Microbial evolution of carbazonyloxy-based chalcones

Article abstract of DOI:10.1007/s11164-012-0915-0

The Claisen-Schmidt condensation reaction was carried out between a carbazol-based acetyl group and various aldehydes. Reaction was performed in metal alkoxide as a alkali homogenous catalyst. A series of 12 1-{4-[3-(9H-carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(substituted aryl)-propenone were synthesized and characterized using FTIR, ¹H NMR, and ¹³C NMR spectroscopy analysis. Synthesized compounds were tested against bacteria and fungi strains.

Full text of DOI:10.1007/s11164-012-0915-0

Res Chem Intermed
DOI 10.1007/s11164-012-0915-0
Microbial evolution of carbazonyloxy-based chalcones
•
M. H. Malani B. Z. Dholakiya
Received: 11 September 2012 / Accepted: 6 November 2012
Ó Springer Science+Business Media Dordrecht 2013
Abstract The Claisen–Schmidt condensation reaction was carried out between a
carbazol-based acetyl group and various aldehydes. Reaction was performed in
metal alkoxide as a alkali homogenous catalyst. A series of 12 1-{4-[3-(9H-car-
bazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(substituted
aryl)-propenone
were synthesized and characterized using FTIR, H NMR, and 13C NMR spec-
troscopy analysis. Synthesized compounds were tested against bacteria and fungi
strains.
1
Keywords Claisen–Schmidt Á Antibacterial Á Antifungal
Introduction
Microbial disease is a major problem in worldwide, so it is necessary to
continuously develop novel antibacterial agents with broad spectrum activity [1].
Clinical diagnosis of microbial disease is still a concern. A number of synthetic and
semisynthesis chemical entities and drugs are used in clinical practice such as
sulfonamide, nitrofuran, penicillium, cephalosporin, tetra macrolides, and oxazoli-
dines [2].
The Claisen–Schmidt (CS) condensation between an acetyl group and aldehyde
is a valuable C–C bond-forming reaction to produce chalcones. Chalcones resemble
the flavonoid families which are synthesized at production levels to preserve the
health of plants against infections and parasites. They have attracted increasing
M. H. Malani Á B. Z. Dholakiya (&)
Department of Applied Chemistry, S.V. National Institute of Technology, Ichhanath, Surat 395007,
Gujarat, India
e-mail: bzd.svnit@gmail.com
M. H. Malani
e-mail: maheshmalani.svnit@gmail.com
123

M. H. Malani, B. Z. Dholakiya
attention due to a number of pharmacological applications [3, 4]. Chalcones are the
main precursors for the biosynthesis of flavonoids, which are frequent components
of the human diet. For example, Licochalcone A isolated from the roots of
Glycyrrhiza inflata (licorice) has in vitro and in vivo antimalarial and antileish-
manial activity, and 3-methoxy-4-hydroxyloncocarpin isolated from the roots of
Lonchocarpus utilis inhibits NADH:ubiquinone oxidoreductase activity [5]. The CS
condensation is carried out in basic or acidic media under homogeneous conditions,
but with many drawbacks, such as catalyst recovery and waste disposal problems
[6]. As a potential alternative, heterogeneous acidic and basic catalysts for the CS
condensation, for example, zeolites [7, 8], alumina [9], barium hydroxides [10, 11],
MgO [12], calcined hydrotalcites [13–15], natural phosphates modified with sodium
nitrate or KF [16–18], and aminopropyl-functionalized SBA-15 [19, 20], have
received much attention over the past few years. The acid catalyzed condensation
for preparation of chalcone generally uses AlCl3, BF3, dry HCl, and RuCl3 [21].
Our research group has tried the synthesis of chalcone by metal alkoxide. Potassium
t-butoxide gave better results than metal hydroxides such as NaOH and KOH.
Moreover, metal alkoxide enhanced the rate of reaction and gave comparatively
good yield.
Experimental
Materials and methods
All reagents were of analytical reagent grade and were used without further
purification. Solvents employed were purified by standard procedure before use.
4-(Oxiran-2-ylmethoxy)-9H-carbazole was prepared as per the reported process [22]
and p-aminoacetophenone was purchased from Aldrich, The melting points were
determined in open capillary on Veego (Model: VMP-D) electronic apparatus and
are uncorrected. The reactions were monitored and the Rf values were determined
using analytical thin layer chromatography (TLC) with Merck Silica gel 60 and
F-254 pre-coated plates (0.25 mm thickness). Spots on the TLC plates were
visualized using ultraviolet light (254 nm). FTIR spectra (4,000–400 cm-1) were
1
recorded on a Shimadzu 8400-S spectrophotometer using KBr disks. H and 13C
NMR spectra were recorded on a Bruker 400 MHz model spectrometer using
DMSO and TMS as internal reference (chemical shifts in d ppm).
Synthesis of 1-(4-{[3-(9H-carbazol-4-yloxy)-2-
hydroxypropyl]amino}phenyl)ethanone
A mixture of 4-(oxiran-2-ylmethoxy)-9H-carbazole (1.0 gm, 4.17 mmol), 4-amino
acetophenone (0.56 gm, 4.17 mmol), potassium carbonate (1.15 gm, 8.35 mmol),
and 10 ml acetonitrile as a solvent was taken in round-bottom flasks. The reaction
mass was heated at 58–62 °C with constant stirring for 8 h (Fig. 1). The reaction
was monitored by using thin layer chromatography. After completion of the
reaction, the mass was cooled to 25–30 °C, filtered for removal of salt and the
123

