Antimycobacterial activity of 5-arylidene derivatives of hydantoin

Article abstract of DOI:10.1016/S0014-827X(02)01292-2

The synthesis of various 5-arylidene-2-thiohydantoins and results of the primary assay in vitro for their antimycobacterial activity is reported. Eight of those compounds exhibited >90% inhibition of Mycobacterium tuberculosis growth and for them the minimum inhibitory concentrations, cytotoxicity (IC₅₀) and the selectivity index values were determined. The most active structure, (5Z)-5-(1,1′-biphenyl-4-ylmethylene)-2-thioxoimidazolidin-4-one, showed MIC=0.78 μg/ml. For all compounds logP and logD (pH 6.5) values were calculated.

Full text of DOI:10.1016/S0014-827X(02)01292-2

Il Farmaco 57 (2002) 909Á916
/
www.elsevier.com/locate/farmac
Antimycobacterial activity of 5-arylidene derivatives of hydantoin
K. Kiec´-Kononowicz *, E. Szyman´ska
Department of Chemical Technology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, ul. Medyczna 9, PL 30-688 Krako´w,
Poland
Received 15 March 2002; received in revised form 10 May 2002; accepted 25 June 2002
Abstract
The synthesis of various 5-arylidene-2-thiohydantoins and results of the primary assay in vitro for their antimycobacterial activity
is reported. Eight of those compounds exhibited ꢀ
inhibitory concentrations, cytotoxicity (IC50) and the selectivity index values were determined. The most active structure, (5Z)-5-
(1,1?-biphenyl-4-ylmethylene)-2-thioxoimidazolidin-4-one, showed MICꢀ0.78 mg/ml. For all compounds log P and log D (pH 6.5)
values were calculated.
/90% inhibition of Mycobacterium tuberculosis growth and for them the minimum
/
´
# 2002 Published by Editions scientifiques et me´dicales Elsevier SAS.
Keywords: Arylidene 2-thiohydantoins; Antimycobacterial activity
1. Introduction
viously synthesized [7Á10] and new 5-arylidene-hydan-
/
toin derivatives bearing the thiocarbonyl group as a
pharmacophore. The synthesis of the new compounds
and the results of their in vitro screening against M.
tuberculosis H37Rv are reported.
According to data of the World Health Organization
[1] tuberculosis is considered to be the most chronic
communicable disease in the world. The increasing
resistance of Mycobacterium tuberculosis to currently
available therapy and the large number of epidemic
infections due to Mycobacterium avium complex are
stimulating factors in the research of new active
compounds. The studies on current antimycobacterial
agents show the connection of the antitubercular activity
with the presence of some suitable fragments of the
agent molecule [2,3]. The list of these pharmacophores
includes isonicotinic acid hydrazides, pyrazinoic acids,
b-lactams, fluoroquinolones, compounds containing a
thiocarbonyl group (thioamides, thioureas), compounds
containing an alkylthio group bound to an electron-
deficient atom of carbon, oxazolidinones, nitroimida-
zoles and others.
As a part of structureÁ
tions we decided to determine lipophilicity, expressed as
log P (octanolÁwater coefficient) and log D6.5 (distribu-
tion coefficient at pH 6.5*pH of the small intestine)
/activity relationship considera-
/
/
values.
2. Chemistry
The synthetic pathways leading to the new imidazo-
lidine-4-one derivatives are illustrated in Scheme 1. The
target compounds were prepared as a result of con-
densation of 2-thiohydantoin with suitable aldehydes
(or ketones) according to two methods. The mixture of
starting materials was refluxed in acetic acid with
anhydrous sodium acetate (method 1 [11] compounds
The interesting results of our previous studies on
antibacterial and -mycobacterial activity of imidazoline-
4-one derivatives [4Á6] prompted us to continue our
/
1Á
[12] compounds 46Á
products III. Some benzaldehyde derivatives, needed as
the starting material for the synthesis of 40Á45, were
/45) or in toluene with ammonium acetate (method B
investigations in this field. In the present work we
focused on the antimycobacterial effect of both pre-
/
48) to give with good yields solid
/
* Corresponding author
E-mail address: mfkonono@kinga.cyf-kr.edu.pl (K. Kiec´-
Kononowicz).
obtained by the alkylation of m- or p-hydroksybenzal-
dehyde (Scheme 2).
´
0014-827X/02/$ - see front matter # 2002 Published by Editions scientifiques et me´dicales Elsevier SAS.
PII: S 0 0 1 4 - 8 2 7 X ( 0 2 ) 0 1 2 9 2 - 2

