Synthesis and antiviral evaluation of some C3-symmetrical trialkoxy-substituted 1,3,5-triazines and their molecular geometry

Article abstract of DOI:10.1248/cpb.c15-00309

As one of our projects, we here report some new molecular modifications of 2,4,6-trichloro-1,3,5-triazine (TCTAZ: 1) to symmetrical 2,4,6-trialkoxy- or 2,4,6-triaryloxy-substituted 1,3,5-triazine (TAZ) molecules, as well as the results of anti-herpes simplex virus type 1 (anti-HSV-1) activity evaluation of synthesized 2,4,6-trisubstituted TAZ derivatives. Among the tested 2,4,6-trisubstituted TAZ derivatives, we reconfirmed that a C₃-symmetrical TAZ derivative, 4e, shows the highest level of anti-HSV-1 activity with a good selectivity index. In this paper, we also report the results of the preparation of newly targeted TAZ derivatives and the structure-activity relationships (SARs) of these trialkoxy-substituted TAZ derivatives and related compounds. The sugar recognition properties of C₃-symmetrical TAZ derivative 4e are also described.

Full text of DOI:10.1248/cpb.c15-00309

Vol. 63, No. 11
Chem. Pharm. Bull. 63, 935–944 (2015)
935
Note
Synthesis and Antiviral Evaluation of Some C3-Symmetrical Trialkoxy-
Substituted 1,3,5-Triazines and Their Molecular Geometry
Nobuko Mibu,a Kazumi Yokomizo,b Hatsumi Aki,a Norimasa Ota,a Hiroyuki Fujii,a
Ai Yuzuriha,a Shiori Saneyoshi,b Aoi Tanaka,b Airi Koga,a Jianrong Zhou,b Takeshi Miyata,b and
,a
Kunihiro Sumoto*
a Faculty of Pharmaceutical Sciences, Fukuoka University; 8–19–1 Nanakuma, Jonan-ku, Fukuoka 814–0180,
b
Japan: and Faculty of Pharmaceutical Sciences, Sojo University; 4–22–1 Ikeda, Kumamoto 862–0082, Japan.
Received April 6, 2015; accepted July 24, 2015
As one of our projects, we here report some new molecular modifications of 2,4,6-trichloro-1,3,5-tri-
azine (TCTAZ: 1) to symmetrical 2,4,6-trialkoxy- or 2,4,6-triaryloxy-substituted 1,3,5-triazine (TAZ) mole-
cules, as well as the results of anti-herpes simplex virus type 1 (anti-HSV-1) activity evaluation of synthesized
2,4,6-trisubstituted TAZ derivatives. Among the tested 2,4,6-trisubstituted TAZ derivatives, we reconfirmed
that a C3-symmetrical TAZ derivative, 4e, shows the highest level of anti-HSV-1 activity with a good selectiv-
ity index. In this paper, we also report the results of the preparation of newly targeted TAZ derivatives and
the structure–activity relationships (SARs) of these trialkoxy-substituted TAZ derivatives and related com-
pounds. The sugar recognition properties of C3-symmetrical TAZ derivative 4e are also described.
Key words 1,3,5-triazine; C3 symmetry; anti-herpes simplex virus type 1; structure–activity relationship;
plaque reduction assay; isothermal titration calorimetry
The glycocalyx at the cell surface, containing glycoproteins, of newly targeted trisubstituted TAZ derivatives together with
proteoglycans and glicolipids, plays an important role in vari- the results of biological evaluation of synthesized 2,4,6-trisub-
ous cell-to-cell communications. Specific interactions of these stituted TAZ derivatives. We also describe the structure–ac-
carbohydrates with lectins (protein receptors) are important tivity relationships (SARs) of 2,4,6-trialkoxy- or 2,4,6-triary-
biological processes, including the processes of bacterial or loxy-substituted TAZ derivatives and related compounds.
viral infection and tumor metastasis.1–3)
Synthesis of Target Compounds The main targeted sym-
From the viewpoint of molecular symmetry, many host metrical 2,4,6-trialkoxy-substituted TAZ derivatives with a
receptors that consist of homo-oligometric units (homo- TAZ template were prepared by a procedure with TCTAZ (1)
multiligands) often construct symmetric macromolecule ar- as a starting material. The overall process for the preparation
chitectures such as C2- or C3-symmetrical geometry receptor of target molecules involving three nucleophilic substitution
systems. These phenomena of macromolecules connected with reaction stages in one pot is shown in Chart 1. Preparation of
many biological stages have encouraged scientists to develop all of the targeted symmetrical alkoxy- and/or aryloxy-trisub-
new multivalent symmetrical synthetic molecules to find new stituted TAZ derivatives (4) was conducted by nucleophilic
bioactive compounds or leads. Results of many works related substitutions of TCTAZ (1) with an alcohol (b–iH) or a phe-
to the above conception have been published over the past nol derivative (j–lH) (Chart 1). As we reported previously,8,9)
few decades.4–7) The terms identical twin-drugs and triplet- the reactivity of chloro-substituted triazines was gradually
drugs (symmetrical bivalent and trivalent molecules) are now decreased by the accumulation of electron-donating alcohol
commonly used in medicinal chemistry and related scientific substituents (as with amine substituents). For the preparation
fields. In connection with our synthetic works on such sym- of intermediate monoalkoxy-substituted TAZ (2) by alcohols
metrical molecules, we have already designed and synthesized (bH, e–iH), the following procedure is conventional. Thus,
a few new symmetrical molecules and evaluated their bioac- easy access for the target intermediates 2 was achieved from
tivities in order to find new types of bioactive compounds.8–17) TCTAZ (1) with collidine as a base (Method C) under mild
In connection with the above projects, we have recently conditions (0°C to room temperature within 1h). The gen-
reported some molecular modifications of 2,4,6-trichloro- eration of dialkoxy-substituted TAZ (3) needed harder reaction
1,3,5-triazine (TCTAZ) (1) to symmetrical 2,4,6-trisubstituted conditions (reflux for 1d, and so on), especially for reactions
1,3,5-triazine (TAZ) molecules and the results of biological with secondary alcohols. However, the use of n-BuLi in these
evaluation of synthesized symmetrical 2,4,6-trisubstituted reactions was effective for the formation of intermediate-
TAZ derivatives.8,9) Among previously targeted trisubstituted disubstituted TAZ (3) and final trisubstituted TAZ derivatives
TAZ derivatives, we found that a C3-symmetrical TAZ deriva- (4). We consider that the generated alkoxide anions (RO−)
tive with three isopropoxy groups on a TAZ template such as may act as better nucleophiles in the substitution reactions.
compound 4e showed a high level of anti-herpes simplex virus The reactions with n-BuLi are sometimes accompanied by the
(HSV)-1 activity and low cytotoxity, and it therefore seemed formation of undesired butyloxy-substituted TAZ derivatives,
to be a potential lead in the search for preferred anti-HSV-1 and the separation of target TAZ derivatives was not facile
activity with a good selectivity index (SI).
by either chromatography or recrystallization.8) Therefore, we
In this paper, we report the results of further preparation used an alternative method with NaH for generation of RO−
*To whom correspondence should be addressed. e-mail: kunihiro@adm.fukuoka-u.ac.jp
© 2015 The Pharmaceutical Society of Japan

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Chem. Pharm. Bull.
