, 2.01, 1.99, 1.93 (4br s, 12H, 4 ꢂ COCH3), 1.49, 1.30 (2br s, 6H,
2 ꢂ CH3-isopropylidene); 13C NMR (CDCl3): d (ppm) 170.5, 170.3,
170.1, 169.8 (COCH3), 163.7, 150.6 (2 CO-uracyl), 153.8, 153.4 (2
NHCO), 142.4, 102.3 (2 CH-uracyl), 114.1 (C-isopropylidene), 95.8,
85.0, 84.7, 81.6, 79.0, 71.9, 70.9, 67.7, 67.1 (C-1-U to C-4-U, C-1-Glc
to C-5 Glc), 65.7, 61.1 (C-5-U, C-6-Glc), 27.0, 25.4 (CH3-isopropyli-
dene), 20.6, 20.5, 20.4 (COCH3); Anal. Calcd for C28H36N4O17
(700.62): C, 48.00; H, 5.18; N, 8.00. Found: C, 48.05; H, 5.24; N, 7.96.
1.5. (20,30-O-Isopropylidene-50-uridyl) 4-(2,3,4-tri-O-acetyl-b-
D-
xylopyranosyl)allophanate (11)
1.2. General procedure for the synthesis of (20,30-O-isopropylidene-
Prepared by the general procedure (Section 1.2) from 20,30-O-
isopropylidene-uridine 1 (100 mg, 0.35 mmol) to give 150 mg
(68%) of 11 as a colourless syrup. Rf = 0.25 (5:1 EtOAc-hexane);
50-uridyl) 4-(2,3,4,6-tetra-O-b-
D-glycopyranosyl)allophanates (9–11)
20,30-O-Isopropylidene-uridine8 (1, 100 mg, 0.35 mmol) was dis-
solved in dry THF (2 mL) under N2 atm and cooled to ꢁ26 °C. Some
freshly heated molecular sieves were added and after ꢀ5 min stir-
[a
]
D
ꢁ17 (c 0.9, CHCl3); 1H NMR (DMSO-d6): d (ppm) 8.22 (d, 1H,
J1-Xyl, NH = 9.4 Hz, NH), 7.64 (d, 1H, J = 8.1 Hz, CH-uracyl), 5.79 (d,
1H, J1,2-U = 2.5 Hz, H-1-U), 5.58 (d, 1H, J = 8.0 Hz, CH-uracyl), 5.31
(pseudo t, 1H, J3,4-Xyl = 9.1 Hz, H-3-Xyl), 5.21 (pseudo t, 1H, J1,2-
Xyl = 9.2 Hz, H-1-Xyl), 5.06 (dd, 1H, J2,3-U = 6.3 Hz, H-2-U), 4.91
(pseudo t, 1H, J2,3-Xyl = 9.0 Hz, H-2-Xyl), 4.85 (ddd, 1H, J4,5b-
Xyl = 9.7 Hz, H-4-Xyl), 4.79 (dd, 1H, J3,4-U = 3.2 Hz, H-3-U), 4.32
(dd, 1H, J4,5a-U = 2.7, H-5a-U), 4.28 (ddd, 1H, J4,5b-U = 5.3 Hz, H-4-
U), 4.25 (dd, J5a,5b-U = 10.9 Hz, H-5-Ub), 3.89 (dd, 1H, J4,5a-
Xyl = 5.3 Hz, H-5a-Xyl), 3.56 (pseudo t, J5a,5b-Xyl = 11.3 Hz, H-5b-
Xyl), 1.99, 1.98, 1.97 (3br s, 9H, 4 ꢂ COCH3), 1.48, 1.29 (2br s, 6H,
2 ꢂ CH3-isopropylidene); 13C NMR (CDCl3): d (ppm) 170.3, 169.8,
169.7 (COCH3), 163.9, 150.5 (2 CO-uracyl), 153.8, 153.3 (2 NHCO),
142.5, 102.1 (2 CH-uracyl), 114.0 (C-isopropylidene), 95.9, 85.3,
84.7, 81.5, 78.9, 71.8, 70.0, 68.7 (C-1-U to C-4-U, C-1-Gal to C-5-
Gal), 65.8, 63.8 (C-5-U, C-6-Gal), 27.0, 25.4 (CH3-isopropylidene),
20.6, 20.5 (COCH3); Anal. Calcd for C25H32N4O15 (628.54): C,
47.77; H, 5.13; N, 8.91. Found: C, 47.81; H, 5.19; N, 8.99.
