One-pot synthesis of oxygen and nitrogen-bridged calix[2]arene[2]triazines

Article abstract of DOI:10.1080/10610278.2013.875175

A simple and powerful one-pot reaction method was developed for the synthesis of heteracalixaromatics. In the presence of a base, one-pot macrocyclic condensation reaction between cyanuric chloride and 1,3-phenylene diols and diamines proceeded effectively under very mild conditions to afford a number of functionalised oxygen and nitrogen-bridged calix[2]arene[2]triazines in 33-54% yields. The method was applied in a multigram-scale (14.4 g) preparation of tetraoxacalix[2]arene[2]triazine.

Full text of DOI:10.1080/10610278.2013.875175

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One-pot synthesis of oxygen and nitrogen-bridged
calix[2]arene[2]triazines
Xu-Dong Wanga, De-Xian Wanga, Zhi-Tang Huanga & Mei-Xiang Wangb
a Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular
Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing
100190, P.R. China
b Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology (Ministry of
Education), Tsinghua University, Beijing 100084, P.R. China
Published online: 05 Feb 2014.
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To cite this article: Xu-Dong Wang, De-Xian Wang, Zhi-Tang Huang & Mei-Xiang Wang (2014) One-pot synthesis of oxygen and
nitrogen-bridged calix[2]arene[2]triazines, Supramolecular Chemistry, 26:7-8, 601-606, DOI: 10.1080/10610278.2013.875175
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Supramolecular Chemistry, 2014
Vol. 26, Nos. 7–8, 601–606, http://dx.doi.org/10.1080/10610278.2013.875175
One-pot synthesis of oxygen and nitrogen-bridged calix[2]arene[2]triazines
Xu-Dong Wanga, De-Xian Wanga*, Zhi-Tang Huanga and Mei-Xiang Wangb*
aBeijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of
Chemistry, Chinese Academy of Sciences, Beijing 100190, P.R. China; Key Laboratory of Bioorganic Phosphorous Chemistry and
Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, P.R. China
b
(Received 5 November 2013; accepted 10 December 2013)
A simple and powerful one-pot reaction method was developed for the synthesis of heteracalixaromatics. In the presence of
a base, one-pot macrocyclic condensation reaction between cyanuric chloride and 1,3-phenylene diols and diamines
proceeded effectively under very mild conditions to afford a number of functionalised oxygen and nitrogen-bridged calix-
[2]arene[2]triazines in 33–54% yields. The method was applied in a multigram-scale (14.4 g) preparation of tetraoxacalix-
[2]arene[2]triazine.
Keywords: heteracalixaromatics; calix[2]arene[2]triazine; one-pot synthesis
Introduction
various aspects in supramolecular chemistry, development
of practical methods for the preparation of heteracalix[2]-
arene[2]triaiznes is therefore badly needed. We report
herein the simple and efficient one-pot synthesis of oxygen
and nitrogen-bridged calix[2]arene[2]triazines. A multi-
gram preparation of tetraoxacalix[2]arene[2]triazine is
also demonstrated.
Heteracalixaromatics, or heteroatom-bridged calix(het)-
arenes, are a new type of synthetic macrocyclic host
molecules (1–3). Because of their tunable cavity structures
and regulable electronic features determined by the nature of
the bridging heteroatoms, heteracalixaromatics have found
wide applications in supramolecular chemistry ranging from
selective interactions with metal ions (4–6), organometallic
clusters (7), anions (8–10, 25) and electron-neutral organic
molecules (11, 12) including fullerenes (13–15), fabrica-
tions of coordination cages and metal–organic frameworks
(16–18) to HPLC stationary phases (19), Langmuir–
Blodgett films (20) and CO2 absorption materials (21, 22).
Oxygen and nitrogen-bridged calix[2]arene[2]triazines are
important members of heteracalixaromatics (1–3, 23).