Vol. 63, No. 11 (2015)
Chart 1. Synthesis of Trialkoxy-Substituted TAZ Derivatives (4)
Chart 2. CS-Symmetrical Aminoaryloxy-Substituted TAZ Derivatives (5, 6)
(Method A) for the preparation of target molecules, according
to the method reported by Spielman et al.18)
The results (yields, reaction conditions and isolated prod-
ucts) for the preparation of target C3-symmetrical trisubstitut-
ed TAZ derivatives (4b–l) are summarized in Table 1. In order
to find an alternative method to obtain trialkoxy TAZ (4f),
we tried a procedure using triethylamine (TEA)19) (Method B,
Chart 3. Synthesis of CS-Symmetrical Trialkoxy-Substituted TAZ De-
rivatives
Entry 6); however, only undesired by-products (7–9) were ob-
tained. This reaction can be assumed to result in the formation
of quaternary N-triazinylammonium salts as reactive interme- was replaced by one isopropoxy group were also prepared
diates from the substitution reaction of TEA.20,21) Therefore, from reactions of 2e for a comparison of their geometrical fea-
most of the reactions of TCTAZ (1) with various alcohols tures and antiviral activities (Chart 3 and see Experimental).
were performed by Method A, and trialkoxy TAZ derivatives All structures of the synthesized compounds were easily
(4g–i) were easily isolated by recrystallization after work-up confirmed by spectroscopic and analytical data. The geom-
in 35–45% yields (Entries 7–9).
etries of symmetrical structures of target TAZ derivatives
In the case of reactions of TCTAZ (1) with some phenol described in this article were also confirmed by 13C-NMR
derivatives (j–lH), the target C3-symmetrical derivatives (4j–l) spectroscopic data (see Experimental for details).
were obtained by the procedures using TEA (Method B) and
collidine (Method C). Results of our synthetic trials with
phenol derivatives for targeted C3-symmetrical tri-substituted
TAZ derivatives are also shown in Table 1.
Results and Discussion
The structures of targeted C3- and a few CS-symmetrical
2,4,6-trisubstituted TAZ derivatives obtained from TCTAZ
We also synthesized CS-symmetrical aminoaryloxy-substi- and the results of their biological evaluations [anti-HSV-1 ac-
tuted TAZ derivatives (5, 6 in Chart 2) from the reactions of tivities (EC50) by plaque reduction assays22) and cytotoxicities
TCTAZ, phenol (kH or lH), and 4-piperidinemethanol (pH) against Vero cells (IC50)] are summarized in Table 2 together
stepwise using Method C with collidine in Step 1 (see Experi- with data for aciclovir.23) Calculated logP values24) for the
mental).
compounds are also shown in Table 2. There was no distinct
As a result, we revealed that the reactions of TCTAZ (1) correlation between logP values and EC50 values or between
with various alcohols or phenols (b–lH) provide a conven- logP values and IC50 values among the compounds listed in
tional procedure for preparation of targeted C3-symmetrical Table 2.
trisubstituted TAZ molecules (4b–l). Some other isolated un-
expected trisubstituted TAZ derivatives (7, 8) as by-products face with trialkoxy TAZ derivatives, all three oxygen atoms of
are also shown in Table 1. alkoxy groups on the TAZ template and three TAZ ring nitro-
In supramolecular interactions of glycocalyx at the cell sur-
Two CS-type compounds (4dde and 4ggg) in which one of gen lone pairs are expected to display the remarkable charac-
the three alkoxy groups in the C3-type molecules 4d and 4g teristics of hydrogen bonding acceptors or a Lewis base. We

Vol. 63, No. 11 (2015)
Chem. Pharm. Bull.
937
Table 1. Synthesis of C3-Symmetrical Trisubstituted TAZ Derivatives (4) from Reactions of TCTAZ (1) with Various Alcohols or Phenols (ROH or
ArOH)
Entry
1
ROH
Method
A
Ratio of 1:ROH:(Additive)
1:bH:(NaH)=1:3.3:(3.15)
Conditions
1) reflux 5h, N2
Products (yield %)a)
4b (41)
2) reflux 1h, N2
1) rt 15min to reflux 4h, Ar
2) reflux 1h, Ar
2
3
A
A
1:cH:(NaH)=1:4.5:(3.15)
1:dH:(NaH)=1:4.5:(3.15)
4c (74)
4d (69)
1) rt 0.5h to reflux 19h, N2
2) rt 20min to reflux 1h, N2
1) rt 15min to reflux 1h, N2
2) rt 15min to reflux 1h, N2
4
5
A
A
1:eH:(NaH)=1:4.5:(3.15)
1:fH:(NaH)=1:4.5:(3.15)
4e (77)
4f (72)
1) reflux 15h, N2
2) reflux 1h, N2
6
7
B
A
1:fH:(TEA)=1:5:(3.5)
rt 19h, Ar, THFc)
7 (30), 8 (8)
4g (38)b)
1) rt 0.5h to reflux 12h, N2
2) rt 10min to reflux 1h, N2
1:gH:(NaH)=1:3.3:(3.15)
1) reflux 19h, N2
2) reflux 1h, N2
8
9
A
A
1:hH:(NaH)=1:4.5:(3.15)
1:iH:(NaH)=1:4.5:(3.15)
4h (35)b)
4i (45)b)
1) rt 15min to reflux 14h, N2
2) rt 20min to reflux 1h, N2
10
11
C
B
1:jH:(collidine)=1:3.1:(3.1)
1:kH:(TEA)=1:3.1:(3.1)
rt 2d
4j (95)
4k (74)
rt 18h, acetonec)
c)
12
B
1:lH:(TEA)=1:3.1:(3.1)
4l (40)
reflux 19h to reflux 0.5h, CH2Cl2
a) Yield obtained from TCTAZ (1). b) Yield obtained after recrystallization. c) Solvent used.

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Chem. Pharm. Bull.
Vol. 63, No. 11 (2015)
Table 2. Anti-HSV-1 Activity (EC50), Cytotoxicity (IC50) against Vero Cells, and Calculated LogP
Compound
EC50 (µM) IC50 (µM)
LogPa)
Compound
EC50 (µM) IC50 (µM)
LogPa)
4a
>100
>100
1.39
4l
85.0
>200
9.15
4b
4c
>100
>100
>200
>100
0.93
6.37
5jppc)
6jjpb)
>6.3
42.2
3.52
4.62
32.2
303.6
4d
4eb)
4f
>100
>100
8.87
3.36
6.28
4.78
5kpp
6kkp
5lpp
6llp
>25
>25
35.4
63.9
25.5
8.1
4.67
6.91
4.67
6.91
1.87
479.8
>100
>100
>200
>100
37.1
4g
>200
4h
4i
>100
>100
>100
>200
6.04
7.29
4dde
4egg
>100
>100
>200
>200
7.04
4.31
4j
>100
>100
>200
>200
5.72
9.15
7
>100
>200
>444
5.2
d)
4k
Aciclovir
1.1
−0.76
a) LogP was calculated by using ChemBioDraw 14.0. b) Data were taken from ref. 8. c) Data were taken from ref. 9. d) Data were taken from ref. 23.
considered that a high level of antiviral activity of compound droxymethylpiperidine groups on the TAZ template, was
4e is probably produced by the unique symmetrical structure used for a key starting structure for three-stage modification
and chemical property.