ring OCNCOCl (28 lL, 0.35 mmol) was added in one portion. The
reaction mixture was kept at ꢁ26 °C for a day. Then a solution of
O-peracetylated b- -glycopyranosylamine (6 or or 8,
0.35 mmol) and Et3N (49 L, 0.35 mmol) in dry THF (2 mL) was
a
D
7
l
added dropwise at 0 °C. The reaction mixture was allowed to warm
to rt. When the reaction was complete (TLC 10:1 EtOAc-hexane),
the mixture was concentrated under reduced pressure and the res-
idue was purified by column chromatography (5:1 EtOAc-hexane).
1.3. (20,30-O-Isopropylidene-50-uridyl) 4-(2,3,4,6-tetra-O-acetyl-
b-
D-glucopyranosyl)allophanate (9)
Prepared by the general procedure (Section 1.2) from 20,30-O-
isopropylidene-uridine 1 (100 mg, 0.35 mmol) to give 200 mg
(81%) of 9 as a colourless syrup. Rf = 0.32 (15:1 EtOAc-hexane);
[
a]
D
ꢁ41 (c 1.0, CH2Cl2); 1H NMR (DMSO-d6): d (ppm) 11.42 (br
1.6. O,O0-Bis-(20,30-O-isopropylidene-50-uridyl) iminodicarboxylate
(12)
s, 1H, NH), 10.46 (br s, 1H, NH), 8.20 (d, 1H, J1-Glc, NH = 9.5 Hz,
NH), 7.65 (d, 1H, J = 8.3 Hz, CH-uracyl), 5.80 (d, 1H, J1,2-U = 2.3 Hz,
H-1-U), 5.59 (d, 1H, J = 8.3 Hz, CH-uracyl), 5.42 (pseudo t, 1H, J3,4-
Glc = 9.6 Hz, H-3-Glc), 5.38 (pseudo t, 1H, J1,2-Glc = 9.7 Hz, H-1-Glc),
5.07 (dd, 1H, J2,3-U = 6.3 Hz, H-2-U), 4.93 (pseudo t, 2H, J2,3-
Glc = 9.5 Hz, H-2-Glc, H-4-Glc), 4.79 (dd, 1H, J3,4-U = 2.2 Hz, H-3-
U), 4.35–4.23 (m, 3H, H-4-U, H-5a-U, H-5b-U), 4.16–3.92 (m, 3H,
H-5-Glc, H-6a-Glc, H-6b-Glc), 2.00, 1.99, 1.98, 1.95 (4br s, 12H,
4 ꢂ COCH3), 1.48, 1.29 (2br s, 6H, 2 ꢂ CH3-isopropylidene); 13C
NMR (CDCl3): d (ppm) 170.7, 170.2, 169.8, 169.3 (COCH3), 163.5,
151.1 (2 CO-uracyl), 153.1, 153.0 (2 NHCO), 143.8, 102.4 (2 CH-
uracyl), 113.9 (C-isopropylidene), 97.2, 87.0, 84.7, 82.1, 78.6,
73.1, 70.0, 68.0 (C-1-U to C-4-U, C-1-Glc to C-5-Glc), 66.4, 61.7
Prepared by the general procedure (Section 1.2). Colourless syr-
up. Rf = 0.12 (15:1 EtOAc-hexane); [
a
]
D ꢁ36 (c 1.1, CHCl3); 1H NMR
(CDCl3): d (ppm) 9.93 (br s, 2H, 2 ꢂ NH-uracyl), 8.59 (br s,
1H,OOCNHCOO), 7.44 (d, 2H, J = 8.0 Hz, 2 ꢂ CH-uracyl), 5.80 (d,
2H, J = 8.0 Hz, 2 ꢂ CH-uracyl), 5.70 (d, 2H, J1,2 = 1.9 Hz, 2 ꢂ H-1),
5.13 (dd, 2H, J2,3 = 6.5 Hz, 2 ꢂ H-2), 4.92 (dd, 2H, J3,4 = 3.4 Hz,
2 ꢂ H-3), 4.52–4.36 (m, 6H, 2 ꢂ H-4, 2 ꢂ H-5, 2 ꢂ H-50), 1.59, 1.38
(2br s, 12H, 4 ꢂ CH3); 13C NMR (CDCl3): d (ppm) 163.9, 150.3 (2
CO-uracyl), 151.0 (OOCNHCOO), 142.8, 102.5 (2 CH-uracyl), 114.5
(C-isopropylidene), 94.8 (C-1), 84.7, 84.4, 80.6 (C-2, C-3, C-4),

166
M. Tóth, L. Somsák / Carbohydrate Research 345 (2010) 163–167
65.3 (C-5), 27.1, 25.3 (CH3); Anal. Calcd for C26H31N5O14 (637.55):
C, 48.98; H, 4.90; N, 10.98. Found: C, 49.05; H, 4.97; N, 11.02.
