Synthesis and in vitro antifungal activity of 4-substituted phenylguanidinium salts

Article abstract of DOI:10.1016/j.farmac.2004.03.001

A series of 4-substituted phenylguanidinium derivatives was synthesized and its antimicrobial activity was evaluated in vitro against eight potentially pathogenic strains of fungi.

Full text of DOI:10.1016/j.farmac.2004.03.001

IL FARMACO 59 (2004) 443–450
www.elsevier.com/locate/farmac
Synthesis and in vitro antifungal activity of 4-substituted
phenylguanidinium salts
Gabriela Braunerová a, Vladimír Buchta b, Luis Silva b, Jirˇí Kuneš a, Karel Palát Jr. a,*
a Department of Inorganic and Organic Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové 500 05, Czech Republic
b Department of Biological and Medical Sciences, Faculty of Pharmacy, Charles University, Heyrovského 1203, Hradec Králové 500 05, Czech Republic
Received 8 August 2003; accepted 3 March 2004
Available online 06 May 2004
Abstract
A series of 4-substituted phenylguanidinium derivatives was synthesized and its antimicrobial activity was evaluated in vitro against eight
potentially pathogenic strains of fungi.
© 2004 Elsevier SAS. All rights reserved.
Keywords: Guanidines; Sulfides; Antifungal activity
1. Introduction
2. Chemistry
Compounds 1a–r were prepared from commercially
available p-chloronitrobenzene and thiols by standard proce-
dures [3,4]. Compounds 2 were prepared by the reduction of
nitro group by the method IA described by Bellamy and Ou
[5] as reported in Scheme 1. Sulfanylphenylamines 2 were
then transferred by the standard process to ammonium chlo-
rides 3. Compounds 3a–c, f, g were synthesized directly
from compounds 1a–c, f, g by the reduction in acidic condi-
tions by the method IB published by Ferry et al. [6]. Title
compounds 4a–u were synthesized from cyanamide and phe-
nylammonium chlorides [7].
Compound 2s was prepared directly from p-bromoaniline
and benzenethiol in N-N, dimethylformamide (DMF) by the
method described by Rajsner et al. [3]. In the case of com-
pounds 3t and u we have used commercial substituted
amines which were transferred to ammonium chlorides.
The increasing frequency of systemic mycoses and the
emergence of new opportunistic fungi resistant to antifungal
drugs in the last years is a great health problem. Fungal
infections are one of the important opportunistic infections in
immunocompromised patients. The number of immunocom-
promised patients is increasing due to the intensive therapy
being administered those with cancer, organ transplant, and
human immunodeficiency virus (HIV) infection. Efficient
control of fungal pathogens is an urgent necessity and the
design of new antifungal compounds is very important.
Guanidine derivatives present various biological activity,
guanidine derivatives guazatine [1] (bis(8-guanidino-
octyl)amine) and dodine [2] (1-dodecylguanidinium acetate)
provide effective and broader control of microorganisms in
various industrial systems and for household, agricultural,
and biomedical products.
In our work a novel class of the 4-substituted phenylguani-
dinium salts 4 is presented, where guanidinium group is
connected directly to the aromatic ring.
3. Microbiology
All compounds 4a–u were evaluated in vitro for antimi-
crobial activity by the broth microdilution method against
representative human pathogenic fungi (Candida albicans:
CA; Candida tropicalis: CT; Candida krusei: CK; Candida
glabrata: CG; Trichosporon beigelii: TB; Trichophyton
* Corresponding author.
E-mail address: palat@faf.cuni.cz (K. Palát).
© 2004 Elsevier SAS. All rights reserved.
doi:10.1016/j.farmac.2004.03.001

444
G. Braunerová et al. / IL FARMACO 59 (2004) 443–450
were constructed on RHF/AM1 level, the lowest energy
conformer was chosen after the conformational search.
Chemical shifts in H NMR spectra were calculated using
TNDO/1 semi-empirical method with d-orbitals for second
row atoms and without special slater exponents for shielding
(shielding constant for proton—22.0 ppm).
I A
R
NH2
R
NO2
1
2
1
I B
II
III
R
NH2.HCl
R
NH C NH2.HNO3
NH
4.1. General procedure of preparation
of 1-nitro-4-(substituted)benzenes (1)
3
4
To a mixture of 0.06 mol of alkylthiol and 0.06 mol of
potassium carbonate in DMF 0.02 mol of powdered copper
was added. After 15 min 0.08 mol of p-chloronitrobenzene
was added and the mixture was heated to 150 °C for 3–5 h
under anhydrous conditions. The completion of the reaction
was controlled by TLC chromatography. The mixture was
filtered and water was added to the filtrate after cooling. 1a–r
were obtained as yellow crystals or oil.
R: a= C2H5S-
b= C3H7S-
c= C4H9S-
l= C13H27S-
m= C14H29S-
n= C15H31S-
o= C16H33S-
p= p-CH3C6H4S-
q= C6H5CH2S-
r= C6H11S-
s= C6H5S-
d= C5H11S-
e= C6H13S-
f= C7H15S-
g= C8H17S-
h= C9H19S-
i= C10H21S-
j= C11H23S-
k= C12H25S-
1a: yield 27%; m.p. 39.9–42.0 °C (Ref. [11]: m.p. 43–
44 °C); IR (KBr): 2975, 2930, 1653, 1594, 1597, 1511, 1478,
1340, 1264, 1184, 1092, 853 cm–1. 1b: yield 33%; b.p.
135–143 °C/0.50 Torr (Ref. [12]: oil); IR (CHCl3): 2967,
2933, 2875, 2848, 1596, 1582, 1518, 1480, 1458, 1365,
1340, 1317, 1294, 1238, 1183, 1113, 1092 cm–1. 1c: yield
34%; oil (Ref. [13]: b.p. 192–195/12 Torr); IR (CHCl3):
2960, 1605, 1580, 1526, 1478, 1343, 1171, 1110, 1095,
1014, 853 cm–1. 1d: yield 89%; m.p. 20.0 °C (Ref. [14]: b.p.
163–165 °C/2 Torr); IR (CHCl3): 3028, 2960, 2932, 2873,
1638, 1595, 1580, 1514, 1479, 1467, 1340 cm–1. 1e: yield
71%; m.p. 22,8 °C (Ref. [4]: 25–26 °C); IR (KBr): 3421,
2957, 2930, 2857, 1594, 1578, 1511, 1479, 1466, 1378,
1334, 1184, 1091, 853 cm–1. 1f: yield 57%; m.p. 26.5–
28.4 °C (Ref. [4]: 27–29 °C); IR (KBr): 2958, 2930, 2872,
2857, 1595, 1580, 1514, 1479, 1467, 1340, 1279 cm–1. 1g:
yield 47%; m.p. 29.5–31.0 °C (Ref. [15]: 35 °C); IR (KBr):
3448, 2959, 2926, 2853, 1580, 1508, 1465, 1336, 1120,
1097, 852, 837 cm–1. 1h: yield 55%; m.p. 25.0–25.8 °C (Ref.