[A→B (CS-symmetry)→C (CS-symmetry)→D (C3-symmetry)]
For the strategy of molecular modification, we considered (see Chart 4). We carried out step-by-step introduction of the
a step-by-step modification approach for determining the same alkoxy or related aryloxy functionality into the template
relationship between the geometry and nature of the alkoxy instead of a 4-hydroxymethylpiperidine group involved in the
group. C3-symmetrical molecule A, which has three 4-hy- key starting C3-symmetrical lead A.

Vol. 63, No. 11 (2015)
Chem. Pharm. Bull.
939
Table 3. Binding Constants (Ka) and Thermodynamic Parameters of Complexes of Compound 4e with Sugar Derivatives in Aqueous 25% 2-Propanol
at 298.15K
Stoichiometry of
binding (4e:Sugar)
−1
Entry
Sugar*
Ka [M
]
ΔG [kJmol−1
]
ΔH [kJmol−1
]
−TΔS [kJmol−1
]
1
2
3
4
MeO-α-Gal
MeO-β-Gal
MeO-α-Man
MeO-β-Man
1:1
1:1
21,500
5,350
−24.7
−21.3
ND**
−29.1
−3.44
−8.03
ND**
−4.93
−21.3
−13.2
ND**
−24.2
ND**
1:1
ND**
126,000
*MeO-α/β-Gal and MeO-α/β-Man stand for methyl α/β-D-galactopyranoside and methyl α/β-D-mannopyranoside, respectively. **Not determined.
ed and triaryloxy-substituted C3-symmetrical TAZ derivatives
than the original compound 4e.8) These results indicate that
the molecule 4e is the best structural feature for anti-HSV-1
activity in the present modifications.
In calorimetric experiments for sugar recognition of C3-
symmetrical antiviral active lead 4e, a few of the binding
reactions that we have tried with sugar derivatives (see Exper-
imental) were exothermic. Binding reactions with some mono-
saccharides obtained by calorimetric experiments showed
interesting binding properties as listed in Table 3.
−1
The Ka values of compound 4e were 2.15×104 M for meth-
Chart 4. Three-Stage Modification of TAZ Molecule A
−1
yl α-D-galactopyranoside (MeO-α-Gal), 5.35×103 M for meth-
−1
For modification to the targeted molecular structure D, we yl β-D-galactopyranoside (MeO-β-Gal), and 1.26×105 M for
carried out a few simple modifications of a C3-symmetrical methyl β-D-mannopyranoside (MeO-β-Man), and each of the
TAZ derivative 4e with three isopropoxy groups on a TAZ binding reactions had a 1:1 stoichiometry. The reaction with
template to other C3-symmmetrical trialkoxy TAZ derivatives MeO-β-Man showed a high value of Ka and thermodynamic
such as compounds 4a–i. However, none of the C3-symmetri- parameters of ΔG=−29.1kJ/mol, ΔH=−4.93kJ/mol, and
cal trialkoxy-substituted TAZ molecules in which three iso- −TΔS=−24.2kJ/mol. However, for the reaction of compound
propoxy moieties in the TAZ template had been replaced with 4e with MeO-α-Man, no heat of binding was detected and the
other different alkoxy groups showed significant anti-HSV-1 thermodynamic parameters (ΔG, ΔH, and −TΔS) including
activity at a dose of 100µM, indicating no enhancement effect Ka could not be determined by repeated isothermal titration
of this modification. Thus, C3-type compounds (4a–d) having calorimetry (ITC) experiments as shown in Table 3. From a
aliphatic-chain alkoxy groups on the TAZ template showed no comparison of the Ka values of C3-symmetrical compound 4e,
significant anti-HSV-1 activity at a dose of 100µM. The size of the binding affinity for MeO-α-Gal was about 4-times stron-
cycloalkyloxy groups consisting of C5–C7 carbons (C3-type ger than that for MeO-β-Gal. In the reactions of compound
compounds 4g, 4h, and 4i) was also not a preferred structural 4e with the set of MeO-α/β-Man, MeO-β-Man showed a high
feature for antiviral activity of C3-symmetrical trialkoxy-sub- binding constant (Ka=1.26×105 M−1), but that of the reaction
stituted TAZ derivatives. The trialkoxy-substituted C3-type with MeO-α-Man was not exothermic as shown by ITC ex-
derivatives prepared in this study, except for C3-symmetrical periments. Furthermore, in both reactions of compound 4e
lead 4e, were inactive.
with the set of methyl α/β-D-glucopyranoside (MeO-α/β-Glc),
Comparing symmetrical geometric features, two CS-type no heat of binding was detected by repeated ITC experiments.
compounds (4dde and 4egg) in which one of the three al- Thus, the results obtained for compound 4e by ITC experi-
koxy groups in the C3-type molecules 4d and 4g is replaced ments indicated that the binding reactions were very sensitive
by one isopropoxy group also showed no biological activities to the structural features of a monosaccharide moiety. These
(anti-HSV-1 activity or cytotoxic activity) at a dose of 100µM. results (properties) are particularly interesting because our
Furthermore, two CS-type compounds (5epp8) and 6eep8) hav- previously synthesized highly cytotoxic symmetrical lectin-
ing one or two isopropoxy groups in the template A were also like compound E (Fig. 1) showed β-anomer selectivity in
inactive at a dose of 100µM (see ref. 8).
its binding reactions with a few monosaccharides including
Regarding triaryloxy-substituted TAZ derivatives, three MeO-α/β-Gal and MeO-α/β-Glc.10) We now consider that the
C3-type compounds (4j–l) showed lower levels of biological selectivity of the symmetrical small molecule 4e between
activitiy (anti-HSV-1 activity or cytotoxic activity) than those a few monosaccharides and the behaviors of these different
of the corresponding CS-type molecules (B: 5jpp,9) 5kpp, and sensitivities of these carbohydrates are characteristic and that
5lpp and C: 6jjp,8) 6kkp, and 6llp). However, these CS-sym- this carbohydrate recognition property may be responsible for
metrical derivatives were not superior to the C3-type lead 4e its high anti-HSV-1 activity, providing a large SI value for
in terms of both anti-HSV-activity and SI value. Derivatiza- compound 4e.
tion to these C3-type compounds with the same three alkoxy
substituents on the TAZ template was also found to be not study, none of the synthesized symmetrical TAZ derivatives
effective for increasing anti-HSV-1 activity.
showed higher levels of anti-HSV-1 activity than that of the
Among the symmetrical TAZ derivatives prepared in this
Through these modifications described above, we unfortu- 2,4,6-triisopropoxy derivative 4e. Although more precise eval-
nately could not find more antiviral active trialkoxy-substitut- uation regarding the peculiarity of three isopropoxy groups on

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Chem. Pharm. Bull.
