502 Lee et al.
Asian J. Chem.
188 (M+). 1e Mass (m/e) 222 (M+).
6.42-6.44 (t, 3H), 6.35-6.37 (t, 3H); 13C NMR (CDCl3, 50
MHz): δ 159.1, 119.51,118.98, 118.50, 118.03, 114.44,
113.16, 112.74, 112.35, 111.88, 111.51, 88.23; Anal. calcd.
for C16H13N5: C, 69.80; H, 4.76; N, 25.44; Found: C, 69.78; H,
4.74, N, 25.41.
Physical data of 9-arylcarbazoles: 4a IR (KBr, νmax, cm-1)
3070-2980 w (aromatic C-H), 1600-1400s (aromatic C=C),
1120 s (C-O), 1210s (C-N), 800-650 w (=CH, aromatic OOP);
1H NMR (CDCl3, 200 MHz) δ 3.83 (s, 3H, CH3), 7.02-8.19
(m, 12H, phenyl and carbazolyl group); Mass (m/e): 274
(M++1, 25), 273 (M+, 100), 258, 242, 166. 4b IR (neat) 3050-
2900w (aromatic C-H), 1550s, 1390s (NO2), 1500-1450s
(aromatic C=C), 1230s (C-N), 760-720w (=CH. Aromatic
OOP) cm-1; 1H NMR (CDCl3, 300 MHz) δ 6.34-7.68 (m, 12H,
phenyl and carbazolyl group); Mass (m/e) 268 (M+), 242, 166,
140, 46, 30. 4c IR (KBr, νmax, cm-1) 3050-2950w (aromatic
C-H), 1590s (aromatic C=C), 1240s (C-N), 760-700s (=CH
aromatic OOP); 1H NMR (CDCl3, 200 MHz) δ 7.20-8.18 (m,
13H, phenyl and carbazolyl group); 13C NMR (CDCl3, 50.32
MHz) δ 129.89, 127.45, 125.91, 120.30, 119.89, 109.76; Mass
(m/e): 244 (M++1, 23), 243 (M+, 100), 166, 140, 77. 4d IR
(neat) 3050-2900w (aromatic C-H), 1550s, 1390s (NO2), 1500-
1450s (aromatic C=C), 1230s (C-N), 760-720w (=CH, aromatic
OOP) cm-1; 1H NMR (CDCl3, 300 MHz) δ 6.34-7.68 (m, phenyl
and carbazolyl group); Mass (m/e): 288, 242, 166, 140, 46,
30. 4e IR (neat) 3030-3010w (aromatic C-H), 1500-1450s
(aromatic C=C), 1215s (C-N), 1005s (aryl-Br), 770-710s
(=CH, aromatic OOP); 1H NMR (CDCl3, 200 MHz) δ 7.25-
8.20 (m, 12H, phenyl and carbazolyl group); Mass (m/e): 323
(M++2, 103), 321(M+, 100), 241, 166, 140, 76.
2,4,6-Tri-pyrrol-1-yl-[1,3,5]triazine (9): Isolated yield
: 29 % (30 %); m.p.: 187-189 ºC; Rf : 0.35 (TLC eluent; CHCl3:
n-hexane = 1 : 40, v/v); Mass (70 eV), m/z (rel. Int. %): 276
(10), 51 (100), 129 (30), 75 (30), 102 (20); 1H NMR (CDCl3,
200 MHz): δ 7.81-7.84 (t, 6H), 6.39-6.41 (t, 6H); 13C NMR
(CDCl3, 50 MHz): δ 182.21, 138.88, 138.36, 132.95, 132.41.
RESULTS AND DISCUSSION
Generarlly, synthetic methods of 1-arylpyrroles 3 from
amines 1 and 2 have been known for a long time8-11. 1-Aryl-
pyrroles 3 were obtained in quantitative yields by the general
method (Table-1). The effect of organic dicarboxylic acids on
the synthesis of 3 was investigated (Table-2). Among organic
dicarboxylic acids, adipic acid gave the highest yield of 3c
(Table-2, Entry 1) (Scheme-I).
NH2
g. CH3COOH
reflux
N
+
H3CO
OCH3
O
R
R
1
2
3
1-(2-aminophe-nyl)pyrrole (6a):Yield : 73 %; m.p.: 102-
103 ºC; Rf : 0.44 (TLC eluent; n-hexane : EtOAc = 20 : 1, v/v);
1H NMR (CDCl3, 200 MHz) : δ 3.68 (s, 2H), 6.31-6.35, (s,
2H), 6.72-6.78 (m, 2H), 6.79-6.82 (s, 4H), 7.10-7.15 (m, 2H);
Mass (70eV), m/z : 158.