[16]: 32 °C); IR (KBr): 3440, 2953, 2923, 2853, 1593, 1579,
1508, 1478, 1338, 1091, 853 cm–1. 1i: yield 96%; m.p.
41.6–42.8 °C (Ref. [4]: 43–45 °C); IR (KBr): 3029, 2956,
2938, 2855, 1671, 1595, 1580, 1514, 1479, 1466, 1366,
1281 cm–1. 1j: yield 60%; m.p. 38.5–40.5 °C; IR (KBr):
3432, 2943, 2916, 2851, 1592, 1581, 1505, 1472, 1334,
1098, 833 cm–1. 1k: yield 68%; m.p. 49.0–51.5 °C (Ref. [17]:
48.3–49.4 °C); IR (KBr): 3432, 2958, 2918, 2849, 1617,
1592, 1581, 1508, 1479, 1344, 1117, 1098, 853 cm–1. 1l:
yield 68%; m.p. 43.5–45.0 °C; IR (KBr): 3432, 2943, 2850,
1592, 1580, 1506, 1472, 1345, 1318, 1117, 1098, 853 cm–1.
1m: yield 89%; m.p. 56.1–57.0 °C (Ref. [18]: 55–57 °C); IR
(KBr): 3443, 2958, 2918, 2849, 1591, 1578, 1506, 1470,
1362, 1346, 1097, 835 cm–1. 1n: yield 34%; m.p. 57.8–
59.0 °C; IR (KBr): 3432, 3110, 2943, 2915, 2850, 1592,
1581, 1506, 1437, 1362, 1345, 1099, 854 cm–1. 1o: yield
69%; m.p. 62.5–64.3 °C (Ref. [14]: 66–67 °C); IR
(KBr):3440, 2960, 2917, 2849, 1592, 1580, 1507, 1480,
1470, 1362, 1346, 1117, 1080, 1098, 853 cm–1. 1p: yield
t= C7H15-
u=C6H13O-
Scheme 1. Reagents: (I) tin(II) chloride; (II) hydrogen chloride; (III) 1.
cyanamide/2. nitric acid.
mentagrophytes: TM; Aspergillus fumigatus: AF; and Ab-
sidia corymbifera: AC). The minimal inhibitory concentra-
tions (MICs, µmol l–1) of the synthesized compounds 4a–u
are presented in Table 1.
4. Experimental
Melting points were measured on Nagema microheating
table Boëtius and are uncorrected. Elemental analysis was
performed for compounds 4a–u on the CE Instruments EA
11100 analyzer and the results were within 0.4% of the
theoretical values. Infrared spectra (IR) were recorded on the
Nicolet Impact 400 spectrophotometer (mmax in cm–1). H
1
and 13C NMR spectra were registered on a Varian Mercury
Vx BB 300 spectrometer, peak positions are given in parts
per million (d) relative to the standard chemical shift of the
solvent. Coupling constants are reported in hertz. Fluka cel-
lulose powder was used for column chromatography. Thin-
layer chromatography (TLC) plates Silufol UV 254/366
(Kavalier) were used to monitor reactions. Calculations of
log P values were carried out on a PC computer by program
HyperChem v. 7.1, Hypercube Inc. using atomic parameters
derived by Ghose et al. [8] and later extended by Viswa-
nadhan et al. [9]. Atomic contributions of the molar refrac-
tivity (MR) were derived by Refs. [9,10]. Molecular models

Table 1
Antifungal activity after 24, 48, 72 and 120 h of compounds 4a–u
MICa
CA
CT
CK
CG
TB
AF
AC
24h
TM
72h
log P
Molar
(µmol l–1
)
refractivity
(Å3)
Compound
24h
48h
24h
48h
24h
48h
24h
48h
24h
48h
24h
48h
48h
120h
500
4a
>1000 >1000 >1000 >1000 125
>1000 >1000 >1000 >1000 250
125
1000
>1000 500
>1000 >1000 >1000 >1000 >1000 125
>1000 >1000 >1000 >1000 >1000 250
1.873
2.342
2.738
3.134
3.531
3.927
4.323
4.719
5.116
5.512
5.908
5.908
5.908
5.908
6.305
6.701
7.097
7.494
3.679
3.307
3.116
3.212
4.285
3.187
3.997
3.552
57.946
62.470
67.071
71.672
76.273
80.874
85.475
90.076
94.677
99.278
103.880
103.880
103.880
103.880
108.481
113.082
117.683
122.284
78.017
77.811
74.212
72.976
72.939
69.830
70.90
4b
250
>1000 >1000 1000
500
4c
1000
125
1000
250
500
1000
250
31.25
7.81
7.81
15.63
7.81
7.81
15.63
3.91
15.63
7.81
3.91
7.81
31.25
250
31.25
15.63
15.63
31.25
7.81
7.81
15.63
7.81
62.5
15.63
7.81
15.63
62.5
250
250
500
500
1000
250
500
1000
500
>1000 >1000 125
250
4d
125
62.5
31.25
31.25
15.63
7.81
7.81
3.91
15.63
15.63
3.91
3.91
7.81
31.25
250
125
250
250
1000
500
1000
500
125
125
4e
31.25
31.25
7.81
7.81
15.63
7.81
31.25
31.25
7.81
7.81
31.25
125
62.5
62.5
15.63
15.63
15.63
7.81
31.25
31.25
31.25
7.81
125
31.25
15.63
≤7.81
7.81
15.63
3.91
15.63
31.25
15.63
31.25
31.25
250
62.5
62.5
31.25
15.63
7.81
7.81
3.91
31.25
15.63
7.81
3.91
7.81
125
31.25
15.63
7.81
3.91
7.81
3.91
7.81
3.91
1.95
≤1.95
31.25
250
62.5
31.25
7.81
7.81
7.81
7.81
7.81
7.81
3.91
3.91
62.5
250
62.5
31.25
15.63
7.81
7.81
15.63
31.25
7.81
3.91
3.91
31.25
125
125
≤1.95
31.25
31.25
7.81
15.63
3.91
1.95
≤1.95
≤1.95
≤1.95
1.95
3.91
7.81
125
≤1.95
62.5
31.25
7.81
15.63
3.91
7.81
≤1.95
≤1.95
≤1.95
3.91
3.91
31.25
125
4f
31.25
≤7.81
7.81
62.5
31.25
15.63
15.63
15.63
62.5
62.5
7.81
31.25
>125
>500
>250
>125
1000
500
125
125
4g
31.25
62.5
15.63
62.5
62.5
15.63
15.63
15.63
>125
>500
>250
>125
1000
500
31.25
62.5
62.5
62.5
62.5
125
4h
4i
15.63
15.63
15.63
31.25
62.5
4j
4k
4k-acetate
4k-sorbate
62.5
15.63
>125
>500
>250
>125
1000
500
4k-base
31.25
31.25
>500
250
4l
4m
250
4n
250
>250
>125
250
>250
>125
250
>250
125
125
>250
>125
500
>250
125
>250
>125
250
>250
>125
500
4o
125
>125
250
>125
125
>125
500
4p
250
62.5
15.63
125
250
250
4q
250
250
250
500
31.25
1000
62.5
7.81
31.25
3.91
1.95
62.5
1000
250
125
250
250
62.5
500
15.63
500
125
4r
500
1000
>500
31.25
125
1000
500
>1000 1000
>1000 500
500
500
1000
500
1000
500
500
4s
500
500
31.25
3.91
500
250
250
125
>500
62.5
500
31.25
7.81
125
31.25
15.63
250
4t
15.63
125
7.81
62.5
3.91
1.95
15.63
62.5
3.91
3.91
15.63
125
31.25
125
15.63
125
15.63
125
31.25
125
250
250
4u
31.25
3.91
1000
62.5
31.25
1000
62.5
31.25
Dodine
Ketoconazole
7.81
<0.24
7.81
<0.24
7.81
0.49
7.81
1.95
7.81
<0.24
7.81
<0.24
7.81
7.81
15.63
7.81
15.63
0.98
15.63
1.95
0.98
139.066
a Minimum inhibitory concentrations.

