Synthesis of a C-glucosylated cyclopropylamide and evaluation as a glycogen phosphorylase inhibitor

Article abstract of DOI:10.1016/j.bmcl.2008.07.098

The synthesis of carbohydrate-based glycogen phosphorylase inhibitors is attractive for potential applications in the treatment of type 2 diabetes. A titanium-mediated synthesis led to a benzoylated C-glucosylated cyclopropylamine intermediate, which underwent a benzoyl migration to afford the corresponding 2-hydroxy-C-glycoside. X-ray crystallographic studies revealed a unit cell composed of four molecules as pairs of dimers connected through two hydrogen bonds. The deprotection of the benzoate esters under Zemplen conditions afforded a glycogen phosphorylase inhibitor candidate displaying weak inhibition toward glycogen phosphorylase (16% at 2.5 mM).

Full text of DOI:10.1016/j.bmcl.2008.07.098

Bioorganic & Medicinal Chemistry Letters 18 (2008) 4774–4778
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis of a C-glucosylated cyclopropylamide and evaluation
as a glycogen phosphorylase inhibitor
Philippe Bertus a,b, Jan Szymoniak b, Erwann Jeanneau c, Tibor Docsa d, Pál Gergely d,
Jean-Pierre Praly e,f,g, Sébastien Vidal e,f,g,
*
a CNRS UMR 6011, Unité de Chimie Organique Moléculaire et Macromoléculaire (UCO2M), Université du Maine, Avenue O. Messiaen, F-72085 Le Mans Cedex 9, France
b Institut de Chimie Moléculaire de Reims, CNRS (UMR 6229), Université de Reims, 51687 Reims Cedex 2, France
c Centre de Diffractométrie Henri Longchambon, Université Claude Bernard Lyon 1, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France
d Cell Biology and Signaling Research Group of the Hungarian Academy of Sciences, Department of Medical Chemistry, Research Centre for Molecular Medicine,
University of Debrecen, H-4032 Debrecen, Nagyerdei krt. 98, Hungary
e CNRS, UMR5246, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Laboratoire de Chimie Organique 2—Glycochimie, 43 Boulevard du 11 Novembre 1918,
F-69622 Villeurbanne, France
f Université de Lyon, F-69622 Lyon, France
g Université Lyon 1, 43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne, France
a r t i c l e i n f o
a b s t r a c t
Article history:
The synthesis of carbohydrate-based glycogen phosphorylase inhibitors is attractive for potential appli-
Received 9 July 2008
Revised 24 July 2008
Accepted 25 July 2008
Available online 30 July 2008
cations in the treatment of type 2 diabetes. A titanium-mediated synthesis led to a benzoylated C-glu-
cosylated cyclopropylamine intermediate, which underwent
a benzoyl migration to afford the
corresponding 2-hydroxy-C-glycoside. X-ray crystallographic studies revealed a unit cell composed of
four molecules as pairs of dimers connected through two hydrogen bonds. The deprotection of the ben-
zoate esters under Zemplén conditions afforded a glycogen phosphorylase inhibitor candidate displaying
weak inhibition toward glycogen phosphorylase (16% at 2.5 mM).
Keywords:
Cyclopropane
Titanium
Ó 2008 Elsevier Ltd. All rights reserved.
Nitrile
Acyl migration
C-Glycoside
Glycogen phosphorylase
Glycogen phosphorylase (GP) plays an important role in the
control of glycemia.1–4 This enzyme is responsible for the depoly-
merization of glycogen in which a terminal glucose unit is cleaved
and phosphorylated to produce glucose-1-phosphate and glycogen
missing one glucose unit. GP is mostly located in the muscles for
the production of glucose as a source of energy, but also in the liver
where it contributes to hepatic glucose production. The inhibition
of this enzyme is therefore attractive for the development of new
treatments of type 2 diabetes.5–8 GP possesses various binding
sites on which several types of molecules can act as inhibitors. A
large set of glucose-based molecules has been designed as ligands
binding to the active site of GP, and many of them were moderate
or potent competitive inhibitors of this enzyme.5,6,9–12
We have shown that inhibition of GP was enhanced by the
hydrophobicity and the electron density of aromatic moieties in
the aglycon.11,12 Based on these observations, we designed a short
synthetic route to C-glucosylated cyclopropylamides from a C-glu-
cosyl cyanide through
a titanium-mediated cyclopropanation
developed recently.13–22 This methodology was also applied to
the synthesis of ester-protected ribofuranosyl cyanides.23 The
amide function would therefore act as a donor and acceptor of
H-bonds, and the cyclopropyl and phenyl rings as hydrophobic res-
idues that can be accommodated in the b-channel next to the ac-
tive site of GP.