Derived from cyanuric chloride and resorcinol or m-
phenylenediamine, these macrocyclic compounds provide
versatile platforms for the construction of sophisticated
functional macrocycles (24–27) and complex molecular
architectures (28). Oxacalix[2]arene[2]triazines have been
demonstrated recently as unique hosts to selectively interact
with anions of varied geometries and shapes through
intriguing anion-p interactions (8).
Heteracalix[2]arene[2]triazines have been synthesised
by a step-wise fragment coupling approach (23). Although
the strategy works very effectively for the synthesis of
diverse oxygen and nitrogen-bridged calix[2]arene[2]-
triazines, especially unsymmetrically substituted ones, the
isolation and purification of the linear trimeric intermedi-
ates are sometimes tedious, and overall chemical yields
are less satisfactory in some cases. For further exploration
of the application of heteracalix[2]arene[2]triazines in
Results and discussion
To optimise one-pot synthesis of tetraoxacalix[2]arene[2]-
triazine 3a, we first investigated the effect of base
(2.4 equiv.) on the macrocyclic condensation reaction
between cyanuric chloride 1 and resorcinol 2a in acetone
at ambient temperature. As summarised in Table 1,
inorganic bases such as Na2CO3, K2CO3 and Cs2CO3 were
able to promote macrocyclisation reaction, giving desired
product 3a in 36%, 48% and 23% isolated yield,
respectively (entries 1–3, Table 1). Cesium fluoride,
however, did not effect the formation of macrocycle 3a
(entry 4, Table 1). While the use of organic bases including
triethylamine, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU)
and 1,4-azabicyclo[2.2.2]octane (DABCO) did not lead to
the expected product (entries 5–7), interestingly, macro-
cyclic condensation reaction proceeded effectively to
afford 3a in 52% yield when diisopropylethylamine
(DIPEA) was employed (entry 8, Table 1). It is important
to note that the solvent played a critical role in the reaction.
Polar solvents such as acetone and acetonitrile were
beneficial to the reaction, yielding product 3a in 52% and
49% yield (entries 8 and 9, Table 1), respectively. On the
contrary, tetrahydrofuran (THF) and 1,4-dioxane appeared
*Corresponding authors. Email: dxwang@iccas.ac.cn; wangmx@mail.tsinghua.edu.cn
q 2014 Taylor & Francis

602
X.-D. Wang et al.
Table 1. Optimisation of one-pot synthesis of tetraoxacalix[2]arene[2]triazine 3a.a
Cl
N
O
Cl
N
N
N
N
+
O
O
N
Cl
Cl HO
OH
N
1
N
2a
O
N
Cl
3a
Entry
Base (equiv.)
Solvent
Temp.
Conc. (mM)
Time (h)
Yield (%)b,c
1
2
3
4
5
6
7
8
Na2CO3 (2.4)
K2CO3 (2.4)
Cs2CO3 (2.4)
CsF (2.4)
Et3N (2.4)
DBU (2.4)
DABCO (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (2.4)
DIPEA (1.2)
DIPEA (3.6)
DIPEA (2.4)
Acetone
Acetone
Acetone
Acetone
Acetone
Acetone
Acetone
Acetone
CH3CN
THF
1,4-Dioxane
Acetone
Acetone
Acetone
Acetone
Acetone
Acetone
Acetone
Acetone
Rt
Rt
Rt
Rt
Rt
Rt
Rt
Rt
Rt
Rt
Rt
40
Reflux
0
Rt
Rt
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
200
24
24
24
24
24
24
24
24
12
24
24
18
12
96
48
96
24
24
6
36
48
23
Trace
Trace
0
0
52
49
0
9
10
11
12
13
14
15
16
17
18
19d
0
52
48
42
46
47
12
47
41
Rt
Rt
Rt
a 1 (1 mmol), 2a (1 mmol), base (2.4 mmol) and 66 ml of solvent were used.
b Isolated yield.
