The Journal of Organic Chemistry
Note
1.37−1.26 (m, 40H), 0.91−0.88 (q, 12H); 13C NMR (100 MHz,
CDCl3-d1, 298 K) δ 151.0, 142.8, 124.9, 124.7, 108.5, 106.6, 31.9, 30.7,
29.4, 29.34, 29.3, 24.3, 22.7, 14.1; FTIR (KBr disk; ν in cm−1) 2926,
2854, 1732, 1606, 1556, 1464, 1394, 1261, 1221, 1097, 1016, 970, 949,
862, 802, 725, 659, 611, 524; ESI MS m/z calcd 868.66, found 891.63
[M+ + Na]. Anal. Calcd for C54H80N10: C, 74.61; H, 9.28; N, 16.11.
Found: C, 74.48; H, 9.21; N, 16.25.
(170 mg, 0.242 mmol), triphenylphosphine (200 mg, 0.762 mmol),
and CuI (200 mg, 1.05 mmol) as additional catalyst. Freshly distilled
anhydrous triethylamine (20 mL) and 1,4-dioxane (10 mL) were
added. The Schlenk tube was carefully degassed by freeze and thaw
cycles. 1-Octyne (2.15 mL (d = 0.746 g/mL), 14.5 mmol) was added
under argon by syringe, and the resulting mixture was heated to 80 °C
for 48 h. It was then cooled to room temperature and allowed to stir
for an additional 1 h. The mixture was filtered through filter paper and
washed with 1,4-dioxane, and the filtrate was evaporated in vacuo to
get a dark brown solid which was column chromatographed on silica
(100−200 mesh) using (8:92) EtOAc/hexane to isolate 4 as a white
solid: yield 2.0 g (82%); mp 86−87 °C; 1H NMR (400 MHz, CDCl3,
298 K) δ 8.56 (s, 2H), 8.34 (s, 2H), 7.78 (s, 2H), 4.48−4.43 (q, 2H),
2.43−2.39 (t, 4H), 1.65−1.58 (p, 5H), 1.5−1.4 (p, 7H), 1.34−1.25
(m, 10H), 0.94−0.91 (t, 6H); 13C NMR (100 MHz, CDCl3-d1, 298 K)
δ 163.8, 150.2, 145.0, 143.7, 129.1, 109.4, 107.0, 93.1, 70.4, 62.3, 31.4,
29.7, 28.7, 22.6, 19.5, 14.3, 14.1; FTIR (KBr disk; ν in cm−1) 3113,
2928, 2856, 1730, 1618, 1574, 1469, 1390, 1348, 1305, 1234, 11890,
1099, 1030, 964, 895, 864, 819, 790, 769, 733, 655, 617, 507; LC−MS
m/z calcd 499.29, found 500.50. Anal. Calcd for C30H37N5O2: C,
72.12; H, 7.46; N, 14.02. Found: C, 72.36; H, 7.41; N, 14.15.
Ethyl 2,6-Bis(4-octyl-1H-pyrazol-1-yl)isonicotinate (5). To a
degassed solution of 4 (0.619 g, 1.23 mmol) in EtOAc (200 mL) was
added 10% Pd/C (0.350 g, 0.3 mmol), and the mixture was stirred
under a H2 bladder and monitored by TLC. After 4 days, the mixture
was filtered through a Celite plug to remove activated Pd/C.
Afterward, the plug was washed with 100 mL of EtOAc and the
collected fraction was concentrated in vacuo to afford 5 as yellowish
gummy oil: yield 0.618 g (99%); 1H NMR (400 MHz, CDCl3-d1, 298 K)