The readily available glucosyl cyanide 124 was first reacted un-
der standard13 titanium-mediated cyclopropanation conditions
(Scheme 1). However, the addition of EtMgBr to a mixture of 1
and Ti(Oi-Pr)4 in Et2O, followed by BF3ꢀEt2O, did not give the ex-
pected primary cyclopropylamine 2, but the benzamide 3 in 62%
yield. This amide resulted presumably from a regioselective migra-
tion of the benzoyl group from the 2-position to the amine. Inter-
estingly, when the reaction was performed without a Lewis acid
(BF3ꢀEt2O), the same amide 3 was obtained in a slightly better yield
(66%).25 Changing the solvent (THF or Et2O) or performing the
Analysis of the structures of glucose-based inhibitors of GP
highlights a few preferred structural features of the aglycons.
Among them, hydrogen bonds in the urea, carbonyl groups in the
acylated glucosyl-ureas,10 and hydrophobic residues as in the C-
glucosylated 1,2,4-oxadiazoles (Fig. 1) have to be considered.
* Corresponding author. Tel./fax: +33 0472 44 83 49.
E-mail address: sebastien.vidal@univ-lyon1.fr (S. Vidal).
0960-894X/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2008.07.098

P. Bertus et al. / Bioorg. Med. Chem. Lett. 18 (2008) 4774–4778
4775
OH
OH
O
N
N
O
O
O
Ar
Ar
HO
HO
HO
HO
N
N
OH
OH
OH
C
-Glucosylated 1,2,4-oxadiazoles
OH
O
O
O
H
N
H
HO
HO
HO
N
Ar
HO
N
H
Ar
OH
Acylated glucosyl-ureas
OH
O
O
C
-Glucosyl-cyclopropylamide
Figure 1. Structures of some glucose-based inhibitors of glycogen phosphorylase and of the cyclopropylamide inhibitor candidate.
OBz
OBz
O
O
a
BzO
BzO
BzO
BzO
CN
NH2
OBz
OBz
1
2
OH
OBz
O
O
b
O
O
HO
HO
BzO
BzO
N
Ph
N
H
Ph
OH
OH
H
4
3
Scheme 1. Reagents and conditions: (a) EtMgBr (2.2 equiv), Ti(Oi-Pr)4 (1.1 equiv), Et2O–THF, rt, 1 h (66%); (b) NaOMe, MeOH (93%).
addition of the Grignard reagent at lower temperature did not
influence the outcome of the reaction, providing invariably the
amide 3 as the main product. The benzoate esters were finally re-
moved under Zemplén conditions to obtain the expected C-glu-
cosylated cyclopropyl-benzamide 426 (Scheme 1).
Such a benzoyl migration in the glucopyranose series is note-
worthy, since a similar amide formation was not observed for a re-
lated 2-benzoylated ribofuranose derivative (Fig. 2).23 2C-selective
acetyl groups migration was similarly observed while preparing
substituted C-glycopyranosyl-methylamines.27,28
The benzoyl group migration occurred either during the cyclo-
propanation process through a spiro-cyclopropylated six-mem-
bered ring system and hydrolysis (Fig. 3, path A), or after
formation of the cyclopropylamine, via intramolecular aminolysis
of the most accessible benzoate group (Fig. 3, path B).