446
G. Braunerová et al. / IL FARMACO 59 (2004) 443–450
61%; m.p. 78.0–79.0 °C (Ref. [19]: 80–81 °C); IR (KBr):
3432, 3089, 1594, 1575, 1512, 1492, 1477, 1364, 1337,
1181, 1094, 1086, 1075, 853 cm–1. 1q: yield 63%; m.p.
119.3–120.8 °C (Ref. [20]: 121.9–122.9 °C); IR (KBr):
3443, 3097, 1593, 1575, 1509, 1495, 1452, 1337, 1183,
1091, 1030, 853, 838 cm–1. 1r: yield 80%; m.p. 53.7–54.8 °C
(Ref. [21]: 56–57 °C); IR (KBr): 3447, 2936, 2923, 2916,
2902, 2852, 1593, 1577, 1507, 1449, 1348, 1270, 1098,
836 cm–1.
4.3. General procedure of preparation
of 4-(substituted)phenylammonium chlorides (3)
4.3.1. Method II
The solution of 0.01 mol of 2 in dry diethyl ether was
cooling with ice and saturated with dry hydrogen chloride for
15 min, crystals were filtered off. The residue was recrystal-
lized from ethanol and product 3 was obtained as white
crystals.
3d: yield 37%; IR (KBr): 3440, 2958, 2927, 2858, 1608,
1491, 1467, 1120, 1094, 1016, 804 cm–1. 3e: yield 50%; IR
(KBr): 3440, 2955, 2926, 1608, 1492, 1466, 1095, 1043,
803 cm–1. 3h: yield 94%; IR (KBr): 3432, 2956, 2922, 2853,
1608, 1492, 1120, 1094, 1043, 802 cm–1. 3i: yield 67%; IR
(KBr): 3428, 2957, 222, 2853, 1609, 1491, 1467, 1095,
805 cm–1. 3j: yield 82%; IR (KBr): 3432, 2957, 2920, 2852,
1492, 1094, 805 cm–1. 3k: yield 90%; IR (KBr): 3432, 2957,
2920, 2852, 1609, 1492, 1470, 1121, 1096, 1016, 804 cm–1.
3l: yield 63%; IR (KBr): 3432, 2957, 2920, 2852, 1609,
1491, 1469, 1095, 805 cm–1. 3m: yield 83%; IR (KBr): 3432,
2956, 2919, 2851, 1608, 1568, 1491, 1470, 1121, 1095,
804 cm–1. 3n: yield 76%; IR (KBr): 3432, 2920, 2851, 2343,
1636, 1559, 1469, 1094, 805 cm–1. 3o: yield 89%; IR (KBr):
3447, 2957, 2919, 2851, 1609, 1492, 1470, 1437, 1121,
1095, 805 cm–1. 3p: yield 90%; IR (KBr): 3567, 3443, 1654,
1618, 1489, 1085, 1016, 808 cm–1. 3q: yield 58%; IR (KBr):
3427, 3061, 2922, 2853, 1636, 1608, 1560, 1492, 1453,
1094, 807 cm–1. 3r: yield 50%; IR (KBr): 3431, 2930, 2853,
1609, 1491, 1449, 1094, 808 cm–1. 3s: yield 95%; IR (KBr):
3432, 3054, 2853, 2587, 1611, 1491, 1477, 1439, 1084,
1094, 1019, 811 cm–1. 3t: yield 93%; IR (KBr): 3427, 2953,
2923, 2853, 1614, 1515, 1465, 1425, 1123, 1099, 828,
810 cm–1. 3u: yield 96%; IR (KBr): 3425, 2955, 2927, 2857,
1610, 1515, 1474, 1256, 1176, 1114, 1031, 821 cm–1.
4.2. General procedure of preparation
of 4-(substituted)phenylamines (2)
4.2.1. Method IA
The mixture of 0.01 mol of 1 and 0.01 mol of tin(II)chlo-
ride dihydrate in dry ethanol was heated to 70 °C under
nitrogen atmosphere for 3–5 h. After cooling, the solution
was alkalized with 50% sodium hydroxide to pH 7.5 and
extracted with ethyl acetate. Ethyl acetate extracts were dried
with sodium sulfate, filtrated and evaporated in vaccuo. The
residue was then recrystallized from ethanol and product was
obtained as white crystals.
2d: yield 60%; m.p. 84.5–90.0 °C; IR (KBr): 3406, 2942,
2956, 2926, 1607, 1568, 1497, 1463, 1413, 1284, 1095,
811 cm–1. 2e: yield 69%; b.p. oil (Ref. [4]: 130 °C/5 Torr); IR
(CHCl3): 3401, 3009, 2957, 2929, 2856, 1620, 1598, 1496,
1422, 1276 cm–1. 2h: yield 81%; m.p. 24.3–27.8 °C (Ref.
[16]: 28–30 °C); IR (KBr): 3447, 2953, 2923, 2852, 1620,
1598, 1496, 1465, 1279, 1176, 1098, 822 cm–1. 2i: yield
43%; m.p. 38.1–40.1 °C (Ref. [4]: 42 °C); IR (KBr): 3427,
2954, 2920, 2872, 2851, 1620, 1599, 1497, 1465, 1277,
1098, 816 cm–1. 2j: yield 80%; m.p. 43.2–45.0 °C; IR (KBr):
3424, 2953, 2919, 2850, 1620, 1599, 1497, 1464, 1420,
1257, 1099, 808 cm–1. 2k: yield 73%; m.p. 34.6–36.8 °C
(Ref. [22]: 35–37 °C); IR (KBr): 3390, 3208, 2916, 2849,
1629, 1593, 1495, 1463, 1287, 1176, 826 cm–1. 2l: yield
65%; m.p. 39.5–41.5 °C; IR (KBr): 3359, 2953, 2919, 2850,
1622, 1496, 1471, 1260, 816 cm–1. 2m: yield 47%; m.p.
45.1–47.2 °C; IR (KBr): 3447, 2954, 2918, 2850, 1620,
1597, 1497, 1463, 1256, 813 cm–1. 2n: yield 83%; m.p.