When the reaction was complete (TLC, 7:3 CHCl3-CH3OH), the solu-
tion was neutralized with a cation exchange resin Amberlyst 15 (H+
form). Filtration and removal of the solvent resulted in 76 mg crude
product, which was dissolved in 0.5 mL TFA/water (9:1) and stirred
at rt. When the reaction was complete (TLC, 1:2 CHCl3-CH3OH), the
solution was diluted with water and the solvent was evaporated un-
der reduced pressure. The residue was purified by column chroma-
tography (1:2 CHCl3-CH3OH) to yield 16 as a colourless oil (42 mg,
1.7. N-(20,30-O-Isopropylidene-50-uridyl)urea (13)
Gaseous NH3 (dried with KOH) and CO2 (dried with CaCl2) were
bubbled through dry EtOAc (1.5 mL) for 15 min; ammonium carba-
mate was formed as a white solid. Then a solution of 50-azido-50-
deoxy-20,30-O-isopropylidene-uridine16 (4, 100 mg, 0.32 mmol) in
60%). Rf = 0.37 (1:2 CHCl3-CH3OH); [a]
D +24 (c 0.3, DMSO); 1H NMR
dry EtOAc (1 mL) followed by
a
solution of Ph3P (95 mg,
(D2O); d (ppm) 7.66 (d, 1H, J = 7.9 Hz), 5.87 (d, 1H, J = 7.9 Hz), 5.81
(d, 1H, J = 3.5 Hz), 4.91 (d, 1H, J = 9.5 Hz), 4.37 (pseudo t, 1H,
J = 3.8 Hz, 4.2 Hz), 4.18–4.08 (m, 2H), 3.88 (d, 1H, J = 10.7 Hz), 3.72
(dd, 1H, J = 5.6 Hz, 11.8 Hz), 3.68–3.39 (m, 6H); 13C NMR (D2O): d
(ppm) 166.8, 156.5, 152.1 (2 CO-uracyl, 2 NHCO), 142.8, 102.9 (2
CH-uracyl), 91.1, 82.6, 80.9, 78.0, 77.1, 73.8, 72.5, 70.8, 69.9 (C-1-U
to C-4-U, C-1-Glc to C-5-Glc), 61.2, 40.8 (C-5-U, C-6-Glc); Anal. Calcd
for C17H25N5O12 (491.41): C, 41.55; H, 5.13; N, 14.25. Found: C,
41.58; H, 5.17; N, 14.32.
0.36 mmol) in dry EtOAc (2 mL) was added. The reaction mixture
was stirred at rt. When the reaction was complete (TLC, 7:3
CHCl3-CH3OH), the solvent was removed by evaporation under re-
duced pressure. The residue was purified by column chromatogra-
phy (4:1 CHCl3-CH3OH) to give 11 as a colourless oil (74 mg, 70%).