Microbial evolution of carbazonyloxy based chalcones
filtrate was evaporated to dryness under reduced pressure to get the crude
compound. Recrystallization was carried out in acetone as solvent to get the pure
compound (1.4 g, 90 % yield). The obtained compound was a light cream-colored
powder having melting point of 51–53 °C [23].
Preparation of chalcone from 1-(4-{[3-(9H-carbazol-4-yloxy)-2-hydroxypropyl]
amino} phenyl) ethanone 4a–4l
The target compounds were prepared as shown in Fig. 1. CS condensation of 1-(4-
{[3-(9H-carbazol-4-yloxy)-2-hydroxypropyl]amino}phenyl) ethanone and various
aldehydes (Fig. 1). The reaction was carried out under basic condition in alcoholic
solution at 55–60 °C for 12 h. The final compound was isolated from water at
6–7 pH. Isolated compounds were recrystallized in ethanol. Synthesized compounds
were characterized by various spectroscopic techniques. Derivatives and physical
parameters are shown in Table 1 [23].
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(4-methoxy-
phenyl)-propenone 4a Yield 77 %; m.p. 152–153 °C; 1H NMR (400 MHz,
DMSO), 2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH),
3.3 d ppm (1H, d, –CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm
(2H, d, Ar–O–CH2), 4.3 d ppm (3H, s, –OCH3), 6.18 d ppm (1H, t, –NH aliphatic),
6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H, dd, –NH–p-Ar–C=O),
8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (12H, m, Ar–H), 7.87 d ppm
(1H, dd, –NH–p-Ar–C=O); 13C NMR (400 MHz, DMSO) 49, 58, 67, 73, 78, 100,
110, 118, 121, 123, 125, 128, 128.7, 129, 130, 134.6, 138, 140, 142.5, 157,
189 d ppm; FTIR (KBr) tmax cm-1: 3,030 (C=C), 1,713 (C=O), 1,342 (C–N of Ar),
812 (p-disubstituted Ar), 3,310 (N–H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(2-hydroxy-
phenyl)-propenone 4b Yield 58 %; m.p. 102–103 °C; 1H NMR (400 MHz,
DMSO), 2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d
ppm (1H, d, –CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–
Fig. 1 Reaction scheme of synthesized compounds 4a-l
123

