Synthesis, chemical properties, and biological evaluations of some twin-drug type C2-symmetrical derivatives

Article abstract of DOI:10.3987/COM-12-12654

We describe the synthesis and chemical properties of newly designed C ₂-symmetrical twin-drug type aminoguanidines or 4- aminomethyloxazolidinone derivatives (4-7) in which a long chain alkyl group [-(CH2)10-] was used as a linker. Synthesis of some triplet-drug type symmetrical oxazolidinones (8) is also described. Among the tested compounds, the aminoguanidine derivative 4a showed the highest α-glucosidase inhibition activity (IC50 = 76.3 μmol/L).

Full text of DOI:10.3987/COM-12-12654

HETEROCYCLES, Vol. 87, No. 3, 2013
665
HETEROCYCLES, Vol. 87, No. 3, 2013, pp. 665 - 675. © 2013 The Japan Institute of Heterocyclic Chemistry
Received, 19th December, 2012, Accepted, 17th January, 2013, Published online, 22nd January, 2013
DOI: 10.3987/COM-12-12654
SYNTHESISꢀ
CHEMICAL PROPERTIES, AND BIOLOGICAL
EVALUATIONS OF SOME TWIN-DRUG TYPE C2-SYMMETRICAL
DERIVATIVES
Fumiko Fujisaki, Haruka Usami, Saya Nakashima, Sho Nishida, Toshihiro
Fujioka, Nobuhiro Kashige, Fumio Miake, and Kunihiro Sumoto*
Faculty of Pharmaceutical Sciences, Fukuoka University, Nanakuma, Jonan-Ku,
Fukuoka 814-0180, Japan; E-mail: kunihiro@adm.fukuoka-u.ac.jp
Abstract – We describe the synthesis and chemical properties of newly designed
C2-symmetrical twin-drug type aminoguanidines or 4-aminomethyloxazolidinone
derivatives (4-7) in which a long chain alkyl group [-(CH2)10-] was used as a
linker. Synthesis of some triplet-drug type symmetrical oxazolidinones (8) is also
described. Among the tested compounds, the aminoguanidine derivative 4a
showed the highest !-glucosidase inhibition activity (IC50 = 76.3 µmol/L).
Extensive studies on molecular recognition properties of biomolecules have been carried out, and it is
well known that many types of receptors or functionalized proteins in the native state often have a high
order of interface symmetry. Molecular recognition of C2- or C3-symmetrical macromolecules is an
interaction that is often found in several important biological processes.1-7 We have therefore designed
some symmetrical target molecules for the purpose of developing new biologically active substances that
interfere with a sugar recognition process or a sugar chain function. From this view point, we have
already reported a few examples of the design and synthesis of C2- or C3-symmetrical and other
symmetrical molecules and results of their biological evaluations.8-10 We previously found that two
C2-symmetrical compounds (1a and 1b) (Table 1) in which a biphenyl group was used as a linker showed
significant antibacterial activity.8
As an extension of our molecular modification studies on these symmetrical molecules for finding new
bioactive leads, we attempted further additional synthesis of some new C2-symmetrical twin-drug type
aminoguanidine or 4-aminomethyloxazolidinone11 derivatives in which a long chain alkyl [-(CH2)10-]
group was used as a linker in the designed molecules.12 In this article, we describe the synthesis and
chemical properties of newly designed twin-drug type symmetrical derivatives. We also present the result
of biological evaluations of the synthesized compounds.

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HETEROCYCLES, Vol. 87, No. 3, 2013
SYNTHESIS OF TARGET TWIN-DRUG TYPE MOLECULES
In our previous works on twin-drug type molecules, we obtained some synthetic C2-symmetrical
molecules (1a,b-3a,b) by reactions of dicarboxylic acid derivatives and corresponding aminoguanidines8
(Table 1).