Rf = 0.38 (7:3 CHCl3-CH3OH); [
a
]
+6 (c 1.1, CH3OH); 1H NMR
D
(DMSO-d6): d (ppm) 7.71 (d, 1H, J = 8.0 Hz, CH-uracyl), 6.18 (t,
1H, JNH,5a = 5.8 Hz, JNH,5b = 5.8 Hz, NH), 5.76 (d, 1H, J1,2 = 2.8 Hz,
H-1), 5.63 (d, 1H, J = 8.0 Hz, CH-uracyl), 5.52 (br s, 2H, NH2), 5.00
(dd, 1H, J2,3 = 6.6 Hz, H-2), 4.67 (dd, 1H, J3,4 = 4.1 Hz, H-3), 3.97–
3.91 (m, 1H, J4,5a = 6.0 Hz, J4,5b = 6.9 Hz, H-4), 3.34–3.28 (m, 1H,
H-5a), 3.17–3.10 (m, 1H, J5a,5b = 13.3 Hz, H-5b), 1.47, 1.27 (2br s,
6H, CH3); 13C NMR (DMSO-d6): d (ppm) 163.2, 150.2 (2 CO-uracyl),
158.5 (NHCONH), 142.8, 101.8 (2 CH-uracyl), 113.3 (C-isopropyli-
dene), 91.7 (C-1), 85.4, 83.4, 81.3 (C-2, C-3, C-4), 41.2 (C-5), 26.9,
25.1 (CH3); Anal. Calcd for C13H18N4O6 (326.31): C, 47.85; H,
5.56; N, 17.17. Found: C, 47.92; H, 5.63; N, 17.21.
1.11. 1-(2,3,4,6-Tetra-O-acetyl-b-D
-glucopyranosyl)-5-(20,30-O-
isopropylidene-50-uridyl)biuret (18)
Urea 13 (100 mg, 0.306 mmol) was dissolved in dry toluene
(6 mL), then some freshly heated molecular sieves and crystalline
isocyanate 1721 (252 mg, 0.675 mmol) were added. The reaction
mixture was stirred at reflux temperature until the reaction was
complete (ꢀ1 day, TLC, 10:1 EtOAc-hexane). Then the molecular
sieves were filtered off with suction and the solvent was evapo-
rated under reduced pressure. The residue was purified by column
chromatography (1:1 to 5:1 EtOAc-hexane). Three products were
isolated in the order of elution: 20 (122 mg), 19 (9 mg, 4%) and
18 (134 mg, 63%).
1.8. O-(20,30-O-Isopropylidene-50-uridyl)carbamate (14)
Prepared by the general procedure (Section 1.2). Colourless syr-
up. Rf = 0.23 (15:1 EtOAc-hexane); [a]
D +36 (c 0.8, CHCl3); lit.11 mp
184–186 °C, lit.24 178–179 °C. 1H NMR (CDCl3): d (ppm) 9.78 (s, 1H,
NH), 7.30 (d, 1H, J = 8.0 Hz, CH-uracyl), 5.72 (d, 1H, J = 8.0 Hz, CH-
uracyl), 5.60, (d, 1H, J1,2 = 2.1 Hz, H-1), 5.25 (br s, 2H, NH2), 5.08
(dd, 1H, J2,3 = 6.6 Hz, H-2), 4.84 (dd, 1H, J3,4 = 3.1 Hz, H-3), 4.42–
4.28 (m, 3H, H-4, H-5a, H-5b), 1.57, 1.36 (2br s, 6H, CH3); The 1H
NMR spectrum recorded in DMSO-d6 fully corresponded to the re-
ported data.11 13C NMR (CDCl3): d (ppm) 163.4, 150.0 (2 CO-ura-
cyl), 156.5 (NHCOO), 142.4, 102.4 (2 CH-uracyl), 114.4 (C-
isopropylidene), 95.7 (C-1), 85.8, 84.6, 81.2 (C-2, C-3, C-4), 64.8
(C-5), 27.1, 25.2 (CH3).