c In addition to macrocyclic product 3a, reaction also gave a mixture of inseparable oxacalix[3]arene[3] triazine, oxacalix[4]arene[4] triazine and
oligomers.
d 1 (1 mmol), 2a (1 mmol), base (2.4 mmol) and 5 ml of solvent were used.
detrimental to macrocyclisation, giving no targeted
macrocyclic product (entries 10 and 11, Table 1). To
further improve the chemical yield of the one-pot synthesis
of 3a, influence of reaction temperature, time and the
quantity of DIPEA on the macrocyclic condensation
reaction was also examined. Almost comparable yields
were observed when the reaction temperature was
increased to above 408C (entries 12 and 13, Table 1).
Macrocycle 3a was isolated in a slightly diminished yield
after an elongated time when the reaction was performed
at 08C (entry 14, Table 1). Chemical yield did not
necessarily increase with the increase of reaction time
from 24 h (entry 8, Table 1) to 48 h and to 96 h (entries 15
and 16, Table 1). It should be pointed out that the use of an
excess amount of DIPEA (3.6 equiv.) did not result in the
increase of chemical yield, while the reaction became less
efficient when the quantity of DIPEA was halved (entries
17 and 18). Noticeably, the one-pot reaction took place
very well under high substrate concentration conditions
such as 200 mM to produce the product in an only slight
decreased yield (entry 19, Table 1). The efficient formation
of oxacalix[2]arene[2]triazine 3a implies most probably a
thermodynamic process of the reaction.
The one-pot reaction was successfully applied in the
synthesis of other functionalised tetraoxacalix[2]arene[2]-
triazines. Outcomes compiled in Table 2 show, for
instance, the synthesis of oxacalix[2]arene[2]triazines 3b
and 3c that contain either benzyloxy or benzyloxycarbonyl
functionality on the upper-rim position of the macrocyclic
ring from resorcinol derivatives 2b and 2c, respectively
(entries 2 and 3, Table 2). The one-pot reaction between
methyl 4-(benzyloxy)-3,5-dihydroxybenzoate 2d, a gallic
acid derivative and cyanuric chloride 1 under the
optimised conditions afforded both upper and lower-rim
functionalised oxacalix[2]arene[2]triazine product 3d in
39% yield (entry 4, Table 2).
Encouraged by the one-pot synthesis of tetraoxacalix-
[2]arene[2]triazines, synthesis of nitrogen-bridged calix-
[2]arene[2]triazines was then attempted (Table 3). To our
delight, the one-pot reaction protocol was readily extended
to the synthesis of tetraazacalix[2]arene[2]triazine deriva-
tives that had only been obtained by a step-wise fragment

Supramolecular Chemistry
Table 2. One-pot synthesis of tetraoxacalix[2]arene[2]triazines 3.a
603
R1
Cl
N
R1
O
DIPEA
acetone
rt
N
N
R2
1 +
O
O
R2
HO
OH
N
R2
N
2a–d
O
N
R1
Cl
3a–d
Entry
2
X
R1
R2
Time (h)
3
Yield (%)b
1
2
3
4
2a
2b
2c
2d
O
O
O
O
H
OBn
CO2Bn
CO2Me
H
H
H
24
24
24
24
3a
3b
3c
3d
52
38
41
39
OBn
a Substrate concentration used for 2 was 15 mM.
b Isolated yield.