M. H. Malani, B. Z. Dholakiya
O–CH2), 6.18 d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH),
7.29 d ppm (1H, dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7
d ppm (11H, m, Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C = O); 9.0 d ppm (1H, s,
–OH), 13C NMR (400 MHz, DMSO) 59, 68, 73, 78, 100, 110, 118, 121, 124, 125,
128, 128.7, 129, 130.2, 134.6, 138, 141, 142.5, 156, 188 d ppm; FTIR (KBr) tmax
cm-1: 3,045 (C=C), 1692 (C=O), 1,334 (C–N of Ar), 818 (p-disubstituted Ar),
3,365 (N–H), ,3235 (–OH).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-phenyl-prope-
1
Æ
none 4c Yield 82 %; m.p. 93–95 C; H NMR (400 MHz, DMSO), 2.5 d ppm
(1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm (1H, d, –CH=CH),
3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–O–CH2), 6.18 d ppm
(1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H, dd, –
NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (12H, m, Ar–
H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O); 13C NMR (400 MHz, DMSO) 59, 68,
73, 78, 100, 110, 118, 121, 124, 125, 128, 128.7, 129, 130.2, 134.6, 138, 141, 142.5,
Table 1 Physiochemical parameter of synthesized compounds
Sr.No R1, R2 and R3
Molecular
formula
Yield (%) Physical parameter
4a
4b
R1, R2 = H
R3 = OCH3
R1 = OH
C31H28N2O4
C30H26N2O4
C30H26N2O3
79
68
86
Off-white powder M.P.
150–155 °C (decomposed)
Creamish-colored powder m.p. 102–104 °C
R2, R3 = H
R1, R2, R3=H
R2, R3 = H
R1 = Cl
4c
Light yellow powder m.p. 93–95 °C
Brown-colored powder m.p. 163–165 °C
4d
C30H25ClN2O3 72
4e
4f
R1, R2 = H
R3 = Cl
C30H25ClN2O3 78
Reddish-brown powder m.p. 184–190 °C
Yellow-colored powder m.p. 190–193 °C
Pale yellow-colored powder m.p. 170–175 °C
R1, R3 = H
R2 = NO2
R1 = H
C30H25N3O5
C31H27N3O6
82
88
4g
R2 = NO2
R3 = OCH3
R1, R2 = H
R3 = CH3
4h
C31H28N2O3
88
Pale yellow-colored powder m.p. 168–171 °C
Dark yellow-colored powder m.p. 184–187 °C
Off-white to pale yellow-colored
4i
4j
R1, R2, R3 = H C34H28N2O3
85
85
R1, R2 = H
R3 = OH
C30H26N2O4
C32H30N2O5
C30H25N3O5
powder m.p. 150–151 °C
4k
4l
R1 = H
75
84
Pale yellow-colored powder m.p. 153–155 °C
R2, R3 = OCH3
R1, R2 = H
R3 = NO2
Brown colored powder m.p. 146–148 °C
123

Microbial evolution of carbazonyloxy based chalcones
156, 188 d ppm; FTIR (KBr) tmax cm-1: 2,990 (C=C), 1,653 (C=O), 1,338 (C–N of
Ar), 819 (p-disubstituted Ar), 3,223 (N–H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(2-chloro-phe-
1
nyl)-propenone 4d Yield 62 %; m.p. 163–165 °C; H NMR (400 MHz, DMSO),
2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm (1H, d, –
CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–O–CH2), 6.18
d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H,
dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (11H, m,
Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O); 13C NMR (400 MHz, DMSO) 59,
68, 73, 78, 100, 110, 118, 121, 124, 125, 128, 128.7, 129, 130.2, 134.6, 138, 141,
142.5, 156, 188 d ppm; FTIR (KBr) tmax cm-1: 2,928 (C=C), 1,670 (C=O), 1,348
(C–N of Ar), 823 (p-disubstituted Ar), 3,338 (N–H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(4-chloro-phe-
1
Æ
nyl)-propenone 4e Yield 74 %; m.p. 184–188 C; H NMR (400 MHz, DMSO),
2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm (1H, d, –
CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–O–CH2), 6.18
d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H,
dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (11H, m,
Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C = O); 13C NMR (400 MHz, DMSO) 59,
68, 73, 78, 100, 110, 118, 121, 124, 125, 128, 128.7, 129, 130.2, 134.6, 138, 141,
142.5, 156, 188 d ppm; FTIR (KBr) tmax cm-1: 2,965 (C=C), 1,640 (C=O), 1,339
(C–N of Ar), 833 (p-disubstituted Ar), 3,240 (N–H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(3-nitro-phe-
1
nyl)-propenone 4f Yield 84 %; m.p. 190–193 °C; H NMR (400 MHz, DMSO),
2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm (1H, d, –
CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–O–CH2), 6.18
d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H,
dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (11H, m,
Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O); 13C NMR (400 MHz, DMSO) 59,
68, 73, 78, 100, 110, 118, 121, 124, 125, 128, 128.7, 129, 130.2, 134.6, 138, 141,
142.5, 156, 188 d ppm; FTIR (KBr) tmax cm-1: 2,985 (C=C), 1,705 (C=O), 1,355
(C–N of Ar), 836 (p-disubstituted Ar), 3,380 (N–H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(4-methoxy-3-
1
nitro-phenyl)-propenone 4g Yield 86 %; m.p. 170–173 °C; H NMR (400 MHz,
DMSO), 2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm
(1H, d, –CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–O–
CH2), 4.3 d ppm (3H, s, –OCH3), 6.18 d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H,
t, –CHOHCH2NH), 7.29 d ppm (1H, dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH–
carbazole), 6.6–7.7 d ppm (10H, m, Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O);
13C NMR (400 MHz, DMSO) 48, 59, 68, 72, 78, 100, 110, 118, 121, 124, 125, 128,
128.3, 129, 130.2, 134.6, 138, 141, 142, 155, 187 d ppm; FTIR (KBr) tmax cm-1
:
2,928 (C=C), 1,720 (C=O), 1,322 (C–N of Ar), 816 (p-disubstituted Ar), 3,315 (N–
H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(4-methyl-phe-
1
nyl)-propenone 4h Yield 88 %; m.p. 168–171 °C; H NMR (400 MHz, DMSO),
2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm (1H, d, –
123

