One-pot, three-component synthesis of 3-(5-amino-1H-pyrazol-4-yl)-3-(2- hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl)indolin-2-ones

Article abstract of DOI:10.1080/00397910903062298

A clean, efficient, one-pot, three-component method for the synthesis of 3-(5-amino-1H-pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl) indolin-2-one derivatives by condensation reaction of dimedone, 1H-pyrazol-5-amines, and isatins in aqueous media is reported.

Full text of DOI:10.1080/00397910903062298

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One-Pot, Three-Component Synthesis
of 3-(5-Amino-1H-pyrazol-4-yl)-3-(2-
hydroxy-4,4-dimethyl-6-oxocyclohex-1-
enyl)indolin-2-ones
Somayeh Ahadi a , Peiman Mirzaei a & Ayoob Bazgir a
a Department of Chemistry, Faculty of Science, Shahid Beheshti
University, G.C., Tehran, Iran
Version of record first published: 12 Mar 2010.
To cite this article: Somayeh Ahadi, Peiman Mirzaei & Ayoob Bazgir (2010): One-Pot, Three-
Component Synthesis of 3-(5-Amino-1H-pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-
enyl)indolin-2-ones, Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 40:8, 1224-1230
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Synthetic Communications1, 40: 1224–1230, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903062298
ONE-POT, THREE-COMPONENT SYNTHESIS OF
3-(5-AMINO-1H-PYRAZOL-4-YL)-3-(2-HYDROXY-
4,4-DIMETHYL-6-OXOCYCLOHEX-1-ENYL)INDOLIN-
2-ONES
Somayeh Ahadi, Peiman Mirzaei, and Ayoob Bazgir
Department of Chemistry, Faculty of Science, Shahid Beheshti University,
G.C., Tehran, Iran
A clean, efficient, one-pot, three-component method for the synthesis of 3-(5-amino-1H-
pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl)indolin-2-one derivatives
by condensation reaction of dimedone, 1H-pyrazol-5-amines, and isatins in aqueous media
is reported.
Keywords: Dimedone; isatin; oxindole; pyrazole
INTRODUCTION
Polyfunctionalized heterocyclic compounds play important roles in the drug
discovery process, and analysis of drugs in late development or on the market shows
that 68% of them are heterocycles.[1,2] Therefore, it is not surprising that research on
the synthesis of polyfunctionalized heterocyclic compounds has received significant
attention.
Isatin and its derivatives have proved to be versatile starting materials for the
synthesis of heterocyclic, and noncyclic, natural products and analogs, as well as for
the synthesis of potentially important compounds with biological activities.[3]
Oxindoles are well known among these compounds (Fig. 1). Oxindoles are useful
as antibacterial, anti-inflammatory, and laxative products.[4,5] Furthermore, these
heterocyclic compounds were recently isolated from plants. For example, the marine
alkaloid convolutamydine A, isolated from the marine bryozoan Amathia convolute
was found to show potent activity in the differentiation of HL-60 human promyelo-
cytic leukenie cell.[6]
The 3,3-substituted oxindoles have been shown to possess mechanism-specific
antiproliferative, antibacterial, antiprotozoal, and anti-inflammatory activities.[7–10]
Compounds 1 and 2 have been used as laxatives.[5] Therefore, recently, a few
methods have been developed for the synthesis of 3,3-substituted oxindoles.[5,11–13]
Received April 21, 2009.
Address correspondence to Ayoob Bazgir, Department of Chemistry, Faculty of Science, Shahid
Beheshti University, G.C., Evin, Tehran 1983963113, Iran. E-mail: a_bazgir@sbu.ac.ir
1224