coupling approach. Under the identical basic conditions
for the synthesis of 3, reaction of m-phenylenediamine 4a
with cyanuric chloride 1 proceeded sluggishly. Gratify-
ingly, when a mixture of reactants and base was refluxed in
acetone for 2 days, tetraazacalix[2]arene[2]triazine 5a was
obtained in 54% yield (entry 1, Table 3). N,N0-dimethyl-m-
phenylenediamine 4b and N,N0-dibenzyl-m-phenylenedia-
mine 4c underwent macrocyclic condensation reaction
equally well with cyanuric chloride 1 to afford
tetraazacalix[2]arene[2]trazines that contain methyl (5b)
and benzyl (5c) substituents on the bridging nitrogen
(entries 2 and 3, Table 3). Noticeably, inorganic base
K2CO3 appeared superior to organic base DIPEA in the
preparation of 5b (entry 2, Table 3). A functionalised
tetraazacalix[2]arene[2]triazine 5d was conveniently
synthesised in 46% yield from a similar one-pot reaction
simply by using methyl 3,5-diaminobenzoate 4d as a
starting material (entry 4, Table 3). The one-pot reaction
was also found efficient for the construction of both upper-
and lower-rim disubstituted tetraazacalix[2]arene[2]tria-
zines. This has been exemplified by the preparation of
macrocycle 5e from the reaction of cyanuric chloride 1
with 2-(benzyloxy)-5-(t-butyl)benzene-1,3-diamine 4e1
(entry 5, Table 3).
Table 3. One-pot synthesis of tetraazacalix[2]arene[2]triazines 5.a
R1
R
N
Cl
N
R1
DIPEA
acetone
reflux
N
N
R2
1
+
R
N
N R
R
R
R2
N
H
N
H
N
R2
N
4a–e
N
R
R1
N
Cl
5a–e
Entry
4
R
R1
R2
Time (h)
5
Yield (%)b
1
4a
4b
4c
4d
4e
H
Me
Bn
H
H
H
H
H
H
H
H
OBn
48
48
48
48
48
5a
5b
5c
5d
5e
54
42
51
46
33
2c
3
4
5
CO2Me
t-Bu
H
a Substrate concentration of 4 was 5 mM.
b Isolated yield.
c K2CO3 was used as a base.

604
X.-D. Wang et al.
To demonstrate practical utility of the one-pot synthesis,
in acetone (100 ml) at room temperature. After addition
(ca. 5 h), the resulting mixture was refluxed for 2 days.
Pure azacalix[2]arene[2]triazine product 5a, 5d or 5e was
simply collected through filtration as white precipitates
after completion of the reaction. For the synthesis of 5c,
the resulting mixture was concentrated to about 50 ml.
Pure product 5c precipitated from the solution was
collected through filtration. The filtrate was concentrated
again and the residue was chromatographed on a silica gel
column using a mixture of petroleum ether and
dichloromethane (1:1) as an eluent to give another portion
of pure product 5c.
a multigram-scale preparation of 3a was executed. Thus,
under very mild conditions, the reaction of cyanuric chloride
1 (0.2mol) with resorcinol 2a (0.2mol) produced 14.4g of
pure oxacalix[2]arene[2]triazine 3a.
Conclusions
In conclusion, we have developed a facile and convenient
one-pot reaction method for the synthesis of oxygen and
nitrogen-bridged calix[2]arene[2]triazine derivatives from
readily available starting materials under very mild
conditions. A multigram (14.4 g) synthesis of oxacalix-
[2]arene[2]triazine was also demonstrated. In comparison
with the fragment coupling approach that gives low overall
chemical yields (23), the convenient one-pot reaction
strategy developed in this study shows high efficiency in
the construction of oxygen and nitrogen-bridged calix[2]-
arene[2]triazines.
Synthesis of nitrogen-bridged calix[2]arene[2]triazine 5b
To a well-stirred solution of cyanuric chloride (185 mg,
1 mmol) in acetone (100 ml) was added a mixture of 4
(136 mg, 1 mmol), K2CO3 (330 mg, 2.4 mmol) and water
(20 ml) in acetone (80 ml) at room temperature. After
addition (ca. 5 h), the resulting mixture was refluxed for
2 days. Acetone was removed using a rotary evaporator,
and crude product 5b was collected as precipitates by
filtration. The crude product was dissolved in THF, and
then was subjected to silica gel column chromatography
using a mixture of petroleum ether, dichloromethane and
methanol (10:10:1) as an eluent to give pure 5b.
