Synthesis and characterization of some substituted chromones as an anti-infective and antioxidant agents

Article abstract of DOI:10.1002/jhet.5570450607

(Chemical Equation Presented) A series of substituted chromones were synthesized and characterized by spectral data. Some of the synthesized compounds were tested for in-vitro antibacterial, antifungal and antioxidant activity. Two compounds have shown ve

Full text of DOI:10.1002/jhet.5570450607

Nov-Dec 2008
1597
Synthesis And Characterization Of Some Substituted Chromones As
An Anti-infective And Antioxidant Agents
Milind Rodea, R. C. Guptaa, B. K. Karaleb and S. S. Rindhec*
a Torrent Research Center, Bhat village, Gandhinagar - 382428, Gujarat, India.
b Dept of Chemistry, Radhabai Kale Mahila Mahavidyalaya, Ahmednagar - 414001, Maharashtra, India.
c Dept of Chemistry, New Arts Commerce and Science college, Ahmednagar - 414001, Maharashtra, India.
milindrode@yahoo.com
Received February 4, 2008
N
O
O
O
O
OH
O
O
O
O
N
O
O
N
4a
5r
O
O
O O
S
O
O
O
Br
O
O
O
N
5f
5i
N
N
O
A series of substituted chromones were synthesized and characterized by spectral data. Some
of the synthesized compounds were tested for in-vitro antibacterial, antifungal and antioxidant
activity. Two compounds have shown very good antioxidant activity and some of the chromone
derivatives have exhibited moderate antibacterial and antifungal activity.
J. Heterocyclic Chem., 45, 1597 (2008).
INTRODUCTION
show antihistamine and antagonistic activity against
leukotriene-D4 [4]. Substituted chromones have been
reported to show potential anticancer activity [5].
Lockhart et al reported the central stimulant activity of 3-
chromonanamine derivatives [6].
A series of sulfonamide derived chromones, previously
reported as inhibitors of carbonic anhydrase, have been
found to show in vitro antibacterial and antifungal activity
[7]. Chromones having heterocyclic substituents at the 2-
position have been reported to possess anti-bacterial and
antifungal activities and also found to exhibit good
phosphodiesterase-IV inhibition activity and some
chromones have potential HIV-integrase inhibition
activity [8]. Owing to the biological importance of
chromones, we herein, report the synthesis and biological
testing of some chromones.
Chromones and other related ring systems, have several
interesting biological activities. In addition, chromones
are also interesting structural scaffolds and have for
example, been designed to be used as mimetics of short
peptides. The wide range of applications observed for
chromone derivatives and their potential use in drug
discovery implicates the importance of access to efficient
synthetic routes to such compounds.
According to the literature survey, chromone
compounds are associated with various physiological and
biological properties and thus, find important use in
medicine. Excessive calpain activation contributes to
serious cellular damage and has been found in many
pathological conditions.
Chromones derived from ketoamides showed very good
selective μ – calpain inhibition [1]. 3-(1H-Tetrazol-5-yl)-
chromones have been found to show very good
antiallergic activity [2]. Substituted chromones have been
found to have coronary vasodilatory activity [3].
(Piperidinylalkoxy) chromones have been reported to
RESULTS AND DISCUSSION
In the present work, substituted benzaldehydes 1 were
treated with 2'-Hydroxyacetophenone 2 in presence of
NaOH in MeOH at reflux temperature to yield the

1598
M. Rode, R. C. Gupta, B. K. Karale and S. S. Rindhe
Vol 45
Compounds 4 were further substituted at the hydroxy
position by various alkyl halide and arylsulfonyl halide
derivatives using base (viz K2CO3) and DMF.
Scheme 1
O
O
R2
R2
NaOH, MeOH
The structures of the compound 4 were confirmed by
+
R1CHO
1
1
R1
spectral techniques (ms, ir and H nmr). In the H nmr
spectra, OH proton resonance of 4a was observed at 9.73
ꢀ as a singlet and its ir stretching band appeared at 3258
cm-1. Compound 4a showed a singlet at 3.80 ꢀ due to the
methoxy group and a triplet corresponding to piperazine
at 3.5 ꢀ and 3.7 ꢀ.