M. H. Malani, B. Z. Dholakiya
CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 3.8 d ppm (3H, s, –CH3) 4.1 d ppm
(2H, d, Ar–O–CH2), 6.18 d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –
CHOHCH2NH), 7.29 d ppm (1H, dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH–
carbazole), 6.6–7.7 d ppm (11H, m, Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O);
13C NMR (400 MHz, DMSO) 41, 57, 68, 73, 78, 100, 110, 118, 121, 124, 125, 126,
128.7, 129, 130.2, 134, 138, 141, 142.5, 154, 190 d ppm; FTIR (KBr) tmax cm-1
:
2,917 (C=C), 1,647 (C=O), 1,331 (C–N of Ar), 819 (p-disubstituted Ar), 3,300 (N–
H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-naphthalen-1-
yl-propenone 4i Yield 82 %; m.p. 184–187 °C; 1H NMR (400 MHz, DMSO), 2.5
d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm (1H, d, –
CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–O–CH2), 6.18
d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H,
dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (13H, m,
Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O); 13C NMR (400 MHz, DMSO) 59,
68, 73, 78, 100, 110, 118, 121, 124, 125, 127, 128, 128.5, 129, 130.2, 131,
133,134.6, 138, 141, 142.5, 156, 188 d ppm; FTIR (KBr) tmax cm-1: 2,933 (C=C),
1,680 (C=O), 1,314 (C–N of Ar), 838 (p-disubstituted Ar), 3,420 (N–H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(4-hydroxy-
phenyl)-propenone 4j Yield 75 %; m.p. 150–151 °C; 1H NMR (400 MHz,
DMSO), 2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d
ppm (1H, d, –CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–
O–CH2), 6.18 d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH),
7.29 d ppm (1H, dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7
d ppm (11H, m, Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O), 9.1 d ppm (1H, s, –
OH); 13C NMR (400 MHz, DMSO) 59, 68, 73, 78, 100, 110, 118, 121, 124, 125,
128, 128.7, 129, 130.2, 134.6, 138, 141, 142.5, 156, 188 d ppm; FTIR (KBr) tmax
cm-1: 2,980 (C=C), 1,695 (C=O), 1,319 (C–N of Ar), 830 (p-disubstituted Ar),
3,365 (N–H), 3258 (–OH).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(3,4dimethoxy-
phenyl)-propenone 4k Yield 65 %; m.p. 153–155 °C; 1H NMR (400 MHz,
DMSO), 2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d
ppm (1H, d, –CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–
O–CH2), 4.3 d ppm (3H, s, –OCH3), 4.5 d ppm (3H, s, –OCH3), 6.18 d ppm (1H, t, –
NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H, dd, –NH–p-Ar–
C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (10H, m, Ar–H), 7.87 d
ppm (1H, dd, –NH–p-Ar–C=O); 13C NMR (400 MHz, DMSO) 48, 51, 57, 69, 72,
80, 101, 111, 118, 122, 124, 125, 128, 128.7, 129, 130, 134.6, 138.1, 141, 142.5,
156.1, 188.2 d ppm; FTIR (KBr) tmax cm-1: 3,000 (C=C), 1,670 (C=O), 1,336 (C–
N of Ar), 822 (p-disubstituted Ar), 3,378 (N–H).
1-{4-[3-(9H-Carbazol-4-yloxy)-2-hydroxy-propylamino]-phenyl}-3-(4-nitro-phe-
1
nyl)-propenone 4l Yield 79 %; m.p. 146–148 °C; H NMR (400 MHz, DMSO),
2.5 d ppm (1H, s, –OH aliphatic), 3.34 d ppm (1H, d, –CH=CH), 3.3 d ppm (1H, d, –
CH=CH), 3.5 d ppm (1H, m, –CH2CHOHCH2), 4.1 d ppm (2H, d, Ar–O–CH2), 6.18
d ppm (1H, t, –NH aliphatic), 6.8 d ppm (2H, t, –CHOHCH2NH), 7.29 d ppm (1H,
dd, –NH–p-Ar–C=O), 8.23 d ppm (1H, s, NH– carbazole), 6.6–7.7 d ppm (11H, m,
123