Cyclopropyl-benzamide 3 afforded single crystals suitable for X-
ray crystallography by slow evaporation of a solution in dichloro-
methane followed by washing of the crystals with diethyl ether.29
A colorless crystal with dimensions 0.07 ꢁ 0.07 ꢁ 0.11 mm3 was
selected for X-ray structure analysis (Fig. 4). The compound crys-
tallized in the non-centrosymmetric space group P21 with an
asymmetric unit consisting of four independent molecules
(Z0 = 4), which is due to the different orientations of phenyl groups
from one molecule to another (Fig. 5). Two types of hydrogen
bonds were observed (Table 1): an intramolecular O–HꢀꢀꢀO bond
between the carbonyl of the amide and the hydroxyl group at
the 2-position and an intermolecular N–HꢀꢀꢀO bond between NH
of the amide and the carbonyl of the O-6 benzoate, leading to the
formation of dimeric entities (Fig. 6). The three-dimensional pack-
ing was achieved through C–HꢀꢀꢀO interactions. All bond distances
and angles were in agreement with the expected values.30 The
crystal packing contained solvent accessible voids of 208.7 Å3 per
unit cell (3.1% of the total volume).
The inhibition of the hydroxylated cyclopropyl-benzamide 4
was evaluated against rabbit muscle glycogen phosphorylase b
(RMGPb).31 No inhibition was observed at a concentration of
625 lM and 16% inhibition at 2.5 mM. The poor biological activity
observed could be attributed to unfavorable structural and confor-
mational features of the cyclopropyl group or to its inability to
establish binding interactions with the active site of GP. Neverthe-
BzO
O
BzO
O
CN
EtMgBr (2.2 equiv)
Ti(O -Pr)4 (1.1 equiv)
NH2
i
then BF3O•Et2O (2 equiv)
BzO
OBz
BzO
OBz
55%
Figure 2. Titanium-mediated cyclopropanation afforded the expected cyclopropylamine in good yield in the presence of benzoyl protecting groups in the ribofuranose series.

4776
P. Bertus et al. / Bioorg. Med. Chem. Lett. 18 (2008) 4774–4778
OBz
O
BzO
BzO
Ti(O
i
Pr)2
EtMgBr + Ti(OiPr)
4
+
CN
OBz
1
OBz
OBz
O
Path A
O
BzO
BzO
BzO
BzO
Ti(OiPr)2
N
O
O
N
Ph
Ti
PrO
i
Oi
Pr
O
Ph
O
Path B H2O
H2O
OBz
OBz
O
O
O
BzO
BzO
BzO
BzO
N
H
Ph
NH2
OH
O
3
O
Ph
2
Figure 3. Proposed pathways for the formation of the cyclopropyl-benzamide 3.
Figure 5. Overlay of two molecules of cyclopropyl-benzamide 3 in the same unit
cell displaying different orientations of the phenyl rings.
Figure 4. Representation of the X-ray crystal structure of cyclopropyl-benzamide 3.
In conclusion, titanium-mediated cyclopropanation of the tetra-
benzoylated b-D-glucopyranosyl cyanide afforded a 1-benzamide
less, binding at the inhibitor site cannot be ruled out due to the
presence of a phenyl ring in the inhibitor’s aglycon structure which
could interact with the protein. The use of computer-aided strate-
gies (e.g., fragment-based drug design) will be considered for the
design of other C-glucosylated cyclopropyl-amides with poten-
tially better ability to bind the active site of GP.
