86
S. M. Bonesi and R. Erra-Balsells
Vol. 38
3,6-Diiodo-2-acetoxycarbazole (2c).
3-Bromo-1-iodocarbazole (3a).
This compound was obtained as white needles (hexane), mp
192-193°; ir (potassium bromide): 3426 (NH), 1762, 1135
(C=O), 1073, 1055, 1017 (Ar-I) cm ; H-nmr (dimethylsulfox-
This compound was obtained as white needles (hexane, ethyl
acetate), mp 91-92°; ir (potassium bromide): 3420 (NH), 1080,
1058, 1030 (Ar-Br and Ar-I) cm ; H-nmr (dimethyl-
-1
1
-1 1
ide-d ): δ 8.24 (s, 1H, NH), 8.03 (d, 1H, 5-H, J = 1.4 Hz), 7.98
sulfoxide-d ): δ 11.1 (s, 1H, NH); 8.38 (s, 1H, 4-H), 8.13 (d, 1H,
6
6
(s, 1H, 4-H), 7.67 (dd, 1H, 7-H, J = 1.7, 8.5 Hz), 7.10 (d, 1H, 8-H,
5-H, J = 7.8 Hz), 7.74 (s, 1H, 2-H), 7.60-7.46 (m, 2H, 6-H and
7-H, J = 1.2, 7.8 Hz), 7.16 ppm (d, 1H, 8-H, J = 7.8 Hz); C-nmr
13
J = 8.4 Hz), 7.02 (s, 1H, 1-H), 2.47 ppm (s, 3H, CH CO);
3
13
C-nmr (dimethylsulfoxide-d ): δ 107.1, 157.9, 138.9, 138.7,
(dimethylsulfoxide-d ): δ 80.7, 138.5, 111.0, 118.4, 119.4, 118.4,
6
6
+.
134.2, 131.0, 129.1, 124.0, 123.5, 113.1, 107.2, 82.0, 79.7, 21.2
ppm; ms: m/z 77 (M+, 13), 435 (16), 308 (100), 182 (9), 164 (4),
154 (13), 126 (12).
125.3, 110.8, 132.3, 139.4, 124.6, 138.7 ppm; ms: m/z 373 (M ,
100), 371 (91), 246 (20), 244 (22), 166 (5), 165 (44), 164 (40),
138 (21), 137 (17), 82 (36).
Anal. Calcd. for C H NBrI: C, 38.75; H, 1.88; N, 3.77; O,
Anal. Calcd. for C H NO I : C, 35.18; H, 2.09; N, 2.93; O,
12
7
14 10
2 2
21.48; I, 34.12. Found: C, 38.80; H, 1.89; N, 3.78.
6.69; I, 53.11. Found: C, 35.21; H, 2.10; N, 2.94.
Iodination Reaction of 3-Nitrocarbazole (4) with N-Iodo-
succinimide.
General Procedure for the Iodination Reaction of Carbazoles
3 - 4 with Sodium Periodate/Iodine /Catalytic Acid and Sodium
Periodate /Potassium Iodide/Catalytic Acid Systems.
The iodination reaction of 3-nitrocarbazole (4) was performed
according to the general procedure described above. These
reactions were conducted at room temperature. The yellowish
solid residue was separated by column chromatography (silica
gel-hexane-ethyl acetate mixtures) to give two crystalline
products 4a and 4b. The percentage yield of the products
obtained are presented in Table V (see Result and Discussion).
These set of reactions were also performed in glacial acetic.
To a stirred solution of 3-bromocarbazole (3) (100 mg,
0.41 mmol) in ethanol (20 ml) solid sodium periodate (0.10 to
0.41 mmol depending on the stoichiometry used) and molecular
iodine previously ground (0.20 to 0.62 mmol depending on the
stoichiometry used) were added. Then concentrated sulfuric acid
(42 µl to 1.68 ml depending on the stoichiometry used, δ:
1.85 g/ml) was added gently. The reaction was stirred for an
appropriate time in the absence of light at controlled temperature
(70°) until tlc and hplc analysis indicated the reaction was
complete. The workup was conducted in a similar manner as
described above. The brownish residue was separated by column
chromatography (silica gel-hexane-ethyl acetate mixtures) to
give 3a and 3b. The percentage yield of the products obtained are
presented in Tables III and IV. Also, this set of reactions were
performed in glacial acetic acid, which works as solvent and acid
catalysis simultaneously. The percentage yield of the products
obtained are presented in Tables III and IV.
6-Iodo-3-nitrocarbazole (4a).
