Synthesis and biological evaluation of new barbituric and thiobarbituric acid fluoro analogs of benzenesulfonamides as antidiabetic and antibacterial agents

Article abstract of DOI:10.1016/j.jfluchem.2012.06.032

A novel series of benzenesulfonamide derivatives of barbituric and thiobarbituric acids (2-12) were synthesized by condensation and cyclization reactions of various ureido and thioureido derivatives of sulfanilamides. Different substituents have been inco

Full text of DOI:10.1016/j.jfluchem.2012.06.032

Journal of Fluorine Chemistry 142 (2012) 96–104
Contents lists available at SciVerse ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
Synthesis and biological evaluation of new barbituric and thiobarbituric acid
fluoro analogs of benzenesulfonamides as antidiabetic and antibacterial agents
*
Hassan M. Faidallah , Khalid A. Khan
Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
A R T I C L E I N F O
A B S T R A C T
Article history:
A novel series of benzenesulfonamide derivatives of barbituric and thiobarbituric acids (2–12) were
synthesized by condensation and cyclization reactions of various ureido and thioureido derivatives of
sulfanilamides. Different substituents have been incorporated at C-5 of barbituric and thiobarbituric
acid. Fluoro- and trifluoroacetyl substituents have been installed on various positions and their
comparative biological screening was performed with the corresponding non-fluorinated analogs. The
synthesized compounds were evaluated for their antimicrobial and antidiabetic activities. Some of the
target compounds with fluorine substitution have shown very good antibacterial and antidiabetic
activities.
Received 4 May 2012
Received in revised form 27 June 2012
Accepted 28 June 2012
Available online 4 July 2012
Keywords:
Barbituric and thiobarbituric acids
Fluorinated analogs
ß 2012 Elsevier B.V. All rights reserved.
Benzenesulfonamides
Antimicrobial and antidiabetic activity
1. Introduction
drugs. Recently, some of the barbituric and thiobarbituric acid
analogs have been reported to show antimicrobial [7,8], antifungal
The barbiturates (BA) and thiobarbiturates (TBA) exert a broad
range of pharmacological actions, including sedation, general
anesthesia, and anticonvulsant and anxiolytic effects. They bind to
[9], antiviral [10] and antitumor [11] activities. However, no report
on the fluoro or trifluoromethyl substitution is found concerning
this class of compound as antimicrobial and/or as antidiabetic
agents. Therefore in the light of aforementioned studies we have
proposed to synthesize fluoro and trifluoromethyl analogs of
benzenesulfonamide derivatives of barbituric and thiobarbituric
acids along with alkyl and aryl substitutions on the position-5. The
present proposal involves the synthesis of a novel series of
benzenesulfonamides of barbituric and thiobarbituric acids 2–12
(Scheme 1). The biological profiles of fluorinated BA and TBA were
compared with non-fluorinated analogs.
specific regions of various receptors e.g. to
g-aminobutyric acid
(GABA), nicotinic-acetylcholine (nAChR) or BK (big potassium)
channel receptors which are all ligand-gated ion channels [1,2].
The binding to the GABA receptor requires that the C-5 atom be
substituted by alkyl or aryl groups i.e. the BA and TBA are not
biologically active themselves. The substitution enhances lipid
solubility and facilitates transport of BA and TBA toward their
enzyme targets [3]. 5-Benzylidene barbiturate and thiobarbiturate
derivatives have been shown to exhibit inhibitory effect against
mushroom tyrosinase and antibacterial activities against Gram-
positive and Gram-negative bacteria [4]. It was also reported that
the inhibitory effects of 5-benzylidene thiobarbiturates on
tyrosinase were more potent than 5-benzylidene barbiturates.
The position C-5 is therefore critical in enhancing the lipid
solubility of the barbiturate or thiobarbiturates and hence pivotal
in modulating the biological activity. Furthermore, in heterocyclic
2. Results and discussion
2.1. Chemistry
Some new thiobarbituric and barbituric acids with incorpo-
ration of sulfa drugs and fluorine atom as the target for chemical
modification to enhance their biocidal effects were synthesized.
Thus, addition of aryl isothiocyanates and isocyanates to some
sulfa drugs 1a–d in warming DMF yielded N,N0-disubistituted
thiourea and urea derivatives 2 and 3 respectively. Their IR spectra
showed beside the absorption bands corresponding to the NH
group at 3216–3288 cmꢀ1, two bands at 1345–1372 cmꢀ1 and
compounds fluorine incorporation on key positions plays
a
significant role to alter the physico-chemical and biological
characteristics of these molecules [5,6]. Fluorine substitution
modulates the steric and electronic parameters thereby influenc-
ing both the pharmacodynamic and pharmacokinetic properties of
1177–1190 cmꢀ1 for the SO2N function, in addition to
a
characteristic C55S band at 1155–1165 cmꢀ1 and a urea carbonyl
absorption at 1645–1665 cmꢀ1 for compounds 2 and 3 respective-
ly. Following the literature method [12], heterocyclization of the
* Corresponding author. Tel.: +966 567743180; fax: +966 2 6952293.
E-mail address: hfaidallahm@hotmail.com (H.M. Faidallah).
0022-1139/$ – see front matter ß 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jfluchem.2012.06.032

H.M. Faidallah, K.A. Khan / Journal of Fluorine Chemistry 142 (2012) 96–104
97
Z
R1
a = H
SO2NHR1
X
X
X
N
H
NH2
HN
S
b = CH3CO
N=C=Z
N
N
N
c =
O
O
HN
N
H
SO2NHR1
SO2NHR1
N
2: Z=S
S
1
N
H
3: Z=O
d =
Ph
N
H
Y
8
S
C
H2N
NH2
(Z=S)
CH2(COOCH3)2
CH3ONa
CHO
Y
SO2NHR1
X
SO2NHR1
X
Z
Z
N
N
N
N
(F3CCO)2O
Y
O
O
O
O
SO2NHR1
CHO
X
O
CF3
Z
4: Z=S
5: Z=O
6: Z=S
7: Z=O
N
H
N
O
O
N2H2
Y
SO2NHR1
X
9: Z=S
10: Z=O
Z
N
N
O
HN
N
CF3
11: Z=S
12: Z=O
Scheme 1. Synthesis of thiobarbiturates and their trifluoromethyl analogs.
thiourea and urea derivatives 2 and 3 via refluxing with malonic
acid in acetyl chloride led to the direct formation of thiobarbituric
4 and barbituric 5 acids respectively. Fluorination of compounds 4
and 5 by treatment with trifluoroacetic anhydride in THF afforded
the 5-trifluoroacetyl derivatives 6 and 7 respectively. The IR
spectra of the thiobarbituric acid derivatives 4 exhibited absorp-
tion bands at 1140–1152 cmꢀ1 and 1668–1678 cmꢀ1 for the C55S
and C55O functional groups respectively. The barbituric acids 5,
however, exhibited only the carbonyl absorption at 1669–
1685 cmꢀ1. On the other hand, the IR spectra of the pyrimidine
derivatives 5 and 7 were characterized by the appearance of a new
band at 1705–1715 cmꢀ1 attributed to the COCF3 group. The
structures of the compounds 2–7 were further supported by
elemental analysis (Table 1) and their 1H NMR and 13C NMR data
(Table 2).