Microbial evolution of carbazonyloxy based chalcones
Ar–H), 7.87 d ppm (1H, dd, –NH–p-Ar–C=O); 13C NMR (400 MHz, DMSO) 59,
68, 73, 78, 100, 110, 118, 121, 124, 125, 128, 128.7, 129, 130.2, 134.6, 138, 141,
142.5, 156, 188 d ppm; FTIR (KBr) tmax cm-1: 2,978 (C=C), 1,705 (C=O), 1,343
(C–N of Ar), 828 (p-disubstituted Ar), 3,348 (N–H).
Antibacterial studies
All the synthesized compounds were tested for their antibacterial activity (MIC)
in vitro by the broth dilution method with bacteria E. coli MTCC 443, P. aeruginosa
MTCC 1688, S. aureus MTCC 96, and S. pyogenus MTCC 442C, taking Ampicilin,
Chloramphenicol, Ciprofloxacin, Gentamycin, and Norfloxacin as standard drugs
[24].
Antifungal studies
All the synthesized compounds were tested for their antifungal activity (MIC)
in vitro by the broth dilution method with fungi C. albicans MTCC 227 and A.
clavatus MTCC 1323, taking Nystatin and Greseofulvin as standard drugs [24].
Table 2 Antibacterial activity against different strain
Antibacterial activity table
Minimum inhibition concentration
Strain
no.
Code
no.
E. coli MTCC
443
P. aeruginosa MTCC S. aureus MTCC S. pyogenus MTCC
1688
96
442
1
M 1
M 2
M 3
M 4
M 5
M 6
M 7
M 8
M 9
M 10
M 11
M 12
100
62.5
125
250
100
125
250
250
200
62.5
200
100
200
125
100
200
62.5
250
200
100
250
125
125
200
200
250
125
200
500
500
250
200
250
100
100
125
200
500
200
500
250
500
500
200
250
125
200
250
2
3
4
5
6
7
8
9
10
11
12
Standard drug (lg/ml)
Gentamycin
Ampicillin
0.05
1
0.25
250
50
0.5
100
50
100
50
–
Chloramphenicol
Ciprofloxacin
Norfloxacin
50
25
10
25
50
50
10
10
10
123