59.0–61.2 °C; IR (KBr): 3363, 2954, 2918, 2849, 1618,
1498, 1472, 1257, 809 cm–1. 2o: yield 76%; m.p. 55.5–
57.2 °C (Ref. [14]: 64–65 °C; IR (KBr): 3363, 2954, 2917,
2850, 1624, 1498, 1473, 1463, 1420, 1277, 1257, 1098 cm–1.
2p: yield 73%; m.p. 73.0–73.9 °C (Ref. [19]: 72.5–73.5 °C;
IR (KBr): 3465, 3360, 1619, 1597, 1492, 1496, 1299, 1285,
1177, 1083, 1016, 824, 807 cm–1. 2q: yield 54%; oil (Ref.
[23]: 75 °C); IR (KBr): 3488, 3398, 3030, 3008, 2926, 2854,
1620, 1598, 1495, 1453, 1422, 1280 cm–1. 2r: yield 51%;
m.p. 28.6–30.1 °C; IR (KBr): 3588, 3455, 3024, 2928, 2851,
1653, 1620, 1597, 1495, 1448, 1285, 1264, 1176, 1120, 997,
825 cm–1. 2s: yield 58%; m.p. 94.5–97.0 °C (Ref. [24]:
95 °C); IR (KBr): 3452, 3354, 3323, 1618, 1595, 1494, 1478,
1440, 1295, 1176, 1024, 738 cm–1.
4.3.2. Method IB
The solution of 0.3 mol of tin(II)chloride dihydrate in
concentrated hydrochloric acid was added to a mixture of
0.01 mol of 1 in diethyl ether. Mixture was then stirred for
2 h. The residue was recrystallized from ethanol and product
was obtained as white crystals.
3a: yield 24%; IR (KBr): 3444, 2972, 2869, 2575, 1610,
1560, 1491, 1447, 1203, 1121, 1096, 1053, 1016, 808 cm–1.
3b: yield 58%; IR (KBr): 3567, 3427, 2964, 2927, 2872,
2564, 1609, 1492, 1120, 1095 cm–1. 3c: yield 43%; IR (KBr):
3441, 2957, 2929, 2872, 1617, 1560, 1490, 1465, 1120,
1095, 1051, 804 cm–1. 3f: yield 90%; IR (KBr): 3427, 2957,
2924, 2855, 1608, 1492, 1468, 1121, 1095, 1016, 803 cm–1.
3g: yield 52%; IR (KBr): 3432, 2957, 2923, 2854, 1609,
1491, 1467, 1095, 805 cm–1.
4.4. General procedure of preparation
of 4-(substituted)phenylguanidinium nitrates (4)
4.4.1. Method III
A mixture of 0.01 mol of 3 and 0.012 mol of cyanamide
was heated at 120–130 °C for 15 min, after cooling the melt

G. Braunerová et al. / IL FARMACO 59 (2004) 443–450
447
was dissolved in cold water, acidified with concentrated
nitric acid and cooled. The separated crystalline solid was
collected by filtration, recrystallized from water and purified
by a column chromatography (ethanol/H2O, 1:4).
(300 MHz, DMSO): d 9.53 (bs, 1H, NH), 7.39–7.30 (m AA′,
BB′ overlapped, 6H, 2H Ar + 4H NH2), 7.20–7.13 (m AA′,
BB′, 2H, Ar), 2.95 (t, 2H, J = 7.14 Hz, SCH2), 1.65–1.48 (m,
2H, CH2), 1.44–1.17 (m, 10H, CH2), 0.84 (t, 3H, J = 6.87 Hz,
CH3); 13C NMR (75 MHz, DMSO): d 156.0, 135.1, 132.9,
129.0, 125.7, 32.2, 31.4, 28.8, 28.7, 28.3, 22.3, 14.2. 4h:
yield 79%; m.p. 109.4–111.9 °C; IR (KBr): 3339, 2953,
2923, 2851, 1687, 1626, 1568, 1497, 1384, 1326, 1098,
4a: yield 26%; m.p 127.5–129.1 °C; IR (KBr): 3567,
3393, 3181, 2977, 2927, 1683, 1622, 1568, 1497, 1384,
1
13335, 1254, 1094 cm–1; H NMR (300 MHz, DMSO): d
9.51 (bs, 1H, NH), 7.40–7.28 (m AA′, BB′ overlapped, 6H,
2H Ar + 4H NH2), 7.21–7.14 (m AA′, BB′, 2H, Ar), 2.98 (q,
1
1050, 815 cm–1; H NMR (300 MHz, DMSO): d 9.53 (bs,
2H, J = 7.42 Hz, SCH2), 1.23 (t, 3H, J = 7.42 Hz, CH3); 13
C
1H, NH), 7.38–7.30 (m AA′, BB′ overlapped, 6H, 2H Ar +
4H NH2), 7.20–7.14 (m AA′, BB′, 2H, Ar), 2.95 (t, 2H,
J = 7.14 Hz, SCH2), 1.63–1.49 (m, 2H, CH2), 1.44–1.17 (m,
12H, CH2), 0.84 (t, 3H, J = 6.80 Hz, CH3); 13C NMR
(75 MHz, DMSO): d 156.0, 135.1, 132.9, 129.0, 125.7, 32.2,
31.5, 29.1, 28.9, 28.8, 28.7, 28.3, 22.3, 14.2. 4i: yield 65%;
m.p. 107.3–109.0 °C; IR (KBr): 3378, 2954, 2923, 2851,
1675, 1627, 1568, 1496, 1384, 1325, 1284, 1251, 1097 cm–1;
1H NMR (300 MHz, DMSO): d 9.51 (bs, 1H, NH), 7.37–7.30
(m AA′, BB′ overlapped, 6H, 2H Ar + 4H NH2), 7.20–7.14
(m AA′, BB′, 2H, Ar), 2.95 (t, 2H, J = 7.15 Hz, SCH2),
1.62–1.48 (m, 2H, CH2), 1.44–1.16 (m, 14H, CH2), 0.84 (t,
3H, J = 6.87 Hz, CH3); 13C NMR (75 MHz, DMSO): d 155.9,
135.1, 132.9, 129.1, 125.7, 32.2, 31.5, 29.1, 28.9, 28.8, 28.7,
28.3, 22.3, 14.2. 4j: yield 91%; m.p. 111.0–113.0 °C; IR
(KBr): 3383, 2953, 2922, 2851, 1676, 1625, 1568, 1497,
1384, 1328, 1098, 815 cm–1; 1H NMR (300 MHz, DMSO): d
9.50 (bs, 1H, NH), 7.37–7.31 (m AA′, BB′ overlapped, 6H,
2H Ar + 4H NH2), 7.19–7.14 (m AA′, BB′, 2H, Ar), 2.95 (t,
2H, J = 7.14 Hz, SCH2), 1.63–1.50 (m, 2H, CH2), 1.45–1.18
(m, 16H, CH2), 0.84 (t, 3H, J = 6.87 Hz, CH3); 13C NMR
(75 MHz, DMSO): d 155.9, 135.1, 132.8, 129.0, 125.7, 32.2,
31.5, 29.2, 29.2, 28.9, 28.8, 28.7, 28.3, 22.3, 14.2. 4k: yield
82%; m.p. 115.9–117.3 °C; IR (KBr): 3347, 2955, 2922,
2851, 1676, 1624, 1568, 1497, 1384, 1327, 1284, 1098,
815 cm–1; 1H NMR (300 MHz, DMSO): d 9.56 (bs, 1H, NH),
7.37–7.30 (m AA′, BB′ overlapped, 6H, 2H Ar + 4H NH2),
7.19–7.13 (m AA′, BB′, 2H, Ar), 2.93 (t, 2H, J = 7.41 Hz,
SCH2), 1.63–1.48 (m, 2H, CH2), 1.42–1.13 (m, 18H, CH2),
0.83 (t, 3H, J = 6.87 Hz, CH3); 13C NMR (75 MHz, DMSO):
d 155.7, 135.2, 132.6, 129.0, 125.6, 32.3, 31.7, 29.4, 29.3,
29.3, 29.1, 28.9, 28.8, 28.5, 22.5, 14.4. 4l: yield 67%; m.p.