OH
1
OH
3
2
NaOH, H2O
MeOH, RT
O
O
O
OH
R1
R2
O
R2
R3X, K2CO3
DMF
R3
O
Compound 4a was treated with 3,5-dimethyl-
benzenesulfonyl chloride in the presence of K2CO3 in
R1
5
4
1
DMF to get 5b. The H nmr spectra of 5b showed singlet
of methoxy at 3.83 ꢀ, singlet of two methyl groups at 2.24
ꢀ and triplet of piperazine at 3.12 ꢀ and 3.44 ꢀ
respectively. The structural data of all chromone
derivatives is shown in Table 1.
corresponding chalcone 3, which on treatment with H2O2
and NaOH in MeOH by Algar Flynn Oymanda (AFO)
reaction [9,10] produced the corresponding 3-hydroxy
chromone 4.
Table 1
Structure of Synthesized Chromones
O
R2
O
R3
O
R1
M.P.
(0 °C)
Yield
in %
Compd.
R1
R3
R2
4a
5a
5b
5c
H
H
H
H
H
97
80
77
55
65
4-trifluoromethoxy benzenesulfonyl
3,5- dimethyl benzenesulfonyl
4-N-acetyl benzenesulfonyl
168
210
142
O
N
N
4b
5d
5e
5f
5g
5h
4c
5i
H
Br
H
Br
Br
H
H
H
H
H
H
H
H
H
Br
Br
174
187
176
153
173
158
128
125
163
243
169
178
195
217
155
85
45
62
78
48
59
88
84
78
79
88
55
48
65
75
4'-methyl-1,1'-biphenyl-2-carbonitrile
N,N-dimethyl acetamido
-CH2-CH2-OPh
2,4 – difluorobenzyl
Cyclohexyl methyl
H
Biphenyl sulfonyl
3,5-difluorophenyl sulfonyl
4-N-acetyl benzenesulfonyl
H
2,4 - difluorobenzyl
4'-methyl-1,1'-biphenyl-2-carbonitrile
- CH2COOH
N
N
N
5j
O
5k
4d
5l
5m
5n
5o
-CH2-CH2-OPh
4e
5p
5q
H
H
H
H
115
127
159
90
74
72
Cyclohexyl methyl
3,5 –difluorobenzyl
4f
5r
5s
5t
H
H
H
H
H
185
189
184
176
64
88
78
61
N,N-dimethyl acetamido
Ethyl
CH(COOH)2
O
O
O
O

Nov-Dec 2008
Synthesis And Characterization Of Some Substituted Chromones
1599
Antioxidant activity. The antioxidant activity of the test
compounds was determined by DPPH method using L-
ascorbic acid (antioxidant agent) as a positive control.
Amongst the compounds screened for antioxidant activity, 4a
and 5k show 91.7% and 89.2% antioxidant activity
respectively at 200 μg/mL concentration as shown in Table 6.
Antimicrobial. The in vitro antimicrobial activity of
test compounds was assessed against 24 hr cultures of
several selected bacteria and fungi. The bacteria used
were Escherchia coli, Staphylococcus aureus, and
Streptococcus faecium; the fungi used were Candida
albicans, Candida krusei and Aspergillus fumigatus.
The antimicrobial activity was performed by agar
diffusion method at 1 mg/mL concentration in DMSO.
Nutrient agar and potato dextrose agar were used to culture
the bacteria and fungi respectively. Fluconazole and
Vancomycin were used as the standard for the evaluation of
antibacterial and antifungal activities respectively.