New twin-drug type symmetrical
molecules (4a and 4b) that used a
longer methylene chain alkyl
[-(CH2)10-] group as
between two
a
linker
terminal
aminoguanidine moieties were also
obtained from the reaction of
dicarboxylic acid dichloride with a
corresponding
aminoguanidine
derivative in 62.8% and 15.5%
yields, respectively.
The
obtained
N-acyl
aminoguanidine derivative 4a was
easily cyclized to form the
corresponding triazole derivative 5
in 25.6% yield by simply heating at
160—180 °C for 3 h (Scheme 1). A
similar cyclization stepwise to a
triazole
ring
system
by
of
intramolecular
dehydration
N-acyl aminoguanidines 2a was reported in our previous paper.8
The C2-symmetrical structures of the products (4a and 5) were confirmed by 13C-NMR spectroscopic
analysis. The two twin-drug type molecules showed magnetically equivalent signals assignable to half of
the symmetrical molecules, indicating a C2-symmetrical molecular feature in solution.
H
H2N
HN
NH2
NH
H
N
N
H
H
(CH2)8
- 2H2O
N
N
H2N
NH2
N
(CH2)8
N
N
N
H
H
N
N
O
neat, 160-180 °C, 3 h
O
5 (25.6%)
4a
Scheme 1

HETEROCYCLES, Vol. 87, No. 3, 2013
667
The protocol for preparation of new twin-drug type aminoguanidine derivatives (4a and 4b) and a
symmetrical triazole derivative 5 and their physical and spectroscopic data are shown in detail in the
Experimental section.
With reference to the structure of a twin-drug type compound 4b, the obtained evidence, especially that
from 13C-NMR measurements, is not fully consistent with a single structure of an expected
13
C2-symmetrical molecule 4b in solution, showing the characteristic two sets of C-NMR signal patterns
(161.4, 167.4 and 158.4, 172.3 ppm, respectively) ascribable to two quaternary carbons (guanidinium
carbons and C=O) for the terminal N-acylaminoguanidine moieties (see Experimental). This probably
arises from the existence of two types of C2-symmetrical molecular features in solution. We speculated
that the formation of intramolecular 5-membered hydrogen bonds in the terminal N-acylaminoguanidine
moieties including two imidazoline rings is involved in the tautomer-like conversion {[4bA]
[4bB]}.
13
The broadening of the C-signal at the C(2) position in the imidazoline ring supports this tautomer-like
conversion13 (see Figure 1).
NH
HN
H
H
N
N
N
(CH2)8
N
N
H
N
H
O
O
[4bA]
N
H
N
H
N
N
N
N
H
(CH2)8
N
N
H
H
H
O
O
[4bB]
4b
Figure 1
As part of our structural modification studies on a new class of bioactive leads, we have further aimed to
prepare two twin-drug type oxazolidinone derivatives,11 7a and 7b, having two N(3)-substituted
oxazolidinone rings14-18 (Scheme 2).
O
O
H2N
O
(CH2)8
O
TEA
O
N
N
+
Cl
(CH2)8
2
N
O
H
H
O
Cl
N
N
in CH2Cl2
rt, 3 h
O
R
O
R
R
O
7a (66.7%)
7b (34.2%)
6a, 6b
R =
6a, 7a:
6b, 7b: R =
N
F
O
Scheme 2

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HETEROCYCLES, Vol. 87, No. 3, 2013
Synthesis of these new twin-drug type oxazolidinone analogues (7a and 7b) was also achieved from the
reaction of dicarboxylic dichloride and corresponding 4-aminomethyloxazolidinones 616 (see
Experimental for details).
The obtained twin-drug type compound (7a or 7b) is expected to be a mixture of three twin-drug type
molecules, i.e., a Cs-symmetrical meso compound and two enantiomeric C2-symmetrical molecules, that
have the same absolute configuration regarding two C(4)-substituted oxazolidin-2-one rings in each
molecule. All of the obtained diastereomeric mixtures showed very simple symmetrical 13C-NMR in
DMSO-d6, and we could not distinguish the above two diastereomers from their 13C-NMR spectra.