Products 3a, 3c, 3d and 5a–c are known compounds,
and they gave identical spectroscopic data as that reported
in the literature (23–26). New compounds 3b, 5d and 5e
were fully characterised and their characterisation data are
listed as follows.
Experimental section
General information
Melting points are uncorrected. All solvents were dried
according to standard procedures prior to use. All other
major chemicals were obtained from commercial sources
and used without further purification.
General procedure for the one-pot synthesis of
oxygen-bridged calix[2]arene[2]triazines 3
Compound3a(whitesolid,115 mg, 52%):m.p.. 3008C
1
(lit. (23) . 3008C); H NMR (300MHz, CDCl3) d 7.31
To a well-stirred solution of DIPEA (310 mg, 1.2 mmol) in
acetone (33 ml) was added drop-wise a solution of
cyanuric chloride 1 (185 mg, 1 mmol) and 2 (110 mg for
2a, 216 mg for 2b, 244 mg for 2c, 274 mg for 2d, 1 mmol)
in acetone (33 ml) at room temperature. After addition (ca.
3 h), the resulting mixture was kept stirring for another
1 day. The solvent was then removed using a rotary
evaporator, the residue was dissolved in ethyl acetate
(50 ml) and was washed with water (3 £ 30 ml). Organic
phase was dried over anhydrous Na2SO4. After filtration,
the filtrate was concentrated. The residue was chromato-
graphed on a silica gel column using a mixture of
petroleum ether and ethyl acetate (4:1 for 3a, 6:1 for 3b,
5:1 for 3c and 3d, respectively) as an eluent to give pure
tetraoxacalix[2]arene[2]triazine products 3a–d.
(t, J ¼ 8.2 Hz, 2H), 6.90 (dd, J ¼ 8.2, 2.1 Hz, 4H), 6.70
(t, J ¼ 2.1 Hz, 2H).
Compound 3b (white solid, 118 mg, 38%): m.p. 186–
1878C; 1H NMR (300 MHz, CDCl3) d 7.36–7.30 (m,
10H), 6.56 (d, J ¼ 2.0 Hz, 4H), 6.34 (t, J ¼ 2.0 Hz, 2H),
4.97 (s, 4H); 13C NMR (75 MHz, CDCl3) d 174.5, 172.3,
160.7, 152.1, 135.5, 128.7, 128.4, 127.3, 108.2, 106.6,
70.8; MS (MALDI-TOF) m/z (%) 655.0 [M þ H]þ(100),
656.0 (44), 657.0 (78), 658.0 (24), 659.0 (16), 677
[M þ Na]þ(20), 678.0 (9), 679.0 (16), 680.0 (5). Anal.
calcd for C32H20N6O6Cl2: C, 58.64; H, 3.08; N, 12.82.
Found: C, 58.62; H, 3.17; N, 12.67.
Compound 3c (white solid, 145 mg, 41%): m.p. 216–
2178C (lit. (24) 216–2178C); 1H NMR (300 MHz, CDCl3)
d 7.61 (d, J ¼ 2.2 Hz, 4H), 7.41–7.36 (m, 10H), 6.92
(t, J ¼ 2.2 Hz, 2H), 5.31 (s, 4H).
General procedure for the one-pot synthesis of
nitrogen-bridged calix[2]arene[2]triazines 5a and 5c–e
Compound 3d (white solid, 150 mg, 39%): m.p. 230–
2318C (lit. (26) 230–2328C); 1H NMR (300 MHz, CDCl3)
d 7.60 (s, 4H), 7.26–7.17 (m, 6H), 7.05–7.02 (m, 4H),
4.87 (s, 4H), 3.87 (s, 6H).