Table 2
Compound
Compound
Elemental Analysis
Calcd % (Found %)
Elemental Analysis
Calcd % (Found %)
C
H
N
C
H
N
72.88
(72.86)
60.26
(60.24)
75.46
(75.44)
80.24
(80.22)
81.64
(81.62)
72.93
(72.91)
60.73
(60.71)
68.44
5.65
(5.64)
4.21
(4.20)
4.43
(4.43)
4.49
(4.48)
4.17
(4.18)
5.13
(5.12)
4.17
(4.16)
5.41
(5.40)
4.99
6.54
(6.52)
8.78
75.13
(75.11)
71.90
(71.88)
63.16
(63.14)
65.23
(65.21)
76.36
(76.34)
83.15
(83.14)
61.22
(61.20)
67.85
6.71
(6.69)
4.15
(4.14)
3.26
(3.26)
4.11
(4.10)
4.12
(4.11)
4.59
(4.60)
3.35
(3.35)
4.12
(4.11)
6.03
8.48
(8.46)
4a
4b
4c
4d
4e
4f
5h
5i
(8.76)
5j
2.72
(2.72)
5k
5l
2.77
(2.77)
5m
5n
5o
4.29
(4.28)
4.69
(4.68)
6.72
5a
5b
(68.43)
65.27
(65.25)
(67.84)
82.92
(82.90)
5c
5p
(4.98)
(6.70)
(6.01)
77.27
(77.25)
59.69
(59.67)
64.22
(64.20)
70.85
(70.84)
5.12
(5.10)
4.83
(4.82)
4.72
(4.71)
4.79
(4.78)
9.49
(9.47)
9.94
(9.92)
7.02
(7.02)
8.00
(7.98)
77.58
(77.57)
70.58
(70.56)
73.59
(73.57)
66.66
(66.65)
3.91
(3.90)
5.58
(5.57)
5.61
(5.60)
4.61
(4.60)
5d
5e
5f
5q
5r
5s
5t
2.35
(2.35)
5g
Table 3
Compound
IR
(cm-1)
Spectral data
1H nmr ꢀ (ppm)
Mass
M+
1680,
2829,
3258
1595,
1670,
3555
1596,
1680,
2829,
3255
1596,
1670,
3560
1340,
1596,
1670,
3564
1250,
1679,
3569
ꢀ 3.51ꢁ3.53 (t, 4ꢂ), 3.74 (t, 4H), 3.80 (s, 3H), 6.90-7.03 (m, 5H), 7.08-7.12 (d, 2H),
7.30-7.38 (t, 1H), 7.59-7.63 (s, 1H), 7.68-7.74 (d, 1H), 8.03-8.08 (d, 1H), 8.38-8.39 (d,
1H), 9.73 (s, 1H)
ꢀ 3.44 (t, 4H), 3.65 (t, 4H), 6.65-6.68 (t, 1H), 6.73 (t, 2H), 6.87-6.91 (d, 2H), 6.96-6.99
(t, 1H), 7.55-7.58 (d, 1H), 7.72-7.75 (d, 1H), 7.91 (s, 1H), 8.14 (d, 1H), 8.62-8.65 (d,
1H), 9.73 (s, 1H).
4a
4b
428
478
ꢀ 3.90-3.93 (s, 3H), 7.151-7.195 (dd, 1H), 7.34-7.38 (t, 2H), 7.67-7.74 (q, 3H), 7.85-7.89
(t, 2H), 8.05-8.09 (d, 1H), 8.52-8.54 (d, 1H), 9.04 (s, 1H)
4c
4d
4e
4f
318
314
338
510
ꢀ 7.22-7.30 (m, 5H), 7.40-7.53 (dd, 4H), 8.11-8.25 (d, 4H), 9.07 (s, 1H)
ꢀ 7.10-7.17 (q, 2H), 7.44- 7.48 (d,1H), 7.54-7.61 (t, 3H), 7.73-7.75 (dd, 1H), 8.15-8.16
(t, 2H), 8.22-8.27 (d, 2H), 8.45-8.49 (d, 1H), 8.69 (s, 1H), 9.09 (s, 1H) .