POLYFUNCTIONALIZED HETEROCYCLIC COMPOUNDS
1225
Figure 1. Examples of biologically active oxindoles.
Heterocycles containing the pyrazole ring are important targets in synthetic
and medicinal chemistry because this fragment is a key moiety in numerous biologi-
cally active compounds,[14–16] among them such prominent drug molecules as
Celecoxib and Pyrazofurines. Recently, they have also emerged as potential atypical
antipsychotics.[17]
As part of our program aimed at developing new selective and environmentally
friendly methodologies for the preparation of heterocyclic compounds,[18–24] we
performed the synthesis of 3-(5-amino-1H-pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-
6-oxocyclohex-1-enyl) indolin-2-ones through a condensation reaction employing
water as the reaction medium. In fact, as clearly stated by R. A. Sheldon, it is
generally recognized that ‘‘the best solvent is no solvent and if a solvent (diluent)
is needed it should preferably be water.’’[25]
RESULTS AND DISCUSSION
To achieve suitable conditions for the synthesis of 3-(5-amino-1H-pyrazol-4-
yl)-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl)indolin-2-ones 4, we tested the
reaction of 1,3-diphenyl-1H-pyrazol-5-amine 1a, dimedone 2, and isatin 3a as a
simple model substrate in various solvents and under solvent-free classical heating
conditions in the presence of p-toluenesulfonic acid (p-TSA), an inexpensive and
available catalyst (Scheme 1). In refluxing solvents or under solvent-free conditions,
the yield of product was very poor. The results are shown in Table 1. It was found
that water was the solvent of choice for the reaction, and the desired product was
obtained in good yield in water (entry 2).
To explore the scope and limitations of this reaction, we extended the reaction
of 1H-pyrazol-5-amines 1a,b and dimedone 2 with a range of isatins 3a–h under simi-
lar conditions (using H2O=p-TSA) for 24 h, furnishing the respective 3-(5-amino-1H-
pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl)indolin-2-ones 4a–m
in good yields (Scheme 1). The optimized results are summarized in Table 2. The
results were good in terms of yields and product purity in the presence of p-TSA,
but without it the yields of products were poor (<30%), even after 60 h.
The nature of these compounds as 1:1:1 adducts was apparent from their mass
spectra, which displayed, in each case, the molecular ion peak at appropriate m=z

1226
S. AHADI, P. MIRZAEI, AND A. BAZGIR
Scheme 1. Synthesis of oxindoles 4.
values. Compounds 4 are stable solids whose structures are fully supported by
infrared (IR), 1H NMR and 13C NMR spectroscopy, mass spectrometry (MS),
and elemental analysis.
We have not established an exact mechanism for the formation of oxindoles 4,
but two reasonable possibilities are indicated in Scheme 2. Addition of pyrazol-
5-amine 1 to isatin 3 leads to highly reactive intermediate 5 via a standard nucleophi-
lic addition.[26] Interception of 5 by dimedone 2, possibly through its enol tautomer,
produces product 4 (pathway A). Isatin 3 and dimedone 2 would react to produce
Table 1. Solvent effects on the reaction time and yielda
Entry
Conditions
Time (h)
Yield (%)
1
2
3
4
5
Solvent-free, 100ꢀC
Water (reflux)
CH3CN (reflux)
12
24
24
12
24
45
77
40
64
58
EtOH (reflux)
Dimethylformamide (reflux)
aDimedone (1 mmol), 1,3-diphenyl-1H-pyrazol-5-amine (1 mmol), isatin (1 mmol), and p-TSA (0.1 g).
Table 2. Synthesis of oxindoles 4
Product 4
R
X
Y
Yield (%)
a
b
c
d
e
f
H
H
H
H
H
Br
77
83
81
75
90
73
72
76
73
80
70
72
77
H
H
NO2
H
Me
Me
Et
H
H
H
Br
H
H
g
h
i
H
Me
Br
Et
Et
H
H
H
NO2
H
j
NO2
NO2
NO2
NO2
k
l
Me
Et
H
H
H
NO2
m