In 1893, the Italian chemist Pietro Biginelli reported the acid-
catalyzed cyclocondensation reaction of ethyl acetoacetate,
benzaldehyde and urea [13]. The reaction was performed simply
by heating a mixture of the three components dissolved in ethanol
with a catalytic amount of HCl at reflux temperature. The product
of this novel one-pot, three-component synthesis that precipitated
on cooling of the reaction mixture was identified correctly by
Biginelli as 3,4-dihydropyrimidin-2(1H)-one (DHPM). Following
this protocol, the target molecules, 1,3,5-trisubistitute-2,7-
dithioxo-octahydropyrimido[4,5-d]pyrimidin-4-ones (8) were
synthesized in good yield by the one pot reaction of thiobarbituric
acids 4, aromatic aldehydes and thiourea in refluxing ethanol using
few drops of concentrated hydrochloric acid as catalyst [8,14,15].
Their IR spectra showed beside the absorption bands correspond-
ing to the NH group at 3222–3288 cmꢀ1, two thiocarbonyl
absorptions at 1155–1165 cmꢀ1 and 1077–1080 cmꢀ1 for the
two C55S groups. The structures of the above compound 8 were
further supported by their 1H NMR and 13C NMR data (Table 2).
Furthermore, condensation of the pyrimidine derivatives 4 and 5
with aromatic aldehydes afforded the corresponding arylidine
derivatives 9 and 10. The 1H NMR spectra of these arylidines are
characterized by a singlet of one proton intensity at
d8.08–
8.32 ppm attributed to the CH55 proton. Finally, cyclization of the
fluoropyrimidines 6 and 7 with hydrazine hydrate afforded
the pyrazole–pyrimidine derivatives 11 and 12. The structures
of the pyrimidine derivatives 9–12 were supported by elemental
analysis (Table 1) and their 1H NMR and 13C NMR data (Table 2).
2.2. Biological evaluation
2.2.1. In vitro antibacterial and antifungal activities
The antibacterial activity of the synthesized compounds
revealed that twenty-six out of the tested forty five compounds
displayed variable inhibitory effects on the growth of the tested
Gram positive and Gram negative bacterial strains. In general, most

98
H.M. Faidallah, K.A. Khan / Journal of Fluorine Chemistry 142 (2012) 96–104
Table 1
Characterization data of compounds 2–12.
Compound no.
Y
X
Yield (%)
m.p. (8C)
Mol. formula
Calc.%
C
Found%
C
H
N
H
N
2a1
2a2
2b1
2b2
2c
H
80
82
78
76
74
76
72
81
85
79
80
72
74
70
74
76
75
68
76
72
77
76
72
71
70
72
69
72
68
70
64
72
76
68
69
65
68
66
64
67
69
66
80
81
82
78
79
77
82
78
79
74
76
72
73
72
67
69
65
64
66
67
64
65
180–181
174–176
148–150
138–140
150–152
158–160
130–132
220–21
C13H13N3O2S2
50.79
45.68
51.56
46.93
49.34
58.78
54.59
53.60
47.93
54.04
48.98
47.12
56.47
51.19
46.89
51.79
47.84
49.88
58.01
54.39
53.48
48.80
53.86
49.60
47.96
56.02
45.86
42.74
46.78
43.84
45.57
52.85
50.04
47.48
44.14
48.29
45.17
55.26
51.69
51.84
45.40
48.69
59.60
55.30
55.47
51.74
61.74
57.14
57.32
56.31
53.50
53.34
57.14
52.05
61.59
58.23
46.25
43.08
53.30
50.35
47.90
44.50
48.68
51.64
4.26
3.54
4.33
3.68
3.88
4.26
3.75
4.50
3.71
4.54
3.84
3.46
3.88
3.49
2.95
3.62
3.12
3.30
3.70
3.29
3.65
3.07
3.77
3.24
2.97
3.39
2.57
2.19
2.75
2.39
2.55
2.96
2.64
2.66
2.26
2.84
2.46
3.67
3.07
3.26
2.70
2.72
3.70
3.03
3.24
2.64
3.83
3.13
3.35
3.54
2.93
2.72
3.26
2.69
3.55
3.05
2.59
2.21
2.98
2.66
2.68
2.28
2.86
2.73
13.67
12.29
12.03
10.95
17.98
15.58
14.47
14.42
12.90
12.60
11.42
17.17
14.97
11.19
10.25
10.07
9.30
50.81
45.77
51.67
47.01
49.34
58.86
54.61
53.62
48.04
54.18
49.10
47.22
56.58
51.23
46.97
51.81
47.82
49.76
58.14
54.40
53.51
48.92
53.76
49.55
48.12
56.14
45.92
42.63
46.87
43.90
45.64
52.91
50.12
47.51
44.28
48.33
45.20
55.21
51.64
51.80
45.31
48.62
59.64
55.51
55.56
51.88
61.82
57.25
57.23
56.38
53.61
53.48
57.22
52.13
61.67
58.14
46.35
43.12
53.28
50.46
48.11
44.45
48.70
51.71
4.17
3.52
4.38
3.72
3.76
4.18
3.68
4.60
3.82