However, three stereoisomeric components (1:2:1) in product 7a could be detected by HPLC
enantioseparation.19
In this study, newly designed triplet-drug type symmetrical oxazolidinone derivatives (8a and 8b) using a
1,3,5-cis-cyclohexanetricarbonyl framework were also prepared for comparison of biological activities
(Scheme 3).
O
R
O
N
COCl
TEA
H2N
CONH
ClOC
COCl,
O
N
3
HNOC
CONH
in CH2Cl2
rt, 3 h
R
O
R
N
O
N
R
O
6a, 6b
O
O
R =
6a, 8a:
8a (37.8%)
8b (80.9%)
6b, 8b: R =
N
O
F
Scheme 3
The fragments of oxazolidinone moieties incorporated in the designed triplet-drug type molecules 8a and
8b are based on previous biological results of this series mimicking the molecule of linezolid.20
The symmetrical structures of these triplet-drug type compounds were easily confirmed by 13C-NMR
spectroscopic analysis. The two triplet-drug type molecules (8a and 8b) showed magnetically equivalent
signals ascribable to a third of the molecules.21 Elemental analyses for both triplet-drug type compounds
were carried out by high-resolution FAB-MS spectra (see Experimental).

HETEROCYCLES, Vol. 87, No. 3, 2013
669
BIOLOGICAL ASSAYS AND DISCUSSION
Regarding antibacterial activities of the synthesized C2-symmetrical derivatives, none of the new
C2-symmetrical twin-drug type aminoguanidine or oxazolidinone derivatives that have a long chain alkyl
group [-(CH2)10-] as a linker in the molecule showed significant antibacterial activities against either
gram-negative (E. coli) or gram-positive (S. aureus) bacteria at a dose of >128 µg/mL. These results
indicate that a long chain alkyl [-(CH2)10-] linker seems to be less effective for enhancement of
antibacterial activity than a linker having a biphenyl group (1a or 1b).8
In this study, we also evaluated the activities of new synthesized C2-symmetrical aminoguanidines as well
as some of the previously obtained twin-drug type C2-symmetrical aminoguanidine derivatives for
inhibition of !-glucosidase.
Some compounds in this series (1a, 1b and 4a) that have been tested showed significant inhibitory
activity against !-glucosidase (IC50 = 76.3~279.6 µmol/L). Among the evaluated samples, compound 4a
in which a long chain alkyl group [-(CH2)10-] was introduced as a linker showed the highest inhibitory
activity against !-glucosidase (IC50 = 76.3 µmol/L). Compounds (1a and 1b) that have a biphenyl group
as a linker showed weaker inhibitory activity (IC50 = 279.6 and 259.9 µmol/L, respectively) than that of
compound 4a. The other compounds showed no remarkable inhibitory activity. This results indicate that
twin-drug type aminoguanidines that have a longer linker such as biphenyl or [-(CH2)10-] groups in the
molecule are more favorable for inhibitory activity against !-glucosidase than those having a benzene or
pyridine ring as a linker.
Based on these results of bioassays, we are studying further synthetic molecular modifications for C2- or
C3-symmetrical or other types of symmetric derivatives by introduction of different linkers into target
molecules in order to find useful bioactive leads.
EXPERIMENTAL
1
Melting points are uncorrected. IR spectra were measured by a Shimadzu FT/IR-8100 spectrometer. H-
and 13C-NMR spectra were obtained by a JEOL JNM A-500 at rt. The chemical shifts were expressed in "
ppm downfield from an internal tetramethylsilane (TMS) signal. The signal assignments were confirmed
1
1
1
by H - H two-dimensional (2D) correlation spectroscopy (COSY), H - 13C heteronuclear multiple
1
quantum coherence (HMQC), and H -13C heteronuclear multiple-bond connectivity (HMBC) spectra.