POLYFUNCTIONALIZED HETEROCYCLIC COMPOUNDS
1227
Scheme 2. Proposed mechanism of the reaction.
highly reactive intermediate 6,[27] followed by a nucleophilic addition with pyrazol-
5-amine 1 to afford oxindol 4 (pathway 5).
EXPERIMENTAL
General
Melting points were measured on an Elecrtothermal 9100 apparatus and are
uncorrected. Mass spectra were recorded on a Finnigan-MAT 8430 mass spec-
trometer operating at an ionization potential of 70 eV. 1H and 13C NMR spectra were
recorded on a Bruker DRX-300 Avance spectrometer at 300.13 and 75.47 MHz,
respectively. IR spectra were recorded using a Fourier transform (FT)–IR apparatus.
Elemental analyses were performed using a Heracus CHN-O-Rapid analyzer.
General Procedure for the Preparation of 3-(5-Amino-1,3-diphenyl-
1H-pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl)
indolin-2-one (4a)
A mixture of dimedone (1 mmol), 1,3-diphenyl-1H-pyrazol-5-amine (1 mmol),
isatine (1 mmol), and p-TSA (0.1 g) in refluxing water (5 ml) was stirred for 24 h.
The progress of the reaction was monitored by thin-layer chromatography (TLC).
After completion of reaction, the reaction mixture was filtered, and the precipitate
was washed with water. The residue was recrystallized from EtOH to afford the pure
product 4a. White powder (77%); mp 290ꢀC dec. IR (KBr) (nmax=cmꢁ1): 3305, 3070,
1
1706, 1608. MS (EI, 70 eV) m=z (%): 504 (Mþ, 10), 489 (10), 402 (100). H NMR
(300 MHz, DMSO-d6): dH(ppm) 0.93 (3H, s, CH3), 1.01 (3H, s, CH3), 1.96 and

1228
S. AHADI, P. MIRZAEI, AND A. BAZGIR
2.08 (2H, AB system, J ¼ 16.1 Hz, CH2), 2.58 (2H, s, CH2), 3.57 (1H, bs, OH
exchanged with solvent), 6.48–7.60 (16H, m, H-Ar and NH2), 9.79 (1H, s, NH).
13C NMR (DMSO-d6): dC (ppm) 27.3, 28.6, 32.4, 41.4, 49.4, 51.1, 101.9, 108.7,
109.1, 121.5, 123.6, 124.2, 127.6, 128.1, 128.2, 129.0, 129.9, 133.2, 137.4, 138.1,
138.6, 142.8, 149.8, 153.0, 179.9, 193.5. Anal. calcd for C31H28N4O3: C, 73.79; H,
5.59; N, 11.10%. Found: C, 73.74; H, 5.55; N, 11.17%.
Selected Characterization Data
3-(5-Amino-1,3-diphenyl-1H-pyrazol-4-yl)-5-bromo-3-(2-hydroxy-4,4-
dimethyl-6-oxocyclohex-1-enyl)indolin-2-one (4b). Cream powder (83%);
mp 240ꢀC dec. IR (KBr) (nmax=cmꢁ1): 3219, 2957, 1714, 1616. MS (EI, 70 eV) m=z
1
(%): 582 (Mþ, 7), 564 (5), 482 (100), 402 (45). H NMR (300 MHz, DMSO-d6):
dH(ppm) 0.98 (6H, s, 2CH3), 1.98 (2H, s, CH2), 2.58 (2H, s, CH2), 6.40–7.65
(15H, m, H-Ar and NH2), 9.90 (1H, s, NH), 9.94 (1H, s, OH). 13C NMR
(DMSO-d6): dC (ppm) 27.6, 28.2, 32.5, 41.3, 49.5, 50.8, 101.2, 108.1, 111.0, 113.0,
124.5, 126.3, 127.8, 128.2, 128.3, 128.9, 129.9, 130.4, 133.0, 137.4, 138.0, 140.7,
142.1, 149.8, 153.5, 179.6, 193.7. IR (KBr) cmꢁ1: 3219.4, 2957.49 and 2859.91,
1714.69, 1616.47. Anal. calcd. for C31H27BrN4O3: C, 63.81; H, 4.66; N, 9.60%.
Found: C, 63.87; H, 4.61; N, 9.66%.
3-(5-Amino-1,3-diphenyl-1H-pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-6-
oxocyclohex-1-enyl)-5-nitroindolin-2-one (4c). Light brown powder (81%); mp
215ꢀC dec. IR (KBr) (nmax=cmꢁ1): 3224, 2952, 1735, 1617. MS (EI, 70 eV) m=z (%):
1
549 (Mþ, 5), 529 (20), 419 (100). H NMR (300 MHz, DMSO-d6): dH 0.99 (6H, s,
2CH3), 2.05 (2H, s, CH2), 2.51 and 2.65 (2H, AB system, J ¼ 24.7 Hz, CH2),
6.58–8.03 (15H, m, H-Ar and NH2), 10.03 (1H, s, NH), 10.55 (1H, s, OH). 13C
NMR (DMSO-d6): dC (ppm) 27.8, 28.0, 32.6, 41.2, 49.3, 50.7, 100.8, 107.6, 109.0,
118.8, 124.5, 125.4, 127.9, 128.2, 128.5, 129.0, 129.9, 132.8, 137.9, 139.1, 142.2,
149.4, 149.8, 154.2, 180.6, 193.9. Anal. calcd. for C31H27N5O5: C, 67.75; H, 4.95;
N, 12.74%. Found: C, 67.70; H, 4.89; N, 12.68%.
3-(5-Amino-1,3-diphenyl-1H-pyrazol-4-yl)-3-(2-hydroxy-4,4-dimethyl-6-
oxocyclohex-1-enyl)-1-methylindolin-2-one (4d). Cream powder (75%); mp
294ꢀC dec. IR (KBr) (nmax=cmꢁ1): 3333, 3051, 2955, 1691, 1624. MS (EI, 70 eV)
m=z (%): 500 (Mþ-H20, 50), 416 (100), 426 (26), 387 (45).1H NMR (300 MHz,
DMSO-d6): dH (ppm) 0.97 (3H, s, CH3), 1.01 (3H, s, CH3), 1.93 and 2.06 (2H, AB
system, J ¼ 24.3 Hz, CH2), 2.60 (2H, s, CH2), 2.62 (3H, s, CH3), 6.58–7.65 (16H,
m, H-Ar and NH2), 9.93 (1H, s, OH). 13C NMR (DMSO-d6): dC (ppm) 25.9, 27.3,
28.6, 32.5, 41.4, 48.8, 50.9, 102.0, 107.7, 108.2, 122.2, 123.8, 124.1, 127.6, 127.9,
128.0, 128.1, 128.9, 129.9, 133.0, 137.5, 138.1, 143.6, 149.7, 153.5, 178.2, 193.4 Anal.
calcd. for C32H30N4O3: C, 74.11; H, 5.83; N, 10.80%. Found: C, 74.17; H, 5.77; N,
10.87%.
3-(5-Amino-1-(4-nitrophenyl)-3-phenyl-1H-pyrazol-4-yl)-3-(2-hydroxy-4,
4-dimethyl-6-oxocyclohex-1-enyl)-1-methylindolin-2-one (4k). Yellow pow-
der (70%); mp > 320ꢀC. IR (KBr) (nmax=cmꢁ1): 3465, 3219, 1714, 1601. MS (EI,
70 eV) m=z (%): 563 (Mþ, 10), 538 (Mþ, 40), 368 (70), 57 (100). 1H NMR

