Chemical Papers
mixture was refuxed for 8 h and allowed to room tempera-
ture. Now required quantity of crushed ice was added to
the reaction mixture, fltered and recrystallized from etha-
nol which yielded 5-substituted-1-methyl indole-3-carbohy-
drazides 14a–b.
J = 7.2 Hz, Ar–H), 8.36 (1H, s, Ar–H), 8.85 (1H, s, Ar–H),
10.40 (2H, broad singlet, 2-NH) ppm; 13C NMR: (400 MHz,
DMSO–d6): δ 32.5, 32.8, 110.1, 110.8, 111.6, 112.7, 120.4,
121.9, 123.9, 126.0, 127.0, 132.5, 134.4, 136.5, 140.8,
161.3, 161.5, 182.4 ppm. MS (ESI): m/z = 453 (M + H)+;
Anal Calcd for C21H17N4BrO3: C, 55.64; H, 3.78; N, 12.36.
Found: C, 57.57; H, 3.69; N, 12.39.
1-methyl-1H-indole-3-carbohydrazide(14a) (Alemany
et al. 1975) yellow color solid. Yield: 61%. m.p: 150-152oc;
1H NMR (400 MHz, CDCl3): δ 3.80 (3H, s, -NCH3),
4.14 (2H, s, -NH2), 7.24-7.32 (3H, m, Ar–H), 7.34 (1H,
d, J = 7.6 Hz, Ar–H), 7.66 (1H, s, -NH), 7.93 (1H, d,
J = 7.6 Hz, Ar–H) ppm.
5-bromo-N’-[(5-bromo-1-methyl-1H-indol-3-yl)
(oxo)acetyl]-1-methyl-1H-indole-3-carbo hydrazide
(17b) yellow solid; Yield: 79%; m.p: 150-152oc; IR (KBr):
3644, 3245, 3094, 2955, 1735 cm−1; 1H NMR (400 MHz,
DMSO-d6): δ 3.31 (3H, s, -NCH3), 3.42 (3H, s, -NCH3),
7.11-7.23 (2H, m, Ar–H), 7.62-7.74 (3H, m, Ar–H), 8.11
(1H, s, Ar–H), 8.20-8.23 (1H, m, Ar–H), 8.62 (1H, s, Ar–H),
11.30 (1H, broad singlet, NH); 12.25 (1H, broad singlet,
NH) ppm; MS (ESI): m/z = 532 (M + H)+; Anal Calcd for
C21H16N5BrO: C, 47.39; H, 3.03; N, 10.53. Found: C, 47.34;
H, 2.98; N, 10.61.
5-bromo-1-methyl-1H-indole-3-carbohydrazide(14b)
yellow color solid. Yield: 74%. m.p: 250–252 °C; 1H NMR
(400 MHz, CDCl3): δ 3.81 (3H, s, -NCH3), 4.11 (2H, s,
-NH2), 7.04 (1H, s, Ar–H), 7.21 (1H, d, J = 8.8 Hz, Ar–H),
7.38 (1H, m, Ar–H), 7.60 (1H, s, Ar–H), 8.13 (1H, s, -NH)
ppm; HRMS calculated for C10H11N3OBr: 268.00800;
found:268.00775.
N’-[(5-bromo-1-methyl-1H-indol-3-yl)(oxo)acetyl]-
1-methyl-1H-indole-3-carbohydrazide (17c) yellow solid;
Yield: 66%; m.p: 163-164oc; IR (KBr): 3345, 3064, 2932,
1678 cm−1; 1H NMR (400 MHz, DMSO-d6): δ 3.84 (3H, s,
-NCH3), 3.90 (3H, s, -NCH3), 7.18-7.42 (7H, m, Ar–H), 8.02
(1H, s, Ar–H), 8.20 (1H, d, J = 7.55 Hz, Ar–H); 8.74 (1H,
broad singlet, -NH), 8.89 (1H, broad singlet, -NH) ppm;
13C NMR (400 MHz, DMSO-d6): δ 24.75, 34.92, 108.7,
112.3, 113.3, 124.2, 124.6, 129.3, 136.2, 137.3, 160.4,
189.04 ppm; MS (ESI): m/z = 453 (M + H)+; Anal Calcd
for C21H17N4BrO3: C, 55.64; H, 3.78; N, 12.36. Found: C,
57.59; H, 3.72; N, 12.41.