4.66
3.90
3.58
3.98
3.51
2.88
3.71
3.22
3.29
3.68
3.21
3.77
3.14
3.84
3.35
3.01
3.47
2.63
2.08
2.74
2.43
2.62
2.87
2.58
3.76
2.36
2.80
2.56
3.77
3.05
3.28
3.04
2.82
3.80
3.09
3.28
2.71
3.94
3.18
3.40
3.62
3.04
2.84
3.31
2.70
3.54
3.12
2.61
2.34
3.04
2.78
2.76
2.34
2.91
2.83
13.76
12.31
12.15
11.02
18.13
15.61
14.55
14.32
13.01
12.77
11.58
17.21
15.12
11.24
10.36
10.18
9.35
Cl
H
C13H12ClN3O2S2
C15H15N3O3S2
Cl
H
C15H14ClN3O3S2
C16H15N5O3S2
2d1
2d2
3a1
3a2
3b1
3b2
3c
H
C22H19N5O2S2
Cl
H
C22H18ClN5O2S2
C13H13N3O3S
Cl
H
248–50
C13H12ClN3O3S
C15H15N3O4S
240–242
257–59
Cl
Cl
Cl
H
C15H14ClN3O4S
C16H14ClN5O4S
C22H18ClN5O3S
C16H13N3O4S2
266–268
228–230
181–182
190–192
130–134
158–159
192–194
208–210
168–170
226–227
272–274
235–236
276–278
244–246
216–218
215–216
200–202
140–143
296–298
338–340
283–285
228–230
188–190
212–214
240–242
190–192
170–172
166–167
154–156
160–162
146–148
192–193
198–199
176–178
188–190
206–208
230–232
260–262
250–252
245–248
250–252
240–242
261–262
257–258
250–252
282–284
220–222
224–226
208–210
200–202
256–258
269–270
280–282
3d
4a1
4a2
4b1
4b2
4c
Cl
H
C16H12ClN3O4S2
C18H15N3O5S2
Cl
H
C18H14ClN3O5S2
C19H15N5O5S2
15.31
13.53
12.69
11.69
10.67
10.47
9.64
15.42
13.61
12.73
11.70
10.78
10.58
9.75
4d1
4d2
5a1
5a2
5b1
5b2
5c
H
C25H19N5O4S2
Cl
H
C25H18ClN5O4S2
C16H13N3O5S
Cl
H
C16H12ClN3O5S
C18H15N3O6S
Cl
Cl
Cl
H
C18H14ClN3O6S
C19H14ClN5O6S
C25H18ClN5O5S
C18H12F3N3O5S2
C18H11ClF3N3O5S2
C20H14F3N3O6S2
C20H13ClF3N3O6S2
C21H14F3N5O6S2
C27H18F3N5O5S2
C27H17ClF3N5O5S2
C18H12F3N3O6S
C18H11ClF3N3O6S
C20H14F3N3O7S
C20H13ClF3N3O7S
C24H19N5O3S3
14.72
13.07
8.91
14.84
13.22
9.04
5d
6a1
6a2
6b1
6b2
6c
Cl
H
8.31
8.28
8.18
8.21
Cl
H
7.67
7.75
12.65
11.41
10.81
9.23
12.58
11.32
10.93
9.41
6d1
6d2
7a1
7a2
7b1
7b2
8a1
8a2
8a3
8a4
8a5
9a1
9a2
9a3
9a4
10a1
10a2
10a3
10a4
10a5
10a6
10b
10c
10d1
10d2
11a1
11a2
11d1
11d2
12a1
12a2
12b
12d
H
Cl
H
Cl
H
8.58
8.60
8.45
8.58
Cl
H
7.90
8.11
H
13.43
12.56
12.55
11.03
11.83
9.07
13.48
12.64
12.64
11.00
11.88
8.98
2,4-diF
H
H
C24H17F2N5O3S3
C24H18ClN5O3S3
C24H17BrClN5O3S3
C24H16ClF2N5O3S3
C23H17N3O4S2
Cl
Cl
Cl
H
4-Br
2,4-diF
H
2,4-diF
H
H
C23H15F2N3O4S2
C23H16ClN3O4S2
C23H14ClF2N3O4S2
C23H17N3O5S
8.41
8.38
Cl
Cl
H
8.44
4.82
2,4-diF
H
7.87
7.94
9.39
9.42
2,4-diF
H
H
C23H15F2N3O5S
C23H16ClN3O5S
C24H18ClN3O6S
C23H15Cl2N3O5S
C23H14ClF2N3O5S
C25H17F2N3O6S
C26H16ClF2N5O6S
C32H22ClN5O5S
C32H20ClF2N5O5S
C18H12F3N5O3S2
C18H11ClF3N5O3S2
C27H18F3N7O3S2
C27H17ClF3N7O3S2
C18H12F3N5O4S
C18H11ClF3N5O4S
C20H14F3N5O5S
C27H17ClF3N7O4S
8.69
8.76
Cl
Cl
Cl
Cl
H
8.72
8.77
4-CH3O
4-Cl
8.21
8.14
8.14
8.20
2,4-diF
2,4-diF
2,4-diF
H
8.11
8.09
8.00
7.98
Cl
Cl
Cl
H
11.67
11.22
10.61
14.98
13.95
16.08
15.22
15.52
14.42
14.19
15.61
11.76
11.31
10.74
15.02
14.15
16.20
15.21
15.64
14.33
14.24
15.78
2,4-diF
Cl
H
Cl
H
Cl
Cl
Cl
of the compounds showed better activity profile against the Gram
positive rather than the Gram negative bacteria. Among the Gram
positive bacteria Staphylococcus aureus and Bacillus subtilis showed
relatively high sensitivity toward the tested compounds. In this
view, compounds 6c and 10a2 were equipotent to Ampicillin (MIC
Ampicillin. Furthermore, compounds 4c, 4d1, 4d2, 5c, 8a2, 8a5, 9a2,
10a6, 10b, 10d2 and 11d2 (MIC 25 g/mL) showed 25% of the
activity of Ampicillin against the same organism. With regard to
the activity against B. subtilis, the best activity was displayed by
compounds 6c, 6d2, 10a2 and 10c which were equipotent to
m
6.25
m
g/mL) against S. aureus, whereas the analogs 6a2, 6b2, 6d2,
g/mL) were 50% less active than
Ampicillin (MIC 12.5
8a5, 9a4, 10b and 11d1 (MIC 25
m
g/mL), whereas the analogs 4a2, 4d2, 5c, 6a2,
g/mL) which represented half the
7a1, 7a2, 9a4, and 10c (MIC 12.5
m
m

Table 2
1H NMR and 13C NMR Spectral data (
d/ppm) of compounds 2–12.
Compound
no.