High FAB-MS spectra were obtained by a JEOL JMS-HX110 mass spectrometer. The following
abbreviations in parentheses were used for cyclohexane ring (Cyc), morpholine ring (Mor), oxazolidinone
ring (Oxaz).
2,2'-Dodecanedioylbis(hydrazinecarboximidamide) Dihydrochloride (4a)
Aminoguanidine hydrochloride (0.85 g, 7.70 mmol) was added portionwise to dodecanedioyl dichloride

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HETEROCYCLES, Vol. 87, No. 3, 2013
(1.00 g, 3.74 mmol) with stirring at rt, and the resulting mixture was heated at 150—160 °C for 15 min.
After cooling, the mixture was triturated with EtOH and isolated insoluble material was collected by
filtration. The crystalline substance was washed with AcOEt to give 4a as a white solid (0.98 g, 62.8%).
Mp 219—221 °C (dec). IR (KBr) cm-1: 3320, 3170, 1695, 1671. FAB-MS (positive) m/z: 343 (M+H)+.
1H-NMR (DMSO-d6) ": 1.26 (12H, s, dodecane H-4, H-5, H-6, H-7, H-8, H-9), 1.51 (4H, t, J = 6.5 Hz,
dodecane H-3, H-10), 2.17 (4H, t, J = 7.5 Hz, dodecane H-2, H-11), 7.0—8.2 {8H, br, C=(N+H2)NH2},
13
9.53 (2H, s, CONHNH), 10.03 (2H, s, CONHNH). C-NMR (DMSO-d6) ": 24.3 (dodecane C-3, C-10),
28.5, 28.6, 28.8, 28.8 (dodecane C-4, C-5, C-6, C-7, C-8, C-9), 33.0 (dodecane C-2, C-11), 158.7
{NHC(=NH)NH2}, 172.6 (CO). Anal. Calcd for C14H30N8O2ꢁ2HCl: C, 40.48; H, 7.77; N, 26.98. Found:
C, 40.58; H, 7.70; N, 26.71.
N’1,N’12-Bis(4,5-dihydro-1H-imidazol-2-yl)dodecanedihydrazide (4b)
A slurry of dodecanedioyl dichloride (1.00 g, 3.74 mmol) and 2-hydrazinoimidazoline hydrobromide
(1.35 g, 7.46 mmol) in DMF (1 mL) was heated at 160 °C for 1 h. After cooling, the precipitated material
was washed with AcOEt and dissolved in water (10 mL). This aqueous solution was made alkaline (ca.
pH 11) with K2CO3 and concentrated in vacuo. The residue was purified by column chromatography
(silica gel) with EtOH/NH3 (28%ꢀaq) (95:5) as a solvent to give 4b as a white solid (0.23 g , 15.5%). Mp
174#190 °C (dec). IR (KBr) cm-1: 3264, 2925, 1662, 1613. FAB-MS (positive) m/z: 395 (M+H)+.
1H-NMR (DMSO-d6) ": 1.23—1.24 (12H, s, dodecane H-4, H-5, H-6, H-7, H-8, H-9), 1.44#1.50 (4H, br,
dodecane H-3, H-10), 1.98 (4H x 3/4, t, J = 7.5 Hz, dodecane H-2, H-11), 2.21 (4H x 1/4, t, J = 7.5 Hz,
dodecane H-2, H-11), 3.27 (8H, s, imidazole H-4, H-5), 5.86—6.22 (4H, br, NH), 7.5#9.0 (2H, br, NH).
13C-NMR (DMSO-d6) ": 24.2, 25.4, 25.4, 28.7, 28.7, 28.8, 28.8, 28.9, 28.9, 31.3, 34.1, 34.1 (dodecane C),
42.2 (br, imidazole C-4, C-5), 158.4, 161.4 (imidazole C-2), 167.4, 172.3 (CO). Anal. Calcd for
C18H34N8O2 • 0.6 H2O: C, 53.34; H, 8.75; N, 27.65. Found: C, 53.34; H, 8.47; N, 27.93.