General procedure for the synthesis of triketo diazo
compounds (17a–c)
A solution of oxalyl chloride (9.7 g, 7.6 mmol) was added
drop wise to a 0 °C cold solution of N- methyl indoles (5 g,
38.11 mmol) soluble in 35 mL diethyl ether. The mixture
was stirred at 0 °C over a period of 3 h under cooling con-
dition and the precipitated solid was collected by suction
fltration, washed with cold diethyl ether and dried under
reduced pressure to give 2-oxo acetyl chloride indole deriva-
tives 16a–b as crude products. It was impossible to purify
the tri keto diazo compounds in the column chromatography.
The products 16a-b are not purifed because these products
aredecomposed in silicagel during chromatography. Hence,
we directly used these crude products for next reaction with-
out further purifcation.
General procedure for the synthesis of triazinones
(18a–c) The synthesis of triazinones was achieved through
cyclo condensation between amidrazone and ketoester func-
tions (Garg and Stoltz 2005). But we proposed diferent
tri keto diazo compounds 17a–c (2.207 mmol) were dis-
solved in 7 volumes of acetic acid and methanol mixture
(1:1 ratio). To this mixture, ten times ammonium acetate was
added and allowed the reaction mixture for refux over 10 h.
Crushed ice was added to the reaction mixture and neutral-
ized with aqueous sodium carbonate to yield the crude prod-
ucts. The pure products are obtained from crude products
by column chromatography with 3:2 ratio ethyl acetate and
hexane to give pure triazinone 18a-c derivatives.
A solution of tri ethyl amine (9.02 mmol) in 5 volumes of
THF was added dropwise to the above oxo acetyl chloride
indole derivatives (9.02 mmol). The reaction mixture was
refuxed over a period of 4 h and poured in crushed ice. This
was neutralized with 10 mL HCl (0.01 N) to remove excess
tri ethyl amine to get crude products and purifed by column
chromatography with 3:2 ratio ethyl acetate and hexane to
give pure triazinone 17a–c derivatives. The formation of
these bis-acyl hydrazines was supported by literature of the
(Mielczarek et al. 2014).
3-(5-bromo-1-methyl-1H-indol-3-yl)-5-(1-methyl-
1H-indol-3-yl)-1,2,4-triazin-6(1H)-one (18a) yellow
solid; Yield: 60%; m.p: 165-167oc; IR (KBr): 3348, 3015,
2986, 1694 cm−1; 1H NMR (400 MHz, DMSO – d6): δ 3.92
(6H, s, 2 –NCH3), 7.21–7.39 (4H, m, Ar–H), 7.50 (2H, d,
J = 7.36HZ, Ar–H), 7.55 (1H, broad, NH), 7.85 (1H, broad,
N=C–OH), 8.31 (1H, d, J = 7.55 HZ, Ar–H), 8.811 (2H,
s, Ar–H) ppm; 13C NMR (400 MHz, DMSO – d6): δ 31.6,
32.3, 98.7, 108.6, 114.6, 117.3, 122.2, 122.8, 125.8, 127.2,
5-bromo-1-methyl-N’-[(1-methyl-1H-indol-3-yl)(oxo)
acetyl]-1H-indole-3-carbohydrazide (17a) yellow solid;
Yield: 72%; m.p: > 300oc; IR (KBr): 3641, 3100, 2936,
1
1691 cm−1; H NMR (400 MHz, DMSO-d6): δ 3.86 (3H,
s, -NCH3), 3.94 (3H, s, -NCH3), 7.30-7.37 (3H, m, Ar–H),
7.50-7.53 (1H, d, J = 8.8 Hz, Ar–H), 7.60-7.62 (1H, d,
J = 7.6 Hz, Ar–H), 8.08 (1H, s, Ar–H), 8.29-8.31 (1H, d,
1 3