Med Chem Res
Table 1 Ability of 1a,b to reduce the biofilm formation of S. aureus 6538, S. aureus 25923, and S. aureus 29213 bacterial strains and to inhibit
SrtA, expressed as IC50 (lM)
Compound
IC50 (lM)
S. aureus
2
S. aureus
29213
S. aureus
6538
SrtA
5923
1
1
a
91
1.6
21
39.3
18.2
50
57
b
43.4
3
0 min at 0–10 °C and for 90 min at room temperature. Then
ml of water was added, and the product was collected by
Anal. Calcd. for C15
H
13
F
2
N
3
O
4
: C, 53.42; H, 3.88; N,
3
12.46. Found C, 53.58; H, 3.94; N, 12.51.
filtration, washed with water, and dried.
Ethyl 3-(5-methyl-1,2-oxazol-3-yl)-2-[2-(4-nitrophenyl)hy-
drazinylidene]-3-oxopropanoate (12d) Orange powder
Ethyl 2-[2-(3,4-dichlorophenyl)hydrazinylidene]-3-(5-methyl-
1
,2-oxazol-3-yl)-3-oxopropanoate (12a) Orange powder
(EtOH); yield: 99 %, m.p.: 100–102 °C; IR (KBr) mmax
1
(
(
EtOH); yield: 20 %; m.p.: 125 °C; IR (KBr) mmax 3136
3160 (NH), 1671 (CO) cm-1; H NMR (CDCl
3
, 300 MHz):
), 4.3841 (q, 2H,
), 6.49 (s, 1H oxazole H-4), 7.42 (d, 2H, C ), 8.27
-
NH), 1678 (CO) cm ; H NMR (CDCl , 300 MHz):
1
1
d = 1.38 (t, 3H, CH
CH
(d, 2H, C
(CDCl , 300 MHz): d = 180.99 (CO, C-3), 170.43 (C,
), 2.56 (s, 3H, CH
3
3 3
d = 1.36 (t, 3H, CH ), 2.52 (s, 3H, CH ), 4.40 (q, 2H, CH ),
2
H
6 4
3
3
2
1
3
6
.42 (s, 1H oxazole H-4), 7.13–7.45 (3H, a set of signals,
H ), 12.96 (s, 1H, exchangeable, NH); C NMR
6 4
1
C H ), 12.88 (s, 1H, exchangeable, NH).; C NMR
3
6
3
3
(
CDCl , 300 MHz): d = 180.97 (CO, C-3), 169.98 (C, C,
isoxazole C-5); 162.82 (C, CO-OCH
0
2
CH
3
), 162.02 (C,
0
3
isoxazole C-5), 163.33 (C, CO-OCH CH ), 162.22 (C,
2
isoxazole C-3), 146.63 (C, C-1 ), 144.07 (CH, C-4 ), 129.03
3
0
0
0
0
0
isoxazole C-3), 141.18 (C, C-1 ), 133.60 (C, C-2), 131.17
(C, C-2), 125.76 (C, C-3 , 5 ), 115.64 (CH, C-2 , 6 ), 102.10
(CH, isoxazole C-4), 62.26 (CH , O-CH CH ), 13.96 (CH
O-CH CH ), 12.33 (CH , isoxazole C-5); Anal. Calcd. for
: C, 52.03; H, 4.07; N, 16.18. Found C, 52.15;
H, 4.14; N, 16.33.
0
0
0
(
(
CH, C-3 ), 128.31 (C, C-5 ), 127.12 (CH, C-4 ), 117.70
0
2
2
3
,
3
0
CH, C-6 ), 115.28 (CH, C-2 ), 102.26 (CH, isoxazole C-4),
1.85 (CH , O-CH CH ), 14.00 (CH , O-CH CH ), 12.30
2
3
3
6
C H N O
15 14 4 6
2
2
3
3
2
3
(
CH , isoxazole C-5); Anal. Calcd. for C H Cl N O : C,
3 15 13 2 3 4
4
8.67; H, 3.54; N, 11.35. Found C, 48.71; H, 3.68; N, 11.43.