5,5'-(Decane-1,10-diyl)bis(4H-1,2,4-triazol-3-amine) Dihydrochloride (5)
Aminoguanidine hydrochloride (1.65 g, 14.9 mmol) was added portionwise to dodecanedioyl dichloride
(1.00 g, 3.74 mmol) with stirring at rt, and the resulting mixture was heated at 160—180 °C for 3 h. After
cooling, the mixture was washed with water to give 5 as a white solid (0.38 g, 25.6%) as a solid material.
1
Mp >188 °C. IR (KBr) cm-1: 1698. FAB-MS (positive) m/z: 307 (M+H)+. H-NMR (DMSO-d6) ":
1.25—1.27 (12H, m, decane H-3, H-4, H-5, H-6, H-7, H-8), 1.59—1.63 (4H, m, decane, H-2, H-9), 2.51
(4H, t, J = 1.8 Hz, decane H-1, H-10), 8.0 (4H, br, NH2), 13.6 (2H, br, triazole NH). 13C-NMR
(DMSO-d6) ": 24.8 (decane C-1, C-10), 26.1 (decane C-2, C-9), 28.2, 28.5, 28.8 (decane C-3, C-4, C-5,
C-6, C-7, C-8), 151.0 (triazole C-3, C-5, C-3’, C-5’). Anal. Calcd for C14H26N8ꢁ2HClꢁH2O: C, 42.32; H,
7.61; N, 28.20. Found: C, 42.22; H, 7.42; N, 28.08.
N1,N12-Bis((3-([1,1'-biphenyl]-4-ylmethyl)-2-oxooxazolidin-4-yl)methyl)dodecanediamide (7a)

HETEROCYCLES, Vol. 87, No. 3, 2013
671
A solution of dodecanedioyl dichloride (0.122 g, 0.457 mmol), 4-(aminomethyl)-3-(3-biphenyl-4-
ylmethyl)oxazolidin-2-one (6a)16 (0.258 g, 0.914 mmol) and TEA (0.092 g, 0.911 mmol) in CH2Cl2 was
stirred at rt for 3 h. The reaction mixture was washed with water, 1 N HCl, and then with 5% aqueous
Na2CO3. After removal of the solvent under reduced pressure, the residue was crystallized by the addition
of CH3CN (5 mL, 50 °C). Compound 7a (0.232 g, 66.7%) was obtained by filtration as a white solid. Mp
123—124 °C. IR (KBr) cm-1: 1739, 1666. FAB-MS (positive) m/z: 759 (M+H)+. 1H-NMR (DMSO-d6) ":
1.22#1.24 (12H, m, dodecane H-4, H-5, H-6, H-7, H-8, H-9), 1.45#1.48 (4H, m, dodecane H-3, H-10),
2.07 (4H, dd, J = 8.0, 7.0 Hz, dodecane H-2, H-11), 3.27#3.37 (4H, m, CONHCH2), 3.68#3.72 (2H, m,
Oxaz H-4), 4.05 (2H, dd, J = 9.0, 6.0 Hz, Oxaz H-5), 4.27 (2H, d, J = 15.5 Hz, CHH-Ph), 4.31 (2H, d, J =
9.0 Hz, Oxaz H-5), 4.62 (2H, d, J = 15.5 Hz, CHH-Ph), 7.36—7.38 (6H, m, Ar-H), 7.44#7.48 (4H, m,
13
Ar-H), 7.64#7.67 (8H, m, Ar-H), 7.97 (2H, t, J = 6.0 Hz, CONHCH2). C-NMR (DMSO-d6) ": 25.2
(dodecane C-3, C-10), 25.6, 28.7, 28.8, (dodecane C-4, C-5, C-6, C-7, C-8, C-9), 35.3 (dodecane C-2,
C-11), 38.1 (CONHCH2), 44.6 (CH2-Ph), 53.6 (Oxaz C-4), 64.9 (Oxaz C-5), 126.6, 126.9 (Ar C), 127.4
(Ar C-4’), 128.3, 128.9 (Ar C), 135.6 (Ar C-1), 139.4 (Ar C-4 or Ar C-1’), 139.7 (Ar C-1’ or Ar C-4),
157.7 (Oxaz C-2), 173.0 (CONH). Anal. Calcd for C46H54N4O6: C, 72.80; H, 7.17; N, 7.16. Found: C,
72.88; H, 7.32; N, 7.16.