Vol. 63, No. 11 (2015)
[chloroform-d3 (CDCl3) (77.00ppm), methanol-d4 (CD3OD)
(49.00ppm)] for 13C-NMR. The abbreviations qu=quintet,
dd=double doublets, and dm=double multiplets are used for
1
the multiplicity of H-NMR data. The signal assignments were
1
confirmed by two-dimensional (2D)-NMR analyses: H–1H 2D
l
correlation spectroscopy (COSY), H–l3C heteronuclear mul-
1
tiple-quantum coherence (HMQC), and H–l3C heteronuclear
multiple-bond connectivity (HMBC). Microanalyses were per-
formed with a Yanaco MT-6 CHN corder. Routine monitoring
of reactions was carried out using precoated Kieselgel 60F254
plates (E. Merck). Open and flash column chromatography
separations of the reaction products were performed on silica
gel (Kanto 60N) with a UV detector. Commercially available
starting materials and compound 4a were used without further
Fig. 1. Compound E
the TAZ template is needed, the reported compatibility of the purification, and dry solvents were used in all reactions.
isopropyl group on a few benzene-based symmetrical artificial General Procedure for the Preparation of Trialk-
receptors25) with some monosaccharides seems to indicate oxy-1,3,5-triazine Derivatives (Method A18)): Example:
the possibility of important hydrophobic interactions of this Preparation of 2,4,6-Tris(1-heptyloxy)-1,3,5-triazine (4d)
side chain as a recognition site for carbohydrates through a (Entry 3): (Step 1) To a solution of n-heptanol (dH, 5.23g,
combination of hydrogen bonding, CH–π interaction and van 45.0mmol) in dry benzene (10mL) was added NaH (60% in
der Waals contacts.26) The results of calorimetric experiments mineral oil, 1.26g, 31.5mmol) at room temperature under an
indicate that binding interactions of compound 4e with these N2 atmosphere. A suspension of sodium n-heptyloxide was
sugars (MeO-α/β-Gal and MeO-β-Man) have both favorable prepared by stirring at room temperature for 0.5h and then
hydrophobic interaction and hydrogen bonding formation. In refluxing for 19h. (Step 2) After cooling to room tempera-
addition, in calorimetric experiments of an anti-HSV-1 inac- ture, compound 1 (1.84g, 10.0mmol) in dry benzene (20mL)
tive C3-type molecule 4g that has three cyclopentyloxy groups was added dropwise with stirring. After stirring for 20min
on the TAZ template with MeO-α/β-Gal, no heat of binding at room temperature, the reaction mixture was refluxed for
was detected, indicating that the three isopropoxy groups in 1h. After cooling to room temperature, the resulting mixture
the C3-type compound 4e may play an important role in these was acidified with acetic acid (ca. 2mL) and then diluted with
exothermic binding interactions with carbohydrates such as water (ca. 20mL). The separated organic layer was washed
MeO-α/β-Gal. Applications of C3-symmetrical functional with water (ca. 20mL) and dried over magnesium sulfate
receptor molecules in the area of molecular recognition have (MgSO4). Evaporation of the solvent gave a pale yellow re-
led to significant advances, and it is also expected that the use sidual oil. To this residue was added n-hexane (ca. 10mL), and
of C3-symmetrical molecules will lead to many developments insoluble solids were removed. The filtrate was purified by
in molecular recognition stages.27) Regarding carbohydrate flash chromatography (n-hexane:EtOAc=97:3→95:5) to give
recognition by C3-type symmetrical small molecules, we 4d (2.91g, 69%) as a colorless oil.
consider that the results obtained for diastereo-selective sugar
4d: IR (NaCl) cm−1: 1566 (C=N) 1145, 1118 (C–O of ether).
recognition in some monosaccharides such as MeO-α/β-Gal 1H-NMR (CDCl3) δ: 0.88 (9H, t, J=7.0Hz, H7′), 1.26–1.37
by compound 4e may provide useful information for research (18H, m, H4′, 5′, 6′), 1.38–1.46 (6H, m, H3′), 1.75–1.81 (6H,
on carbohydrates recognition, especially by an achiral small m, H2′), 4.38 (6H, t, J=6.7Hz, H1′). 13C-NMR (CDCl3) δ:
molecule with three-fold (C3-geometrical) symmetry.28)
13.98 (C7′), 22.53 (C6′), 25.76 (C3′), 28.64 (C2′), 28.91 (C4′),
On the basis of this information on sugar recognition of C3- 31.69 (C5′), 68.45(C1′), 173.16 (C=N). Positive-ion FAB-MS
symmetrical antiviral active TAZ derivative 4e, we are also m/z: 424 (M+H+). HR-FAB-MS m/z: 424.3547 (Calcd for
planning to carry out further molecular modifications to the C24H46N3O3: 424.3539). Anal. Calcd for C24H45N3O3: C, 68.04;
related trisubstituted TAZ derivatives with branched C3–C5 H, 10.71; N, 9.92. Found: C, 67.88; H, 10.88; N, 9.91.
alkoxy groups similar to the isopropoxy group. Further details
2,4,6-Tris(2-methoxyethoxy)-1,3,5-triazine (4b) (Entry 1)
of an SAR study and additional calorimetric experiments This compound was prepared from the reaction of compound
including other prepared TAZ derivatives will be described 1 with 2-methoxyethanol (bH) by using Method A under the
separately.
conditions shown in Table 1. Separation of the products by
flash chromatography (n-hexane:EtOAc=35:65→30:70) gave
4b (41%) as a pale yellow oil.
Experimental
Melting points were determined using a micro melting point
4b: IR (NaCl) cm−1: 1569 (C=N), 1151, 1122 (C–O of
apparatus (Yanaco MP-S3) without correction. IR spectra ether). 1H-NMR (CDCl3) δ: 3.40 (9H, s, OCH3), 3.72 (6H,
were measured by a Shimadzu FTIR-8100 IR spectropho- t, J=4.9Hz, H2′), 4.54 (6H, t, J=4.9Hz, H1′). 13C-NMR
tometer. Low- and high-resolution mass spectra (LR-MS and (CDCl3) δ: 58.91 (OCH3), 67.23 (C1′), 70.04 (C2′), 172.97
HR-MS) were obtained by a JEOL JMS HX-110 double-focus- (C=N). Positive-ion FAB-MS m/z: 304 (M+H+). HR-FAB-MS
ing model equipped with an FAB ion source interfaced with a m/z: 304.1498 (Calcd for C12H22N3O6: 304.1509). Anal. Calcd
JEOL JMA-DA 7000 data system. H- and 13C-NMR spectra for C12H21N3O6·0.2H2O: C, 49.96; H, 7.03; N, 13.69. Found: C,
l
were obtained by JEOL JNM A-500. Chemical shifts were 49.95; H, 6.93; N, 13.72.
expressed in δ ppm downfield from an internal TMS signal for
2,4,6-Tris(1-pentyloxy)-1,3,5-triazine (4c)18) (Entry 2)
lH-NMR and the carbon signal of the corresponding solvent This compound was prepared from compound 1 and 1-penta-

Vol. 63, No. 11 (2015)
Chem. Pharm. Bull.
941
nol (cH) (Method A) under the conditions shown in Table 1. 40.98 (C1′), 164.75 (C=N). Positive-ion FAB-MS m/z: 295
Separation of the reaction products by flash chromatography (M+H+). HR-FAB-MS m/z: 295.2611 (Calcd for C15H31N6:
(n-hexane:EtOAc=93:7→95:5) gave 4c (74%) as a colorless 295.2610).
1
oil.