derivative. It originated from the selective migration of the 2-ben-
zoyl group to the newly created amine. The selectivity of the ben-
zoyl group transfer from the 2-position to the amine moiety can be
advantageous for the selective synthesis of 2-deoxy-2-amino
glycosides. The crystal packing of the benzamide displayed four
molecules in the unit cell with two dimers held together by two

P. Bertus et al. / Bioorg. Med. Chem. Lett. 18 (2008) 4774–4778
4777
Table 1
Distances and angles characterizing hydrogen bonds observed in each molecule present in the unit cell of cyclopropyl-benzamide 3
D–H (Å)
HꢀꢀꢀA (Å)
DꢀꢀꢀA (Å)
D–HꢀꢀꢀA (°)
N25–H251ꢀꢀꢀO210
O83–H831ꢀꢀꢀO140
N138–H1381ꢀꢀꢀO265ii
O181–H1811ꢀꢀꢀO187
N185–H1851ꢀꢀꢀO50
O243–H2431ꢀꢀꢀO300
N298–H2981ꢀꢀꢀO105vi
O22–H221ꢀꢀꢀO27
0.85
0.81
0.87
0.82
0.87
0.81
0.86
0.84
2.10
1.93
2.07
1.87
2.12
1.98
2.06
1.98
2.930 (5)
2.702 (5)
2.893 (5)
2.667 (5)
2.961 (5)
2.738 (5)
2.887 (5)
2.778 (5)
165
159
158
165
162
155
163
159
Figure 6. Dimers formed through intermolecular N–HꢀꢀꢀO hydrogen bonds (dotted lines) in the same unit cell.
9. Oikonomakos, N. G.; Somsak, L. Curr. Opin. Invest. Drugs 2008, 9, 379.
N–HꢀꢀꢀO hydrogen bonds. The hydroxylated cyclopropyl-benzam-
10. Oikonomakos, N. G.; Kosmopoulou, M. N.; Zographos, S. E.; Leonidas, D. D.;
Chrysina, E. D.; Somsák, L.; Nagy, V.; Praly, J.-P.; Docsa, T.; Toth, B.; Gergely, P.
Eur. J. Biochem. 2002, 269, 1684.
ide was found a weak inhibitor of GP (16% inhibition at 2.5 mM).
11. Benltifa, M.; Vidal, S.; Fenet, B.; Msaddek, M.; Goekjian, P. G.; Praly, J.-P.;
Brunyánszki, A.; Docsa, T.; Gergely, P. Eur. J. Org. Chem. 2006, 4242.
12. Benltifa, M.; Vidal, S.; Gueyrard, D.; Goekjian, P. G.; Msaddek, M.; Praly, J.-P.
Tetrahedron Lett. 2006, 47, 6143.
13. For a review, see: Bertus, P.; Szymoniak, J. Synlett 2007, 4, 1346.
14. Bertus, P.; Szymoniak, J. Chem. Commun. 2001, 5, 1792.
15. Bertus, P.; Szymoniak, J. J. Org. Chem. 2002, 67, 3965.
16. Bertus, P.; Szymoniak, J. J. Org. Chem. 2003, 68, 7133.
17. Laroche, C.; Harakat, D.; Bertus, P.; Szymoniak, J. Org. Biomol. Chem. 2005, 3,
3482.
Acknowledgments
The authors wish to acknowledge the financial support from the
CNRS (PICS Program No. 4576) and Université Claude Bernard Lyon
1 (France) as well as grants from the Hungarian Science Research
Fund (OTKA K60620) and the Hungarian Ministry of Health (EET
083/2006).
18. Bertus, P.; Szymoniak, J. Synlett 2003, 265.
19. Laroche, C.; Behr, J.-B.; Szymoniak, J.; Bertus, P.; Schutz, C.; Vogel, P.; Plantier-
Royon, R. Bioorg. Med. Chem. 2006, 14, 4047.
References and notes
20. Laroche, C.; Plantier-Royon, R.; Szymoniak, J.; Bertus, P.; Behr, J.-B. Synlett 2006, 223.
21. Laroche, C.; Bertus, P.; Szymoniak, J. Tetrahedron Lett. 2003, 44, 2485.
22. Bertus, P.; Menant, C.; Tanguy, C.; Szymoniak, J. Org. Lett. 2008, 10, 777.
23. Laroche, C.; Behr, J.-B.; Szymoniak, J.; Bertus, P.; Plantier-Royon, R. Eur. J. Org.
Chem. 2005, 54, 5084.