Characterization of 18: Colourless oil; Rf = 0.13 (5:1 EtOAc - hex-
ane); [a]
D ꢁ38 (c 1.0, CHCl3); 1H NMR (DMSO-d6): d (ppm) 11.44 (br
s, 1H, NH), 8.93 (br s, 1H, NH), 8.02 (d, 1H, J1-Glc, NH = 10.2 Hz, NH),
7.70 (d, 1H, J = 8.4 Hz, CH-uracyl), 7.55 (br s, 1H, NH), 5.78 (d, 1H,
J1,2-U = 1.9 Hz, H-1-U), 5.64 (d, 1H, J = 8.4 Hz, CH-uracyl), 5.41
(pseudo t, 1H, J3,4-Glc = 9.6 Hz, H-3-Glc), 5.33 (pseudo t, 1H,
J1,2-Glc = 9.2 Hz, H-1-Glc), 5.02 (dd, 1H, J2,3-U = 6.5 Hz, H-2-U), 4.92
(pseudo t, 1H, J4,5-Glc = 9.5 Hz, H-4-Glc), 4.85 (pseudo t, 1H,
J2,3-Glc = 9.5 Hz, H-2-Glc), 4.70 (dd, 1H, J3,4-U = 4.5 Hz, H-3-U), 4.16–
3.95 (m, 4H, H-4-U, H-5a-U, H-5b-U, H-5-Glc), 3.46–3.30 (m, 2H,
H-6a-Glc, H-6b-Glc), 2.00, 1.99, 1.95 (3br s, 12H, 4 ꢂ COCH3), 1.47,
1.28 (2br s, 6H, 2 ꢂ CH3-isopropylidene); 13C NMR (CDCl3): d
(ppm) 170.7, 170.1, 169.5 (COCH3), 163.7, 154.9, 154.8 (2 CO-uracyl,
2 NHCO), 143.8, 102.7 (2 CH-uracyl), 114.4 (C-isopropylidene), 86.3,
84.0, 81.5, 78.8, 73.2, 73.0, 70.1, 68.0 (C-1-U to C-4-U, C-1-Glc to C-
5-Glc), 61.6, 41.1 (C-5-U, C-6-Glc), 27.1, 25.3 (CH3-isopropylidene),
20.7, 20.6, 20.5 (COCH3); Anal. Calcd for C28H37N5O16 (699.63): C,
48.07; H, 5.33; N, 10.01. Found: C, 48.12; H, 5.25; N, 9.93.
1.9. 50-Uridyl 4-(b-
D-glucopyranosyl)allophanate (15)
Allophanate 9 (100 mg, 0.14 mmol) was dissolved in dry CH3OH
(2 mL) and one drop of AcCl was added. The reaction mixture was
stirred at rt. The precipitate formed was filtered off to yield 15 as
an amorphous solid (50 mg, 71%). Rf = 0.65 (1:3 CHCl3-CH3OH);
[a
]
D
ꢁ4 (c 0.4, H2O); 1H NMR (DMSO-d6 + D2O); d (ppm) 7.65 (d,
1H, J = 8.0 Hz, CH-uracyl), 5.81 (d, 1H, J = 5.8 Hz), 5.68 (d, 1H,
J = 8.0 Hz, CH-uracyl), 4.72 (d, 1H, J = 9.0 Hz), 4.31–4.28 (m, 2H),
4.16 (pseudo t, 1H, J = 5.6 Hz, 5.9 Hz), 4.05 (dd, 1H, J = 3.4 Hz,
7.2 Hz), 3.97 (pseudo t, 1H, J = 4.5 Hz, 4.7 Hz), 3.43 (dd, 1H,
J = 5.3 Hz, 11.9 Hz), 3.22–2.99 (m, 5H); 13C NMR (D2O): d (ppm)
162.4, 147.8 (2 CO-uracyl), 151.5, 151.4 (2 NHCO), 138.0, 98.4 (2
CH-uracyl), 85.5, 80.3, 76.4, 73.6, 72.5, 69.8, 68.0, 65.5, 65.4 (C-1-
U to C-4-U, C-1-Glc to C-5-Glc), 56.9, 56.7 (C-5-U, C-6-Glc); Anal.
Calcd for C17H24N4O13 (492.40): C, 41.47; H, 4.91; N, 11.38. Found:
C, 41.52; H, 5.00; N, 11.42.