9: H-NMR (CDCl3) δ: 1.16 (12H, t, J=7.0Hz, H2′), 3.56
4c: IR (NaCl) cm−1: 1567 (C=N), 1144, 1116 (C–O of (8H, qu, J=7.0Hz, H1′), 3.87 (3H, s, OCH3). 13C-NMR
ether). 1H-NMR (CDCl3) δ: 0.91 (9H, t, J=7.0Hz, H5′), (CDCl3) δ: 13.26 (C2′), 41.28 (C1′), 53.27 (OCH3), 165.54 (C4,
1.32–1.45 (12H, m, H3′, 4′), 1.75–1.82 (6H, m, H2′), 4.38 (6H, 6), 170.92 (C2). Positive-ion FAB-MS m/z: 254 (M+H+). HR-
t, J=6.7Hz, H1′). 13C-NMR (CDCl3) δ: 13.85 (C5′), 22.30 FAB-MS m/z: 254.1982 (Calcd for C12H24N5O: 254.1981).
(C4′), 27.91 (C3′), 28.30 (C2′), 68.40 (C1′), 173.14 (C=N).
2,4,6-Tris(cyclopentyloxy)-1,3,5-triazine (4g) (Entry 7)
Positive-ion FAB-MS m/z: 340 (M+H+). HR-FAB-MS m/z: This compound was obtained from the reaction of compound
340.2601 (Calcd for C18H34N3O3: 340.2600). Anal. Calcd for 1 with cyclopentanol (gH) (Method A) under the conditions
C18H33N3O3·0.4H2O: C, 62.36; H, 9.83; N, 12.12. Found: C, shown in Table 1. After work-up of the reaction mixture,
62.47; H, 9.87; N, 12.34.
crude orange solid material 4g was obtained. Recrystallization
Preparation of 2,4,6-Tris(2-propoxy)-1,3,5-triazine (4e)8,18) from EtOAc gave 4g (38%) as colorless crystals.
(Entry 4) This compound was obtained in 77% yield from
4g: mp 146–148°C (from EtOAc). IR (KBr) cm−1: 1561
1
the reaction of compound 1 with isopropanol (eH) by using (C=N), 1129 (C–O of ether). H-NMR (CDCl3) δ: 1.60 (6H,
Method A under the conditions shown in Table 1. Recrystalli- m, H3′, 4′), 1.78–1.90 (12H, m, H3′, 4′, 2′, 5′), 1.92–2.00 (6H,
zation from EtOH gave analytically pure 4e as colorless crys- m, H2′, 5′), 5.46 (3H, qu, J=3.1Hz, H1′). 13C-NMR (CDCl3)
tals, mp 106–108°C (from EtOH). Spectral data (IR, NMR, δ: 23.77 (C3′, 4′), 32.71 (C2′, 5′), 80.59 (C1′), 172.68 (C=N).
and MS) and elemental analysis data of the product 4e were Positive-ion FAB-MS m/z: 334 (M+H+). HR-FAB-MS m/z:
consistent with those of the authentic sample.8)
334.2130 (Calcd for C18H28N3O3: 334.2131). Anal. Calcd for
2,4,6-Tris(3-pentyloxy)-1,3,5-triazine (4f)18) (Entry 5) C18H27N3O3: C, 64.84; H, 8.16; N, 12.60. Found: C, 64.71; H,
This compound was prepared from compound 1 and 3-penta- 8.21; N, 12.54.
nol (fH) (Method A) under the conditions shown in Table 1.
2,4,6-Tris(cyclohexyloxy)-1,3,5-triazine (4h) (Entry 8)
Separation of the reaction products by flash chromatography This compound was obtained from compound 1 and cyclo-
(n-hexane:EtOAc=98:2→95:5) afforded 4f (72%) as colorless hexanol (hH) (Method A) under the conditions shown in Table
solids. An analytical sample of 4f was obtained by recrystal- 1. After work-up of the reaction mixture, crude pale yellow
lization from water as colorless crystals.
solid material 4h was obtained. Recrystallization from EtOH
4f: mp 66–67°C (from H21O). IR (KBr) cm−1: 1553 (C=N), afforded 4h (35%) as colorless crystals.
1137, 1100 (C–O of ether). H-NMR (CD3OD) δ: 0.95 (18H,
4h: mp 230–233°C (from EtOH). IR (KBr) cm−1: 1561
t, J=7.5Hz, CH3), 1.69–1.76 (12H, m, CH2), 5.08 (3H, qu, (C=N), 1126, 1010 (C–O of ether). 1H-NMR (CDCl3) δ:
J=6.1Hz, CH). 13C-NMR (CD3OD) δ: 9.84 (CH3), 27.33 (CH2), 1.24–1.33 (3H, m, H4′), 1.35–1.44 (6H, m, H3′, 5′), 1.54–1.62
82.30 (CH), 174.60 (C=N). Positive-ion FAB-MS m/z: 340 (9H, m, H4′, 2′, 6′), 1.76–1.83 (6H, m, H3′, 5′), 1.97–2.03 (6H,
(M+H+). HR-FAB-MS m/z: 340.2602 (Calcd for C18H34N3O3: m, H2′, 6′), 5.03–5.10 (3H, m, H1′). 13C-NMR (CDCl3) δ:
340.2600). Anal. Calcd for C18H33N3O3: C, 63.68; H, 9.80; N, 23.79 (C3′, 5′), 25.39 (C4′), 31.58 (C2′, 6′), 76.14 (C1′), 172.71
12.38. Found: C, 63.53; H, 9.84; N, 12.35.
(C=N). Positive-ion FAB-MS m/z: 376 (M+H+). HR-FAB-MS
Reaction of Compound 1 with 3-Pentanol (fH): Forma- m/z: 376.2602 (Calcd for C21H34N3O3: 376.2600). Anal. Calcd
tion of N2,N2,N4,N4-Tetraethyl-6-(pentan-3-yloxy)-1,3,5-tri- for C21H33N3O3: C, 67.17; H, 8.86; N, 11.19. Found: C, 67.11; H,
azine-2,4-diamine (7), N2,N2,N4,N4,N6,N6-Hexaethyl-1,3,5- 8.87; N, 11.15.
triazine-2,4,6-triamine (8),20) and N2,N2,N4,N4-Tetraethyl-
2,4,6-Tris(cycloheptyloxy)-1,3,5-triazine (4i) (Entry 9)
6-methoxy-1,3,5-triazine-2,4-diamine (9)29) (Method B) This compound was prepared from the reaction of compound
(Entry 6) To a solution of compound 1 (1.84g, 10.0mmol) 1 and cycloheptanol (iH) by using Method A under the condi-
in dry tetrahydrofuran (THF) (20mL) was added 3-pentanol tions shown in Table 1. After work-up of the reaction mixture,
(fH, 4.41g, 50.0mmol) and TEA (3.54g, 35.0mmol) at room crude yellow solid material 4i was obtained. Recrystallization
temperature in an atmosphere of argon. After stirring for 19h from EtOH gave 4i (45%) as colorless crystals.
at room temperature, the resulting precipitates (TEA·HCl salt)
4i: mp 175–177°C (from EtOH). IR (KBr) cm−1: 1562
1
were removed by filtration. After evaporation of the solvent, (C=N), 1129 (C–O of ether). H-NMR (CDCl3) δ: 1.44–1.51
the products were separated by flash chromatography (n-hex- (6H, m, H3′, 6′), 1.56–1.62 (12H, m, H4′, 5′), 1.69–1.76 (6H,
ane:EtOAc=99:1→95:5) to give 8 (8%) as a colorless oil, 7 m, H3′, 6′), 1.79–1.86 (6H, m, H2′, 7′), 2.01–2.07 (6H, m,
(30%) as a colorless oil, and 9 (2%) as a pale yellow oil.