To a well-stirred solution of cyanuric chloride 1 (185 mg,
1 mmol) and DIPEA (310 mg, 2.4 mmol) in acetone
(100 ml) was added drop-wise a solution of 4 (108 mg for
4a, 288 mg for 4c, 166 mg for 4d, 270 mg for 4e, 1 mmol)
Compound 5a (white solid, 115 mg, 54%):
1
m.p. . 3008C (lit. (23) . 3008C); H NMR (300 MHz,

Supramolecular Chemistry
605
DMSO-d6) d 10.0 (s, 4H), 7.78 (s, 2H), 7.23 (t, J ¼ 8.0 Hz,
2H), 6.81 (dd, J ¼ 8.0, 1.8 Hz, 4H).
1
m.p. . 3008C (lit. (23) . 3008C); H NMR (300 MHz,
brine (5 £ 100 ml), and then dried with anhydrous
Na2SO4. After removal of solvent, the residue was
chromatographed on a silica gel column using petroleum
ether and then a mixture of petroleum ether and ethyl
acetate (40:1) as mobile phase to give pure 2-(benzyloxy)-
5-(tert-butyl)-1,3-dinitrobenzene (9.1 g, 92%) as yellow
Compound 5b (white solid, 105 mg, 42%):
CDCl3) d 7.18 (t, J ¼ 11.1, 2H), 6.84 (dd, J ¼ 8.1, 1.8 Hz
4H), 6.70 (s, 2H), 3.25 (s, 12H).
1
Compound 5c (white solid, 205 mg, 51%): m.p. 279–
2808C (lit. (25) 282–2838C); 1H NMR (300 MHz, DMSO-
d6) d 7.31 (t, J ¼ 8.2 Hz, 2H), 6.90 (dd, J ¼ 8.2, 2.1 Hz,
4H), 6.70 (t, J ¼ 2.1 Hz, 2H).
solids: m.p. 102–1038C; H NMR (400 MHz, CDCl3) d
8.04 (s, 2H), 7.48 (dd, J ¼ 7.8, 2.3 Hz, 2H), 7.47–7.25 (m,
3H), 5.19 (s, 2H), 1.38 (s, 18H); 13C NMR (100 MHz/
CDCl3) d 148.9, 145.5, 143.5, 134.9, 129.2, 129.1, 128.8,
126.4, 79.1, 35.3, 30.9; IR (KBr, disc, cm21) n 2962, 1538,
1527, 1367, 1346; MS (ESI) m/z (%) 375 [M þ HCOO]2
(100), 376 (10), 377 (2). Anal. calcd for C17H18N2O5: C,
61.81; H, 5.49; N, 8.48. Found: C, 61.81; H, 5.50; N, 8.42.
Compound 5d (white solid, 120 mg, 46%):
1
m.p. . 3008C; H NMR (300 MHz, DMSO-d6) d 10.22
(s, 4H), 8.03 (s, 2H), 7.40 (s, 4H), 3.84 (s, 6H). 13C NMR
(75 MHz, CF3CO2D) d 171.5, 163.2, 163.1, 138.9, 136.2,
132.9, 129.6; IR (KBr, disc, cm21) n 3317, 1719, 1593,
1481, 1411, 1296; MS (MALDI-TOF) m/z (%) 555.4
[M þ H]þ(100), 556.4 (15), 557.4 (50), 558.4 (10). Anal.