1.12. 1-(2,3,4,6-Tetra-O-acetyl-b-
isopropylidene-50-uridyl)urea (19)
D
-glucopyranosyl)-3-(20,30-O-
Isolated from the reaction described in Section 1.11. Colourless
oil; Rf = 0.50 (5:1 EtOAc-hexane); [
+28 (c 0.4, CHCl3); 1H NMR
a
]
D
(DMSO-d6): d (ppm) 11.41 (br s, 1H, NH), 7.74 (d, 1H, J = 8.3 Hz,
CH-uracyl), 7.01–6.95 (m, 2H, 2 ꢂ NH), 5.78 (d, 1H, J1,2-U = 1.8 Hz,
H-1-U), 5.63 (d, 1H, J = 8.0 Hz, CH-uracyl), 5.33 (pseudo t, 1H, J3,4-
Glc = 9.4 Hz, H-3-Glc), 5.21 (pseudo t, 1H, J1,2-Glc = 9.5 Hz, H-1-Glc),
5.07 (dd, 1H, J2,3-U = 6.5 Hz, H-2-U), 4.89 (pseudo t, 1H, J4,5-
Glc = 9.5 Hz, H-4-Glc), 4.80 (pseudo t, 1H, J2,3-Glc = 9.5 Hz, H-2-Glc),
4.73 (dd, 1H, J3,4-U = 4.2 Hz, H-3-U), 4.12 (dd, 1H, J5,6a = 4.9 Hz,
J6a,6b = 12.3 Hz, H-6a-Glc), 4.05–3.94 (m, 3H, H-5-Glc, H-4-U, H-
6b-Glc), 3.25–3.14 (m, 2H, H-5a-U, H-5b-U), 1.99, 1.98, 1.96, 1.93
(4br s, 12H, 4 ꢂ COCH3), 1.49, 1.29 (2br s, 6H, 2 ꢂ CH3-isopropyli-
1.10. 1-(b-D
-Glucopyranosyl)-5-(50-uridyl)biuret (16)
Biuret 18 (100 mg, 0.14 mmol) was dissolved in dry CH3OH
(1 mL), and a solution of NaOCH3 (1 M in CH3OH) was added to the
solution in a catalytic amount. The reaction mixture was kept at rt.

M. Tóth, L. Somsák / Carbohydrate Research 345 (2010) 163–167
167
dene); 13C NMR (CDCl3): d (ppm) 171.5, 170.6, 170.0, 169.4
(COCH3), 162.7, 150.4 (2 CO-uracyl), 151.8 (NHCONH), 143.8,
103.0 (2 CH-uracyl), 114.4 (C-isopropylidene), 97.3, 86.5, 84.5,
81.4, 80.3, 73.7, 72.7, 70.4, 68.0 (C-1-U to C-4-U, C-1-Glc to C-5-
Glc), 61.5, 47.3 (C-5-U, C-6-Glc), 27.2, 25.3 (CH3-isopropylidene),
20.8, 20.7 (COCH3); Anal. Calcd for C27H36N4O15 (656.59): C,
49.39; H, 5.53; N, 8.53. Found: C, 49.44; H, 5.59; N, 8.60.
2. Compain, P.; Martin, O. R. Bioorg. Med. Chem. 2001, 9, 3077–3092.
3. Jung, K.-H.; Schmidt, R. R. In Carbohydrate-Based Drug Discovery; Wong, C.-H.,
Ed.; Wiley: Weinheim, 2003; pp 609–659.
4. Walker-Nasir, E.; Ahmad, I.; Saleem, M.; Hoessli, D. C. Curr. Org. Chem. 2007, 11,
591–607.
5. Tvaroška, I. Trends Glycosci. Glycotechnol. 2005, 17, 177–190.
6. Wong, C. H. Carbohydrate-Based Drug Discovery; Wiley: Weinheim, 2003.
7. Gorbatenko, V. I. Tetrahedron 1993, 49, 3227–3257.
8. Cornia, M.; Menozzi, M.; Ragg, E.; Mazzini, S.; Scarafoni, A.; Zanardi, F.;
Casiraghi, G. Tetrahedron 2000, 56, 3977–3983.