Ethyl 2-[2-(3,4-dichlorophenyl)hydrazinylidene]-3-(1-ethyl-3-
methyl-1H-pyrazol-5-yl)-3-oxopropanoate (12e) Pale yel-
low powder (EtOH); yield: 98 %, m.p.: 198–199 °C; IR
Ethyl 3-(5-methyl-1,2-oxazol-3-yl)-2-[2-(2-nitrophenyl)hy-
drazinylidene]-3-oxopropanoate (12b) Bright yellow
powder (EtOH); yield: 98 %; m.p.: 102–104 °C. IR (KBr)
-
1 1
(KBr) mmax 3188 (NH), 1721 (CO) cm ; H NMR (CDCl
300 MHz): d = 1.36 (t, 3H, CH ), 1.46 (t, 3H, CH ), 2.31 (s,
3H, CH ), 4.37 (q, 2H, CH ), 4.53 (q, 2H, CH ), 6.49 (s, 1H
pyrazole H-4), 7.04–7.42 (3H, a set of signals, C ), 12.61
, 300 MHz):
CH ); 146.72
,
3
-
1 1
mmax 3144 (NH), 1687 (CO), 1666 (CO) cm ; H NMR
3
3
(
CDCl , 300 MHz): d = 1.38 (t, 3H, CH ), 2.54 (s, 3H,
3
2
2
3
3
CH ), 4.44 (q, 2H, CH ), 6.49 (s, 1H oxazole H-4),
3
H
6 3
2
1
3
7
.15–7.68 (4H, a set of signals, C H ), 14.30 (s, 1H,
6
(s, 1H, exchangeable, NH); C NMR (CDCl
3
4
1
3
exchangeable, NH);
C NMR (CDCl , 300 MHz):
3
d = 179.04 (CO, C-3), 163.47 (C, CO-OCH
2
3
0
d = 181.24 (CO, C-3), 170.39 (C, isoxazole C-5), 162.04
C, CO-OCH CH ), 161.49 (C, isoxazole C-3), 138.55 (C,
(C, pyrazole C-5), 141.44 (C, C-1 ), 138.14 (C, C-2), 133.92
0 0
(
(C, pyrazole C-3), 131.18 (CH, C-5 ), 128.38 (C, C-3 ),
2
3
0
0
0
0
0
C-1 ), 136.10 (CH, C-6 ), 135.16 (C, C-2), 130.75 (C,
0
127.72 (C, C-4 ), 116.94 (CH, C-2 ), 114.56 (CH, C-6 ),
113.51 (CH, pyrazole C-4), 61.86 (CH , O-CH CH ), 47.18
(CH , N-CH CH ), 15.88 (CH , N-CH CH ), 14.02 (CH
O-CH CH ), 13.34 (CH , pyrazole C-5); Anal. Calcd. for
C H18Cl N O : C, 51.40; H, 4.57; N, 14.10. Found C,
17 2 4 3
0
0
C-2 ), 125.84 (CH, C-3 ), 123.33 (CH, C-4 ), 118.00 (CH,
2
2
3
0
C-5 ), 102.14 (CH, isoxazole C-4), 62.26 (CH , O-CH
2
2
2
3
3
2
3
,
3
2
CH ), 14.05 (CH , O-CH CH ), 12.33 (CH , isoxazole
3
2
3
3
3
2
3
3
C-5); Anal. Calcd. for C H N O : C, 52.03; H, 4.07; N,
15 14 4 6
1
6.18. Found C, 52.12; H, 4.09; N, 16.25.
Ethyl 2-[2-(2,6-difluorophenyl)hydrazinylidene]-3-(5-methyl-
,2-oxazol-3-yl)-3-oxopropanoate (12c) Orange powder
51.53; H, 4.61; N, 14.25.
Ethyl 2-[2-(2,6-difluorophenyl)hydrazinylidene]-3-(1-ethyl-
3-methyl-1H-pyrazol-5-yl)-3-oxopropanoate (12f) Yellow
powder (EtOH); yield: 41.2 %; m.p.: 102–103 °C; IR (KBr)
1
(
EtOH); Yield: 48.6 %; m.p.: 104–105 °C; IR (KBr) mmax
1
245 (NH), 1671 (CO), 1656 (CO) cm-1; H NMR (CDCl ,
-1
1
3
3
mmax 3245 (NH), 1671 (CO) cm ; H NMR (CDCl
300 MHz): d = 1.28 (t, 3H, CH ), 2.52 (s, 3H, CH ), 4.38 (q,
2H, CH ), 6.66 (s, 1H oxazole H-4), 7.53–8.31 (4H, a set of
signals, C ), 12.26 (s, 1H, exchangeable, NH); Anal.
3
,
3
00 MHz): d = 1.43 (t, 3H, CH ), 2.51 (s, 3H, CH ), 4.45
3
3
3
3
(
q, 2H, CH ), 6.54 (s, 1H oxazole H-4), 6.66–7.26 (3H, a
2
2
set of signals, C H ), 13.69 (s, 1H, exchangeable, NH);
6
H
6 4
3
123