NJC
Paper
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Tetra-p-tolyl 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate
and 3–4 drops of (f). White powder 1.22 g, yield 68%. m.p. 249.6–250.1 1C. H NMR
4
,4 ,4 ,4 -(Cyclobutane-1,2,3,4-tetrayl)tetrabenzoic acid (1.07 g,
1
2
.0 mmol) was dissolved in 18 mL of SOCl
2
anhydrous DMF. The mixture was heated at 70 1C for 24 h and an (600 MHz, CDCl ) d (ppm): 8.030 (d, 8H, J = 8.4 Hz, Ar-H), 7.275
3
excess of SOCl was removed by distillation to give a yellow solid. (d, 8H, J = 8.4 Hz, Ar-H), 7.200 (d, 8H, J = 8.4 Hz, Ar-H), 7.067
2
The solid was cooled to 5 1C and dissolved in 15 mL CH Cl and (d, 8H, J = 8.0 Hz, Ar-H), 4.690 (s, 4H, cyclobu-H), and 2.359
2
2
1
3
5
mL alcohol (or 16 mmol phenol), to which trimethylamine (s, 12H, –CH
3 3
). C NMR (150 MHz, CDCl ) d (ppm): 165.05,
(
10 mL) diluted with CH Cl (10 mL) was then added dropwise, 148.74, 145.22, 135.51, 130.31, 129.98, 128.15, 128.11, 121.35,
2
2
+
achieving pH = 8–9 at room temperature for 24 h. The reaction 47.67, and 20.88. HRMS: [M + K] calculated for C60
48 8
H O :
mixture was washed with saturated NaCl aqueous solution 935.2981; found 935.2966.
0 00 0 00
Tetrakis(4-methoxyphenyl) 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-
(
3 ꢁ 30 mL), and the organic layer was dried over MgSO
4
. After
removal of the solvent by rotary evaporation, the residue was tetrayl)tetrabenzoate (g). White powder 1.33 g, yield 69%.
1
purified by column chromatography (petroleum ether : ethyl m.p. 233.1–233.6 1C. H NMR (600 MHz, CDCl ) d (ppm):
3
acetate = 4 : 1, v/v) to obtain compounds a–i.
8.026 (d, 8H, J = 7.8 Hz, Ar-H), 7.275 (d, 8H, J = 7.8 Hz, Ar-H),
0
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Tetramethyl 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate 7.105 (d, 8H, J = 9.0 Hz, Ar-H), 6.918 (d, 8H, J = 8.4 Hz, Ar-H),
1
13
(
(
(
–
a). White powder 0.61 g, yield 52%. m.p.: 158.5–159.0 1C. H NMR 4.690 (s, 4H, cyclobu-H), and 3.808 (s, 12H, –OCH
600 MHz, CDCl ) d (ppm): 7.819 (d, 8H, J = 7.8 Hz, Ar-H), 7.150 (150 MHz, CDCl ) d (ppm): 165.21, 157.39, 145.32, 144.45,
d, 8H, J = 8.4 Hz, Ar-H), 4.577 (s, 4H, cyclobu-H), and 3.856 (s, 12H, 130.29, 128.12, 122.42, 114.57, 55.64, and 47.67. HRMS:
3
). C NMR
3
3
13
+
3 3 48
COOCH ). C NMR (150 MHz, CDCl ) d (ppm): 166.77, 144.91, [M + Na] calculated for C60H O12: 983.3038; found 983.3023.
+
0
00 0 0 0
129.62, 128.48, 127.92, 51.99, and 47.48. HRMS: [M + Na] calculated
Tetrakis(4-(trifluoromethyl)phenyl) 4,4 ,4 ,4 -(cyclobutane-
for C H O : 615.1989; found 615.1990.
1,2,3,4-tetrayl)tetrabenzoate (h). White powder 1.41 g, yield
36 32 8
0
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1
Tetraethyl 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate 63%. m.p. 152.5–153.0 1C. H NMR (600 MHz, CDCl ) d (ppm):
3
(
b). White powder 0.68 g, yield 52%. m.p. 122.5–122.9 1C. 8.057 (d, 8H, J = 8.4 Hz, Ar-H), 7.695 (d, 8H, J = 7.2 Hz, Ar-H), 7.326
1
13
H NMR (600 MHz, CDCl
3
) d (ppm): 7.831 (d, 8H, J = 8.4 Hz, (t, 16H, J = 6.0–7.2 Hz, Ar-H), and 4.735 (s, 4H, Cyclobu-H).
) d (ppm): 164.30, 153.43, 145.88, 130.49,
), and 1.356 (t, 12H, J = 7.2–14.4 Hz, 128.35, 127.56, 126.88, 124.80, 123.00, 122.21, and 47.68. HRMS:
C
Ar-H), 7.151 (d, 8H, J = 8.4 Hz, Ar-H), 4.574 (s, 4H, cyclobu-H), 4.320 NMR (150 MHz, CDCl
3
(d, 8H, J = 7.2 Hz, –COO–CH
2
1
3
+
–
CH
28.80, 127.87, 60.90, 47.55, and 14.30. HRMS: [M + Na] calculated
for C H O : 671.2615; found 671.2617.