M. H. Malani, B. Z. Dholakiya
Results and discussion
The important infrared spectral bands and their tentative assignments for carbazonyl
1
compounds and their chalcones were recorded as KBr disks. H NMR data of
compound 4c revealed a peak at 8.23 d ppm for –NH carbazol. The 1H NMR data of
compounds 4c revealed signals between 6.6 and 7.7 d ppm for aromatic protons.
The 13C NMR data of compound 4c showed relevant peaks at 128, 129, 130, and
141 d ppm, for aromatic carbon and at 188 d ppm for carbonyl carbon. The IR
spectra of compounds 4c revealed characteristic bands between 3,020 and
3,090 cm-1 confirming the presence of C=C groups. The IR spectrum of the
compounds showed characteristic bands between 1,640 and 1,720 cm-1 confirming
the presence of C=O groups of carbazonyl compounds. The IR spectrum of the
compounds 4f, g and l showed a characteristic band around 1,400 cm-1 confirming
the presence of the –NO2 group [25].
Antibacterial studies
The antibacterial activity of the compounds was studied with four pathogenic
bacteria (Table 2). Ampicilin, Chloramphenicol, Ciprofloxacin, Gentamycin, and
Norfloxacin were used as references for inhibitory activity against bacteria. All
compounds showed quite good antibacterial activity. When compared with the
compounds 4a, c, e, f, and l, the activity was comparable with Ampicilin in the case
of E. coli, while the compounds 4b and j were more active than Ampicilin and
nearly comparable to Chloramphenicol in cthe ase of E. coli. In the case of S.
aureus, the activity of compounds 4a, b, c, d, g, h, i, j, k and l were comparable to
Ampicillin. In vcase of S. pyogenus, the activity of compound 4j was slightly
comparable to Ampicillin. In the case of P. aeruginosa, the activity of compound 4e
was slightly comparable to Chloramphenicol. Comparative analysis for antibacterial
activity of compounds and standard drugs are shown in Table 2 and Fig. 2.
Fig. 2 Comparative chart of bacterial studies with standard drugs
123

Microbial evolution of carbazonyloxy based chalcones
Fig. 3 Comparative chart of fungal studies with standard drugs
Table 3 Antifungal activity against different strain
Antifungal activity table
Minimum inhibition concentration
Strain no.
Code no.
C. albicans MTCC 227
A. clavatus MTCC 1323
1
M 1
M 2
M 3
M 4
M 5
M 6
M 7
M 8
M 9
M 10
M 11
M 12
500
1,000
[1,000
250
500
1,000
[1,000
250
2
3
4
5
500
500
6
200
500
7
500
500
8
1,000
1,000
500
1,000
1,000
1,000
500
9
10
11
[1,000
[1,000
12
1,000
Standard drug
Nystatin
Greseofulvin
100
500
100
100
Antifungal studies
The antifungal activity of compounds was studied with two pathogenic fungi
(Table 3). Nystatin and Greseofulvin were used as references for inhibitory activity
against fungi. All compounds showed quite good antifungal activity. When
compared with the compounds 4a, d, e, f, g and j, the activities were comparable
123

M. H. Malani, B. Z. Dholakiya
with Greseofulvin in the case of C. albicans. In the case of A. clavatus, the activity
of compounds was very poor compared to both the standard drugs. Comparative
analysis for antifungal activity of compounds and standard drugs are shown in
Table 3 and Fig. 3.
Conclusion
The present investigation revealed carbazonyloxy b-hydroxy amine-based chal-
cones as potential leads for development of new antibacterial drugs. Compounds 4b
and 4j proved at least as potent as the reference drug Ampicillin in the case of
E. Coli. Compounds 4a, e and l are comparable with the reference drug Ampicillin
in the case of E. Coli. We can also conclude from the results of antifungal activity of
compounds 4a, e, g and j that they were comparable with the standard drug
Greseofulvin in the case of C. albicans, while compounds 4d and f are more active
compared with Greseofulvin in the case of C. albicans. Carbazonyloxy b-hydroxy
amine-based chalcones are bactericides and fungicides. In the future, carbazonyloxy
b-hydroxy amine-based chalcones will be used for the further development of new
chemical entities.
Acknowledgments We are very grateful to the Department of Applied Chemistry, SVNIT, Surat, for
providing laboratory facilities and to Mr. D. P. Rajani, Microcare Laboratory, Surat, for antimicrobial
activity determinations. We are also grateful to Mr. Avtar Singh SAIF Punjab University for spectral
analysis and to the Centre of Excellence, Vapi, Gujarat, India, for providing us necessary analytical
support.
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