N1,N12-Bis((3-(3-fluoro-4-morpholinobenzyl)-2-oxooxazolidin-4-yl)methyl)dodecanediamide (7b)
A solution of dodecanedioyl dichloride (0.060 g, 0.225 mmol), 4-(aminomethyl)-3-(3-fluoro-4-
morpholinobenzyl)oxazolidin-2-one (6b)16 (0.150 g, 0.485 mmol) and TEA (0.046 g, 0.455 mmol) in
CH2Cl2 was stirred at rt for 3 h. After removal of the solvent, the residue was purified by column
chromatography (SiO2/i-PrOH"EtOH) to give 7b as a white solid (0.068 g, 34.2ꢂ). Mp 116—118 °C.
IR (KBr) cm-1: 1736, 1637. FAB-MS (positive) m/z: 835 (M+Na)+. 1H-NMR (DMSO-d6) ": 1.23 (12H, s,
dodecane H-4, H-5, H-6, H-7, H-8, H-9), 1.45—1.48 (4H, m, dodecane H-3, H-10), 2.05—2.08 (4H, m,
dodecane H-2, H-11), 2.98 (8H, d, J = 4.5 Hz, Mor H-2, H-6), 3.24 (2H, dd, J = 14.5, 4.5 Hz,
CONHCHH), 3.45 (2H, dd, J = 14.5, 7.0 Hz, CONHCHH), 3.64—3.66 (2H, m, Oxaz H-4), 3.72—3.74
(8H, m, Mor H-3, H-5), 4.01—4.04 (2H, m, Oxaz H-5), 4.15 (2H, d, J = 16.0 Hz, CHH-Ph), 4.26—4.29
(2H, t, J = 9.0 Hz, Oxaz H-5), 4.50 (2H, d, J = 16.0 Hz, CHH-Ph), 7.00—7.08 (6H, m, Ar-H), 7.98 (2H, t,
J = 6.0 Hz, CONHCH2). 13C-NMR (DMSO-d6) ": 25.2 (dodecane C-3, C-10), 28.6, 28.7, 28.8 (dodecane
C-4, C-5, C-6, C-7, C-8, C-9), 35.3 (dodecane C-2, C-11), 38.1 (CONHCH2), 44.0 (CH2-Ph), 50.4 (Mor
C-2, C-6), 53.6 (Oxaz C-4), 64.9 (Oxaz C-5), 66.1 (Mor C-3, C-5), 115.4 (d, J = 21 Hz, Ar C-2), 119.1 (d,
J = 3 Hz, Ar C-5), 124.2 (d, J = 3 Hz, Ar C-6), 131.0 (d, J = 7 Hz, Ar C-1), 139.0 (d, J = 8 Hz, Ar C-4),
154.7 (d, J = 245 Hz, Ar C-3), 157.7 (Oxaz C-2), 173.0 (CONH). Anal. Calcd for C42H58F2N6O8ꢁ2HClꢁ
0.5H2O: C, 56.37; H, 6.87; N, 9.39. Found: C, 56.55; H, 6.84; N, 9.13.