δ 8.30 (s, 2H), 8.28 (s, 2H), 7.6 (s, 2H), 4.46−4.42 (q, 2H), 2.56−
2.53 (t, 4H), 1.64−1.62 (t, 4H), 1.36−1.24 (m, 23H), 0.89−0.88
(t, 6H); 13C NMR (100 MHz, CDCl3-d1, 298 K) δ 164.1, 150.8, 143.3,
142.9, 124.9, 124.8, 108.2, 62.0, 31.9, 30.6, 29.4, 29.35, 29.30, 24.30,
22.7, 14.25, 14.1; FTIR (KBr disk; ν in cm−1) 2924, 2853, 1612, 1576,
1547, 1464, 1392, 1261, 1099, 1016, 804; LC−MS analysis m/z calcd
507.71, found 508.65. Anal. Calcd for C30H45N5O2: C, 70.97; H, 8.93; N,
13.79. Found: C, 70.79; H, 8.86; N, 13.65.
1,4-Bis(2,6-bis(4-octyl-1H-pyrazol-1-yl)pyridin-4-yl)benzene
(L1). Compound 8 (60 mg, 0.106 mmol), 1,4-phenylenediboronic acid
(8.85 mg, 0.053 mmol), and Pd(PPh3)4 (6.17 mg, 5 mol %) were
suspended in a N2 gas bubbled solution of dioxane (20 mL) and 2 M
Na2CO3 (5 mL). The mixture was heated to 80 °C for 3 d under
nitrogen atmosphere. The mixture of solvents was removed in vacuo,
and the remaining brown residue was treated with water and extracted
with CH2Cl2 solvent. The separated organic layer was dried over
Na2SO4, and the solvent was removed by evaporation. The solid
residue was washed with MeOH (3 × 5 mL) to remove colored
impurities and to get a white flakelike compound L1: yield 45 mg
1
(90%); mp 105−107 °C; H NMR (400 MHz, CDCl3-d1, 298 K) δ
8.39 (s, 4H), 8.08 (s, 4H), 7.94 (S, 4H), 7.64 (s, 4H), 2.60−2.56
(t, 8H), 1.67−1.61 (t, 8H), 1.37−1.26 (m, 40H), 0.89−0.88 (t, 12H);
13C NMR (100 MHz, CDCl3-d1, 298 K) δ 152.8, 150.8, 142.6, 138.7,
127.8, 125.0, 124.5, 106.3, 31.9, 30.8, 29.5, 29.4, 29.3, 24.3, 22.7, 14.1;
FTIR (KBr disk; ν in cm−1) 3115, 2926, 2852, 1701, 1608, 1558, 1541,
1458, 1394, 1261, 1195, 1016, 954, 798; ESI-MS m/z calcd 944.69,
found 967.66 [M+ + Na]. Anal. Calcd for C60H84N10: C, 76.23; H,
8.96; N, 14.82. Found: C, 76.12; H, 8.91; N, 14.75.
L2 and L3 were prepared as per the above-mentioned procedure for
L1 using the corresponding diboronic acids 13 and 14, respectively.
Yield and spectral data are given below.
For L2. Compound 8 (90 mg, 0.16 mmol), 1,4-phenylenediboronic
acid (19.3 mg, 0.080 mmol) and Pd(PPh3)4 (9.26 mg, 5 mol %): yield
1
70 mg (86%); mp 158−159 °C; H NMR (400 MHz, CDCl3-d1, 298
K) δ 8.39 (s, 4H), 8.11 (s, 4H), 7.95−7.93 (d, 4H), 7.81−7.79 (d,
4 H), 7.64 (s, 4H) 2.61−2.57 (t, 8H), 1.67−1.64 (t, 8H), 1.37−1.26 (m,
40H), 0.89−0.88 (t, 12H); 13C NMR (100 MHz, CDCl3-d1, 298 K) δ
153.2, 150.8, 142.6, 141.43, 137.0, 127.8, 127.7, 125.0, 124.4, 106.3,
31.9, 30.8, 29.4, 29.32, 29.27, 24.3, 22.7, 14.1; FTIR (KBr disk; ν in
cm−1): 2924, 2851, 1612, 1576, 1549, 1462, 1395, 1262, 1198, 1098,
1019, 804; ESI MS m/z calcd 1020.72, found 1043.68 [M+ + Na].
Anal. Calcd for C66H88N10: C, 77.60; H, 8.68; N, 13.71. Found: C,
77.85; H, 8.61; N, 13.61.
2,6-Bis(4-(oct-1-ynyl)-1H-pyrazol-1-yl)isonicotinic Acid (6).
Compound 5 (0.6 g, 1.18 mmol) was dissolved in 25 mL of THF.
Aqueous LiOH (0.2 g, 8.33 mmol, 7 equiv in 75 mL of water) was
added to the THF solution. After 1 h, the THF was removed in vacuo,
and the solution was cooled in an ice bath. To this was then slowly
added 27 mL of 2 M HCl. After 1 h, the white solid product 6 was
isolated by filtration followed by drying in air (0.5 g, >98%): mp 124−
For L3. Compound 8 (100 mg, 0.17 mmol), 1,4′′-phenyl-
enediboronic acid (28.3 mg, 0.089 mmol), and Pd(PPh3)4 (10.2 mg,
1
1
126 °C; H NMR (400 MHz, CDCl3-d1, 298 K) δ 8.46 (s, 2H), 8.36
5 mol %): yield 68.4 mg (70%); mp 177−178 °C; H NMR (400
(s, 2H), 7.72 (s, 2H), 4.8−4.6 (broad, OH) 2.60−2.56 (t, 4H), 1.69−
1.63 (t, 4H), 1.38−1.24 (m, 20H), 0.92−0.89 (t, 6H); 13C NMR (100
MHz, CDCl3-d1, 298 K) δ 165.8, 150.6, 143.6, 143.0, 125.3, 124.9,
109.0, 31.9, 30.6, 29.4, 29.4, 24.3, 22.7, 14.1; FTIR (KBr disk; ν in
cm−1) 3427 (broad-COOH), 3113, 2926, 2854, 1707, 1618, 1574,
1460, 1392, 1261, 1192, 1060, 964, 802, 721, 673, 611, 408; LC−MS
analysis m/z calcd 479.65, found 478.40.