H2′, 7′), 5.23 (3H, m, H1′). 13C-NMR (CDCl3) δ: 22.80 (C3′,
7: IR (NaCl) cm−1: 1568 (C=N), 1225, 1096 (C–O of ether). 6′), 28.36 (C4′, 5′), 33.66 (C2′, 7′), 78.63 (C1′), 172.58 (C=N).
1H-NMR (CDCl3) δ: 0.93 (6H, t, J=7.5Hz, H1″, 5″), 1.16 (12H, Positive-ion FAB-MS m/z: 418 (M+H+). HR-FAB-MS m/z:
t, J=7.0Hz, H2′), 1.60–1.76 (4H, m, H2″, 4″), 3.56 (8H, q, 418.3075 (Calcd for C24H40N3O3: 418.3070). Anal. Calcd for
J=7.0Hz, H1′), 4.97–5.02 (1H, m, H3″). 13C-NMR (CDCl3) C24H39N3O3: C, 69.03; H, 9.41; N, 10.06. Found: C, 69.08; H,
δ: 10.03 (C1″, 5″), 13.35 (C2′), 26.72 (C2″, 4″), 41.24 (C1′), 9.61; N, 10.07.
78.23 (C3″), 165.62 (C2, 4), 170.90 (C6). Positive-ion FAB-
Procedure for the Synthesis of 2,4,6-(1,3-Benzodioxol-
MS m/z: 310 (M+H+). HR-FAB-MS m/z: 310.2577 (Calcd for 5-yloxy)-1,3,5-triazine (4j) (Method C) (Entry 10) To a
C16H32N5O: 310.2607). Anal. Calcd for C16H31N5O·0.5H2O: C, solution of compound 1 (922mg, 5.0mmol) in dry acetone
60.34; H, 10.13; N, 21.99. Found: C, 60.37; H, 10.11; N, 22.10.
(25mL) was added sesamol (jH, 2.14g, 15.5mmol) and col-
1
8: H-NMR (CDCl3) δ: 1.14 (18H, t, J=7.0Hz, H2′), 3.53 lidine (1.88g, 15.5mmol) at room temperature. After stirring
(12H, q, J=7.0Hz, H1′). 13C-NMR (CDCl3) δ: 13.47 (C2′), for 2d at room temperature, the resulting precipitates were

942
Chem. Pharm. Bull.
Vol. 63, No. 11 (2015)
collected and the obtained material was added to CH2Cl2 (ca. triazine-2,4-diyl]bis-4-piperidinemethanol (5kpp) (Step 1)
60mL). The resulting mixture was stirred for 30min at room A mixture of compound 1 (922mg, 5.0mmol), phenol (kH,
temperature, and then the insoluble precipitates were collected 973mg, 6.0mmol), and collidine (727mg, 6.0mmol) in dry
and the obtained material was added to EtOH (ca. 150mL). acetone (10mL) was stirred for 10min at 0°C and kept for
After stirring for 1h at room temperature, the insoluble crude 15min at room temperature. The resulting colorless precipitat-
precipitates 4j were collected as a white solid (2.31g, 95%). ed material (collidine·HCl) was removed by filtration and then
An analytical sample of 4j was obtained by recrystallization the solvent was evaporated to afford a yellow solid. (Step 2) To
from acetone as colorless crystals.
this material in dry CH3CN (10mL) was added 4-piperidine-
4j: mp 249–250°C (from acetone). IR (KBr) cm−1: 1579 methanol (pH, 2.30g 20.0mmol), and the resulting mixture
(C=N), 1175, 1140, 1040 (C–O). 1H-NMR (CDCl3) δ: 5.98 was stirred for 1h at room temperature. After evaporation of
(6H, s, H2), 6.58 (3H, dd, J=8.2, 2.4Hz, H6), 6.63 (3H, d, the solvent, a solvent (ca. 10mL of n-hexane:2-PrOH=80:20)
J=2.4Hz, H4), 6.75 (3H, d, J=8.2Hz, H7). 13C-NMR (CDCl3) was added to the residue, and then the insoluble materials
δ: 101.80 (C2), 103.68 (C4), 107.92 (C7), 113.84 (C6), 145.63 were filtered to give crude 5kpp (1.92g, 4.1mmol, 81%) as a
(C7a), 146.00 (C5), 148.04 (C3a), 174.05 (C=N). Positive- white solid. Recrystallization from propionitrile (EtCN) gave
ion FAB-MS m/z: 490 (M+H+). HR-FAB-MS m/z: 490.0888 an analytically pure product 5kpp.
(Calcd for C24H16N3O9: 490.0887). Anal. Calcd for C24H15N3O9:
C, 58.90; H, 3.09; N, 8.59. Found: C, 58.92; H, 3.14; N, 8.61.
5kpp: mp 126–128°C (from EtCN). IR (KBr) cm−1: 1580
(C=N), 1323 (C–F), 1107, 1029 (C–O). H-NMR (CDCl3) δ:
1
Procedure for the Synthesis of 2,4,6-[3-(Trifluoro- 1.10–1.25 (4H, m, H3′β, 5′β), 1.58 (2H, brs, OH), 1.68–1.82
methyl)phenoxy]-1,3,5-triazine (4k)30) (Method B) (Entry (6H, m, H4′α, 3′α, 5′α), 2.72–2.85 (4H, m, H2′β, 6′β), 3.50
11)
A
mixture of compound
1
(922mg, 5.0mmol), (4H, d, J=5.8Hz, H1), 4.50–4.82 (4H, m, H2′α, 6′α), 7.36 (1H,
3-(trifluoromethyl)phenol (kH, 2.51g, 15.5mmol), and TEA dm, J=7.9Hz, H5‴), 7.41–7.47 (2H, m, J=7.6Hz, H4‴, 6‴)
(1.57g, 15.5mmol) in dry acetone (20mL) was stirred for 7.52–7.54 (1H, m, H2‴). 13C-NMR (CDCl3) δ: 28.50 (C3′, 5′),
18h at room temperature. After evaporation of the solvent, 39.03 (C4′), 43.37 (C2′, 6′), 67.55 (C1), 119.61 (q, J=4.1Hz,
CH2Cl2 (ca. 100mL) and 10% HCl (100mL) were added to C2‴), 121.40 (q, J=4.1Hz, C4‴), 123.82 (q, J=272.6Hz, CF3),
the reaction mixture. The separated organic layer was washed 125.19 (C6‴), 129.35 (C5‴), 131.15 (q, J=32.4Hz, C3‴), 152.82
with brine (40mL) and dried over MgSO4. Evaporation of the (C1‴), 165.78 (C2″, 4″), 170.60 (C6″). Positive-ion FAB-MS
solvent gave crude white solid material 4k. Recrystallization m/z: 468 (M+H+). HR-FAB-MS m/z: 468.2229 (Calcd for
from 2-PrOH gave analytically pure 4k (74%) as a colorless C22H29F3N5O3: 468.2222). Anal. Calcd for C22H28F3N5O3 : C,
amorphous solid.
56.52; H, 6.04; N, 14.98. Found: C, 56.52; H, 5.90; N, 14.99.