ꢀ 4.23 ꢁ 4.37 (t, 4ꢂ), 4.43-4.49 (t, 4H), 6.43 -6.47 (t, 1H), 6.74-6.78 (d, 1H), 6.91-7.01
(m, 4H), 7.16-7.18 (d, 2H), 7.29-7.48 (m, 5H), 7.84-7.86 (d, 1H), 7.89-7.91 (d, 1H),
7.98-8.11 (dd, 2H), 9.73 (s, 1H)

1600
M. Rode, R. C. Gupta, B. K. Karale and S. S. Rindhe
Vol 45
Table 4
Spectral data
1H nmr ꢀ (ppm)
IR
(cm-1)
Mass
M+
Compound
1680,
3.09ꢀ3.10 (t, 4ꢁ), 3.52ꢀ3.53 (t, 4ꢁ), 3.80 (s, 3H), 6.88-6.90 (m, 4H), 6.92-6.99 (d,
3H), 7.02-7.05 (d, 2H), 7.36 (d, 1H), 7.42 – 7.44 (d, 1H), 7.52 – 7.54 (d, 1H), 7.63-
7.79 (d, 1H), 7.85 – 7.92 (m, 2H), 8.06- 8.07 (d, 1H).
2.24 (s, 6ꢁ), 3.12 (s, 4H), 3.44 (s, 4H), 3.83 (s, 3H), 6.86 (d, 3H), 6.94-6.99 (m, 4H),
7.20-7.29 (t, 2H), 7.59 (m, 3H), 7.77-7.86 (dd, 2H), 8.08 (d, 1H).
5a
2829,
1030,
1675,
1030,
2882,
2951
652
596
5b
5c
1030,
1598,
1692,
2836,
3277
3.09ꢀ 3.10 (t, 4ꢁ), 3.39 (s, 3H), 3.53 -3.60 (t, 4H), 3.80-3.82 (s, 3H), 6.85 -6.87 (d,
1H), 6.90-6.94 (t, 2H), 7.10-7.12 (d, 1H), 7.49 (s, 1H), 7.52-7.56 (t, 2H), 7.58- 7.65
(q, 3H), 7.72-7.78 (q, 3H), 7.84-7.88 (t, 2H), 8.06-8.08 (d, 1H), 9.73 (s, 1H),
625
1598,
1726,
2245
1666,
1726 ,
2844,
2924
1604,
1705,
2960
1233,
1600,
2840,
2940
ꢂ 3.45 – 3.47 (t, 4H), 3.64-3.66 (t, 4H), 5.15-5.16 (s, 2H), 7.10-7.13 (d, 2H), 7.44-7.58
(m, 13H), 7.78-7.82 (m, 5H).
5d
5e
5f
590
563
ꢂ 2.81ꢀ2.82 (s, 3H), 2.90 (s, 3H), 3.39-3.54 (t, 4H), 3.65-3.68 (t, 4H), 4.87 (s, 2H),
6.58-6.66 (t, 1H), 6.86-6.89 (d, 1H), 7.04-7.08 (d, 2H), 7.55-7.59 (t, 1H), 7.75-7.79 (d,
1H), 7.94-7.97 (dd, 1H), 8.12-8.15 (m, 2H), 8.20-8.24 (d, 2H).
