Journal of Materials Chemistry C
Paper
(4a–e) (1.42 mmol), dicyclohexylcarbodiimide (0.31 g, 1.50
mmol) and N,N-dimethyl aminopyridine (0.02 g, 0.15 mmol).
The reaction mixture was stirred at room temperature for 24
hours. The precipitated solid was ltered and solvent was
evaporated under low pressure. The solids were puried by
column chromatography (n-hexane–ethyl acetate 95 : 5).
4-[(2-Hexyl)-2H-tetrazol-5-yl]phenyl 4-hexyloxybenzoate (5a).
Yield: 33%; white solid; Rf ¼ 0.74 (n-hexane–ethyl acetate; 7 : 3);
IR (neat, ymax, cmꢀ1): 2930, 2859, 1736, 1605, 1201, 888. 1H-NMR
(300 MHz, CDCl3): d (ppm) 8.2 (2H, d, J ¼ 9.0 Hz), 7.3 (2H, d, J ¼
9.0 Hz), 6.9 (2H, d, J ¼ 9.0 Hz), 4.6 (2H, t, J ¼ 7.2), 4.1 (2H, t, J ¼
6.6 Hz), 2.1 (2H, quint, J ¼ 7.0 Hz), 1.8 (2H, quint, J ¼ 7.3 Hz),
1.5–1.3 (12H, m), 0.9–0.8 (6H, m). 13C-NMR (75 MHz, CDCl3): d
(ppm) 164.7, 164.4, 163.6, 152.6, 132.3, 128.0, 125.1, 122.4,
121.2, 114.3, 68.3, 53.2, 31.5, 31.0, 31.5–22.4, 14.0, 13.9.
Elemental analysis (%) for C26H34N4O3 (450 g molꢀ1): calcd C
69.31, H 7.61, N 12.43; found C 69.29, H 8.09, N 12.50%.
General method for the deprotection reaction
4-[(2-Alkyl)-2H-tetrazol-5-yl]phenyl acetate (2) (3.1 mmol) was
added to 20 mL methanol followed by addition of KOH (0.173 g,
3.1 mmol) in 5 mL water in a 100 mL round bottomed ask and
reuxed for 12 hours. The mixture was cooled to room
temperature, ltered and concentrated through rotary evapo-
rator. The mixture was poured onto 100 g of ice and acidied
with concentrated HCl to pH 2. The precipitated solid was
ltered and puried by crystallization from ethanol.
4-[(2-Hexyl)-2H-tetrazol-5-yl]phenol (3a). Yield: 80%; white
solid; Rf ¼ 0.71 (n-hexane–ethyl acetate; 7 : 3); IR (neat, ymax
,
cmꢀ1): 3292, 2930, 1620, 853. 1H-NMR (300 MHz, CDCl3): d
(ppm) 8.0 (2H, d, J ¼ 6.6 Hz), 6.9 (2H, d, J ¼ 6.6 Hz), 4.7 (2H, t,
J ¼ 5.4 Hz), 2.1 (2H, quint, J ¼ 5.4 Hz), 1.4–1.3 (8H, m), 0.9 (3H, t,
J ¼ 5.2 Hz). 13C-NMR (75 MHz, CDCl3): d (ppm) 164.8, 157.7,
128.6, 119.9, 115.9, 53.2, 31.1, 29.4, 26.1, 22.4, 13.9.
4-[(2-Heptyl)-2H-tetrazol-5-yl]phenol (3b). Yield: 67%; white
4-[(2-Heptyl)-2H-tetrazol-5-yl]phenyl
4-hexyloxybenzoate
solid; Rf ¼ 0.69 (n-hexane–ethyl acetate; 7 : 3); IR (neat, ymax
,
(5b). Yield: 37%; white solid; Rf ¼ 0.77 (n-hexane–ethyl acetate;
7 : 3); IR (neat, ymax, cmꢀ1): 2922, 2852, 1734, 1603, 1257, 885. 1H-
NMR (300 MHz, CDCl3): d (ppm) 8.2 (2H, d, J ¼ 6.6 Hz), 8.1 (2H, d,
J ¼ 6.6 Hz), 7.3 (2H, d, J ¼ 6.6 Hz), 6.9 (2H, d, J ¼ 6.6 Hz), 4.6 (2H,
t, J ¼ 5.2 Hz), 4.0 (2H, t, J ¼ 4.9 Hz), 2.0 (2H, quint, J ¼ 5.4 Hz), 1.8
(2H, quint, J ¼ 5.1 Hz), 1.5–1.3 (20H, m), 0.9–0.8 (6H, m). 13C-
NMR (300 MHz, CDCl3): d (ppm) 164.7, 164.4, 163.6, 152.6, 132.3,
128.0, 125.1, 122.4, 121.2, 114.3, 68.3, 53.2, 31.7, 31.5, 29.4–22.6,
14.1, 14.0. Elemental analysis (%) for C27H36N4O3 (464 g molꢀ1):
calcd C 72.56, H 8.95, N 9.96; found C 72.84, H 8.97, N 9.86%.