Y
X
1H NMR
13C NMR
Ar–H (m)
NH2 or NH
Other H
Ar–C
CO or CS
Other C
2a1
2a2
2b1
2b2
2c
H
Cl
H
Cl
H
H
Cl
6.74–7.82 (9H)
6.62–7.79 (8H)
6.81–7.84 (9H)
6.78–7.90 (8H)
6.62–7.79 (9H)
6.82–7.68 (15H)
6.76–7.91 (14H)
8.06, 8.19, 8.34
8.12, 8.25, 8.38
8.00, 8.13, 8.24
8.10, 8.24, 8.35
7.89, 8.21, 8.92
7.92, 8.31
120.7, 121.8, 125.6, 129.0, 129.6, 134.9,138.7, 144.0
120.4, 120.7, 124.1, 125.5, 128.5, 134.3, 140.8, 144.6
180.2
2.14 (s, CH3)
2.20 (s, CH3)
2.31 (s, CH2)
173.1, 179.4
16.4 (CH3)
2d1
2d2
8.03, 8.14
120.4, 121.6, 122.2, 122.8, 124.6, 125.2, 127.1, 127.7,
128.6, 129.1, 129.4, 133.6, 136.7, 136.9, 140.4
120.4, 120.7, 124.1, 125.8, 128.6, 134.5, 138.2, 141.2
120.6, 121.8, 125.6, 129.2, 129.4, 134.9, 136.3, 142.0
119.3, 120.2, 122.3, 126.7, 129.4, 133.6, 137.9, 140.2
118.4, 121.3, 124.5, 125.2, 127.7, 132.9, 136.5, 144.2
120.9, 121.2, 123.8, 125.4, 129.0, 134.2, 138.7, 141.6,
163.2
181.3
3a1
3a2
3b1
3b2
3c
H
7.00–7.85 (9H)
7.25–7.92 (8H)
7.13–7.82 (9H)
7.20–7.79 (8H)
7.26–7.90 (8H)
7.98, 8.26
156.3
Cl
H
8.14, 8.43
158.9
8.05, 8.24, 8.64
7.98, 8.34, 8.58
8.10, 8.34, 8.42
2.02 (s, CH3)
2.14 (s, CH3)
2.21 (s, CH2)
155.4, 173.1
154.2, 172.8
16.6 (CH3)
16.2 (CH3)
Cl
Cl
3d
Cl
7.10–7.74 (14H)
7.90, 8.21, 13.4
121.3, 122.2, 123.4, 125.6, 125.9, 127.4, 128.5, 129.1,
130.0, 131.2, 134.2, 136.4, 137.2, 138.8, 140.9
120.4, 120.7, 124.1, 125.7, 128.6, 134.9, 140.8, 144.0
154.6
4a1
4a2
4b1
H
Cl
H
7.02–7.91 (9H)
7.23–7.89 (8H)
7.10–7.92 (9H)
8.02
8.13
8.09
3.17 (s, CH2)
3.20 (s, CH2)
2.06 (s, CH3),
3.19 (s, CH2)
2.13 (s, CH3),
3.42 (s, CH2)
2.28 (s, CH2),
3.30 (s, CH2)
3.56 (s, CH2)
3.62 (s, CH2)
168.1, 169.3, 177.8
168.2, 168.9, 173.3, 178.1
169.1, 169.6, 173.8,178.6
168.2, 168.9, 173.6
34.5 (CH2)
120.3, 121.0, 124.2, 125.8, 127.9, 133.4, 141.2, 143.8
120.7, 121.8, 125.6, 129.3, 129.5, 134.8, 138.9, 143.2
16.6 (CH3), 35.1 (CH2)
16.8 (CH3), 34.9 (CH2)
34.4 (CH2), 53.1 (CH2)
4b2
4c
Cl
H
7.16–7.90 (8H)
6.98–7.82 (9H)
8.18
8.24
120.1, 120.8, 124.6, 126.0, 128.8, 133.8, 139.9, 142.4,
163.2
4d1
4d2
H
7.00–7.91 (15H)
7.12–7.80 (14H)
8.34, 12.88
8.29, 13.12
Cl
120.3, 121.8, 122.2, 123.3, 124.0, 125.5, 127.1, 127.6,
128.5, 129.0, 129.4, 133.9, 136.5, 136.9, 140.1
165.4, 169.2, 177.9
35.0 (CH2)
5a1
5a2
5b1
H
Cl
H
7.09–7.85 (9H)
7.31–7.92 (8H)
7.06–7.86 (9H)
8.02
8.21
8.38
3.53 (s, CH2)
3.61 (s, CH2)
2.14 (s, CH3),
3.54 (s, CH2)
2.26 (s, CH2),
3.50 (s, CH2)
3.55 (s, CH2)
4.26 (s, CH)
4.18 (s, CH)
2.13 (s, CH3),
4.24 (s, CH)
2.19 (s, CH2),
4.19 (s, CH)
4.28 (s, CH)
5c
Cl
7.25–7.91 (9H)
8.09
5d
Cl
H
7.23–7.84 (14H)
7.08–7.98 (8H)
7.10–7.81 (8H)
7.13–7.90 (9H)
8.10, 13.20
8.12
6a1
6a2
6b1
Cl
H
8.26
120.7, 121.8, 125.6, 129.1, 129.4, 134.9, 138.7, 144.3
168.3, 169.4, 178.1, 206.0
167.9, 168.2, 172.9, 204.3
43.4 (CH), 127.8 (CF3)
43.6 (CH), 128.0 (CF3)
8.18
6c
H
H
6.99–7.87 (9H)
7.01–7.92 (15H)
8.20
8.15
6d1
120.2, 121.6, 122.4, 123.2, 124.4, 125.7, 127.2, 127.6,
128.5, 129.1, 129.6, 134.0, 136.3, 137.1, 140.2
7a1
7a2
7b1
H
Cl
H
7.01–7.92 (9H)
7.26–7.90 (8H)
7.00–7.79 (9H)
8.02
8.21
4.30 (s, CH)
4.18 (s, CH)
2.23 (s, CH3),
4.09 (s, CH)
2.17 (s, CH3),
4.12 (s, CH)
4.32 (s, CH),
5.12 (brs, NH)
4.40 (s, CH),
5.12 (brs, NH)
4.34 (s, CH),
5.04 (brs, NH)
119.2, 120.9, 124.8, 128.9, 129.3, 133.1, 137.6, 142.4
120.1, 121.3, 125.8, 129.2, 129.7, 135.1, 139.4, 144.1
153.1, 167.9, 168.2, 177.3
151.9, 168.4, 169.2, 176.4
42.2 (CH), 127.8 (CF3)
16.8 (CH3), 40.9
(CH), 127.1 (CF3)
7b2
8a1
8a2
8a3
Cl
H
7.14–7.90 (8H)
H
6.43–7.92 (16H)a
6.74–7.93 (14H)a
6.64–7.88 (15H)a
120.7, 124.5, 125.3, 125.7, 125.8, 128.2, 128.5, 128.9,
133.9, 138.2, 139.6, 144.4
176.2 (CO), 179.8 (CS),
184.4 (CS)
52.9, 53.8, 73.4 (3CH)
2,4-diF
H
H
117.2, 118.4, 120.7, 124.9, 125.3, 125.9, 126.6, 129.3,
134.4, 135.9, 137.4, 143.3, 145.9, 148.8
Cl

Table 2 (Continued )
Compound
no.