calcd for C22H16Cl2N10O4·2H2O: C, 44.68; H, 3.41; N,
23.69. Found: C, 44.92; H, 3.27; N, 23.38.
Step 2. A mixture of iron powder (1.2 g), which
was washed three times with hydrochloric acid (2 M),
2-(benzyloxy)-5-(tert-butyl)-1,3-dinitrobenzene (330 mg,
1 mmol), water (2 ml) and concentrated hydrochloric acid
(40 ml) in ethanol (8 ml) was heated at 958C for 90 min in a
sealed tube while stirring. After cooling to room
temperature, the mixture was filtered and washed with
ethyl acetate. The filtrates were combined and the solvent
was removed in vacuum. The residue was mixed with
water (50 ml) and extracted with CH2Cl2 (5 £ 50 ml). The
organic phase was dried with anhydrous MgSO4. After
removal of the solvent, the residue was chromatographed
on a silica gel column eluted with a mixture of petroleum
ether and ethyl acetate (15:1) to afford pure 2-(benzyloxy)-
5-(tert-butyl)benzene-1,3-diamine 4e as white solids
Compound 5e (white solid, 125 mg, 33%):
m.p. . 3008C; 1H NMR (300 MHz, DMSO-d6) d 9.39
(s, 4H), 7.06–6.85 (m, 10H), 4.60 (s, 4H), 1.15 (s, 18H);
13C NMR (125 MHz, DMSO-d6) d 168.5, 166.9, 150.9,
145.9, 138.0, 130.9, 128.0, 127.4, 127.3, 125.2, 74.3, 31.5;
IR (KBr, disc, cm21) n 3215, 2962, 1571, 1538, 1488; MS
(ESI) m/z (%) 763.3 [M þ H]þ(100), 764.3 (30), 765.3
(50), 766.3 (20), 767.3 (10). Anal. calcd for C40H40Cl2
N10O2·CH3COCH3: C, 62.85; H, 5.64; N, 17.04. Found:
C, 63.10; H, 5.57; N, 17.16.
1
(250 mg, 93%): m.p. 111–1128C; H NMR (300 MHz,
A typical procedure for a multigram preparation of 3a
CDCl3) d 7.48 (m, 2H), 7.42–7.33 (m, 3H), 6.26 (s, 2H),
4.9 (s, 2H), 1.24(s, 18H); 13C NMR (100 MHz/CDCl3) d
148.9, 145.5, 143.5, 134.9, 129.2, 129.1, 128.8, 126.4,
79.1, 35.3, 30.9; IR (KBr, disc, cm21) n 3446, 3355, 2950,
1612, 1523, 1455, 1434, 1363; MS (CI) m/z (%) 270
[M]þ(100). Anal. calcd for C17H22N2O: C, 75.52; H, 8.20;
N, 10.36; Found: C, 75.29; H, 8.22; N, 10.31.
To a well-stirred solution of DIPEA (62 g, 0.48 mol) in
acetone (250 ml) was added drop-wise a solution of
cyanuric chloride 1 (36.9 g, 0.2 mol) and 2 (22.0 g,
0.2 mol) in acetone (750 ml) at room temperature. After
addition (ca. 3 h), the resulting mixture was stirring for
another 6 h. The solvent was then removed using a rotary
evaporator, the residue was dissolved in ethyl acetate
(500 ml) and was washed with water (3 £ 200 ml). The
organic phase was dried with anhydrous Na2SO4. After
removal of the drying agent and solvent, the residue was
chromatographed on a silica gel column using a mixture of
petroleum ether and ethyl acetate (8:1) as an eluent to
afford pure product 3a (14.4 g, 33%).
Acknowledgements
We thank Mr Yu-Fei Ao who checked the multigram-scale
synthesis of oxacalix[2]arene[2]triazine, and Mr Jiang-Tao Li
who prepared reactant 4e.
Funding
We gratefully thank the National Natural Science Foundation of
China [grant numbers 21072197, 91127008, 21272239,
21132005, 21121004] and Ministry of Science and Technology
[grant numbers 2011CB932501, 2013CB834504] for financial
support.
Preparation of 4e
Step 1. Under argon protection, to a mixture of 4-tert-
butyl-2,6-dinitrophenol (7.2 g, 30 mmol), KOH (3.36 g)
and Cs2CO3 (1.02 g) in dry DMF (200 ml) was added
benzyl bromide (15.6 g, 90 mmol) at room temperature.
The resulting mixture was stirred for overnight. Water was
added and the mixture was extracted with CH2Cl2 (3
£ 200 ml). The combined organic phase was washed with
Note
1. Reactant 4e was synthesised from 4-tert-butyl-2,6-dinitrophe-
nol. For its preparation procedure, see ‘Experimental section’.

606
X.-D. Wang et al.
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