Cyclization of 4,5-Diamino Pyrazole Derivatives and Their Antibacterial Activities
Product in 87% yield, as orange crystals, m.p. 180—182
Product in 67% yield, as buff crystals, m.p. 148—150
1
℃; H NMR (DMSO-d6) δ: 8.2 (s, 2H, NH2), 6.7—8.1
℃; 1H NMR (DMSO-d6) δ: 2.3 (s, 3H, CH3), 4.7 (s, 2H,
(m, 10H, Ar-H); IR (KBr) ν: 3402 (NH2), 1600 (N=O)
NH2), 5.2 (s, 2H, NH2), 7.1—7.7 (m, 9H, Ar-H); IR
-1
-1
+
cm ; MS m/z (%): 264.1 (M , 54), 143 (66.6), 130
(22.3), 103 (17.3) 77 (100), 51 (66.9). Anal. calcd for
C15H12N4O (264.282): C 68.17, H 4.58, N 21.20; found
C 68.27, H 4.66, N 21.42.
(KBr) ν: 33402 (NH2), 1597 (N=N) cm ; MS m/z (%):
264.1 (M+, 100), 191 (50), 165 (40), 77 (50), 51 (60).
Anal. calcd for C16H16N4 (264.32): C 72.70, H 6.10, N
21.20; found C 72.55, H 5.98, N 21.20.
4-Nitroso-1-phenyl-3-p-tolyl-1H-pyrazol-5-amine
(3b) Product in 79% yield, as reddish crystals, m.p.
195—197 ℃; 1H NMR (DMSO-d6) δ: 8.5 (s, 2H, NH2)
2.3 (s, 3H, CH3), 6.7—8.2 (m, 9H, Ar-H); IR (KBr) ν:
3-(4-Fluorophenyl)-1-phenyl-1H-pyrazole-4,5-di-
amine (4c) Product in 75% yield, as buff crystals, m.p.
122—124 ℃; 1H NMR (DMSO-d6) δ: 4.8 (s, 2H, NH2),
5.6 (s, 2H, NH2), 7.1—8.3 (m, 9H, Ar-H); IR (KBr) ν:
-1
-1
3332 (NH2), 1640 (N=O) cm ; MS m/z (%): 278.1
3370 (NH2), 1597 (N=N) cm ; MS m/z (%): 268.1
(M+, 90), 235 (60), 191 (25), 103 (17), 77 (100), 51 (90).
Anal. calcd for C16H14N4O (278.1): C 69.05, H 5.07, N
20.13; found C 69.11, H 5.07, N 20.33.
(M+, 100), 242 (10), 191 (20), 165 (20), 74 (50). Anal.
calcd for C15H13N4F (268.28): C 67.15, H 4.88, N 20.88;
found C 67.05, H 4.79, N 20.96.
3-(4-Fluorophenyl)-4-nitroso-1-phenyl-1H-pyrazol-
5-amine (3c) Product in 83% yield, as brown crystals,
General procedures for the synthesis of 7-(4-meth-
oxyphenyl)-1-phenyl-3-substituted-5-p-tolyl-1,6,7,8-
tetrahydropyrazolo[4,3-b][1,4]diazepine (5a— 5c)
1
m.p. 183—185 ℃; H NMR (DMSO-d6) δ: 8.4 (s, 2H,
NH2), 6.7—8.3 (m, 9H, Ar-H); IR (KBr) ν: 33+55 (NH2),
-1
A mixture of 4a—4c (3.2 mmol) and of 3-(4-meth-
oxyphenyl)-1-p-tolylprop-2-en-1-one (0.8 g, 3.2 mmol)
was refluxed in absolute ethanol (10 mL) and acetic
acid (0.4 mL) for 8 h. The reaction mixture was cooled
to 0 ℃ and the precipitates were collected by filtration.
The solid obtained was crystallized from ethanol.
1630 (N=O) cm ; MS m/z (%): 282.27 (M , 80), 64
(80), 235 (60), 130 (35), 103 (30), 77 (100), 51 (70).
Anal. calcd for C15H11FN4O (282.27): C 63.83, H 3.93,
N 19.85, F 6.73; found C 63.55, H 3.77, N 19.93, F
6.62.