[1-[4,6-Bis[3-(trifluoromethyl)phenoxy)]-1,3,5-triazin-
4k: mp 155–158°C (from 2-PrOH). IR (KBr) cm−1: 1572
1
(C=N), 1321 (C–F), 1183, 1124 (C–O). H-NMR (CDCl3) δ: 2-yl]piperidin-4-yl]methanol (6kkp) This compound was
7.30 (3H, dm, J=7.6Hz, H6′), 7.37 (3H, brs, H2′), 7.45–7.50 prepared from phenol (kH) and amine (pH) by using Method
(6H, m, H4′, 5′). 13C-NMR (CDCl3) δ: 118.76 (q, J=4.1Hz, C at room temperature for 1h in Step 1 and then at room tem-
C2′), 123.18 (q, J=4.1Hz, C4′), 123.33 (q, J=272.1Hz, perature for 18h in Step 2 with the ratio of TCTAZ:kH:col-
CF3), 124.89 (C6′), 130.17 (C5′), 132.16 (q, J=33.1Hz, C3′), lidine:pH=1:2.4:2.4:2. Purification of products by flash
151.43 (C1′), 173.50 (C=N). Positive-ion FAB-MS m/z: 562 chromatography (n-hexane:EtOAc=85:15→70:30) gave 6kkp
(M+H+). HR-FAB-MS m/z: 562.0823 (Calcd for C24H13F9N3O3: (69%) and 5kpp (29%). An analytical sample of 6kkp was
562.0813). Anal. Calcd for C24H12F9N3O3: C, 51.35; H, 2.15; N, obtained by recrystallization from diisopropyl ether as color-
7.49. Found: C, 51.11; H, 2.24; N, 7.57.
less crystals.
2,4,6-[4-(Trifluoromethyl)phenoxy]-1,3,5-triazine
(4l)
6kkp: mp 135.0–136.5°C (from diisopropyl ether). IR (KBr)
(Entry 12) This compound was prepared from the reaction cm−1: 1596 (C=N), 1326 (C–F), 1123, 1068 (C–O). H-NMR
of compound 1 and 4-(trifluoromethyl)phenol (lH) by using (CDCl3) δ: 1.12–1.22 (4H, m, H3′β, 5′β), 1.53 (1H, brs, OH),
Method B under the conditions shown in Table 1. The result- 1.74–1.80 (3H, m, H4′α, 3′α, 5′α), 2.84 (2H, dt, J=13.4,
ing precipitates (TEA·HCl salt) were removed by filtration. 2.4Hz, H2′β, 6′β), 3.51 (2H, d, J=5.8Hz, H1), 4.57 (2H, dm,
After evaporation of the solvent, the products were separated J=13.4Hz, H2′α, 6′α), 7.30–7.34 (2H, m, H5‴), 7.43–7.48 (6H,
by flash chromatography (n-hexane:CH2Cl2=4:6→1:9) to m, H2‴, 4‴, 6‴). 13C-NMR (CDCl3) δ: 28.37 (C3′, 5′), 38.71
give 4l (33%) as a white solid. An analytical sample of 4l was (C4′), 43.88 (C2′, 6′), 67.19 (C1), 119.20 (q, J=4.1Hz, C2‴),
obtained by recrystallization from 2-PrOH gave 4l as colorless 122.19 (q, J=4.1Hz, C4‴), 123.58 (q, J=273.1Hz, CF3), 125.15
1
needles.
(C6‴), 129.74 (C5‴), 131.65 (q, J=32.8Hz, C3‴), 152.12 (C1‴),
4l: mp 217–218°C (from 2-PrOH). IR (KBr) cm−1: 1577 166.21 (C2″, 4″), 171.89 (C6″). Positive-ion FAB-MS m/z: 515
(C=N), 1331 (C–F), 1119, 1066 (C–O). H-NMR (CDCl3) δ: (M+H+). HR-FAB-MS m/z: 515.1524 (Calcd for C23H21F6N4O3:
1
7.23 (6H, d, J=8.5Hz, H2′, 6′), 7.63 (6H, d, J=8.5Hz, H3′, 5′). 515.1518). Anal. Calcd for C23H20F6N4O3: C, 53.70; H, 3.92; N,
13C-NMR (CDCl3) δ: 121.96 (C2′, 6′), 123.65 (q, J=272.0Hz, 10.89. Found: C, 53.63; H, 3.76; N, 10.86.
CF3), 126.94 (q, J=4.1Hz, C3′, 5′), 128.87 (q, J=33.1Hz, C4′),
1,1′-[6-(4-Trifluoromethyl)pheoxy)-1,3,5-triazine-2,4-
153.74 (C1′), 173.39 (C=N). Positive-ion FAB-MS m/z: 562 diyl]bis-4-piperidinemethanol (5lpp) and [1-[4,6-Bis[4-
(M+H+). HR-FAB-MS m/z: 562.0807 (Calcd for C24H13F9N3O3: (trifluoromethyl)phenoxy]-1,3,5-triazin-2-yl]piperidin-4-
562.0813). Anal. Calcd for C24H12 F9N3O3: C, 51.35; H, 2.15; N, yl]methanol (6llp) These compounds were prepared
7.49. Found: C, 51.55; H, 2.15; N, 7.49.
from phenol (lH) and amine (pH) by Method C at room
General Procedure for the Preparation of Aryloxy- temperature for 1h in Step 1 and then at room tempera-
amino-1,3,5-triazine Derivatives (Method C): Example: ture for 0.5h in Step 2 with the ratio of TCTAZ:lH:colli-
Preparation of 1,1′-[6-[3-(Trifluoromethyl)phenoxy]-1,3,5- dine:pH=1:1.8:1.8:2. Purification of products by flash chro-

Vol. 63, No. 11 (2015)
Chem. Pharm. Bull.
943
matography (CH2Cl2 :EtOH=97:3→93:7) gave 6llp (73%) (8H, m, H2′, 3′, 4′, 5′), 1.92–2.00 (4H, m, H2′, 5′), 5.34 (1H,
and 5lpp (19%). Analytical samples of 5lpp and 6llp were qu, J=6.1Hz, H2″), 5.46 (2H, qu, J=3.1Hz, H1′). 13C-NMR
obtained as colorless crystals by recrystallization from EtCN (CDCl3) δ: 21.79 (C1″, 3″), 23.79 (C3′, 4′), 32.71 (C2′, 5′),
and EtOH, respectively.
71.27 (C2″), 80.61 (C1′), 172.48 (C6), 172.80 (C2, 4). Positive-
5lpp: 162–164°C (from EtCN). IR (KBr) cm−1: 1583, 1527 ion FAB-MS m/z: 308 (M+H+). HR-FAB-MS m/z: 308.1977
1
(C=N), 1328 (C–F), 1064, 1038 (C–O). H-NMR (CDCl3) δ: (Calcd for C16H26N3O3: 308.1974). Anal. Calcd for C16H25N3O3:
1.10–1.25 (4H, m, H3′β, 5′β), 1.44 (2H, brs, OH), 1.72–1.86 C, 62.52; H, 8.20; N, 13.67. Found: C, 62.57; H, 8.22; N, 13.55.