118.1–120.0 °C; IR (KBr): 3397, 2956, 2921, 2851, 1671,
NMR (75 MHz, DMSO): d 156.0, 134.8, 132.9, 129.1, 125.7,
26.3, 14.4. 4b: yield 15%; m.p. 94.5–96.0 °C; IR (KBr):
3588, 3567, 3386, 3185, 3039, 2962, 2929, 2873, 1670,
1612, 1595, 1568, 1495, 1452, 1432, 1384, 1279, 1251,
1122, 1095 cm–1; 1H NMR (300 MHz, DMSO): d 9.54 (bs,
1H, NH), 7.40–7.30 (m AA′, BB′ overlapped, 6H, 2H Ar +
4H NH2), 7.21–7.13 (m AA′, BB′, 2H, Ar), 2.94 (t, 2H,
J = 7.14 Hz, SCH2), 1.66–1.50 (m, 2H, CH2), 0.96 (t, 3H,
J = 7.14 Hz, CH3); 13C NMR (75 MHz, DMSO): d 156.0,
135.0, 132.9, 129.2, 125.7, 34.2, 22.1, 13.3. 4c: yield 32%;
m.p. 96.0–98.1 °C; IR (KBr): 3397, 2953, 2924, 2858, 1677,
1617, 1599, 1462, 1348, 1284, 1221, 1098, 1010, 839,
816 cm–1; 1H NMR (300 MHz, DMSO): d 9.26 (bs, 1H, NH),
7.40–7.30 (m AA′, BB′ overlapped, 6H, 2H Ar + 4H NH2),
7.21–7.13 (m AA′, BB′, 2H, Ar), 2.96 (t, 2H, J = 7.15 Hz,
SCH2), 1.63–1.48 (m, 2H, CH2), 1.48–1.31 (m, 2H, CH2),
0.87 (t, 3H, J = 7.14 Hz, CH3); 13C NMR (75 MHz, DMSO):
d 156.0, 135.0, 133.0, 129.1, 125.7, 31.9, 30.8, 21.5, 13.7.
4d: yield 77%; m.p. 87.2–89.3 °C; IR (KBr): 3397, 2928,
2957, 2857, 1670, 1628, 1566, 1495, 1384, 1276, 1251,
1
1093, 815 cm–1; H NMR (300 MHz, DMSO): d 9.54 (bs,
1H, NH), 7.39–7.31 (m AA′, BB′ overlapped, 6H, 2H Ar +
4H NH2), 7.20–7.14 (m AA′, BB′, 2H, Ar), 2.95 (t, 2H,
J = 7.14 Hz, SCH2), 1.64–1.50 (m, 2H, CH2), 1.43–1.20 (m,
4H, CH2), 0.85 (t, 3H, J = 6.87 Hz, CH3); 13C NMR
(75 MHz, DMSO): d 156.0, 135.1, 132.9, 129.0, 125.7, 32.1,
30.5, 28.4, 21.9, 14.1. 4e: yield 67%; m.p. 97.1–100.5 °C; IR
(KBr): 3379, 2954, 2927, 2857, 1671, 1625, 1568, 1497,
1384, 1321, 1283, 1250, 1097, 816 cm–1; 1H NMR
(300 MHz, DMSO): d 9.33 (bs, 1H, NH), 7.39–7.26 (m AA′,
BB′ overlapped, 6H, 2H Ar + 4H NH2), 7.20–7.12 (m AA′,
BB′, 2H, Ar), 2.95 (t, 2H, J = 7.15 Hz, SCH2), 1.64–1.49 (m,
2H, CH2), 1.45–1.32 (m, 2H, CH2), 1.32–1.18 (m, 4H, CH2),
0.85 (t, 3H, J = 6.87 Hz, CH3); 13C NMR (75 MHz, DMSO):
d 155.9, 135.1, 132.9, 129.0, 125.7, 32.2, 31.0, 28.7, 27.0,
22.2, 14.1. 4f: yield 96%; m.p. 98.9–100.8 °C; IR (KBr):
3381, 2953, 2925, 2854, 1671, 1626, 1567, 1496, 1384,
1325, 1284, 1096, 815 cm°1; 1H NMR (300 MHz, CDCl3): d
9.62 (bs, 1H, NH), 7.95 (bs, 4H, NH2), 7.34–7.29 (m AA′,
BB′ 2H, Ar), 7.18–7.12 (m AA′, BB′, 2H, Ar), 2.90 (t, 2H,
J = 7.14 Hz, SCH2), 1.73–1.57 (m, 2H, CH2), 1.49–1.21 (m,
8H, CH2), 0.88 (t, 3H, J = 7.14 Hz, CH3); 13C NMR
(75 MHz, CDCl3) d 156.4, 137.8, 131.1, 129.5, 125.8, 33.3,
31.8, 29.0, 28.9, 28.8, 22.7, 14.2. 4g: yield 78%; m.p. 99.0–
101.1 °C; IR (KBr): 3381, 2956, 2925, 2852, 1671, 1626,
1567, 1466, 1384, 1324, 1096, 815 cm–1, 1H NMR
1
1629, 1566, 1496, 1384, 805 cm–1; H NMR (300 MHz,
DMSO): d 9.52 (bs, 1H, NH), 7.38–7.31 (m AA′, BB′ over-
lapped, 6H, 2H Ar + 4H NH2), 7.20–7.14 (m AA′, BB′ 2H,
Ar), 2.94 (t, 2H, J = 7.14 Hz, SCH2), 1.65–1.49 (m, 2H,
CH2), 1.45–1.13 (m, 20H, CH2), 0.84 (t, 3H, J = 6.87 Hz,
CH3); 13C NMR (75 MHz, DMSO): d 155.9, 135.1, 132.9,
129.0, 125.7, 32.2, 31.5, 29.3, 29.2, 29.2, 28.9, 28.8, 28.7,
28.3, 22.3, 14.2. 4m: yield 84%; m.p. 117.0–118.0 °C; IR
(KBr): 3405, 2956, 2919, 2851, 1670, 1630, 1566, 1496,
1384, 1095, 813 cm–1; 1H NMR (300 MHz, DMSO): d 9.52
(bs, 1H, NH), 7.37–7.31 (m AA′, BB′ overlapped, 6H, 2H Ar
+ 4H NH2), 7.20–7.14 (m AA′, BB′, 2H, Ar), 2.94 (t, 2H,
J = 7.15 Hz, SCH2), 1.64–1.48 (m, 2H, CH2), 1.44–1.14 (m,
22H, CH2), 0.84 (t, 3H, J = 6.87 Hz, CH3); 13C NMR

448
G. Braunerová et al. / IL FARMACO 59 (2004) 443–450
(75 MHz, DMSO): d 156.0, 135.1, 132.9, 129.0, 125.7, 32.2,
31.5, 29.3, 29.2, 29.2, 28.9, 28.8, 28.7, 28.3, 22.3, 14.2. 4n:
yield 89%; m.p. 116.5–117.5 °C; IR (KBr): 3397, 2957,
(m AA′, BB′ overlapped, 6H, 2H Ar + 4H NH2), 7.00–
6.93 (m AA′, BB′, 2H, Ar), 3.94 (t, 2H, J = 6.87 Hz, OCH2),
1.75–1.63 (m, 2H, CH2), 1.47–1.24 (m, 6H, CH2), 0.85
(t, 3H, J = 6.87 Hz, CH3); 13C NMR (75 MHz, DMSO): d
157.8, 156.1, 127.4, 127.2, 115.6, 68.0, 31.3, 28.9, 25.5,
22.4, 14.3.