Y
X
1H NMR
13C NMR
Ar–H (m)
NH2 or NH
Other H
Ar–C
CO or CS
Other C
8a4
8a5
9a1
9a2
4-Br
Cl
Cl
H
6.74–7.79 (14H)a
4.18 (s, CH),
5.07 (brs, NH)
4.20 (s, CH),
5.13 (brs, NH)
8.03 (s, CH5)
120.4, 121.3, 125.2, 125.6, 126.1, 127.7, 128.1, 128.6,
130.5, 131.8, 137.9, 144.4
175.8 (CO), 178.7 (CS), 183.9 (CS)
53.7, 54.2, 72.8 (3CH)
2,4-diF
H
6.81–7.90 (13H)a
7.01–7.89 (16H)b
6.99–7.78 (14H)b
116.9, 117.4, 120.8, 125.6, 125.8, 126.7, 129.4, 133.7,
136.2, 137.4, 142.9, 146.3, 149.0
177.1 (CO), 178.4 (CS), 187.1 (CS)
162.7 (CO), 163.1 (CO), 182.3 (CS)
163.8 (CO), 164.4 (CO), 180.9 (CS)
52.8, 53.2, 73.8 (3CH)
147.4 (CH5)
120.2, 120.7, 124.3, 125.7, 126.3, 127.2, 127.6, 128.2,
128.4, 128.8, 134.7, 135.0, 138.8, 141.5, 147.4
114.8, 117.2, 120.7, 121.8, 123.5, 125.5, 129.1, 129.4,
133.1, 134.9, 136.3, 141.2, 148.3
2,4-diF
H
8.17 (s, CH5)
149.0 (CH5)
9a3
H
Cl
Cl
H
7.25–7.90 (15H)b
6.90–7.92 (13H)b
6.92–7.92 (16H)b
8.08 (s, CH5)
8.24 (s, CH5)
8.32 (s, CH5)
9a4
2,4-diF
H
10a1
119.8, 120.5, 124.8, 125.6, 126.3, 127.0, 127.7, 128.4,
128.5, 134.3, 134.8, 137.9, 141.3
150.2 (CO), 164.3 (CO), 164.8 (CO)
152.1 (CO), 161.4 (CO), 162.3 (CO)
148.4 (CH5)
148.9 (CH5)
10a2
2,4-diF
H
6.80–7.89 (14H)b
8.25 (s, CH5)
115.4, 116.9, 120.7, 121.2, 123.8, 125.9, 129.1, 129.5,
134.4, 134.7, 137.1, 144.3, 147.4
10a3
10a4
H
Cl
Cl
7.12–7.91 (15H)b
6.72–7.89 (14H)b
8.19 (s, CH5)
3.72 (s, OCH3),
8.01 (s, C5H)
8.28 (s, CH5)
4–CH3O
10a5
4-Cl
Cl
7.25–7.89 (14H)b
117.8, 119.2, 120.3, 125.1, 125.8, 126.4, 127.7, 127.8,
128.5, 128.7, 133.9, 134.4, 136.8, 142.4
150.8 (CO), 162.4 (CO), 163.5 (CO)
153.1 (CO), 164.6 (CO), 172.8 (CO)
147.4 (CH5)
148.8 (CH5)
10a6
10c
2,4-diF
2,4-diF
Cl
Cl
6.89–7.90 (13H)b
6.92–7.92 (11H)c
8.40 (s, CH5)
2.05 (s, CH2),
8.01 (s, CH5)
8.11 (s, CH5)
8.09 (s, CH5)
8.32
120.1, 121.4, 123.8, 125.6, 126.7, 128.2, 128.9, 129.1,
132.4, 135.1, 138.9, 140.4, 160.4
c
10d1
10d2
11a1
H
Cl
Cl
H
7.01–7.90 (19H)
6.87–7.91 (17H)
13.1
13.4
11.68
c
2,4-diF
6.98–7.91 (11H)b
120.4, 121.1, 123.8, 125.6, 128.4, 134.2, 137.9, 141.9
119.2, 120.9, 124.4, 126.1, 127.9, 133.7, 138.8, 142.1
161.3 (CO), 179.4 (CS),
160.5 (CO), 184.2 (CS)
164.0 and 164.6
(2C5N), 113.4 (CF3)
163.8 and 164.9
11a2
Cl
7.23–7.86 (10H)b
11.74
(2C5N), 114.8 (CF3)
11d1
12a1
H
H
7.18–7.92 (15H)c
7.00–7.76 (11H)b
11.0
12.3
118.8, 120.7, 123.9, 125.1, 127.6, 132.8, 136.8, 140.9
120.4, 120.7, 124.1, 125.5, 128.9, 134.7, 138.2, 141.4
163.1 (CO), 185.6 (CS)
164.8 and 164.9
(2C5N), 114.1 (CF3)
16.5 (CH3), 164.0,
164.7 (2C5N), 112.8 (CF3)
165.2, 165.6 (2C5N),
115.2 (CF3)
12b
12d
Cl
Cl
7.00–7.94 (8H)
8.1, 11.98
13.5, 12.5
2.15 (s, CH3)
162.4 (CO), 173.4 (CO), 183.3 (CS)
161.8 (CO), 182.0 (CS)
7.28–7.84 (14H)c
120.1, 120.8, 125.0, 125.8, 127.6, 128.4, 129.9, 133.9,
137.4, 138.2, 139.4, 140.6
s, singlet; brs, broad singlet.
a
Ar-H and 2 NH.
b
Ar-H and NH2.
c
Ar-H and NH.

H.M. Faidallah, K.A. Khan / Journal of Fluorine Chemistry 142 (2012) 96–104
101
Table 3
In vitro antimicrobial and antifungal activities of the target compounds 2–12.
Compound no.
Staphylococcus
aureus
Bacillus subtilis
Escherichia coli
Pseudomonas
aeruginosa
Aspergillus niger
Candida
albicans
IZa
MICb
IZ
MIC
IZ
MIC
IZ
MIC
IZ
MIC
IZ
MIC
2a1
2c
6
8
–
–
7
–
–
5
–
100
–
6
–
–
5
–
–
7
9
–
–
5
6
10
7
7
6
9
8
3a
5
–
–
–
–
8
–
3c
9
–
8
–
9
–
5
–
11
19
20
24
16
8
100
100
100
50
100
–
10
21
24
26
21
24
17
16
26
24
25
23
27
26
25
23
9
100
100
50
25
50
25
100
100
25
25
25
50
25
4a1
4a2
4c
22
21
25
24
25
21
22
24
27
26
27
30
25
29
26
25
22
16
24
15
24
20
25
23
27
22
30
17
26
26
27
21
24
20
21
22
25
20
22
21
23
30
–
50
50
25
25
25
100
50
25
25
22
26
24
23
27
20
19
26
25
27
22
28
24
26
23
20
19
18
24
17
25
21
24
20
26
20
29
16
24
25
28
20
23
21
23
24
21
19
23
20
22
30
–
50
25
50
50
25
100
100
25
50
25
50
21
22
26
20
26
19
20
24
24
25
23
27
21
29
22
19
22
9
50
50
25
50
25
100
100
50
25
25
50
20
22
24
21
25
16
19
23
22
24
23
26
22
25
22
20
8
100
50
25
50
25
100
100
50
50
50
50
4d1
4d2
5a1
5a2
5c
14
7
100
–
5
–
5d
6
–
6a2
6b2
6c
12.5
12.5
6.25
9
–
18
20
19
21
16
15
19
–
100
100
100
50
100
100
100
100
100
–
12.5
12.5
50
6.25
12.5
6d1
6d2
7a1
7a2
7b1
8a1
8a2
8a3
8a5
9a1
9a2
9a3
9a4
10a1
10a2
10a3
10a6
10b
10c
10d1
10d2
11a1
11a2
11d1
11d2
12a1
12a2
12b
12d
Ad
25
25
50
25
12.5
12.5
12.5
12.5
50
12.5
50
25
50
–
50
100
50
–
50
100
100
–
100
100
50
23
7
50
–
100
6
–
25
100
25
23
8
50
–
14
6
100
–
18
–
20
7
100
–
100
25
26
20
24
22
25
22
28
12
22
24
26
19
24
20
19
22
22
21
21
24
23
29
–
25
100
25
50
25
50
9
–
16
5
100
–
25
19
24
20
26
22
27
19
25
22
24
22
27
22
24
28
21
26
24
23
26
–
25
100
25
100
25
50
100
25
100
50
21
22
18
23
19
22
12
22
21
23
9
100
50
8
–
50
100
25
100
50
7
–
12.5
50
6.25
10
6
100
–
100
100
50
12.5
12.5
9
–
12.5
100
25
100
50
100
50
100
50
8
–
100
25
50
20
12
23
21
17
9
100
100
50
50
100
–
25
25
25
100
50
12.5
12.5
12.5
25
50
50
25
100
50
100
25
–
20
16
19
23
25
18
20
22
24
28
–
100
100
100
50
12.5
50
50
50
50
25
50
50
100
50
10
11
8
100
100
–
50
25
12.5
50
25
50
50
25
100
50
100
50
100
50
100
100
50
9
–
12.5
25
7
–
100
50
100
50
25
6
–
25
50
50
10
–
100
–
12.5
–
6.25
12.5
6.25
12.5
Ce
–
–
–
–
33
12.5
32
6.25
a
IZ: inhibition zone.