MHz, CDCl3-d1, 298 K) δ 8.41 (s, 4H), 8.12 (s, 4H), 7.79−7.93 (d,
4H), 7.81−7.78 (d, 8H), 7.65−7.64 (d, 4 H),) 2.62−2.58 (t, 8H),
1.73−1.65 (t, 8H), 1.42−1.27 (m, 40 H), 0.93−0.90 (t, 12H); 13C
NMR (100 MHz, CDCl3-d1, 298 K) δ 153.3, 150.8, 142.5, 139.6,
137.9, 136.6, 127.7, 127.6, 127.5, 125.1, 124.4, 106.23, 31.9, 30.8, 29.4,
29.34, 29.31, 24.3, 22.7, 14.1; FTIR (KBr disk; ν in cm−1) 3437, 3354,
3242, 2957, 2920, 2851, 2521, 1798, 1659, 1576, 1481, 1393, 1323,
1190, 984, 920, 872, 808, 714, 633.
2,6-Bis(4-octyl-1H-pyrazol-1-yl)pyridin-4-amine (7). Com-
pound 6 (0.4 g, 0.83 mmol, 1 equiv) was dissolved in a mixture of
3:1 CH2Cl2/THF (50 mL). To this was slowly added oxalyl chloride
(0.09 mL, 1.017 mmol, 1.22 equiv) and the mixture stirred at room
temperature. After 4 h, the solvent was removed in vacuo, and the
resultant residue was dissolved in dry acetone (10 mL). This acetone
mixture was added to a solution of NaN3 (0.234 g, 3.60 mmol, 4.32
equiv) in H2O (20 mL). The solution was immediately extracted with
Et2O (3 × 20 mL). The combined organic fraction was dried with
MgSO4 and concentrated to yield a white solid. The solid was
redissolved in 50 mL of dry benzene; trifluoroacetic acid was added
(0.09 mL, 1.25 mmol, 1.50 equiv), and the solution was heated to
reflux for 16 h. After cooling, the benzene was removed in vacuo, and
the residue was redissolved in CH3OH (50 mL). Solid K2CO3 was
added (0.250 g, 1.80 mmol, and 2.17 equiv) and the mixture
vigorously stirred for 8 h. After 95% of the CH3OH was removed in
vacuo, 70 mL of H2O was added, and the mixture was cooled in an ice
bath for 2 h. The resulting precipitate was isolated by filtration
Preparation of Metallo Supramolecular Polymer [L1·Zn-
(ClO4)2]n (1). To a solution of L1 (17.3 mg, 0.0183 mmol) in 20 mL
of CHCl3 was added 10 mL of a MeOH solution of Zn(ClO4)2·6H2O
(6.81 mg, 0.0182 mmol), and the solution was stirred for 30 min at
room temperature. The obtained solution was concentrated in vacuo,
and the yellowish-white polymer product 1 was precipitated by adding
1
excess of hexane: yield 18.0 mg; H NMR (400 MHz, CDCl3-d1/
CD3OD-d4 (3:2), 298 K) δ 8.85(s, 8H), 8.74 (s, 1H, end group), 8.42
(s, 16H), 8.17 (s, 1H, end group), 8.0 (s,1H, end group), 7.66 (s, 8H),
2.59 (s, 16H), 1.67 (s, 16H), 1.28 (m, 80H), 0.87(m, 24H); FTIR
(KBr disk; ν in cm−1) 3111, 2923, 2853, 1658, 1619, 1564, 1495, 1465,
1396, 1262, 1091(perchlorate Cl−O), 1012, 990, 970, 955, 930, 864,
831, 813, 795, 722, 622, 602; Raman (633 nm; ν in cm−1) 1613, 1454,
1398, 1307, 1201, 1020, 998, and 412 cm−1.
Ethyl 2,6-Bis(4-(oct-1-ynyl)-1H-pyrazol-1-yl)isonicotinate (4).
A Schlenk tube was charged with ethyl 2′,6′-bis(4,4′′-iodopyrazol-1,1′′-yl)-
isonicotinate 3 (2.6 g, 4.86 mmol) together with Pd(PPh3)2Cl2
3624
dx.doi.org/10.1021/jo300050m | J. Org. Chem. 2012, 77, 3620−3626