9. Helferich, B.; Mitrowsky, A. Chem. Ber. 1952, 85, 1–8.
10. Picard, J. A.; Bousley, R. F.; Lee, H. T.; Hamelehle, K. L.; Krause, B. R.; Minton, L.
L.; Sliskovic, D. R.; Stanfield, R. L. J. Med. Chem. 1994, 37, 2394–2400.
11. Camarasa, M. J.; Fernandez-Resa, P.; Garcia-Lopez, M. T.; De las Heras, F. G.;
Mendez-Castrillon, P. P.; Alarcon, B.; Carrasco, L. J. Med. Chem. 1985, 28, 40–46.
12. Jarrahpour, A. A.; Shekarriz, M.; Taslimi, A. Molecules 2004, 9, 29–38.
13. Bertho, A. Liebigs Ann. 1949, 562, 229–239.
14. Takahashi, S.; Okada, A.; Nishiwaki, M.; Nakata, T. Heterocycles 2006, 69, 487–
495.
15. Horwitz, J. P.; Tomson, A. J.; Urbanski, J. A.; Chua, J. J. Org. Chem. 1962, 27, 3045–
3048.
16. Wang, R.; Steensma, D. H.; Takaoka, Y.; Yun, J. W.; Kajimoto, T.; Wong, C.-H.
Bioorg. Med. Chem. 1997, 5, 661–672.
17. Verheyden, J. P. H.; Moffatt, J. G. J. Org. Chem. 1972, 37, 2289.
18. Bozzoli, A.; Kazmierski, W.; Kennedy, G.; Pasquarello, A.; Pecunioso, A. Bioorg.
Med. Chem. Lett. 2000, 10, 2759–2763.
19. Babic, A.; Gobec, S.; Gravier-Pelletier, C.; Le Merrer, Y.; Pecar, S. Tetrahedron
2008, 64, 9093–9100.
20. Winans, K. A.; Bertozzi, C. R. Chem. Biol. 2002, 9, 113–129.
21. Ichikawa, Y.; Matsukawa, Y.; Nishiyama, T.; Isobe, M. Eur. J. Org. Chem. 2004,
586–591.
1.13. N,N0-Bis-(2,3,4,6-tetra-O-acetyl-b-
D-glucopyranosyl)urea (20)
Isolated from the reaction described in Section 1.11. White crys-
tals; mp 152–153 °C; lit.23 mp 153 °C. 1H NMR (CDCl3): d (ppm)
6.21 (d, 2H, J1, NH = 9.2 Hz, NH), 5.30, 5.12, 5.05, 4.90 (4 pseudo t,
8H, J = 9.2 Hz, 10.1 Hz in each, H-1, H-2, H-3, H-4), 4.32 (dd, 2H,
J5,6a = 4.5 Hz, J6a,6b = 12.3 Hz, H-6a), 4.10 (dd, 2H, J5,6b = 1.7 Hz, H-
6b), 3.85 (ddd, 2H, J4,5 = 10.1 Hz, H-5), 2.08, 2.07, 2.04, 2.02 (4br
s, 24H, 8 ꢂ COCH3); 13C NMR (CDCl3): d (ppm) 171.0, 170.6,
169.9, 169.6 (COCH3), 155.7 (CO-urea), 79.8, 73.1, 72.8, 70.4, 68.2
(C-1 to C-5), 61.7 (C-6), 20.6, 20.5, 20.4 (COCH3). The NMR data cor-
respond to the published ones.23
Acknowledgement
This work was supported by the Hungarian Scientific Research
Fund (OTKA 45927).
22. Pintér, I.; Kovács, J.; Tóth, G. Carbohydr. Res. 1995, 273, 99–108.
23. Ichikawa, Y.; Nishiyama, T.; Isobe, M. J. Org. Chem. 2001, 66, 4200–4205.
24. Fleming, W. C.; Lee, W. W.; Henry, D. W. J. Med. Chem. 1973, 16, 570–571.
25. Glamkowski, E. J.; Chiang, Y.; Hamer, R. R. L., EP 430201, 1991.
26. Hurd, R. E. J. Magn. Reson. 1990, 87, 422–428.
References
1. Lairson, L. L.; Henrissat, B.; Davies, G. J.; Withers, S. G. Ann. Rev. Biochem. 2008,
77, 521–555.