ꢂ 3.40ꢀ3.45 (t, 4H), 3.63-3.65 (t, 4H), 4.17-4.19 (t, 2H), 4.39- 4.41 (t, 2H), 6.66- 6.69
(t, 1H), 6.84-6.89 (m, 5H), 6.97-7.01 (d, 2H), 7.20-7.26 (t, 2H), 7.56-7.60 (t, 1H),
7.71-7.76 (d, 1H), 7.92-7.95 (dd, 1H), 8.10-8.14 (q, 3H)
ꢂ 3.44 – 3.47 (t, 4H), 3.66-3.68 (t, 4H), 5.09-5.14 (s, 2H), 6.67-6.70 (q, 1H), 6.90-6.92
(d, 1H), 7.00-7.07 (m, 3H), 7.13-7.18 (m, 2H), 7.48-7.52 (t, 2H), 7.56-7.60 (m, 1H),
7.73-7.76 (d, 1H), 7.79-7.82 (t, 1H), 7.93-7.95 (d, 2H), 8.10-8.16 (q, 1H)
598
525
5g
1596,
1726,
2851,
2936
1027,
1656,
2839
ꢂ 0.87-.90 (m, 1H), 1.04-1.10 (t, 2H), 1.20-1.39 (m, 2H), 1.73-1.76 (d, 3H), 1.83-1.90
(d, 2H), 3.47-3.56 (t, 4H), 3.73-3.79 (t, 4H), 3.84-3.89 (d, 1H), 5.32 (s, 2H), 6.69-6.73
(m, 3H), 6.91-6.98 (m, 1H), 7.00-7.13 (d, 2H), 7.35-7.41 (t, 1H), 7.52-7.60 (t, 2H),
7.64-7.68 (t, 1H), 8.10-8.15 (d, 1H), 8.25-8.27 (m, 1H)
ꢂ 3.73 (s, 3H), 7.03 (d, 1H), 7.08-7.11 (s, 2H), 7.24 (s, 2H), 7.27-7.36 (dd, 2H), 7.44-
7.45 (t, 3H), 7.59-7.63 (d, 2H), 7.66-7.73 (s, 2H), 7.78-7.80 (d, 1H), 7.83-7.88 (d,
1H), 7.91-7.95 (t, 1H), 8.14-8.18 (d, 1H), 8.22-8.24 (s, 1H)
5h
5i
495
534
1134,
1560,
1648,
2627,
2920
ꢂ 3.88 ꢀ3.94 (s, 3ꢁ), 7.12 – 7.13 (t, 1H), 7.14-7.17 (dd, 1H), 7.33 (d, 2H), 7.58-7.62
(t, 1H), 7.75-7.77 (dd, 1H), 7.81 (s, 1H), 7.83-7.91 (q, 3H), 7.93-7.95 (t, 1H), 8.14-
8.16 (dd, 1H), 8.25 (s, 1H).
5j
494
Table 5
Compound
IR
(cm-1)
Spectral data
1H nmr ꢀ (ppm)
Mass
M+
1028,
ꢂ 2.03 (s, 3H), 3.93 (s, 3H), 7.17-7.20 (dd, 1H), 7.25- 7.28 (d, 2H), 7.30- 7.30 (s, 1H),
7.44-7.46 (d, 2H), 7.57-7.61 (t, 1H), 7.70-7.78 (m, 3H), 7.81-7.83 (d, 1H), 7.89-7.93
(t, 1H), 8.13-8.14 (d, 2H)
ꢂ 5.19 (s, 2H), 6.96 (t, 1H), 7.06-7.16 (m, 3H), 7.32-7.33 (t, 1H), 7.43-7.46 (m, 2H),
7.48-7.56 (m, 2H), 7.58 (s, 1H), 7.75-7.85 (d, 2H), 7.85-7.87 (t, 1H), 8.00-8.02 (d,
1H), 8.15-8.18 (dd, 1H), 8.31 (s, 1H)
ꢂ 5.21 (s, 2H), 7.41-7.43 (q, 1H), 7.45-7.46 (d, 2H), 7.49-7.55 (d, 3H), 7.57-7.61 (t,
3H), 7.70-7.78 (m, 3H), 7.80-7.83 (d, 2H), 7.85-7.90 (d, 3H), 7.95-7.97 (d, 1H), 8.13-
8.15 (d, 2H), 8.19-8.20 (d, 1H)
5k
5l
1627,
1696
1233,
1600,
1726
1233,
1600,
1726,
2245
1598,
1758,
2865,
2913
1605,
1807,
2865
2913
515
440
5m
5n
5o
505
451
513