POLYFUNCTIONALIZED HETEROCYCLIC COMPOUNDS
1229
(300 MHz, DMSO-d6): dH 0.99 (3H, s, CH3), 1.02 (3H, s, CH3), 1.95 and 2.09 (2H,
AB system, J ¼ 15.7 Hz, CH2), 2.61 (5H, s, CH2 and CH3), 6.58–7.27 (11H, m, H-Ar
and NH2), 7.94 (2H, d, J ¼ 8.8 Hz, H-Ar), 8.43 (2H, d, J ¼ 8.9 Hz, H-Ar), 10.01 (1H,
s, OH). 13C NMR (DMSO-d6): dC 25.9, 27.4, 28.5, 32.6, 41.45, 48.7, 50.9, 103.0,
107.9, 108.7, 122.3, 123.4, 124.2, 125.5, 127.8, 128.1, 128.6, 128.8, 132.4, 137.2,
137.9, 143.1, 143.6, 146.1, 151.4, 153.2, 177.9, 193.8. Anal. calcd. for C32H29N5O5:
C, 68.19; H, 5.19; N, 12.43%. Found: C, 68.13; H, 5.24; N, 12.49%.
CONCLUSION
In conclusion, we have described a clean, simple, one-pot, three-component
method for the preparation of 3-(5-amino-1H-pyrazol-4-yl)-3-(2-hydroxy-4,4-
dimethyl-6-oxocyclohex-1-enyl)indolin-2-one derivatives in condensation reaction
of 1H-pyrazol-5-amines, dimedone, and isatins under reflux in water.
ACKNOWLEDGMENT
We gratefully acknowledge financial support from the Research Council of
Shahid Beheshti University.
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