1. Fletterick, R. J.; Sprang, S. R. Acc. Chem. Res. 1982, 15, 361.
2. Barford, D.; Johnson, L. N. Nature 1989, 340, 609.
3. Sprang, S. R.; Acharya, K. R.; Goldsmith, E. J.; Stuart, D. I.; Varvill, K.; Fletterick,
R. J.; Madsen, N. B.; Johnson, L. N. Nature 1988, 336, 215.
4. Oikonomakos, N. G.; Skamnaki, V. T.; Tsitsanou, K. E.; Gavalas, G. N.; Johnson, L.
N. Structure 2000, 8, 575.
5. Somsák, L.; Nagy, V.; Hadady, Z.; Docsa, T.; Gergely, P. Curr. Pharm. Des. 2003, 9,
1177.
6. Oikonomakos, N. G. Curr. Prot. Pept. Sci. 2002, 3, 561.
7. Baker, D. J.; Timmons, J. A.; Greenhaff, P. L. Diabetes 2005, 54, 2453.
8. Treadway, J. L.; Mendys, P.; Hoover, D. J. Exp. Opin. Invest. Drugs 2001, 10, 439.
24. Somsák, L.; Nagy, V. Tetrahedron: Asymmetry 2000, 11, 1719.
25. N-[1-(C-3,4,6-tri-O-benzoyl-b-D-glucopyranosyl)cyclopropyl]benzamide (3). EtMgBr
(0.80 mL, 1.1 mmol, 1.4 M in Et2O) was added under argon at rt to a solution of the
nitrile 1 (0.30 g, 0.5 mmol) and Ti(Oi-Pr)4 (0.17 mL, 0.55 mmol) in Et2O/THF (1:1,
10 mL). The solution was stirred at rt for 1 h. Water was added (1 mL), followed by
10% aq HCl (10 mL) and EtOAc (20 mL). A 10% aq NaOH solution was added to the

4778
P. Bertus et al. / Bioorg. Med. Chem. Lett. 18 (2008) 4774–4778
transparent mixture until pH 12. The product was extracted with EtOAc (2ꢁ
parameters refinement and the data reduction were achieved with DENZO/
SCALEPACK (see Ref. 33). The crystal structure was solved by direct methods
with SIR97 (see Ref. 34). Because the data were collected with molybdenum
radiation, there were no measurable anomalous differences; as a consequence
it was admissible to merge Friedel pairs of reflections. All non-hydrogen atoms
were refined anisotropically by full-matrix least-squares calculations based on
F using CRYSTALS (see Ref. 35). The H atoms were located in a difference
Fourier map and repositioned geometrically. The H atoms positions and Uiso
were then refined using soft restraints on the bond lengths and angles to
regularize their geometry (C–H in the range 0.93–0.98 Å, O–H = 0.82 Å and
Uiso(H) = 1.2–1.5 times equiv of the adjacent atom). In the last cycles of the
refinement, they were refined using a riding model. The absolute configuration
of the structure was obtained with a quick data collection using Cu radiation by
examining the Flack parameter. The molecular and crystal structure drawings
were prepared with DIAMOND (see Ref. 36).