General procedures for the synthesis of 1-phenyl-3-
substituted-4,5-diaminopyrazole (4a— 4c)
1,3-Diphenyl-7-(4-methoxyphenyl)-5-p-tolyl-1,6,7,
8-tetrahydropyrazolo[4,3-b][1,4]diazepine
(5a)
Product in 81% yield, as yellow crystals, m.p. 270—272
℃; 1H NMR (DMSO-d6) δ: 2.3 (s, 3H, CH3), 3.8 (s, 3H,
OCH3), 2.7 (d, Jtrans=6.2 Hz, 1H, CH2 at C-3), 3.3 (d,
Jcis=1.4 Hz, 1H, CH2 at C-3), 4.1 (t, J=-14.9 Hz, 1H,
CH at C-2), 5.3 (d, J=4.9 Hz, 1H, NH), 7.1—7.8 (-m,
Method A A solution of NaNO2 (0.26 g, 3.77
mmol) in water (2.5 mL) was added dropwise to a solu-
tion of 5-aminopyrazoles 1a—1c (3.77 mmol) in aque-
ous 4.5 mol/L HCl (50 mL) at 0 ℃. The solution was
stirred at 0 ℃ for 10 min and then a solution of stan-
nous chloride dehydrate (3.4 g, 15.1 mmol) in concen-
trated HCl (20 mL) was added slowly. The resultant
reaction mixture was allowed to warm slowly to room
temperature and stirred for 15 min. The solution was
then basified with NaOH and extracted with ethyl ace-
tate, the combined extracts were dried over anhydrous
magnesium sulphate. Removal of the solvent at reduced
pressure gave the desired products 4a—4c in yields of
15%, 17% and 20%, respectively.
1
24H, Ar-H); IR (KBr) ν:+3361 (NH), 1597 (C=N) cm ;
MS m/z (%): 484.3 (M , 50), 337 (57), 267 (23), 235
(87), 160 (46), 121 (45), 77 (100), 51 (22). Anal. calcd
for C32H28N4O (484.5): C 79.31, H 5.82, N 11.56; found
C 79.11, H 5.89, N 11.76.
7-(4-Methoxyphenyl)-1-phenyl-3,5-di-p-tolyl-1,6,7,
8-tetrahydropyrazolo[4,3-b][1,4]diazepine
(5b)
Product in 79% yield, as yellow crystals, m.p. 300—302
℃; 1H NMR (DMSO-d6) δ: 2.1 (s, 3H, CH3), 3.6 (s, 3H,
OCH3), 2.7 (d, Jtrans=6.0 Hz, 1H, CH2 at C-3), 3.6 (d,
Jcis=1.6 Hz, 1H, CH2 at C-3), 4.9 (t, J=-14.8 Hz, 1H,
CH at C-2), 6.7 (d, J=4.8 Hz, 1H, NH), 6.8—8.5 (m,
Method B 3-Aryl-4-azo pyrazoles (2a—2c) (0.05
mmol) was stirred in boiling aqueous (80%, 25 mL)
ethanol and small portions of powdered sodium dithio-
nite were added until the dye had dissolved and a faint
yellow solution resulted. The solution was then diluted
to 200 mL with hot water; the reaction mixture was dis-
tilled at reduced pressure, the solid obtained was filtered
to give the desired o-diamino compounds 4a—4c.
-1
23H, Ar-H); IR (KBr) ν: 3361 (NH), 1597 (C=N) cm ;
MS m/z (%): 498.3 (M+, 25), 445 (10), 242 (20), 191
(80), 169 (70), 139(75), 107 (30). Anal. calcd for
C33H30N4O (498.6): C 79.49, H 6.06, N 11.24; found C
79.49, H 6.98, N 11.22.
3-(4-Fluorophenyl)-7-(4-methoxyphenyl)-1-phen-
yl-5-p-tolyl-1,6,7,8-tetrahydropyrazolo[4,3-b][1,4]di-
azepine (5c) Product in 80% yield, as yellow crystals,
1,3-Diphenyl-1H-pyrazole-4,5-diamine
(4a)
Product in 61% yield, as buff crystals, m.p. 138—140
℃; 1H NMR (DMSO-d6) δ: 3.5 (s, 2H, NH2), 4.8 (s, 2H,
NH2), 7.2—7.9 (m, 9H, Ar-H); IR (KBr) ν: +3364 (NH2),
1
m.p. 274—276 ℃; H NMR (DMSO-d6) δ: 2.2 (s, 3H,
-1
CH3), 3.8 (s, 3H, OCH3), 2.9 (d, Jtrans=6.1 Hz, 1H, CH2
at C-3), 3.9 (d, Jcis=1.5 Hz, 1H, CH2 at C-3), 5.4 (t, J=
-14.9 Hz, 1H, CH at C-2), 5.8 (d, J=4.7 Hz, 1H, NH),
6.7—8.2 (m, 23H, Ar-H); IR (KBr) ν: 3301 (NH), 1604
1596 (N=N) cm ; MS m/z (%): 250.1 (M , 100), 146
(37), 104 (52), 77 (60), 51 (37). Anal. calcd for
C15H14N4 (250.29): C 72.70, H 5.64, N 22.38; found C
72.65, H 5.60, N 22.28.
+
-1
(C=N) cm ; MS m/z (%): 503.3 (M +1, 75), 461
1-Phenyl-3-p-tolyl-1H-pyrazole-4,5-diamine (4b)
Chin. J. Chem. 2011, 29, 1451— 1459
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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