Direct and
One-pot synthesis
g. CH3COOH
reflux
g. CH3COOH
reflux
H3CO
OCH
3
N
O
R
4
1,2-Dipyrrolylbenzene (7a): Isolated yield : 5 %; Rf: 0.68
(TLC eluent ; EtOAc : n-hexane = 1 : 20, v/v); Mass (70 eV),
m/z (rel. Int. %) : 208 (19), 158 (62), 132 (71), 77 (71), 63
(90), 51 (100); 1H NMR (CDCl3, 200 MHz) : δ 7.62 (m, 2H),
δ 7.58 (m, 2H), δ 7.26 (m, 4H) δ 6.41 (m, 4H); 13C NMR
(CDCl3, 50 MHz) : δ 143.7, 131.3, 131.0, 130.6, 129.4, 122.6,
120.4, 120.1, 110.5, 108.9, 48.9, 29.6; Anal. calcd. for
C14H12N2: C, 80.74; H, 5.81; N, 13.45; Found : C, 80.71; H,
5.80 ; N, 13.43.
Scheme-I: Synthesis of 9-arylcarbazoles
The yield of 3c was the lowest when acetonedicarboxylic
acid was used (Table 2, Entry 3), but N-phenylnortropinone
was formed as the major product in 48 % yield.
TABLE-1
PHYSICAL DATA OF 1-ARYLPYRROLES (3)
R
Yield (%)a
m.p. (ºC)
108-109
180-181
58-596,7
81-827
Lit.8 m.p. (ºC)
108
1-(3-Aminophenyl)-pyrrole (6b):Yield: 28 %; m.p.: 120-
122 ºC; Rf : 0.44 (TLC eluent; n-hexane : EtOAc = 20 : 1, v/v);
1H NMR (CDCl3, 200 MHz): δ 2.20 (s, 2H), 6.20 (s, 2H), 7.10
(m, 2H), 7.30 (s, 2H); Mass (70 eV), m/z: 158.
p-OCH3
p-NO2
H
98
88
98
87
93
a
b
c
180-181
58-59
m-NO2
m-Br
aIsolated yield
81-82
d
e
64-656,7
–
1,3-Dipyrrolylbenzene (7b): Yield: 37 %; m.p.: 107-
108 ºC; Rf : 0.675 (TLC eluent; n-hexane: EtOAc = 5 : 1, v/v);
1H NMR (CDCl3, 200 MHz): δ 6.36-6.38 (t, 4H), 7.10-7.12 (t,
4H), 7.25-7.29 (m, 3H), 7.41-7.60 (m, 1H) Mass (70eV), m/z:
208.
TABLE-2
YIELDS OF 1-PHENYLPYRROLE (3c) DEPENDING
ON THE DICARBOXYLIC ACIDS
1,4-Dipyrrolyl-benzene (7c): Yield : 58 %; m.p. : 213-
214 ºC; Rf : 0.44 (TLC eluent; n-hexane: EtOAc = 10 : 1,
v/v); 1H NMR (CDCl3, 200 MHz): δ 6.17-6.22 (t, 4H), 6.89-
6.96 (m, 4H), 7.16 (m, 2H), 7.36 (m, 2H); Mass (70 eV), m/z:
208.
Refiux
Organic dicarboxylic acid
(min)
Yield
(%)a 3c
Entry
Adipic acid
75
60
87
22
2(48)b
1
2
3
4
5
Tartaric acid
Acetonedicarboxylic acid
3-(Carboxymethylthio)propionic acid
2-Ketoglutaric acid
40
2,4,6-Tripyrrol-1-yl-pyrimidine (8): Isolated yield: 30 %
(39.5 %); m.p. : 171-173 ºC; Rf : 0.26 (TLC eluent; EtOAc:
n-hexane = 1 : 40, v/v); Mass (70 eV), m/z (rel. Int. %): 275
(10), 51 (100), 129 (30), 75 (30), 102 (20); 1H NMR (CDCl3,
200 MHz): δ 7.82-7.84 (t, 3H), 7.61-7.62 (t, 4H), 6.84 (s, 2H),
240
30
42
8
aIsolated yield. bN-Phenylnortropinone
9-Arylcarbazoles (4) were formed by treatment of 1-aryl-