ECOꢀFRIENDLY SYNTHESIS AND in vitro ANTIBACTERIAL ACTIVITIES
315
Characteristic peaks were observed in the EI mass (600 MHz CDCl3)
δ
: 7.70 (d, C=CH,
J
= 15.6 Hz),
spectra of compounds , which followed common 7.56 (d, CH, = 8.4 Hz), 6.92 (d, CH,
1–8
J
J
= 1.8 Hz),
molecular ion peak and fragmentation patterns.
6.32 (s, CH), 6.07 (d, CO=CH,
CH), 3.84 (s,
CH3), 2.23 (s,
161.40, 151.61, 149.92, 142.57, 130.03, 127.61,
122.56, 121.86, 114.31, 105.70, 55.38, 14.46, 13.27;
Anal. calc. for C16H16O3: C, 74.98, H, 6.29. Found: C,
74.92, H, 6.25.
J
= 15.6 Hz), 6.34 (s,
⎯
⎯
OCH3), 3.75 (s, –OCH3), 2.60 (s,
⎯
CH3); 13C NMR (CDCl3)
δ
: 186.01
,
Antimicrobial Activity
The compounds (1–8) were tested for their antiꢀ
bacterial activities by discꢀdiffusion method [16]. The
Gramꢀpositive bacteria and Gramꢀnegative bacteria
utilized in this study included S. aureus, S. pyogenes,
S. typhimurium, and E. coli. The results (see Tables 2
and 3) show that the nitrogenꢀcontaining heterocyclic
chalcones exhibited increased antibacterial activity.
Among the entire eight compounds, pyrazolꢀcontainꢀ
ing chalcone (8) exerted antibacterial activity against
S. aureus and S. pyogenes higher than that of the referꢀ
ence drug chloramphenicol.
(2E)ꢀ3ꢀ(3,4ꢀdimethoxyphenyl)ꢀ1ꢀ(2,5ꢀ
dimethylfuranꢀ3ꢀyl)propꢀ2ꢀenꢀ1ꢀone (3)
Yellow solid: mp 140°C; EIꢀMS m/z (rel. int. %):
288 (75) [M + 1]+; IR (KBr) νmax, cm–1: 3122 (C–H),
1
2961 (C–H), 1654 (C=O), 1587 (C=C); H NMR
(600 MHz, CDCl3)
7.20 (d, CH, = 1.2 Hz), 7.19 (d, CH,
7.11 (s, CH), 6.89 (d, CO=CH,
δ: 7.60 (d, C=CH, J = 15.6 Hz),
J
J
= 1.8 Hz),
J
= 15.6 Hz), 6.34 (s,
EXPERIMENTAL
CH), 2.61 (s, –OCH3), 2.53 (s, –OCH3), 2.29 (s,
General Method for the Synthesis of Chalcones
⎯
CH3), 2.25 (s, –CH3); 13C NMR (CDCl3)
δ
: 186.01
,
To a solution of 1ꢀ(2,5ꢀdimethylꢀfuranꢀ3ꢀyl)ꢀethaꢀ
none (0.34 g, 2.5 mmol) and corresponding active
aldehyde (2.5 mmol) in dry ethanol (20 mL) taken in
a beaker (100 mL), a catalytic quantity of sodium
hydroxide (0.05 g, 1.25 mmol) was added and the
reaction mixture was heated inside a microwave oven
for 35–52 s (at 210 W, i.e. ~30% microwave power)
[15]. The reactions were monitored through TLC
using solvent system ethyl acetate : benzene (2 : 8),
When the reaction was complete the reaction mixture
was cooled in an ice bath and the product thus formed
was filtered, washed with ethanol followed by washing
with water till the washings were neutral and recrystalꢀ
lized from distilled ethanol and chloroform.
157.69, 151.12, 149.95, 149.12, 142.91, 127.87,
122.89, 122.15, 111.02, 109.91, 105.69, 55.98, 55.92,
14.45, 13.29; Anal. calc. for C17H18O4: C, 71.31, H,
6.39. Found: C, 71.27, H, 6.35.
(2E)ꢀ1ꢀ(2,5ꢀdimethylfuranꢀ3ꢀyl)ꢀ3ꢀ(2,4,5ꢀ
trimethoxyphenyl)propꢀ2ꢀenꢀ1ꢀone (
4)
Lightꢀyellow solid: mp 128 ; EIꢀMS m/z (rel.