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K. Kiec-Kononowicz, E. Szymanska / Il Farmaco 57 (2002) 909Á916
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M. tuberculosis than 2-substituted group (1, 4, 5, 7Á
The occurrence of additional halogen atom in benzyli-
dene residue reduced activity (4Á8, 14). Alkyloxy
/9).
/
substituents in the meta and particularly para position
were advantageous as it was observed for 18, 21, 22, 44
and 45. Introducing of the additional aromatic frag-
ment, especially joined by the oxygen atom, to the
Scheme 1.
phenyl ring (Table 2, 36, 40Á
increase of activity. The substitution of hydrogen atom
in double bond of benzylidene residue (46Á48) totally
decreased the antimycobacterial effect.
/
43) caused the strong
The purity of the synthesized compounds was checked
by thin-layer chromatography. Their structures were
confirmed by elemental analyses and spectral data (IR,
1H NMR).
/
Compounds, which inhibited M. tuberculosis growth
to extent higher than 90% were classified to further tests.
The minimum inhibitory concentrations (MICs), cyto-
As the steric position of benzylidene substituent was
C bond, the target compounds could
restricted by Cꢀ
/
occur in either E- or Z-configuration. However, the X-
ray structure analysis as well as theoretical calculations
of this type of compounds indicate Z-form [13].
For all structures the log P and log D6.5 (pH of the
small intestine) values were calculated by means of
Pallas program [14].
toxicity (IC50) and the selectivity index (SIꢀIC50/MIC)
/
values for them were determined (Table 3). Four
structures showed MIC in vitro equal or lower than
3.13 mg/ml and for the most active biphenyl derivative,
36, MIC was 0.78 mg/ml, while for the reference
rifampicin, in this test, MIC was equal to 0.0075 mg/ml
(for isoniazid MICꢀ
investigated compounds displayed in tests too high
cytotoxicity*for all of them (except 35) calculated SI
/
0.025Á
/
0.05 mg/ml). As it is shown,
3. Results and discussion
/
values were lower than 10 and according to TAACF
program, they were not advanced to the further tests.
In order to find a potential antimycobacterial activity
all the compounds were tested according to the Tuber-
culosis Antimicrobial Acquisition and Coordinating
Facility (TAACF) screening program using a broth
microdilution assay, the Microplate Alamar Blue Assay
(MABA) [15]. Primary screening was conducted at 6.25
mg/ml. Results as well as log P combined and log D
values prediction of the obtained compounds taken with
Pallas program are presented in Tables 1 and 2. All
compounds exhibited weak acidic properties.
4. Experimental
4.1. Chemistry
4.1.1. Materials and methods
M.p.s were measured on a Mel.-Temp. II (LD Inc.,
USA) apparatus. The tlc was performed on Merck silica
gel GF254 precoated tlc Al sheets; the used solvent
Among all the compounds tested, eight structures
demonstrated the high level of inhibition of M. tubercu-
losis (ꢀ
philicity ranged from 0.79 to 2.54 (mean 1.46), while, for
comparison, log P of inactive derivatives (inhibition 5
10%) varied from ꢁ0.03 to 1.57 (mean 0.76). However,
the calculated log P and log D values did not show any
apparent correlation between structure and observed
antimycobacterial activity indicating that the other than
acidic properties and lipophilicity factors dominate in
their mode of action.
/
90%). These active compounds displayed lipo-
systems were: (A) CH2Cl2Á
/
EtOAc (1:1); (B) C6H5CH3Á
/
C3H6O (20:1.5); (C) CH2Cl2. Spots were visualized by
UV absorption at 254 nm. Infrared spectra were
measured with FT IR 410 spectrometer (JASCO) in
KBr pellets. The 1H NMR spectra were performed on a
Bruker AC-200F spectrometer or on VARIAN MER-
CURY 300 MHz spectrometer or on a Bruker DPX 400
Avance (400 MHz) spectrometer in DMSO-d6 using
TMS as an internal standard (chemical shifts are
reported in d units). The elemental analyses (C, H, N)
performed at the Department of Pharmaceutical Chem-
istry of the Jagiellonian University, Krako´w (Poland)
/
/
On basis of the obtained screening results we can
state, that among benzylidene substituted compounds
(Table 1) 3- and 4-chloro/bromo/fluoro substituted
structures (2, 3, 10Á/13) showed better effect against
were within 90.4% from the theoretical values.
/
Scheme 2.