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HETEROCYCLES, Vol. 87, No. 3, 2013
N1,N3,N5-Tris((3-([1,1’-biphenyl]-4-ylmethyl)-2-oxooxazolidin-4-yl)methyl)cyclohexane-1,3,5-tricarb-
oxamide (8a)
A solution of 1,3,5-cis-cyclohexanetricarbonyl chloride (0.103 g, 0.379 mmol), 4-(aminomethyl)-3-(3-
biphenyl-4-ylmethyl)oxazolidin-2-one (6a) (0.030 g, 0.106 mmol) and TEA (0.033 g, 0.327 mmol) in
CH2Cl2 was stirred at rt for 3 h. After removal of the solvent under reduced pressure, the residue was
purified by centrifugal chromatography (silica gel) with EtOH as a solvent to give a crystalline product.
This material was washed with water followed by AcOEt to afford the described compound 8a as a white
solid (0.042 g, 37.8%). Mp 139 °C (with dec). IR (KBr) cm-1: 1734, 1653. FAB-MS (positive) m/z: 1009
1
(M+H)+. H-NMR (DMSO-d6) ": 1.43#1.46 (3H, m, Cyc HA-2, HA-4, HA-6), 1.70#1.73 (3H, m, Cyc
HB-2, HB-4, HB-6), 2.25 (3H, t-like, J = 12.0 Hz, Cyc H-1, H-3, H-5), 3.26#3.29 (3H, m, CONHCHH),
3.34#3.39 (3H, m, CONHCHH), 3.71#3.73 (3H, s, Oxaz H-4), 4.04#4.09 (3H, m, Oxaz H-5), 4.26
(3H, d, J = 16.0 Hz, CHH-Ph), 4.28#4.32 (3H, m, Oxaz H-5), 4.62 (3H, d, J = 16.0 Hz, CHHPh),
7.34#7.41 (9H, m, Ar H), 7.44#7.47 (6H, m, Ar H), 7.65#7.68 (12H, m, Ar H), 8.00#8.01 (3H, br,
NH). C13-NMR (DMSO-d6) ": 31.2 (Cyc C-2, C-4, C-6), 38.2 (CONHCH2), 42.8 (Cyc C-1, C-3, C-5),
44.6 (CH2-Ph), 53,6 (Oxaz C-4), 65.0 (Oxaz C-5), 126.6, 127.0 (Ar C), 127.4 (Ar C-4’), 128.3, 128.9 (Ar
C), 135.7 (Ar C-1), 139.4 (Ar C-4 or Ar C-1’), 139.7 (Ar C-1’ or C-4), 157.7 (Oxaz C-2), 174.9
(CONHCH2). HR-MS m/z: 1009.4496. (Calcd for C60H61N6O9 : 1009.4500).
N1,N3,N5-Tris((3-(3-fluoro-4-morpholinobenzyl)-2-oxooxazolidin-4-yl)methyl)cyclohexane-1,3,5-tri-
carboxamide (8b)
A solution of 1,3,5-cis-cyclohexanetricarbonyl chloride (0.034 g, 0.125 mmol), 4-(aminomethyl)-3-(3-
fluoro-4-morpholinobenzyl)oxazolidin-2-one (6b) (0.140 g, 0.453 mmol) and TEA (0.038 g, 0.376 mmol)
in CH2Cl2 was stirred at rt for 3 h. After removal of the solvent, the white residue was purified by column
chromatography using EtOH as a solvent. The obtained crude material was washed with water and then
AcOEt to give 8b as a white solid (0.110 g, 80.9%). Mp 148—152 °C. IR (KBr) cm-1: 1737, 1655.