20 mL). The combined organic extracts were dried (MgSO4). After evaporation of
the solvent, the product was purified by flash chromatography on silica gel (PE/
EtOAc 1:1) to give 3 as a white solid (0.21 g, 66%). Mp = 222 °C. Rf = 0.66 (PE/EtOAc
20
1:1). [a D
]
ꢂ53.0 (c = 1.05/CH2Cl2). IR (KBr): m
(cmꢂ1) 3351, 1724, 1702, 1645,
1602, 1582, 1525, 1452, 1287. 1H NMR (250 MHz, CDCl3). d (ppm) 0.86–0.97 (m, 2H,
CH2CH2), 1.25–1.48 (m, 2H, CH2CH2), 2.85 (d, 1H, J = 9.4 Hz, H-1), 3.81 (td, 1H,
J = 9.7, 3.5 Hz, H-2), 4.00 (ddd, 1H, J = 9.7, 5.3, 3.0 Hz, H-5), 4.42 (dd, 1H, J = 12.1,
5.3 Hz, H-6), 4.57 (dd, 1H, J = 12.1, 3.0 Hz, H-60), 5.35 (d, 1H, J = 3.5 Hz, OH), 5.51 (t,
1H, J = 9.7 Hz, H-4), 5.68 (t, 1H, J = 9.7 Hz, H-3), 6.88 (s, 1H, NH), 7.28–7.58 (m, 12H,
H-ar), 7.75 (d, 2H, J = 7.1 Hz, H-ar), 7.90 (d, 2H, J = 7.1 Hz, H-ar), 7.97 (d, 2H,
J = 7.1 Hz, H-ar), 8.02 (d, 2H, J = 7.1 Hz, H-ar). 13C NMR (CDCl3, 63 MHz). d (ppm)
12.1, 14.3 (2s, 2C, CH2CH2), 32.8 (C–N), 63.6 (C-6), 69.7 (C-4), 70.3 (C-2), 74.8 (C-3),
76.2 (C-5), 86.3 (C-1), 127.1 (s, 2C, CH-ar), 128.1 (s, 2C, CH-ar), 128.3 (s, 4C, CH-ar),
128.6 (s, 2C, CH-ar), 128.8 (s, 2C, C-ar), 129.5 (s, 2C, CH-ar), 129.6 (s, 2C, C-ar), 129.7
(s, 4C, CH-ar), 132.2 (CH-ar), 132.8 (CH-ar), 133.0 (CH-ar), 133.2 (CH-ar), 165.4,
166.1, 166.2 (3s, C@O), 169.9 (PhCONH). HR-ESIMS (positive mode). m/z = [M+H]+
C37H34NO9 calcd 636.2234, found 636.2238. Crystallographic data for (3).
30. Allen, F. H.; Watson, D. G.; Brammer, L.; Orpen, A. G.; Taylor, R. International
Tables for Crystallography, 3rd ed.; Kluwer Academic Publishers: Dordrecht,
Netherlands, 2006; Vol. C, Chapter 9.5, pp 790–811.
C
37H33NO9, Mr = 635.64, monoclinic, space group P21 (No. 4); a = 15.651(1),
31. Glycogen phosphorylase inhibition measurements. Glycogen phosphorylase
was prepared from rabbit skeletal muscle according to the method of
Fischer and Krebs (see Ref. 37), using dithiothreitol instead of -cysteine,
b
b = 22.761(2), c = 19.293(1) Å, b = 102.70(1)°; V = 6704.6(8) Å3; Z = 8; F(000) =
2672; Dx = 1.259 g mꢂ3; S = 1.118 R/wR = 0.050/0.057 for 1693 parameters and
L
14319 reflections with I > 2
r
(I), R/wR = 0.0571/0.0662 for all 16391 independent
and recrystallized at least three times before use. Kinetic experiments were
performed in the direction of glycogen synthesis as described previously
(see Ref. 38). Kinetic data for the inhibition of rabbit skeletal muscle
reflections measured in the range 1.082°–27.893°. CCDC 686021 contains
the supplementary crystallographic data for this molecule. These data can
be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, by
emailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge
Crystallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK; fax: +44
1223 336033.
glycogen phosphorylase were collected using different concentrations of
a-
D
-glucose-1-phosphate (2–20 mM), constant concentrations of glycogen (1%
w/v) and AMP (1 mM), and various concentrations of inhibitor. Inhibitor
was dissolved in dimethyl sulfoxide (DMSO) and diluted in the assay buffer
(50 mM triethanolammine, 1 mM EDTA and 1 mM dithiothreitol) so that
the DMSO concentration in the assay should be lower than 5%. The
enzymatic activities were presented in the form of double-reciprocal plots
(Lineweaver-Burk) applying a nonlinear data analysis program. The means
of standard errors for all calculated kinetic parameters averaged to less
than 10%. IC50 values were determined in the presence of 4 mM a-D-
glucose-1-phosphate, 1 mM AMP, 1% glycogen, and varying concentrations
of the inhibitor.