ꢂ 4.87ꢀ4.95 (s, 2H), 7.42-7.46 (t, 1H), 7.51-7.55 (t, 2H), 7.79-7.81 (d, 2H), 7.82-7.85
(d, 1H), 7.88-7.90 (d, 2H), 8.00-8.03 (dd, 1H), 8.17-8.18 (d, 1H), 8.27-8.32 (d, 2H),
11.35 (bs, 1H)
ꢂ 4.20ꢀ4.22 (t, 2H), 4.50-4.52 (t, 2H), 6.83-6.85 (d, 2H), 6.87-6.91 (t, 1H), 7.21-7.24
(t, 2H), 7.42-7.45 (t, 1H), 7.50-7.54 (t, 2H), 7.71-7.73 (d, 2H), 7.78-7.81 (t, 2H), 7.83
(s, 1H), 8.00-8.02 (dd, 1H), 8.18-8.19 (d, 1H), 8.26-8.28 (d, 2H)

Nov-Dec 2008
Synthesis And Characterization Of Some Substituted Chromones
1601
Table 5 (continued)
Compound
IR
(cm-1)
Spectral data
1H nmr ꢀ (ppm)
Mass
M+
1196,
ꢀ 0.44 - 0.50 (m, 1H), 0.59 – 0.77 (m, 4H), 1.07-1.10 (d, 2H), 1.18-1.21 (d, 1H), 1.44-
1.46 (d, 3H), 3.82-3.84 (d, 2H), 7.10-7.17 (q, 2H), 7.44- 7.48 (d, 1H), 7.54-7.61 (t,
3H), 7.73-7.75 (dd, 1H), 8.15-8.16 (t, 2H), 8.22-8.27 (d, 2H), 8.45-8.49 (d, 1H), 8.69
(s, 1H).
ꢀ 5.19 (s, 2H), 6.36-6.40 (t, 1H), 6.66-6.72 (t, 1H), 7.16-7.20 (t, 1H), 7.31-7.36 (m,
2H), 7.46-7.50 (t, 2H), 7.54-7.58 (t, 2H), 7.60-7.64 (t, 1H), 7.73-7.75 (d, 1H), 8.11-
8.16 (q, 3H), 8.38-8.42 (d, 1H), 8.68 (s, 1H).
1250,
1604,
1696,
1250,
1604,
1696,
5p
434
5q
5r
5s
464
595
538
1592 1666 ꢀ 2.83ꢁ2.84 (s, 3H), 2.95-2.97 (s, 3H), 4.32-4.35 (t, 4H), 4.40-4.43 (t, 4H), 4.94-4.95
2874 2928 (s, 2H), 6.65-6.86 (dd, 1H), 6.76-6.78 (d, 1H), 6.90-7.03 (m, 8H), 7.29-7.33 (m, 4H),
7.39-7.47 (m, 1H), 7.66-7.77 (dd, 1H), 7.82-7.86 (d,1H)
1040,
1250,
1679
1218,
1598,
1671,
1728,
2932
ꢀ 1.25ꢁ1.28 (t, 3H), 4.03-4.09 (q, 2H), 4.32-4.34 (t, 4H), 4.40-4.42 (t, 4H), 6.67-6.70
(dd, 1H), 6.78-6.79 (d, 1H), 6.93-7.03 (m, 7H), 7.27-7.33 (m, 4H), 7.37-7.42 (m, 2H),
7.69-7.76 (q, 2H)
ꢀ 4.23ꢁ4.40 (m 8H), 5.51-5.57 (s,1H), 6.50-6.51 (d, 1H), 6.63 (s, 1H), 6.73-6.99 (m,
7H), 7.09-7.11 (d, 1H), 7.19-7.23 (t, 2H), 7.26-7.30 (t, 2H), 7.34-7.36 (d, 1H), 7.42-
7.44 (t, 1H), 7.97-7.99 (d, 1H), 11.30 (bs, 2H)
5t
612
Table 6
% Antioxidant Activity of Compounds
Compound
Concentration in μg/mL
200
100
50
L-ascorbic acid
98.56
91.86
27.19
89.15
38.76
0.71
97.09
93.77
38.19
74.59
32.83
0.51
88.26
88.26
30.51
53.20
26.65
0.11
4a
5n
5k
5t
5j
5o
0.24
0.12
0.09
Table 7
Anti-bacterial and Anti-fungal Activity of Compounds
Sr.No.
Sample No.
Concentration
Fungal Models
Bacterial Models
(μg/mL)
C.