1
2920, 1672, 1626, 1565, 1496, 1384, 1095, 815 cm–1; H
NMR (300 MHz, DMSO): d 9.51 (bs, 1H, NH), 7.39–7.29
(m, AA′ BB′ overlapped, 6H, 2H Ar + 4NH2), 7.20–7.12 (m,
AA′ BB′ overlapped, 2HAr), 2.94 (t, 2H, J = 7.14 Hz, SCH2),
1.62–1.48 (m, 2H CH2), 1.44–1.14 (m, 24H, CH2), 0.84 (t,
3H, J = 7.15, CH3); 13C NMR (75 MHz, DMSO): d 155.9,
135.1, 132.9, 129.0, 125.7, 32.2, 31.5, 29.3, 29.2, 29.2, 28.9,
28.8, 28.7, 28.3, 22.3, 14.2. 4o: yield 55%; m.p. 119.2–
121.4 °C; IR (KBr): 3397, 2956, 2919, 2850, 1671, 1629,
1567, 1497, 1384, 1327, 1096, 814 cm–1; 1H NMR
(300 MHz, DMSO): d 9.52 (bs, 1H, NH), 7.37–7.29 (m AA′,
BB′ overlapped, 6H, 2H Ar + 4H NH2), 7.20–7.13 (m AA′,
BB′, 2H, Ar), 2.94 (t, 2H, J = 7.14 Hz, SCH2), 1.63–1.48 (m,
2H, CH2), 1.45–1.31 (m, 2H, CH2), 1.31–1.15 (m, 24H,
CH2), 0.84 (t, 3H, J = 6.87 Hz, CH3); 13C NMR (75 MHz,
DMSO): d 156.0, 135.1, 132.9, 129.0, 125.6, 32.2, 31.5,
29.3, 29.2, 28.9, 28.8, 28.7, 28.3, 22.3, 14.2. 4p: yield 47%;
m.p. 171.8–173.9 °C; IR (KBr): 3393, 3193, 1671, 1622,
1597, 1569, 1492, 1384, 1337, 1283, 1254, 1086, 1018 cm–1;
1H NMR (300 MHz, DMSO): d 9.61 (bs, 1H, NH), 7.45–7.35
5. Antimicrobial assays
Before testing, all compounds were dissolved in 100%
dimethyl sulfoxide (DMSO, Sigma) so that the final concen-
tration of DMSO in the test medium did not exceed 1% of the
total solution volume. A stock solution of each antifungal
compound was prepared in the Roswell Park Memorial Insti-
tute (RPMI) 1640 medium with L-glutamine, but without
sodium bicarbonate (Sevapharma, Prague), and then diluted
to the required drug concentration. Drug-free controls were
included. The RPMI medium was buffered to pH
7.0
0.1 with 0.165 M morpholinepropanesulfonic acid
(MOPS, Sigma). All solutions were prepared immediately
before testing.
A set of eight fungal strains (C. albicans ATCC44859,
C. tropicalis 156, C. krusei E28, C. glabrata 20/I, T. beigelii
1188, A. fumigatus 231, A. corymbifera 272, T. mentagro-
phytes 445) of potentially pathogenic fungi for humans was
used for the antifungal screening by means of the modified
National Committee for Clinical Laboratory Standards (NC-
CLS) protocols [25,26]. They included clinical isolates from
biological materials of patients with suspected or proven
mycosis. The fungal isolates were stored in Skim Milk Me-
dium (Becton Dickinson) for 6–10 months at –40 °C before
use. Prior to testing, each isolate was subcultured on Sab-
ouraud dextrose agar (SDA, Difco) to ensure optimal growth
characteristics and purity.
(bs, 4H, NH2), 7.34–7.16 (m, 8H, Ar), 2.30 (s, 3H, CH3); 13
C
NMR (75 MHz, DMSO): d 155.9, 138.2, 134.4, 134.2, 132.5,
130.6, 130.1, 125.7, 20.9. 4q: yield 68%; m.p. 156.8–
158.2 °C; IR (KBr): 3484, 3370, 3058, 2922, 2853, 1694,
1669, 1625, 1564, 1495, 1453, 1384, 1307, 1091, 817 cm–1;
1H NMR (300 MHz, DMSO): d 9.55 (bs, 1H, NH), 7.44–7.19
(m, 11H, 7HAr + 4 NH2), 7.19–7.11 (m, 2H,Ar), 4.24 (s, 2H,
CH2); 13C NMR (75 MHz, DMSO): 155.9, 137.6, 134.6,
133.3, 129.3, 129.0, 128.7, 127.4, 125.5, 36.7 4r: yield 88%;
m.p. 138.8–140.8 °C; IR (KBr): 3420, 3166, 2928, 2852,
1672, 1593, 1494, 1384, 1251, 823 cm–1; 1H NMR
(300 MHz, DMSO): d 9.52 (bs, 1H, NH), 7.45–7.22 (m AA′,
BB′ overlapped, 6H, 2H Ar + 4H NH2), 7.20–7.14 (m AA′,
BB′, 2H, Ar), 3.30–3.18 (m, 1H, SCH), 2.00–1.83 (m, 2H,
The isolates of yeasts and molds had been grown for 1 and
4–14 d, respectively, on a SDA at room temperature. Yeast
and conidia suspensions were prepared in sterile water
supplemented with 0.01% Tween 80. Each suspension of a
yeast and a mold was diluted in the ratio of 1:50 in the RPMI
1640 medium to obtain the final inoculum, which ranged
from 0.5 × 103 to 2.5 × 103 CFU ml–1 and 0.5 × 104 to 5 × 104
CFU ml–1, respectively. The inoculum size was determined
microscopically using the Bürker’s chamber and verified by
plating 100 µl of serial dilutions of each inoculum onto a
SDA plate and incubation until growth became visible.