b
MIC: minimum inhibitory concentration.
c
(–): inactive, MIC ꢁ 200
mg/mL.
d
A: Ampicillin trihydrate.
C: Clotrimazole.
e
potency of Ampicillin. The analogs 4a1, 4c, 4d1, 5d, 7a1, 8a2, 9a2,
10a6, 10d2, 11a1, 11a2, 12a2, and 12d (MIC 50 g/mL) exhibited
inhibitory profile against P. aeruginosa (MIC 25
about 50% of the activity of Ampicillin (MIC 12.5
m
g/mL), which was
g/mL).
m
m
25% of the potency of Ampicillin against the same species.
On the other hand, investigation of the antibacterial potency
against the three tested Gram negative strains revealed that most
of the active compounds showed better growth inhibitory activity
against Escherichia coli when compared with Pseudomonas
aeruginosa. Compound 6d2 was equipotent to Ampicillin (MIC
Concerning the antifungal activity of the tested compounds,
the results revealed that except compounds 2a1, 2c, 3a, 7a2, 8a1
and 8a3 all other tested compounds were able to produce
appreciable growth inhibitory activity against Candida albicans
(MIC values 12.5–100
Clotrimazole (MIC 6.25
10a2, 10d2, 11d1 12a1 and 12d proved to be the most potent
antifungal agents with MIC value 12.5 g/mL and are half as
m
g/mL, respectively) when compared to
m
g/mL). Among these, compounds 6d1,
6.25
noticeable growth inhibitory activity (MIC 12.5
50% of the activity of Ampicillin. Moreover, compounds 4c, 4d2, 5d,
6a2, 8a5, 9a2, 9a4, 10b, 10d2 and 12b (MIC 25 g/mL), exhibited
m
g/mL), whereas the analogs 6c, 10a2 and 10c produced
m
g/mL) which was
m
potent as Clotrimazole. The analogs 4c, 4d2, 5c, 5d, 6a2, 6c, 6d2,
8a5, 9a2, 9a4, 10a6, 10c, 11a2, 12a2 and 12b exhibited recognizable
m
moderate activity against the same organism. Meanwhile, the
tested P. aeruginosa and K. pneumonia strains proved to be weakly
sensitive to most of the tested compounds. Among these,
compounds 4c, 4d2, 6c, 6d2 and 11d2 showed moderate growth
antifungal activity (MIC 25 mg/mL) that represented 25% of the
standard’s activity. It has been found that all of the tested
compounds have low or no antifungal activity against Aspergillus
niger (Table 3).

102
H.M. Faidallah, K.A. Khan / Journal of Fluorine Chemistry 142 (2012) 96–104
A close examination of the structures of the active compounds
From the data presented in Table 4, it is obvious that the 1,3-
disubstituted urea derivatives (3a1 and 3a2) possess marked
hypoglycemic activity. The potency of these compounds is more
than that of phenformin. The corresponding thiourea derivatives
(2a1, 2a2 and 2c) however, have shown a marked reduction in
the hypoglycemic activity suggesting a negative influence of
electronic effects of sulphur. On the other hand although the
activity of the thioureas 2 is low, their cyclic thio-analogs 4 have
shown an improvement in the activity. Here geometric factor
becomes an important variable in enhancing the biological
effects. Introduction of trifluoroacetyl moiety at position 5 of the
thiobarbituric acid ring enhances the hypoglycemic activity of
the thiobarbituric acid derivatives 6.
revealed that the antimicrobial profile of the thiobarbituric and
barbituric compounds 4–12 seemed to be more favorable than their
parent urea and thiourea derivatives 2 and 3 respectively, as
evidenced by their IZ diameters and MIC values recorded in Table 3.
However, it is clear from the observed data that the thiobarbituric
acid derivatives 4 are more active than the corresponding barbituric
acids 5. The enhancement in the antimicrobial activity of TBA
analogswhencomparedwithBAderivativessuggeststhatelectronic
factors are more important for biological activity than geometrical
factors. It was proposed that sulfur in C55S group is a good electron
donor and hydrogen bond acceptor [3]. The second variable in the
biological activity modulation is a trifluoroacetyl group in C-5
position of the thiobarbituric or barbituric nucleus and it has
resulted in a remarkable improvement in the overall antimicrobial
profile. Compound 6d2 showed two folds increase in the activity
against S. aureus, B. subtilis and C. albicans when compared with the
parent 4d2, whereas the analog 6c revealed a distinctive antimicro-
bial activity against all the tested organisms. It showed equipotent
3. Conclusions
The synthesized benzenesulfonamide derivatives of barbituric
and thiobarbituric acids have shown promising antibacterial,
antifungal and antidiabetic activities. The antimicrobial profile of
thiobarbiturates was found to be more promising than the
corresponding barbiturates. The introduction of trifluoroacetyl
group at C-5 has certainly improved the overall antimicrobial
activity of barbituric as well as thiobarbituric acids. Almost all
compounds 4–12 have shown very good antimicrobial activity.
However, some structural prototypes viz., 6c, 6d2 and 10c were
found to be equipotent with Ampicillin. On the other hand, the
hypoglycemic activity was reduced in thiobarbiturates when
compared from the corresponding barbituric acid derivatives.
Compounds 3a1 and 3a2 have been selected for further structure
optimization.
activity to Ampicillin against S. aureus (MIC 6.25
activity against B. subtilis and P. aeruginosa (MIC 12.5
50% of its activity against E. coli (MIC 12.5 g/mL), together with an
appreciable antifungal activity against C. albicans (MIC 25 g/mL).
mg/mL), equipotent
mg/mL) and
m
m
Ontheotherhand, cyclizationofthethiobarbituricacidderivatives4
to the pyrimido[4,5-d]pyrimidine derivatives 8 results in decreasing
the reactivity of most of the tested compounds. Furthermore,
derivatization of the parent barbituric acids 4 and 5 into the
benzylidene functions, enhance the activity of compounds 9 and 10
toward all the tested microorganisms especially those with fluorine
atom in their structures. Meanwhile cyclization of compounds 6 and
7 to the pyrazolo-pyrimidine derivatives 11 and 12 gave rise to
moderatelyactivecompounds, andagainthetrifluoromethylmoiety
play an essential role in increasing the activity toward most of the
tested microorganisms.