A. fumigatus C. krusei S. aureus E. coli S. faecium
albicans
ATCC
14503
ATCC
16424
GO3
FlucoR
MRSA
E710
ESS
2231
VRE 323
1
2
3
4
5
6
7
8
4a
5a
5b
5c
5e
5f
5g
5i
5j
5k
5n
5o
5r
5s
5t
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
10 μg / disc
20 μg / mL
10
10h
12
8h
16
12
16
12
10
10
14
12h
12
12
8
10h
12
10
10
12
10
16
14
12
10
10
10
10h
20h
NA
8
12
8
12
12
nil
10
nil
12
8
10
12
10
12h
10
12
14
12
10
12h
10
14
12h
12
14h
8
12
14
12h
14
14h
12
10
10h
10
10
12
10
14
12
10
14
12
12
10
12
10
8
14
14h
14
12
14h
10
NA
15
9
10
11
12
13
14
15
16
17
8
12
10
12
8
18
NA
14
12h
24h
NA
14vh
NA
15
Fluconazole
Vancomycin
NA
16
All compounds were dissolved in DMSO and tested at 1 mg/mL concentration. In each well 50 μl sample was loaded. The zone of inhibition is
expressed as the diameter of zone in mm.

1602
M. Rode, R. C. Gupta, B. K. Karale and S. S. Rindhe
Vol 45
heated at 80°C for 6 hours. After completion of the reaction,
the contents were cooled to room temperature and poured into
ice water. The solid obtained was separated by filtration and
dried under vacuum. It was purified by column chromatography
using 1% MeOH in DCM. The compounds synthesized by the
above procedure are listed in Table 1 and their characterization
data is given in Table 2, 4 and 5.
The activity is reported by measuring the diameter of
the inhibition zone in mm. Amongst the compounds
screened, 5j, 5k and 5s have shown good activity against
some of the fungi and 5a, 5c, 5e and 5r have shown very
good activity against some of the bacterial strains. The
results are summarized in Table 7.
Chromones with arylsulfonyl linkage at R3 and phenyl-
4-pyridin-2-ylpiperazine, 1-(2-methoxyphenyl)-4-phenyl-
piperazine and 2,4-bis (2-phenoxyethoxy)benzene at R1
showed good antimicrobial activity. While compounds
with the anthracene group at R1 did not show any activity.
General procedure for the preparation of 5 (a-c, i-k).
Equimolar amount of (0.01 mole) 3-hydroxychromone (4) and
arylsulfonyl chloride were taken in DMF with (0.03 mole) K2CO3
at room temperature. The reaction mixture was stirred at room
temperature for 8 hours. After completion of the reaction, the
contents were poured into ice water. The solid obtained was
separated by filtration and dried under vacuum. It was purified by
column chromatography using 1% MeOH in DCM. The
compounds synthesized by the above procedure are listed in Table
1 and their characterization data is given in Table 2, 4 and 5.
EXPERIMENTAL
All recorded melting points were determined in open capillary
and are uncorrected. IR spectra were recorded on Perkin-Elmer
1
FTIR spectrophotometer in KBr disc. The H nmr spectra were
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recorded on a 400 MHz spectrophotometer in DMSO-d6 as a
solvent and TMS as an internal standard. Peak values are shown
in ꢀ ppm. Mass spectra were obtained by Waters mass
spectrometer.
General procedure for the preparation of 3-hydroxy
chromone (4a-f). Compound 3 (0.01 mole) was dissolved in
MeOH (25 mL), with 25 mL water and NaOH (0.03 mole) and
then 5 mL of H2O2 was slowly added to the reaction mixture.
The reaction mixture was stirred at room temperature for 8 hrs,
and then poured into ice water. The solid obtained was separated
by filtration and crystallized with alcohol. The compounds
synthesized by the above procedure are listed in Table 1 and
their characterization data is given in Table 2 and 3.
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General procedure for the preparation of 5 (d-h, l-t).
Equimolar amounts of (0.01 mole) 3-hydroxychromone (4) and
the approporate alkyl halide were taken in DMF with (0.03
mole) K2CO3 at room temperature. The reaction mixture was
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