4-[(2-Octyl)-2H-tetrazol-5-yl]phenyl 4-hexyloxybenzoate (5c).
Yield: 40%; white solid; Rf ¼ 0.79 (n-hexane–ethyl acetate; 7 : 3);
IR (neat, ymax, cmꢀ1): 2927, 2856, 1725, 1603, 1252, 935. 1H-NMR
(300 MHz, CDCl3): d (ppm) 8.2 (2H, d, J ¼ 6.6 Hz), 8.1 (2H, d, J ¼
6.6 Hz), 7.3 (2H, d, J ¼ 6.6 Hz), 6.9 (2H, d, J ¼ 6.6 Hz), 4.6 (2H, t,
J ¼ 5.2 Hz), 4.1 (2H, t, J ¼ 4.9 Hz), 2.1 (2H, quint, J ¼ 5.4 Hz), 1.8
(2H, quint, J ¼ 5.1 Hz), 1.5–1.3 (22H, m), 0.9–0.8 (6H, m). 13C-
NMR (75 MHz, CDCl3): d (ppm) 164.7, 164.4, 163.6, 152.6, 132.3,
128.0, 125.1, 122.4, 121.2, 114.3, 68.3, 53.2, 31.7, 31.5, 29.4–22.6,
14.1, 14.0. Elemental analysis (%) for C28H38N4O3 (478 g molꢀ1):
calcd C 72.56, H 8.95, N 9.96; found C 72.84, H 8.97, N 9.86%.
cmꢀ1): 3155, 2938, 1613, 853. 1H-NMR (300 MHz, CDCl3): d
(ppm) 8.0 (2H, d, J ¼ 8.7 Hz), 6.9 (2H, d, J ¼ 8.7 Hz), 4.6 (2H, t,
J ¼ 7.2 Hz), 2.1 (2H, quint, J ¼ 5.4 Hz), 1.4–1.3 (6H, m), 0.8 (3H, t,
J ¼ 6.6 Hz). 13C-NMR (75 MHz, CDCl3): d (ppm) 164.8, 157.5,
128.5, 120.1, 115.8, 53.2, 31.5, 29.4, 28.5, 26.3, 22.5, 14.0.
4-[(2-Octyl)-2H-tetrazol-5-yl]phenol (3c). Yield: 54%; white
solid; Rf ¼ 0.86 (n-hexane–ethyl acetate; 7 : 3); IR (neat, ymax
,
cmꢀ1): 3163, 2930, 1620, 845. 1H-NMR (300 MHz, CDCl3): d
(ppm) 7.9 (2H, d, J ¼ 8.7 Hz), 6.9 (2H, d, J ¼ 8.7 Hz), 4.0 (2H, t,
J ¼ 6.6 Hz), 1.8 (2H, quint, J ¼ 7.2 Hz), 1.6–1.3 (10H, m), 0.9 (3H,
t, J ¼ 5.8 Hz). 13C-NMR (75 MHz, CDCl3): d (ppm) 165.2, 158.0,
128.8, 120.0, 116.1, 53.4, 31.9, 29.6, 29.2, 29.1, 26.6, 22.8, 14.3.
4-[(2-Nonyl)-2H-tetrazol-5-yl]phenol (3d). Yield: 87%; white
solid; Rf ¼ 0.72 (n-hexane–ethyl acetate; 7 : 3); IR (neat, ymax
,
cmꢀ1): 3163, 2924, 1613, 845. 1H-NMR (300 MHz, CDCl3): d (ppm)
8.0 (2H, d, J ¼ 6.6 Hz), 6.9 (2H, d, J ¼ 6.6 Hz), 4.6 (2H, t, J ¼ 5.4
Hz), 2.1 (2H, quint, J ¼ 5.4 Hz), 1.4–1.3 (12H, m), 0.8 (3H, q, J ¼
5.1 Hz). 13C-NMR (75 MHz, CDCl3): d (ppm) 164.9, 157.9, 128.5,
119.7, 115.9, 53.2, 31.8, 29.4, 29.3, 29.2, 28.9, 26.4, 22.6, 14.1.