4. Experimental
4.1. Chemicals and methods
2.2.2. Antidiabetic activity
Compounds 2a1, 2a2, 2c, 3a1, 3a2, 4a1, 4c, 5a1, 5a2, 6a1, 6c,
7a1, 7c, 8a1, 9a1, 9a2, 10a2, 11a1, 11a2, 12a1, 12d were tested for
hypoglycemic activity using alloxan-treated female albino mice.
Melting points were determined in open glass capillaries on a
Gallenkamp melting point apparatus and were uncorrected. The
infrared (IR) spectra were recorded on Perkin-Elmer 297 infrared
spectrophotometer using the plate technique. The 1H NMR and
13C NMR spectra were recorded in CDCl3 and DMSO-d6 as a solvent
on Bruker DPX-400-FT spectrometer using tetramethylsilane as
the internal standard. Elemental analyses were performed at the
Microanalytical Unit, Faculty of Science, Cairo University, Cairo,
Egypt. Follow up of the reactions and checking the homogeneity of
the compounds were made by TLC on silica gel-protected
aluminum sheets (Type 60 F254, E. Merck) and the spots were
Table 4
Antidiabetic activity of compounds 2–12.
Compounds
Reduction
P
in plasma
glucose level, %
Phenformin
2a1
10
4
<0.01a
0.05
detected by exposure to UV lamp at
l 254. Biological testing was
performed in the Faculty of Medicine University of Alexandria,
Egypt. Reagents were of analytical grade and were used without
further purification.
2a2
3
0.05
2c
5
0.05
3a1
15
14
6
<0.01a
<0.01a
0.05
3a2
4a1
4.1.1. N,N0-disubstituted thioureas (2a–d)
4c
7
0.01a
0.05
A mixture of appropriate sulfonamide 1 (10 mmol) in DMF
(20 mL) and the appropriate isothiocyanate (10 mmol) in dioxin
(20 mL) was heated on a water bath for 1 h, cooled and
then poured onto ice cooled water. The pale yellow solid
thus obtained was filtered and recrystallized from ethanol as
needles.
5a1
4
5a2
2
0.05
6a1
8
<0.01a
<0.01a
0.05
6c
9
7a1
5
7c
2.5
<1
5
0.05
8a1
0.05
9a1
0.05
9a2
7
0.01a
0.01a
0.05
4.1.2. N,N0-disubstituted ureas (3a–d)
10a2
11a1
11a2
12a1
12d
7.5
6
A mixture of appropriate sulfonamide 1 (10 mmol) in DMF
(20 mL) and the appropriate isocyanate (10 mmol) in dioxin
(20 mL) was heated on a water bath for 1 h, cooled then poured
onto ice cooled water. The pale yellow solid thus obtained was
filtered off and recrystallized from ethanol as needles.
7
0.01a
0.05
3
4
0.05
a
Statistically significant.

H.M. Faidallah, K.A. Khan / Journal of Fluorine Chemistry 142 (2012) 96–104
103
4.1.3. 1,3-Disubstituted-2,3-dihydro-2-thioxo-
water; the precipitated trifluoromethyl-pyrazolo-pyrimidine de-
rivative was recrystallized from ethanol as needles.
4,6(1H,5H)pyrimidine-diones (4a–d)
A mixture of the appropriate thiourea derivative 2 (10 mmol)
and malonic acid (15 mmol) in acetyl chloride (10 mL) was heated
on an oil bath for 10 h at 40 8C. The reaction mixture was then
cooled and poured onto crushed ice and the resulting solid was
filtered, washed with water and recrystallized from ethanol as
needles.
4.1.11. 5,7-Disubistituted-3-(trifluoromethyl)-1H-pyrazolo[3,4-
d]pyrimidine-4,6(5H,7H)-diones (12)
A solution of the appropriate trifluoroacetyl-pyrimidine 6
(10 mmol) in DMF (20 mL) was refluxed with hydrazine hydrate
(12 mmol) for 4 h. The reaction mixture was then cooled and
poured onto ice water. The solid that separated was filtered off,
dried, and recrystallized from absolute alcohol as needles.
4.1.4. 1,3-Disubstituted-pyrimidine-2,4,6-triones (5a–d)
A mixture of the appropriate urea derivative 3 (10 mmol) and
malonic acid (15 mmol) in acetyl chloride (10 mL) was heated on
an oil bath for 12 h at 50 8C. The reaction mixture was then cooled
and poured onto crushed ice and the precipitated solid was filtered
off and recrystallized from ethanol as needles.
4.2. Biological evaluation
4.2.1. In vitro antibacterial and antifungal activities
Standard sterilized filter paper discs (5 mm diameter) impreg-
nated with a solution of the test compound in DMSO (1 mg/mL) was
placed on an agar plate seeded with the appropriate test organism in
triplicates. The utilized test organisms were: S. aureus (ATCC 6538)
and B. subtilis (NRRL B-14819) as examples of Gram positive bacteria
and E. coli (ATCC 25922) and P. aeruginosa (ATCC 27853) as examples
of Gram negative bacteria. They were also evaluated for their in vitro
antifungal potential against C. albicans (ATCC 10231) and A. niger
(recultured) fungal strains were utilized as representatives for fungi.
Ampicillin trihydrate and Clotrimazole were used as standard
antibacterial and antifungal agents, respectively. DMSO alone was
used as control at the same above-mentioned concentration. The
plates were incubated at 378 C for 24 h for bacteria and for 7 days for
fungi. Compounds that showed significant growth inhibition zones
(ꢁ14 mm) using the two-fold serial dilution technique, were further
evaluated for their minimal inhibitory concentrations (MICs).
4.1.5. 1,3-Disubstituted-5-trifluoroacetyl-2,3-dihydro-2-thioxo-
4,6(1H,5H)pyrimidine-diones (6a–d)
A solution of the appropriate thiopyrimidine 4 (10 mmol) in
THF (25 mL) was refluxed with trifluoroacetic anhydride
(10 mmol) for 2 h. The reaction mixture was then cooled and
poured into water; the precipitated trifluoroacetyl derivative was
recrystallized from ethanol as needles.
4.1.6. 1,3-Disubstituted-5-trifluoroacetylpyrimidine-2,4,6-triones
(7a–d)
A solution of the appropriate pyrimidine 5 (10 mmol) in THF
(25 mL) was refluxed with trifluoroacetic anhydride (10 mmol) for
2 h. The reaction mixture was then cooled and poured into water;
the precipitated trifluoroacetyl derivative was recrystallized from
ethanol as needles.