3
). C NMR (150 MHz, CDCl
3
) d (ppm): 166.34, 144.87, 129.59, [M + K] calculated for C60
H
36
F
12
00 0 0 0
O
8
: 1151.1850; found 1151.1840.
+
0
1
Tetrakis(4-cyanophenyl) 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-tetrayl)-
tetrabenzoate (i). White powder 0.97 g, yield 52%. m.p. 147.2–
40 40 8
0
00 0 00
1
Tetrabutyl 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate 147.7 1C. H NMR (600 MHz, DMSO-d ) d (ppm): 7.986 (d, 8H,
6
1
(
(
(
c). White powder 0.61 g, yield 40%. m.p. 97.4–97.8 1C. H NMR J = 7.8 Hz, Ar-H), 7.965 (d, 8H, J = 9.0 Hz, Ar-H), 7.602 (d, 8H,
600 MHz, CDCl ) d (ppm): 7.830 (d, 8H, J = 8.4 Hz, Ar-H), 7.152 J = 8.4 Hz, Ar-H), 7.519 (d, 8H, J = 8.4 Hz, Ar-H), and 4.916 (s, 4H,
d, 8H, J = 8.4 Hz, Ar-H), 4.571 (s, 4H, cyclobu-H), 4.265 (t, 8H, cyclobu-H). C NMR (150 MHz, DMSO-d
), 1.713 (t, 8H, J = 7.2–15.0 Hz, O–CH 154.54, 147.33, 134.50, 130.30, 129.17, 126.80, 123.86, 118.79,
), 1.426–1.464 (m, 8H, J = 7.8 Hz, O(CH –CH –), and 0.963 109.40, and 42.69. HRMS: [M + Na] calculated for C60
d, 12H, J = 7.2 Hz, –CH3). C NMR (150 MHz, CDCl ) d (ppm): 963.2425; found 963.2431.
3
1
3
6
) d (ppm): 164.25,
J = 7.2–13.2 Hz, COO–CH
CH
(
2
2
–
+
2
)
2 2
2
36 4 8
H N O :
1
3
3
1
66.40, 144.87, 129.60, 127.88, 64.81, 47.58, 30.79, 19.28, and
+
1
3.73. HRMS: [M + Na] calculated for C H O : 783.3867; X-ray crystal structure
4
8
56 8
found 783.3863.
Single-crystal X-ray diffraction measurements were carried out
using an Agilent SuperNova EosS2 diffractometer using a
graphite monochromatic Cu Ka radiation (l = 1.54184 Å)
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Tetrabenzyl 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate
white (d). White powder 0.77 g, yield 43%. m.p. 110.4–110.9 1C.
1
H NMR (600 MHz, CDCl
.401 (d, 8H, J = 7.2 Hz, Ar-H), 7.360 (t, 8H, J = 7.2–16.8 Hz, Ar-H),
.320 (t, 4H, J = 7.2–16.8 Hz, Ar-H), 7.132 (d, 8H, J = 8.4 Hz, Ar-H),
3
) d (ppm): 7.853 (d, 8H, J = 8.4 Hz, Ar-H),
source. The crystals were kept at 292.0(2) K during data collection.
7
7
59,60
The structures were solved by the ShelXT
structure solution
61
program in Olex2 and refined using Full-matrix Least Squares
1
3
5.292 (s, 8H, –CH –Ar), and 4.549 (s, 4H, cyclobu-H). C NMR
59,60
2
based on F2 with program SHELXL-2018
within Olex2.
(
150 MHz, CDCl ) d (ppm): 166.09, 145.05, 136.03, 129.78, 128.58,
3
Disorder was modelled using standard crystallographic methods
including constraints and restraints where necessary.
+
128.45, 128.19, 127.90, 126.98, 66.68, and 47.54. HRMS: [M + Na]
calculated for C60 : 919.3241; found 919.3236.
48 8
H O
0
00 00 0
Tetraphenyl 4,4 ,4 ,4 -(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate
1
(e). White powder 1.18 g, yield 70%. m.p. 250.6–251.1 1C. H NMR
Results and discussion
Stereochemistry of CBTBAs
(600 MHz, CDCl
3
) d (ppm): 8.049 (d, 8H, J = 8.4 Hz, Ar-H), 7.431
(t, 8H, J = 7.8–16.2 Hz, Ar-H), 7.286 (t, 8H, J = 8.4–17.4 Hz, Ar-H),
7
.254 (d, 4H, J = 6.0 Hz, Ar-H), 7.195 (d, 8H, J = 7.8 Hz, Ar-H), Fig. 1 illustrates the X-ray crystal structure of compound b, and
1
3
and 4.701 (s, 4H, cyclobu-H). C NMR (150 MHz, CDCl ) d the crystal data and experimental data are summarized in Table S2
3
(
1
C
ppm): 164.84, 150.99, 145.59, 130.35, 129.48, 128.12, 128.09, (see the ESI†). CBTBAs exhibited rctt stereochemistry, which was
+
0
00 0 00
25.89, 121.70, and 47.69. HRMS: [M + K] calculated for consistent with the stereochemistry of 4,4 ,4 ,4 -(cyclobutane-
58
56
H
40
O
8
: 879.2355; found 879.2348.
1,2,3,4-tetrayl)tetrabenzoic acid.
This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2019
New J. Chem.