In vitro antifungal activity of the compounds were deter-
mined by the microdilution broth method with a minor modi-
fication (see Inoculum preparation) in sterile, flat-bottom,
96-well microtitration plates according to the reference
document M27-A and M38-P of the NCCLS for yeasts and
filamentous fungi, respectively [25,26].
CH2), 1.79–1.55 (m, 3H, CH2), 1.40–1.08 (m, 5H, CH2); 13
C
NMR (75 MHz, DMSO): d 155.9, 133.8, 133.1, 131.8, 125.4,
45.2, 32.9, 25.5. 4s: yield 52%; m.p. 167.6–168.0 °C; IR
(KBr): 3300, 3130, 1645, 1610, 1384, 1370 cm–1; 1H NMR
(300 MHz, DMSO): d 9.65 (bs, 1H, NH), 7.48–7.29 (m AA′,
BB′ overlapped, 11H, 7H Ar + 4H NH2), 7.26–7.20 (m AA′,
BB′, 2H, Ar); 13C NMR (75 MHz, DMSO): d 155.9, 134.9,
134.6, 132.7, 132.1, 131.1, 129.9, 127.9, 125.7. 4t: yield
67%; m.p. 85.9–87.7 °C; IR (KBr): 3370, 2955, 2926, 2855,
1
1670, 1629, 1515, 1384, 1256, 1118, 838 cm–1; H NMR
(300 MHz, CDCl3): d 9.57 (bs, 1H, NH), 7.94 (bs, 4H, NH2),
7.25–7.20 (m AA′, BB′ 2H, Ar), 7.18–7.11 (m AA′, BB′, 2H,
Ar), 2.60 (t, 2H, J = 7.41 Hz, CH2), 1.66–1.52 (m, 2H, CH2),
1.38–1.17 (m, 8H, CH2), 0.87 (t, 3H, J = 7.41 Hz, CH3); 13
C
NMR (75 MHz, CDCl3): d 156.5, 143.1, 131.3, 130.0, 125.4,
35.5, 31.8, 31.4, 29.3, 29.2, 22.7, 14.2. 4u: yield 89%; m.p.
111.0–113.7 °C; IR (KBr): 3385, 2954, 2934, 1667, 1628,
1582, 1514, 1468, 1384, 1302, 1246, 1175, 1029, 826 cm–1;
1H NMR (300 MHz, DMSO): d 9.25 (bs, 1H, NH), 7.17–7.10
Twofold serial dilutions ranging from 500 to 0.98 µmol l–1
were tested for all compounds provided that a given com-
pound was soluble in DMSO and no precipitation in the
RPMI medium occurred. Wells 1–11 contained the drug

G. Braunerová et al. / IL FARMACO 59 (2004) 443–450
449
serial dilutions in 200 µl volumes, and well 12 contained a
drug-free medium, which served as the growth control for
each strain. Each well was inoculated with 10 µl of the
inoculum suspension, and the microtitration plates were in-
cubated at 35 °C in a humid atmosphere. The MIC (µmol l–1)
was determined visually as the lowest concentrations that
showed 80% growth inhibition as compared with the growth
of the drug-free control wells. The MIC values were read
after 24 and 48 h of incubation without agitation for yeasts
and 72 and 120 h of incubation for T. mentagrophytes.
6.992
8.676
13.638
7.764
3.136
6.441
3.586
6. Results and discussion
1.255
7.182
3D models of three possible tautomers of 4-(ethylsul-
fanyl)phenylguanidinium cation (cation of the compound 4a)
are given on Figs. 1–3. Calculated chemical shifts (ppm) in
1H NMR spectra are also given in these Figures. 4-(Ethyl-
sulfanyl)phenylguanidine-2-ium cation has the lowest en-
ergy (the difference in enthalpies is relatively large—
28.04 and 30.31 kcal mol–1) and 1H chemical shifts are in the
Fig. 3. Calculated chemical shifts (ppm) in 1H NMR spectra of 4-(ethylsul-
fanyl)phenylguanidine-3-ium cation. (DH0298 = 203.8699937 kcal mol–1).
good agreement with observed values. It suggests that this
tautomer is formed from the guanidine base during the pro-
tonation.
The results reported in Table 1 show that compounds are
high effective against tested strains of fungi. Particularly, the
efficacy of some compounds (products) can be compared
with that showed ketoconazole and dodine, used as reference
compounds for inhibitory activity against fungi. The ob-
tained results suggest that the lipophilicity has the significant
influence on the antifungal activity. The activity increases
with the length of the aliphatic chain, the optimum of the
activity lies between C6 and C13. Optimal log P for the most
effective compounds is between 3.531 and 6.305, values for
the MR move between 76.273 and 108.481 Å3. Compounds
with very short (C2–C5) or very long (C14–C16) chain are less
effective. The most effective compounds have MIC between
3.91 and 62.5 µmol l–1. All compounds show the same or
similar activity after 24 and 48 h, what indicates the fungi-
cidal (not fungistatic) mechanism of action. The test results
show that the most active compounds 4j and k (and all of its
salts) has similar efficacy against some strains (A. fumigatus,
A. corymbifera) as the standard ketoconazole which is used
as the reference drug. We also tested some salts and the base
derived from compound 4k. The aim was to study the poten-
tial toxic activity of nitrate anion and the possibility of
potentiation of the action by sorbic acid. We have found that
acetate, sorbate and the base of guanidine show the similar
activities as nitrate.
12.671
6.608
4.066
7.770
3.244
3.747
7.185
5.448
6.664
1.387
7.788
Fig. 1. Calculated chemical shifts (ppm) in 1H NMR spectra of 4-(ethylsul-
fanyl)phenylguanidine-1-ium cation. (DH0298 = 201.5988312 kcal mol–1).
6.795
8.707
7.857
7.625
3.084
7.626
Compounds from the tested series have the best activity in
comparison with dodine against T. mentagrophytes where
compounds 4e, h, j, k and other salts and the base of the
same compound, 4l, m are more active than dodine and
against T. beigelii where five compounds (4h, j, k-acetate,
k-sorbate, and k-base) have the higher activity. Some com-
pounds (4j, k-base) have also better activity against C. gla-
brata than the standard. Few compounds have also compa-
rable efficacy to dodine against C. krusei (4k and other salts
and the base of the same compound, 4j, and t). Compounds
7.340
7.419
1.237
6.344
7.307
Fig. 2. Calculated chemical shifts (ppm) in 1H NMR spectra of 4-(ethylsul-
fanyl)phenylguanidine-2-ium cation. (DH0298 = 173.5579685 kcal mol–1).

450
G. Braunerová et al. / IL FARMACO 59 (2004) 443–450
[8] A.K. Ghose, A. Pritchett, G.M. Crippen, Atomic physicochemical
parameters for three dimensional structure directed quantitative struc-
ture–activity relationships III: modeling hydrophobic interactions, J.