4.2.2. Minimal inhibitory concentration (MIC) measurement
4.1.7. 1,3,5-Trisubistituted-2,7-dithioxo-octahydropyrimido[4,5-
d]pyrimidin-4-ones (8)
The micro-dilution susceptibility test in Mu¨ller-Hinton Broth
(Oxoid) and Sabouraud Liquid Medium (Oxoid) was used for the
determination of antibacterial and antifungal activity, respectively
[16]. Stock solutions of the tested compounds, Ampicillin
trihydrate and Clotrimazole were prepared in DMSO at concentra-
Aromatic aldehydes (10 mmol), substituted thiobarbituric acid
(10 mmol) and thiourea (10 mmol) were dissolved in ethanol
(20 mL) and the mixture refluxed on a water bath in the presence of
a catalytic amount of concentrated HCl. The progress of the
reaction was monitored by TLC. After completion of the reaction,
the concentrated reaction mixture was cooled and poured onto ice-
cold water. The solid that separated was filtered, dried, and
recrystallized from absolute alcohol.
tion of 800
of 200, 100, 50, 25, and 12.5
m
g/mL followed by two-fold dilution at concentrations
g/mL. The microorganism suspen-
m
sions at 106 CFU/mL (colony forming unit/mL) concentrations were
inoculated to the corresponding wells. Plates were incubated at
36 8C for 24–48 h and the minimal inhibitory concentrations (MIC)
were determined. Control experiments were also done.
4.1.8. 5-Arylidine-1,3-disubistituted-2-thioxo-dihydropyrimidine-
4,6-diones (9)
4.2.3. Antidiabetic activity
A solution of the appropriate thiobarbituric acid 4 (10 mmol) in
Twenty one compounds were tested for hypoglycemic activity
using alloxan-treated female albino mice weighing 20 g. Alloxan
100 mg/kg was injected into the tail vein in a 10 mg/mL saline
solution. Three days later the mice were given the test compounds
orally in suspension in 1% carboxymethylcellulose solution at the
rate of 0.2 mmol/kg of the body weight. Each day a group of four
mice was used as a control group and one group of five mice was
given the standard 100 mg of phenformin/kg. Up to six groups of
four mice received the test compounds. Blood samples were
collected into 0.04% NaF solution at 0, 1 and 3 h.
Glucose was determined by the micro-colorimetric copper
reduction technique of Haslewood and Strookman [17]. Results are
expressed as a percentage reduction of the plasma glucose levels
compared with the control value. Statistical significance was assessed
by a Student’s t-test. Statistical significance was accepted where the
calculated t-value exceeded the tabulated t-value at the p = 0.05 level.
absolute ethanol (25 mL) containing
a catalytic amount of
piperidine (0.5 mL) was refluxed with the appropriate aromatic
aldehyde (10 mmol) in the presence of few drops of glacial acetic
acid for 4 h. The reaction mixture was then cooled and poured onto
water; the precipitated arylidine derivative was recrystallized
from ethanol as needles.
4.1.9. 5-Arylidine-1,3-disubistituted pyrimidin-2,4,6-triones (10)
A solution of the appropriate barbituric acid 5 (10 mmol) in
ethanol (25 mL) was refluxed with the appropriate aromatic
aldehyde (10 mmol) in the presence of few drops of glacial acetic
acid for 4 h. The reaction mixture was then cooled and poured onto
water. The solid which separated out was filtered off, dried, and
recrystallized from absolute alcohol.
4.1.10. 5,7-Disubistituted-6-thioxo-3-(trifluoromethyl)-6,7-dihydro-
1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (11)
Acknowledgements
A solution of the appropriate thiobarbituric acid 5 (10 mmol) in
DMF (20 mL) was refluxed with hydrazine hydrate (12 mmol) for
4 h. The reaction mixture was then cooled and poured onto ice
This paper was funded by the Deanship of Scientific
Research (DSR), King Abdulaziz University, Jeddah, under Grant

104
H.M. Faidallah, K.A. Khan / Journal of Fluorine Chemistry 142 (2012) 96–104
[7] S. Vijaya Laxmi, Y. Thirupathi Reddy, B. Suresh Kuarm, P. Narsimha Reddy, P.A.
Crooks, B. Rajitha, Bioorganic and Medicinal Chemistry Letters 21 (2011) 4329–
4331.
No.: 64-130-D1432. The authors acknowledge with thanks DSR
technical and financial support.
[8] V.V. Dabholkar, D.R. Tripathi, Journal of the Serbian Chemical Society 75 (2010)
1033–1040.
References
[9] M. Kidwai, R. Thakur, R. Mohan, Acta Chimica Slovenica 52 (2005) 88–92.
[10] J.H. Lee, S. Lee, M.Y. Park, H. Myung, Virology Journal 8 (2011) 18–21.
[11] V.I. Balas, I.I. Verginadis, G.D. Geromichalos, N. Kourkoumelis, L. Male, M.B.
Hursthouse, K.H. Repana, E. Yiannaki, K. Charalabopoulos, T. Bakas, S.K. Hadji-
kakou, European Journal of Medical Chemistry 46 (2011) 2835–2844.
[12] D. Pareek, M. Chaudhary, P.K. Pareek, R. Kant, K.G. Ojha, S.M.U. Iraqi, A. Pareek, Der
Pharmacia Lettre 2 (4) (2010) 274–283.
[1] T. Morimoto, K. Sakamoto, H. Sade, S. Ohya, K. Muraki, Y. Imaizumi, Molecular
Pharmacology 71 (2007) 1075–1088.
[2] H.R. Arias, E.A. McCardy, M.J. Gallagher, M.P. Blanton, Molecular Pharmacology 60
(2001) 497–506.
[3] I. Novak, B. Kovac, Chemical Physics Letters 493 (2010) 242–244.
[4] Q. Yan, R. Cao, W. Yi, Z. Chen, H. Wen, L. Ma, H. Song, European Journal of Medical
Chemistry 44 (2009) 4235–4243.
[13] P. Biginelli, Gazzetta Chimica Italiana 23 (1893) 360–413.
[14] C.O. Kappe, Tetrahedron 49 (1993) 6937–6963.
[5] B.E. Smart, Journal of Fluorine Chemistry 109 (2001) 3–11.
[6] H.G. Bonacorso, A.P. Wentz, R.V. Lourega, C.A. Cechinel, T.S. Moraes, H.S. Coelho, N.
Zanatta, M.A.P. Martins, M. Hoerner, S.H. Alves, Journal of Fluorine Chemistry 127
(2006) 1066–1072.
[15] C.O. Kappe, Accounts of Chemical Research 33 (2000) 879–888.
[16] A.C. Scott, 13th ed., Mackie and McCartney Practical medical microbiology, vol. 2,
Churchill Livingstone, United Kingdom-Edinburgh, 1989, pp. 161–181.
[17] G.A.D. Haslewood, T.A. Strookman, Biochemical Journal 33 (1939) 920–923.