(6H, m, H4′α, 3′α, 5′α), 2.74–2.87 (4H, m, H2′β, 6′β), 3.51
Antiviral Activity Assay and Cytotoxicity of Synthesized
(4H, d, J=6.1Hz, H1), 4.50–4.86 (4H, m, H2′α, 6′α), 7.30 Trisubstituted TAZ Derivatives The anti-HSV-1 activities
(2H, d, J=8.4Hz, H2‴, 6‴), 7.61 (2H, d, J=8.4Hz, H3‴, 5‴). (EC50) of the synthesized TAZ derivatives were measured by
13C-NMR (CDCl3) δ: 28.53 (C3′, 5′), 39.04 (C4′), 43.39 (C2′, using a plaque reduction assay22) and their cytotoxicity against
6′), 67.57 (C1), 122.28 (C2‴, 6‴), 124.17 (q, J=33.1Hz, CF3), Vero cells (IC50) was also evaluated. The results are summa-
126.16 (q, J=3.1Hz, C3‴, 5‴), 126.77 (q, J=33.1Hz, C4‴), rized in Table 2 together with data for aciclovir.23) Calculated
155.38 (C6″), 165.82 (C2′, 4″), 170.57 (C1″). Positive-ion FAB- logP values24) for the compounds are also shown in Table 2.
MS m/z: 468 (M+H+). HR-FAB-MS m/z: 468.2226 (Calcd for There were few distinct correlations between logP values and
C22H29F3N5O3: 468.2222). Anal. Calcd for C22H28F3N5O3: C, EC50 values or between logP values and IC50 values among
56.52; H, 6.04; N, 14.98. Found: C, 56.44; H, 5.93; N, 14.99.
the compounds listed in Table 2.
Calorimetric Experiments The heat of binding between
6llp: mp 196–199°C (from EtOH). IR (KBr) cm−1: 1562,
1540 (C=N), 1329 (C–F), 1060, 1047 (C–O). 1H-NMR (CDCl3) a tripodal receptor-type TAZ derivative 4e and sugars was
δ: 1.14–1.24 (2H, m, H3′β, 5′β), 1.47 (1H, brs, OH), 1.73–1.84 measured in aqueous 25% 2-propanol solution at 298.15K
(3H, m, H4′α, 3′α, 5′α), 2.85 (2H, dt, J=11.6, 2.1Hz, H2′β, by using an isothermal titration calorimeter (Thermal Activ-
6′β), 3.51 (2H, d, J=5.8Hz, H1), 4.59 (2H, dm, H2′α, 6′α), 7.45 ity Monitor 2270). Titrations were performed by stepwise
(4H, d, J=5.8Hz, H2‴, 6‴), 7.61 (4H, d, J=8.5Hz, H3‴, 5‴). injection of a sugar-containing solution (3.5–4.6mM, or ca.
13C-NMR (CDCl3) δ: 28.41 (C3′, 5′), 39.69 (C4′), 43.91 (C2′, 5mg/mL of dermatan sulfate or heparin sulfate) into a reac-
6′), 67.19 (C1), 122.20 (C2‴, 6‴), 123.91 (q, J=272.1Hz, CF3), tion cell (3mL) loaded with the compound 4e solution (ca.
126.54 (q, J=4.1Hz, C3‴, 5‴), 127.82 (q, J=33.1Hz, C4‴), 310–460µM). Many commercial sugar derivatives of monosac-
154.53 (C4″, 6″), 166.32 (C2″), 171.80 (C1‴). Positive-ion FAB- charide, disaccharide, trisaccharide, tetrasaccharide, oligosac-
MS m/z: 515 (M+H+). HR-FAB-MS m/z: 515.1523 (Calcd for charide, aminosugar and some sulfated glycosaminoglycans
C23H21F6N4O3: 515.1518). Anal. Calcd for C23H20F6N4O3: C, were used for calorimetric experiments; however, observed
53.70; H, 3.92; N, 10.89. Found: C, 53.77; H, 4.06; N, 10.81.
2,4-Bis(heptyloxy)-6-isopropoxy-1,3,5-triazine (4dde) not exothermic. Three typical examples of exothermic binding
and 2,4-Bis(cyclopentyloxy)-6-isopropoxy-1,3,5-triazine reactions for methyl esters of monosaccharide (MeO-α/β-Gal
reactions of compound 4e with many sugar derivatives were
(4egg) The intermediate 2e for the preparation of com- and MeO-α/β-Man) are shown in Table 3. The data obtained
pounds 4dde and 4egg was prepared from the reaction of were analyzed by NanoAnalyze™ Software (TA Instruments,
compound 1 and 2-PrOH (eH) by using Method C at room U.S.A). Binding stoichiometry, Ka and ΔH are shown in Table
temperature for 2.5h with the ratio of TCTAZ:eH:col- 3. The values of ΔG and −TΔS were also calculated from
lidine=1:2.6:2. After removal of the precipitated material the equation ΔG=−RTlnKa=ΔH−TΔS (where R is the gas
(collidine·HCl), purification of the obtained crude product by constant and T is absolute temperature). The heat of bind-
open column chromatography (n-hexane:EtOAc=90:10) gave ing between a tripodal receptor-type TAZ derivative 4g and
2e8) (83%). Title two compounds were prepared from the MeO-α/β-Gal was also measured in aqueous 25% 2-propanol
reactions of compound 2e with alcohol dH or gH by using solution at 298.15K.
Method A under the same conditions as those for the prepa-
ration of 4e (Entry 4 in Table 1) with the ratio of 2e:dH or
Acknowledgment The authors would like to thank Ms.
gH:NaH=1:4:2. Separation of the products by flash chroma- Izumi Sakai, Ms. Marina Sano, Ms. Saki Sawai, and Ms.
tography (n-hexane:EtOAc=95:5→93:7) gave 4dde (75%) as Yuuna Kawaguchi for their valuable technical assistance.
colorless oil or 4egg (42%) as a white solid, respectively. Re-
crystallization from 2-PrOH–H2O gave 4egg as white crystals.
Conflict of Interest The authors declare no conflict of
4dde: IR (NaCl) cm−1: 1560 (C=N), 1146, 1102 (C–O). interest.
1H-NMR (CDCl3) δ: 0.88 (6H, t, J=7.0Hz, H7′), 1.26–1.36
(12H, m, H4′, 5′, 6′), 1.38 (6H, d, J=6.1Hz, H1″, 3″), 1.40–1.46
Supplementary Materials The online version of this ar-
(4H, m, H3′), 1.78 (4H, qu, J=6.7Hz, H2′), 4.37 (4H, t, ticle contains supplementary materials.
J=6.7Hz, H1′), 5.36 (1H, qu, J=6.1Hz, H2″). 13C-NMR
(CDCl3) δ: 13.92 (C7′), 21.69 (C1″, 3″), 22.47 (C6′), 25.71
(C3′), 28.60 (C2′), 28.86 (C4′), 31.64 (C5′), 68.31 (C1′), 71.43
(C2″), 172.52 (C6), 173.14 (C2, 4). Positive-ion FAB-MS
m/z: 368 (M+H+). HR-FAB-MS m/z: 368.2909 (Calcd for
C20H38N3O3: 368.2913). Anal. Calcd for C20H37N3O·0.2H2O: C,
64.73; H, 10.16; N, 11.32. Found: C, 64.71; H, 10.15; N, 11.43.
4egg: mp 94–97°C (from 2-PrOH–H2O). IR (KBr) cm−1:
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