Comput. Chem. 9 (1988) 80–90.
4h, 4, and again k have high efficiency against A. fumigatus,
and compounds 4g, h, i, j, and k against A. corymbifera. The
introduction of an aromatic substituent in the para-position
of the phenyl ring instead of the aliphatic chain caused the
decrease of activity. The compounds with aromatic substitu-
ent as p-tolylsulfanylphenylguanidinium nitrate 4p, p-ben-
zylsulfanylphenylguanidinium nitrate 4q and p-phenyl-
sulfanylphenylguanidinium nitrate 4s show low activities
compared to alkylsulfanyl derivatives. Comparison of hexy-
lsulfanyl 4e and hexyloxy 4u derivatives shows that the
replacement of sulfur atom by oxygen brings the strong
decrease of the activity. On the other hand, hexylsulfanyl
derivative 4e has the similar activity to heptyl derivative 4t. It
indicates that the alkyl series can have also the strong anti-
fungal effect. Considering the antifungal activity of com-
pounds further study will be devoted to the improvement of
the biological profile (activity, spectrum, ortho-substitution).
[9] V.N. Viswanadhan, A.K. Ghose, G.R. Revankar, R.K. Robins, Atomic
physicochemical parameters for three dimensional structure directed
quantitative structure–activity relationships. 4. Additional parameters
for hydrophobic and dispersive interactions and their application for
an automated superposition of certain naturally occurring nucleoside
antibiotics, J. Chem. Inf. Comput. Sci. 29 (1989) 163–172.
[10] A.K. Ghose, G.M. Crippen, Atomic physicochemical parameters for
three-dimensional-structure-directed quantitative structure–activity
relationships. 2. Modeling dispersive and hydrophobic interactions, J.
Chem. Inf. Comput. Sci. 27 (1987) 21–35.
[11] T.L. Evans, R.D. Kinnard, Diaryl sulfide cleavage by sodium sulfide
in dipolar aprotic solvents, J. Org. Chem. 48 (1983) 2496–2499.
[12] W.R. Waldron, E.H. Reid, Influence of sulfur on the color azo dyes, J.
Am. Chem. Soc. 45 (1923) 2399–2417.
[13] Z. Budesinsky, J. Solin, Preparation of asymmetric sulfones, Collect.
Czech. Chem. Commun. 14 (1949) 267–273.
[14] A. Baruffini, F. Gialdi, 4-Aminothiophenol derivatives of antifungal
activity, Farmaco 13 (1958) 911–921.
[15] H. Burton, W.A. Davy, Synthesis of some aryl pyridyl sulfones
(arylsulfonylpyridines), J. Chem. Soc. (1947) 52–55.
[16] M. Uher, K. Antos, L’. Floch, Synthesis and infrared spectra of
p-isothiocyanatophenyl alkyl sulfides and p-isothiocyanatophenyl
alkyl sulfones, Sbornik Prac Chemickej Fakulty SVST (1967) 23–28,
Chem. Abstr. 70 (1969) 19689y.
[17] J.B. Baumann, Displacement of nitrite ion in nitrobenzenes by sodium
thiolates, J. Org. Chem. 36 (1971) 396–398.
[18] R.J. Walsh, K.R.H. Wooldridge, D. Jackson, J. Gilmour, The structure
activity relationship of antibacterial substituted 1-phenyl-4,6-
diamino-1,2-dihydro-2,2-dimethyl-S-triazines, Eur. J. Med. Chem. 12
(1977) 495–500.
Acknowledgements
This work was supported by the research projects MSM
111600001 and 111600002 of the Ministry of Education,
Youth and Sports of the Czech Republic, by the project No.
2990/2003 of the Universities Development Fund, and by the
grant of the Grant Agency of the Czech Republic No.
203/04/0178.
[19] J.B. Hyne, J.W. Greidanus, Nuclear magnetic resonance study of
intramolecular electronic effects in diphenyl sulfides, sulfoxides, and
sulfones, Can. J. Chem. 47 (1969) 803–812.
References
[20] C.A. Kingsbury, The mechanism of dimethyl sulfoxide catalysis in
nucleophilic displacement, J. Org. Chem. 29 (1964) 3262–3270.
[21] D.G. Foster, E.E. Reid, Influence of sulfur on the color of azo dyes.
Further investigations, J. Am. Chem. Soc. 46 (1924) 1348–1936.
[22] A. Baruffini, P. Borgna, G. Calderara, M. Mazza, F. Gialdi,
p-Alkylthioanilide inhibitors of the Hill reaction, Farmaco 25 (1970)
10–35.
[23] T. Takahashi, Synthesis of p-benzylmercaptobenzenearsonic acid, J.
Pharm. Soc. Japan 55 (1935) 875–879 (in German 164–165).
[24] H.J. Cristau, B. Chabaud, A. Chene, H. Christol, Synthesis of diaryl
sulfides by nickel(II)-catalyzed arylation of arenethiolates, Synthesis
11 (1981) 892–894.
[25] National Committee for Clinical Laboratory Standards, reference
method for broth dilution antifungal susceptibility testing of yeasts.
Approved standard. Document M27-A, National Committee for Clini-
cal Laboratory Standards, Wayne, PA, 1997.
[26] National Committee for Clinical Laboratory Standards, Reference
method for broth dilution antifungal susceptibility testing of
conidium-forming filamentous fungi. Proposed standard. Document
M38-P, National Committee for Clinical Laboratory Standards, W
ayne, PA, 1998.
[1] Guanidine derivatives, Chem.Abstr. 65 (1966) 15242b Evans Medical
Ltd, Dutch Patent, 6511047.
[2] Lamb, Glentworth, Dodecylguanidine salts as fruit-tree fungicides,
United States Patent 2867562, Chem. Abstr. 53 (1959) 47349.
[3] M. Rajsner, J. Metysova, E. Svatek, F. Miksik, M. Protiva, Neurotro-
pic and psychotropic agents. LXXVIII. The 2- and 3-fluoro deriva-
tives of clorotepin and related compounds. The 6- and 7-fluoro deriva-
tive of chlorprothixene, Collect. Czech. Chem. Commun. 40 (1975)
719–737.
[4] M. Uher, K. Antos, P. Kristian, L. Drobnica, Isothiocyanates. XVIII,
The synthesis and infrared spectra of (p-isothiocyanatophenyl) alkyl
sulfides and (p-isothiocyanatophenyl) alkyl sulfones, Chem. Zvesti.
21 (1967) 44–56.
[5] F.D. Bellamy, K. Ou, Selective reduction of aromatic nitro compounds
with stannous chloride in nonacidic and nonaqueous medium, Tetra-
hedron Lett 25 (1984) 839–842.
[6] C.W. Ferry, J.S. Buck, R. Baltzly, 4,4’-Diaminodiphenyl sulfone
(p,p’-sulfonylbisaniline), Org. Syn. 22 (1942) 31–34.
[7] R.H. McKee, On the oxygen ethers of the ureas: methyl- and ethyli-
sourea, Am. Chem. J. 26 (1901) 209–264.