°C
int. %): 318 (68) [M + 1]+; IR (KBr) νmax cm–1: 3129
(C
H), 1652 (C=O), 1581 (C=C); 1H NMR
(600 MHz, CDCl3) : 8.01 (d, C=CH, = 15.6 Hz),
7.11 (d, C=CH, = 15.6 Hz), 7.06 (s, CH), 6.33 (s,
CH), 6.51 (s, CH), 2.60 (s, –OCH3), 2.59 (s,
OCH3), 2.29 (s, –OCH3), 2.24 (s, –CH3), 1.75 (s,
CH3); 13C NMR (CDCl3)
: 186.59, 157.28, 159.44,
,
⎯
δ
J
J
⎯
δ
(2E)ꢀ1ꢀ(2,5ꢀdimethylfuranꢀ3ꢀyl)ꢀ3ꢀ(2ꢀ
152.13, 149.78, 143.13, 138.12, 122.71, 122.49,
115.44, 111.31, 105.84, 96.78, 56.50, 56.35, 14.43,
13.29. Anal. calc. for C18H20O5: C, 68.34, H, 6.37;
Found: C, 68.31, H, 6.32.
hydroxyphenyl)propꢀ2ꢀenꢀ1ꢀone (1)
Orange solid: mp 137
°C; EIꢀMS m/z (rel. int. %):
244 (62) [M + 1]+; IR (KBr) νmax
,
cm–1: 3134 (OH),
1
2914 (C–H), 1642 (C=O), 1554 (C=C); H NMR
(600 MHz, CDCl3)
= 15.6 Hz), 7.02 (d, CO=CH,
6.67(m, 6.33 (s, CH), 2.60 (s, –CH3), 2.28 (s, –CH3);
13C NMR (CDCl3)
: 186.23, 157.04, 151.80, 149.70,
δ
: 9.74 (s, OH), 7.73 (d, C = CH,
J
J
= 15.6 Hz), 7.51–
(2E)ꢀ3ꢀ[4ꢀ(dimethylamino)phenyl]ꢀ1ꢀ(2,5ꢀ
dimethylfuranꢀ3ꢀyl)propꢀ2ꢀenꢀ1ꢀone (5)
δ
143.68, 130.17, 122.80, 122.62, 119.11, 111.78,
Yellow solid: mp 116°C; EIꢀMS m/z (rel. int. %):
105.81, 40.15, 40.15, 14.41, 40.30; Anal. calc. for 271 (62) [M+1]+; IR (KBr) νmax, cm–1: 3101(C–H),
1
C15H14O3: C, 74.36, H, 5.82. Found: C, 74.32, H, 1641(C=O), 1604 (C=C), 1167 (C–N); H NMR
5.78.
(600 MHz, CDCl3)
δ: 7.70 (d, C=CH, J = 15.6 Hz),
6.71 (d, CO=CH,
J
= 6Hz), 6,
= 8.4 Hz), 6.71 (d, CH,
. 7.56 (d, CH, J = 6.8 Hz), 6.32 (c, CH), 3.08 (s,
J
= 15.6 Hz), 7.51 (d,
CH,
CH,
J
J
J = 8.4 Hz), 6.67 (d,
(2E)ꢀ1ꢀ(2,5ꢀdimethylfuranꢀ3ꢀyl)ꢀ3ꢀ(4ꢀ
methoxyphenyl)propꢀ2ꢀenꢀ1ꢀone (
2)
⎯
NCH3), 3.03 (s, –NCH3), 2.60 (s, CH3), 2.28 (s,
Lightꢀyellow solid: m.p 85.5°C; EIꢀMS m/z (rel. CH3); δ: 157.04, 151.80, 149.70,
13C NMR (CDCl3)
int. %): 258 (65) [M + 1]+; IR (KBr) νmax, cm–1: 2922 143.68, 130.17, 122.80, 122.62, 119.60, 111.78,
(C–H), 1654 (C=O), 1564 (C=C); 1H NMR 105.81, 40.15, 40.13, 40.12, 14.41, 13.30; Anal. calc.
RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY Vol. 39
No. 3
2013