26. N-[1-(C-b-
D-glucopyranosyl)cyclopropyl]benzamide
(4).
A
solution
of
cyclopropyl-benzamide
3
(337 mg) and NaOMe (5 mg) in CH2Cl2/MeOH
(10 mL, 1:1) was stirred at room temperature for 3 h. The white precipitate
was filtered and washed with petroleum ether (2ꢁ 5 mL) to afford the
hydroxylated benzamide 4 (160 mg, 93%) as a white solid. Mp = 260–262 °C.
ꢂ47.6 (c = 1.03/DMSO). 1H NMR (300 MHz,
20
Rf = 0.47 (EtOAc/MeOH 3:1). [
a
]
D
CD3SOCD3). d (ppm) 0.70–0.96 (m, 3H, CH2CH2), 1.02–1.14 (m, 1H, CH2CH2),
2.52 (m, 1H, H-1), 2.95–3.11 (m, 3H, H-2 H-4 H-5), 3.18 (t, 1H, J = 9.0 Hz, H-3),
3.43 (dd, 1H, J = 11.6, 5.4 Hz, H-6), 3.67 (dd, 1H, J = 11.6, 1.5 Hz, H-60), 7.44 (t,
2H, J = 7.3 Hz, H-ar), 7.54 (t, 1H, J = 7.3 Hz, H-ar), 7.86 (d, 2H, J = 7.3 Hz, H-ar).
13C NMR (75 MHz, CD3SOCD3). d (ppm) 11.4,14.0 (2s, 2C, CH2CH2), 33.0 (C–N),
61.3 (C-6), 70.3 (C-2), 71.9 (C-4), 76.4 (C-3), 80.9 (C-5), 84.7 (C-1), 127.7 (s, 2C,
CH-ar), 128.5 (s, 2C, CH-ar), 132.0 (CH-ar), 133.5 (C-ar), 169.3 (C@O). HR-ESIMS
(positive mode). m/z = 346.2 [M+Na]+, 668.8 [2M+Na]+. HR-ESIMS (negative
mode). m/z = 321.9 [M–H]ꢂ, 358.0 [M+Cl]ꢂ. HR-ESIMS (positive mode). m/
z = [M+Na]+ C16H21NNaO6 calcd 346.1267, found 346.1270.
32. Nonius. COLLECT. Nonius BV, D., The Netherlands, 1997–2001.
33. Otwinowski, Z.; Minor, W.; Carter, C. W., Jr.; Sweet, R. M., Eds.; Academic Press:
New York, 1997; Vol. 276, p 307.
34. Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.; Giacovazzo, C.;
Guagliardi, A.; Moliterni, A. G.; Polidori, G.; Spagna, R. J. Appl. Crystallogr. 1999,
32, 115.
35. Betteridge, P. W.; Carruthers, J. R.; Cooper, R. I.; Prout, K.; Watkin, D. J. J. Appl.
Crystallogr. 2003, 36, 1487.
27. Hart, D. J.; Seely, F. L. J. Am. Chem. Soc. 1988, 110, 1631.
28. Bhat, A. S.; Gervay-Hague, J. Org. Lett. 2001, 3, 2081.
36. Brandenburg, K. P. H. DIAMOND. Version 3. Crystal Impact GbR, Postfach 1251,
D-53002 Bonn, Germany, 1996.
29. The intensities were collected at 150 K on a Nonius KappaCCD diffractometer
37. Fischer, E. H.; Krebs, E. G. Methods Enzymol. 1962, 5, 369.
38. Oikonomakos, N. G.; Skamnaki, V. T.; Osz, E.; Szilágyi, L.; Somsák, L.; Docsa, T.;
}
using graphite-monochromated MoK
a
radiation (k = 0.71073 Å). The data
collection was carried out by the COLLECT program (see Ref. 32) and cell
Tóth, B.; Gergely, P. Bioorg. Med. Chem. 2002, 10, 261.