This compound was obtained as white needles (hexane-ethyl
acetate), mp 256-257°; ir (potassium bromide): 3331 (NH), 1313
-1
1
(NO ); 1090, 1045 (Ar-I) cm ; H-nmr (dimethylsulfoxide-d ):
2
6
δ 11.56 (s, NH), 8.74 (d, 1H, 4-H, J = 1 Hz), 8.27 (m, 2H, 2-H,
5-H, J = 2.2, 8.5 Hz), 7.74 (dd, 1H, 7-H, J = 1.6, 8.5 Hz), 7.60
(d, 1H, 1-H, J = 9.0 Hz), 7.42 ppm (d, 1H, 8-H, J = 8.5 Hz);
13
C-nmr (dimethylsulfoxide-d ): δ 143.1, 140.1, 140.0, 135.1,
6
129.8, 125.0, 121.6, 120.9, 117.8, 114.1, 111.2, 83.3 ppm; ms:
+.
m/z 339 (14), 338 (M , 100), 308 (16), 293 (4), 292 (32), 211
Iodination Reaction of 3-Bromocarbazole (3) with
N-Iodosuccinimide.
(5), 165 (34), 164 (44), 139 (7), 138 (22).
Anal. Calcd. for C H N O I: C, 42.64; H, 2.07; N, 8.29; O,
12
7 2 2
The iodination reaction of 3-bromocarbazole (3) was
performed according to the general procedure described above.
These reactions were conducted at room temperature. The
brownish solid residue was separated by column chromatography
(silica gel-hexane-ethyl acetate mixtures) to give two crystalline
products 3a and 3b. The percentage yield of the products
obtained are presented in Table IV (see Result and Discussion).
These set of reactions were also performed in glacial acetic acid.
9.47; I, 37.53. Found: C, 42.68; H, 2.06; N, 8.31.
8-Iodo-3-nitrocarbazole (4b).
This compound was obtained as white needles (hexane-
ethyl acetate), mp 253-254°; ir (potassium bromide): 3331
-1
1
(NH), 1315 (NO ); 1089, 1040 (Ar-I) cm
; H-nmr
2
(dimethylsulfoxide-d ): δ 11.56 (s, NH), 8.74 (d, 1H, 4-H, J =
6
2.2 Hz), 8.27 (dd, 1H, 2-H, J = 2.2, 9.0 Hz), 8.18 (d, 1H, 5-H,
J = 8.5 Hz), 7.74 (dd, 1H, 7-H, J = 1.6, 8.5 Hz), 7.60 (d, 1H,
1-H, J = 9.0 Hz), 6.98 ppm (dd, 1H, 6-H, J = 8.5 Hz); C-nmr
3-Bromo-6-iodocarbazole (3b).
13
This compound was obtained as white needles (hexane, ethyl
acetate), mp 203-204°; ir (potassium bromide): 3422 (NH), 1084,
(dimethylsulfoxide-d ): δ 140.0, 139.0, 138.5, 135.7, 125.0,
6
122.0, 121.0, 120.9, 120.5, 117.0, 114.1, 72.0 ppm; ms: m/z
-1
1
+.
1065, 1032 (Ar-Br and Ar-I) cm
; H-nmr (dimethyl-
339 (14), 338 (M , 100), 308 (16), 293 (4), 292 (32), 211 (5),
sulfoxide-d ): δ 11.52 (s, 1H, NH), 8.56 (d, 1H, 5-H, J = 1.6 Hz),
165 (34), 164 (44), 139 (7), 138 (22).
6
8.39 (d, 1H, 4-H, J = 1.7 Hz), 7.67 (dd, 1H, 7-H, J = 1.6 and 8.5
Hz), 7.53 (dd, 1H, 2-H, J = 1.7, 8.7 Hz), 7.46 (d, 1H, 1-H, J = 8.7
Anal. Calcd. for C H N O I: C, 42.64; H, 2.07; N, 8.29; O,
12
7 2 2
9.47; I, 37.53. Found: C, 42.67; H, 2.08; N, 8.30.
13
Hz), 7.37 ppm (d, 1H, 8-H, J = 8.5 Hz); C-nmr (dimethyl-
Iodination Reaction of 3-Nitrocarbazole 4 with Sodium
Periodate/Iodine /Catalytic Acid.
sulfoxide-d ): δ 139.1, 138.4, 134.1, 129.1, 128.6, 124.1, 123.1,
6
+.
123.0, 113.6, 113.2, 110.9, 81.7 ppm; ms: m/z 373 (M , 100),
371 (91), 246 (20), 244 (22), 166 (5), 165 (44), 164 (40), 138
(21), 137 (17), 82 (36).
The iodination reaction of 3-nitrocarbazole was performed
according to the general procedure described above. The reaction
was conducted at 70°. The yellowish residue was separated by
column chromatography (silica gel-hexane-ethyl acetate
Anal. Calcd. for C H NBrI: C, 38.75; H, 1.88; N, 3.77; O,
12
7
21.48; I, 34.12. Found: C, 38.79; H, 1.88; N, 3.79.