48
J IRAN CHEM SOC (2013) 10:43–53
3,227 cm-1 (OH); 1H NMR (CDCl3):
d
7.72 (d,
6.87 (dd, J = 2.6, 8.2 Hz, 1H, H8), 5.09 (s, 2H, CH2–Ph),
4.42 (t, J = 4.8 Hz, 2H, CH2CH2OH), 4.09 (t, J = 4.8 Hz,
2H, CH2CH2OH), 2.86 (t, J = 7.0 Hz, 2H, H5), 2.57 (t,
J = 7.0 Hz, 2H, H4), 2.23 ppm (s, 3H, CH3).
J = 8.0 Hz, 1H, H9), 7.46–7.33 (m, 5H, Ph), 6.88 (m, 2H,
6,8), 5.09 (s, 2H, CH2–Ph), 4.12 (t, J = 4.6 Hz, 2H,
H
CH2CH2OH), 3.96 (t, J = 4.6 Hz, 2H, CH2CH2OH), 2.90
(t, J = 7.2 Hz, 2H, H5), 2.64 (t, J = 7.2 Hz, 2H, H4),
2.10 ppm (s, 3H, CH3).
General procedure E. Hydrogenolysis of benzyl-
protected pyrazoles
2-[3-(5-Benzyloxyphenyl)pyrazol-1-yl]ethanol (11a): It
was prepared according to ‘‘General procedure C’’. Yield
12 %; mp 138–140 °C; IR (KBr): m 3,282 cm-1 (OH); H
NMR (CDCl3): d 7.70 (d, J = 8.8 Hz, 2H, H2,6), 7.54 (d,
J = 2.2 Hz, 1H, H5-pyrazole), 7.47 (d, J = 7.2 Hz, 2H,
1
N-Hydroxylethylpyrazole derivatives (10a–f, 0.2 mmol) in
MeOH–AcOH (5:1, 20 ml) were hydrogenated over 10 %
Pd/C (10 mg) at 60 psi and the progress of the reaction was
monitored by TLC. When the reaction was complete, the
resulting mixture was filtered through Celite, and concen-
trated under reduced pressure to give debenzylated residues
(12a–f) [12].
0
2 ,6 ), 7.39 (t, J = 7.2 Hz, 2H, H3 ,5 ), 7.35 (t, J = 7.2 Hz,
0
0
0
H
0
1H, H4 ), 7.04 (d, J = 8.8 Hz, 2H, H3,5), 6.27 (d,
J = 2.2 Hz, 1H, H4-pyrazole), 5.12 (s, 2H, CH2–Ph), 4.20
(t, J = 4.7 Hz, 2H, CH2CH2OH), 3.97 ppm (t, J = 4.7 Hz,
2H, CH2CH2OH).
2-(3-(4-Hydroxyphenyl)pyrazol-1-yl)ethanol (12a):
Yield 89 %; mp 152–153 °C; IR (KBr): m 3,229 cm-1 (OH);
1H NMR (CD3OD): d 7.61 (d, J = 2.2 Hz, 1H, H5-pyra-
zole), 7.59 (d, J = 8.5 Hz, 2H, H2,6), 6.81 (d, J = 8.5 Hz,
2H, H3,5), 6.49 (d, J = 2.2 Hz, 1H, H4-pyrazole), 4.25 (t,
J = 4.5 Hz, 2H, CH2CH2OH), 3.91 ppm (t, J = 4.5 Hz,
2H, CH2CH2OH); MS m/z (%): 204 (M?, 72), 173 (100), 161
(40), 146 (20), 119 (12), 91 (10), 77 (10), 65 (12).
2-[3-(5-Benzyloxyphenyl)-5-methylpyrazol-1-yl]ethanol
(11b): It was prepared according to ‘‘General procedure
C’’. Yield 19 %; mp 137–139 °C; IR (KBr): m 3,265 cm-1
(OH); 1H NMR (CDCl3): d 7.69 (d, J = 8.7 Hz, 2H, H2,6),
0
7.45 (d, J = 7.2 Hz, 2H, H2 ,6 ), 7.37 (t, J = 7.2 Hz, 2H,
0
0 0 0
3 ,5 ), 7.30 (t, J = 7.2 Hz, 1H, H4 ), 7.03 (d, J = 8.7 Hz,
H
2H, H3,5), 6.05 (s, 1H, H4-pyrazole), 5.11 (s, 2H, CH2-Ph),
4.18 (t, J = 4.4 Hz, 2H, CH2CH2OH), 3.95 (t, J = 4.4 Hz,
2H, CH2CH2OH), 2.29 ppm (s, 3H, CH3).
2-(3-(4-Hydroxyphenyl)-5-methylpyrazol-1-yl)ethanol
(12b): Yield 92 %; mp 123–125 °C; IR (KBr): m 3,227 cm-1
(OH); 1H NMR (CD3OD): d 7.57 (d, J = 9.0 Hz, 2H, H2,6),
6.83 (d, J = 9.0 Hz, 2H, H3,5), 6.40 (s, 1H, H4-pyrazole),
4.22 (t, J = 5.5 Hz, 2H, CH2CH2OH), 3.90 (t, J = 5.5 Hz,
2H, CH2CH2OH), 3.28 ppm (s, 3H, CH3); MS m/z (%): 218
(M?, 72), 187 (100), 173 (55), 146 (33), 127 (10), 107 (34),
86 (32), 77 (22), 57 (20).