4-(2-Decyl)-2H-tetrazol-5-yl]phenol (3e). Yield: 75%; white
solid; Rf ¼ 0.85 (n-hexane–ethyl acetate; 7 : 3); IR (neat, ymax
,
4-[(2-Heptyl)-2H-tetrazol-5-yl]phenyl
4-heptyloxybenzoate
cmꢀ1): 3409, 2916, 1620, 845. 1H-NMR (300 MHz, CDCl3): d (ppm)
8.1 (2H, d, J ¼ 6.9 Hz), 7.0 (2H, d, J ¼ 6.6 Hz), 4.6 (2H, t, J ¼ 5.4
Hz), 1.8 (2H, quint, J ¼ 5.1 Hz), 1.4–1.2 (14H, m), 0.9 (3H, t, J ¼ 5.1
Hz). 13C-NMR (75 MHz, CDCl3): d (ppm) 164.9, 160.8, 128.3,
119.9, 114.8, 53.1, 31.8, 29.6, 29.6, 29.5, 28.9, 26.4, 22.7, 18.5, 14.2.
(S)-(+)-4-[2-(3,7-Dimethyloct-6-enyl)-2H-tetrazol-5-yl]phenol
(3f). Yield: 64%; white solid; Rf ¼ 0.71 (n-hexane–ethyl acetate;
7 : 3); 1H-NMR (300 MHz, CDCl3): d (ppm) 8.0 (2H, d, J ¼ 6.6 Hz),
6.9 (2H, d, J ¼ 6.6 Hz), 5.1 (1H, t, J ¼ 5.4 Hz), 4.6 (2H, t, J ¼ 5.2
Hz), 1.7–0.9 (17H, m). 13C-NMR (75 MHz, CDCl3): d (ppm) 164.8,
157.7, 131.7, 128.6, 124.1, 119.9, 115.9, 51.4, 36.6, 36.3, 29.9,
25.7, 25.2, 19.1, 17.7. [a]D ¼ + 10 (1.94, CH2Cl2).
(5d). Yield: 21%; white solid; Rf ¼ 0.60 (n-hexane–ethyl acetate;
7 : 3); IR (neat, ymax, cmꢀ1): 2924, 2851, 1728, 1605, 1207, 896.
1H-NMR (300 MHz, CDCl3): d (ppm) 8.2 (2H, d, J ¼ 8.4 Hz), 8.2
(2H, d, J ¼ 8.4 Hz), 7.3 (2H, d, J ¼ 8.1 Hz), 6.9 (2H, d, J ¼ 8.4 Hz),
4.6 (2H, t, J ¼ 7.2 Hz), 4.1 (2H, t, J ¼ 6.6 Hz), 2.1 (2H, quint, J ¼
6.9 Hz), 1.8 (2H, quint, J ¼ 6.9 Hz), 1.5–1.2 (16H, m), 0.9–0.8 (6H,
m). 13C-NMR (75 MHz, CDCl3): d (ppm) 164.6, 164.4, 163.6,
152.5, 132.3, 128.0, 125.0, 122.3, 121.2, 114.3, 68.3, 53.2, 31.7,
31.5, 29.7–22.5, 14.1, 14.0. Elemental analysis (%) for
C
28H38N4O3 (478 g molꢀ1): calcd C 70.26, H 8.00, N 11.71; found
C 70.64, H 8.43, N 11.02%.
4-[(2-Octyl)-2H-tetrazol-5-yl]phenyl 4-octyloxybenzoate (5e).
Yield: 28%; white solid; Rf ¼ 0.71 (n-hexane–ethyl acetate; 7 : 3);
IR (neat, ymax, cmꢀ1): 2916, 2851, 1728, 1599, 1200, 896. 1H-NMR
(300 MHz, CDCl3): d (ppm) 8.2 (2H, d, J ¼ 8.4 Hz), 8.1 (2H, d, J ¼
General method for the synthesis of 4-[2-(alkyl)-2H-tetrazol-
5-yl]phenyl 4-alkyloxybenzoate
To a solution of 4-[(2-alkyl)-2H-tetrazol-5-yl]phenol (3a–f) (1.42 8.7 Hz), 7.3 (2H, d, J ¼ 8.1 Hz), 6.9 (2H, d, J ¼ 8.7 Hz), 4.6 (2H, t,
mmol) in 20 mL of dry THF was added 4-n-alkoxybenzoic acid J ¼ 7.2 Hz), 4.0 (2H, t, J ¼ 6.6 Hz), 2.1 (2H, quint, J ¼ 7.2 Hz), 1.8
5590 | J. Mater. Chem. C, 2013, 1, 5583–5593
This journal is ª The Royal Society of Chemistry 2013