1
FAB-MS (positive) m/z: 1112 (M+Na)+. H-NMR (DMSO-d6) ": 1.41—1.43 (3H, m, Cyc HA-2, HA-4,
HA-6), 1.64—1.73 (3H, m, Cyc HB-2, HB-4, HB-6), 2.20—2.25 (3H, m, Cyc H-1, H-3, H-5), 2.98 (12H, t,
J = 4.5 Hz, Mor H-2, H-6), 3.25—3.40 (6H, m, CONHCH2), 3.66—3.68 (3H, m, Oxaz H-4), 3.73 (12H, t,
J = 4.5 Hz, Mor H-3, H-5), 4.00—4.04 (3H, m, Oxaz H-5), 4.14 (3H, d, J = 16.0 Hz, CHH-Ph), 4.28 (3H,
t, J = 9.0 Hz, Oxaz H-5), 4.49 (3H, d, J = 16.0 Hz, CHH-Ph), 7.00—7.08 (9H, m, Ar H-2, H-5, H-6),
13
7.96—7.97 (3H, m, CONHCH2). C-NMR (DMSO-d6) ": 31.3 (Cyc C-2, C-4, C-6), 38.1 (CONHCH2),
42.7 (Cyc C-1, C-3, C-5), 44.0 (CH2-Ph), 50.4 (Mor C-2, C-6), 53.5 (Oxaz C-4), 64.9 (Oxaz C-5), 66.1
(Mor C-3, C-5), 115.4 (d, J = 21 Hz, Ar-2), 119.1 (d, J = 3 Hz, Ar-5), 124.2 (d, J = 3 Hz, Ar-6), 131.0 (d,
J = 7 Hz, Ar-1), 139.0 (d, J = 9 Hz, Ar-4), 154.7 (d, J = 245 Hz, Ar-3), 157.7 (Oxaz C-2), 174.9 (CONH).
HR-FAB-MS (positive) m/z: 1112.4685 (Calcd for C54H66O12N9F3Na: 1112.4681).

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BIOLOGICAL ASSAY
!-Glucosidase Inhibition Assay: !-Glucosidase inhibition assays for the synthesized compounds were
performed by the modified method of Shibano et al.22 Dimethyl sulfoxide (DMSO) was usedꢀ as a
solvent to dissolve the test samples. Phosphate buffer (pH = 7.0) was used as a solvent for the enzyme
!-glucosidase or the substrate p-nitrophenyl-!-D-glucopyranoside. After incubation of the reaction
mixture for 30 min at 37 °C and interruption of the reaction by addition of aqueous sodium carbonate, the
amount of generated p-nitrophenol was measured colorimetrically at 405 nm, and !-glucosidase
inhibition activity (IC50) was determined.
Assay for Antibacterial Activity: We used gram-negative bacteria (E. coli NIHJ) and gram-positive
bacteria (S. aureus ATCC6538P) as target organisms for the assay of antibacterial activities of the
synthesized symmetrical compounds. The bioassay for antibacterial activity was carried out by the
authentic method described in our previous report8 to obtain the minimum inhibitory concentration (MIC)
values. Dimethyl sulfoxide (DMSO) was used as a solvent to dissolve the target test compounds.
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HETEROCYCLES, Vol. 87, No. 3, 2013
various biological active compounds.24 Since we have already established a conventional procedure
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leads.
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length as a –CO-(CH2)10-CO- functionality in our designed molecules is attractive and is consistent
with the distance shown above.
13. Tautomer-like conversion {[4bA]
[4bB]} is one of the possible interconversions of the molecule
4b. Many types of the tautomer-like conversion involving terminal functional groups are possible
because of the possibilities of E/Z isomers of amide or hydrazine moiety in addition to imidazoline
ring tautomerization. 5-Membered hydrogen interaction between the terminal imidazoline ring and
E/Z isomers of the hydrazine group is also conceivable. So far, we have no spectroscopic evidence to
define the two C2-symmetrical molecular structures in solution.
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indicating little difference with respect to the signals assignable to substituted oxazolidin-2-one rings
and a linker cyclohexane ring. From the viewpoint of stereochemistry, however, the obtained
product can be considered to be a mixture of four triplet-drug type molecules, i.e., two
C3-symmetrical molecules that have the same absolute configuration regarding three introduced
oxazolidin-2-ones (R,R,R or S,S,S) in the molecules and two enantiometric molecules (R,R,S or

HETEROCYCLES, Vol. 87, No. 3, 2013
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S,S,R). We distinguished the presence of three predominant stereoisomers in the product 8a by an
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