2-(6-Benzyloxyindeno[1,2-c]pyrazol-1(4H)-yl)ethanol
(11c): It was prepared according to ‘‘General procedure
C’’. Yield 45 %; mp 128–130 °C; IR (KBr): m 3,300 cm-1
1
(OH); H NMR (CDCl3): d 7.45–7.32 (m, 7H, Ph, H3,8),
7.15 (dd, J = 2.3, 8.4 Hz, H7), 5.11 (s, 2H, CH2–Ph), 4.47
(t, J = 4.8 Hz, 2H, CH2CH2OH), 4.10 (t, J = 4.8 Hz, 2H,
CH2CH2OH), 3.54 ppm (s, 2H, H4).
2-(2-Hydroxyethyl)-2,4-dihydroindeno[1,2-c]pyrazol-6-ol
(12c): Yield 72 %; mp 216–218 °C; IR (KBr): m 3,229,
3,218 cm-1 (OH); 1H NMR (CD3OD): d 7.50 (d, J = 8.2 Hz,
1H, H8), 7.35 (s, 1H, H3), 6.96 (s, 1H, H5), 6.77 (d, J = 8.2 Hz,
1H, H7), 4.24 (t, J = 5.3 Hz, CH2CH2OH), 3.90 (t,
J = 5.3 Hz, CH2CH2OH), 3.55 ppm (s, 2H, H4); MS m/z (%):
216 (M?, 85), 185 (100), 172 (76), 141 (34), 77 (42), 85 (31).
2-(2-Hydroxyethyl)-4,5-dihydro-2H-benzo[g]indazol-7-
ol (12e): Yield 65 %; mp 202–204 °C; IR (KBr): m 3,203,
2-(6-Benzyloxy-3-methylindeno[1,2-c]pyrazol-1(4H)-
yl)ethanol (11d): Yield 83 %; mp 116–118 °C; IR (KBr): m
3,320 cm-1 (OH); 1H NMR (CDCl3): d 7.45–7.33 (m, 6H,
Ph, H8), 7.14 (d, J = 2.3 Hz, 1H, H5), 6.94 (dd, J = 2.3,
8.3 Hz, 1H, H7), 5.10 (s, 2H, CH2–Ph), 4.39 (t, J = 4.8 Hz,
2H, CH2CH2OH), 4.06 (t, J = 4.8 Hz, 2H, CH2CH2OH),
3.45 (s, 2H, H4), 2.29 ppm (s, 3H, CH3).
2-(7-Benzyloxy-4,5-dihydro-2H-benzo[g]indazol-1-
yl)ethanol (11e): It was prepared according to ‘‘General
procedure C’’. Yield 30 %; mp 87–89 °C; IR (KBr): m
1
3,118 cm-1 (OH); H NMR (DMSO-d6): d 9.35 (s, 1H,
Ph–OH), 7.44 (d, J = 8.2 Hz, 1H, H9), 7.42 (s, 1H, H3),
6.63–6.61 (m, 2H, H6,8), 4.88 (t, J = 5.0 Hz, 1H,
CH2CH2OH), 4.07 (t, J = 5.0 Hz, 2H, CH2CH2OH), 3.70
(q, J = 5.0 Hz, 2H, CH2CH2OH), 2.73 (t, J = 7.2 Hz, 2H,
H5), 2.61 ppm (t, J = 7.2 Hz, 2H, H4); MS m/z (%): 230
(M?, 87), 199 (100), 186 (15), 128 (9), 115 (10).
3,203 cm-1 (OH); 1H NMR (CDCl3):
d 7.73 (d,
J = 8.1 Hz, 1H, H9), 7.46–7.30 (m, 6H, Ph, H3), 6.97 (d,
J = 2.4 Hz, 1H, H6), 6.88 (dd, J = 2.4, 8.1 Hz, 1H, H8),
5.09 (s, 2H, CH2–Ph), 4.46 (t, J = 4.8 Hz, 2H,
CH2CH2OH), 4.12 (t, J = 4.8 Hz, 2H, CH2CH2OH), 2.85
(t, J = 7.2 Hz, 2H, H5), 2.66 ppm (t, J = 7.2 Hz, 2H, H4).
2-(7-Benzyloxy-3-methyl-4,5-dihydro-2H-benzo[g]inda-
zol-1-yl)ethanol (11f): It was prepared according to ‘‘Gen-
eral procedure C’’. Yield 37 %; mp 123–125 °C; IR (KBr): m
3,227 cm-1 (OH); 1H NMR (CDCl3): d 7.71 (d, J = 8.2 Hz,
H9), 7.45–7.34 (m, 5H, Ph), 6.97 (d, J = 2.6 Hz, 1H, H6),
2-(2-Hydroxyethyl)-3-methyl-4,5-dihydro-2H-benzo
[g]indazol-7-ol (12f): Yield 68 %; mp 209–211 °C; IR
(KBr): m 3,313, 3,120 cm-1 (OH); 1H NMR (DMSO-d6): d
9.31 (bs, 1H, Ph–OH), 7.59 (d, J = 8.2 Hz, 1H, H9), 6.63
(d, J = 2.4 Hz, 1H, H6), 6.60 (dd, J = 2.4, 8.2 Hz, 1H,
H8), 4.48 (t, J = 5.6 Hz, 2H, CH2CH2OH), 4.02 (t,
123