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K. Kiec-Kononowicz, E. Szymanska / Il Farmaco 57 (2002) 909Á
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916
911
Table 1
Antimyconbacterial activity of benzylidene hydantoins
4.1.2. Preparation of 2-thiohydantoins
(ArCHꢀ
/
), 1585, 1486, 1249, 1177, 991, 959, 857 cmꢁ1
.
The 2-thiohydantoin derivatives were obtained as
recently described [4,5] or in analogy to the described
procedures [6,7]. The following new derivatives were
prepared:
Anal. (C10H6F2N2OS): C, H, N.
4.1.2.3. Z-5-(4-Ethoxybenzylidene)-2-thiohydantoin
(21). Obtained as described in Ref. [9], the reaction
mixture was refluxed for 5 min, m.p. 238Á241 8C
(yellow crystals from AcOH), yield 83%; Rf (A) 0.42;
Rf (B) 0.84; 1H NMR (300 MHz): d 1.33 (t, Jꢀ
6.87 Hz,
3H, CH3), 4.07 (q, Jꢀ6.87 Hz, 2H, CH2O), 6.44 (s, 1H,
ArCHꢀ), 6.94 (d, Jꢀ8.51 Hz, 2H, H-3?, H-5?), 7.70 (d,
Jꢀ8.79 Hz, 2H, H-2?, H-6?), 12.05 (s, 1H, N1ꢁH), 12.23
(s, 1H, N3ꢁH); IR (KBr): n 3282, 1725 (C4ꢀO), 1640
), 1598, 1479, 1256, 1180, 826, 719 cmꢁ1. Anal.
/
4.1.2.1. Z-5-(3,4-Dichlorobenzylidene)-2-thiohydantoin
(6). Obtained as described in Ref. [9], the reaction
/
mixture was refluxed for 2.0 h, m.p. 260Á
crystals from AcOH), yield 78%; Rf (A) 0.52; Rf (B) 0.84;
1H NMR (400 MHz): d 6.46 (s, 1H, ArCHꢀ
), 7.63Á7.71
(m, 2H, H-5?, H-6?), 8.03 (s, 1H, H-2?), 12.35 (s, 1H, N1ꢁ
H), 12.65 (s, 1H, N3ꢁH); IR (KBr): n 3203 (NH), 1727
/
262 8C (yellow
/
/
/
/
/
/
/
/
/
/
/
(ArCHꢀ
/
(C4ꢀ
/
O), 1653 (ArCHꢀ
/
), 1487, 1464, 1351, 1182, 1084,
(C12H12N2O2S): C, H, N.
891, 811, 751 cmꢁ1. Anal. (C10H6Cl2N2OS): C, H, N.
4.1.2.4. Z-5-(4-Propoxybenzylidene)-2-thiohydantoin
(22). Obtained as described in Ref. [9], the reaction
4.1.2.2. Z-5-(3,5-Difluorobenzylidene)-2-thiohydantoin
(14). Obtained as described in Ref. [9], the reaction
mixture was refluxed for 2.0 h, m.p. 228Á230 8C (yellow
/
mixture was refluxed for 2.0 h, m.p. 278Á
crystals), yield 97% raw product was analytically pure;
Rf (A) 0.54; Rf (B) 0.89; 1H NMR (300 MHz): d 6.44 (s,
/
280 8C (yellow
crystals from AcOH), yield 78%, raw product was
1
analytically pure; Rf (A) 0.47; Rf (B) 0.86; H NMR
(300 MHz): d 0.97 (t, Jꢀ
(m, 2H, CH3CH2), 3.98 (t, Jꢀ
(s, 1H, ArCHꢀ), 6.95 (d, Jꢀ8.52 Hz, 2H, H-3?, H-5?),
7.71 (d, Jꢀ8.80 Hz, 2H, H-2?, H-6?), 12.04 (s, 1H, N1ꢁ
/
7.42 Hz, 3H, CH3), 1.67Á
/1.79
1H, ArCHꢀ
Hz, 2H, H-2?, H-6?), 12.29 (s, 1H, N1ꢁ
N3ꢁH); IR (KBr): n 3203 (NH), 1725 (C4ꢀ
/
), 7.19Á
/
7.26 (m, 1H, H-4?), 7.48 (d, Jꢀ
H), 12.47 (s, 1H,
O), 1649
/
6.87
/6.32 Hz, 2H, CH2O), 6.45
/
/
/
/
/
/
/

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K. Kiec-Kononowicz, E. Szymanska / Il Farmaco 57 (2002) 909Á916
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Table 2
Antimyconbacterial activity of arylidene hydantoins

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913
Table 3
MIC and cytotoxicity values of the selected compounds
H), 12.26 (s, 1H, N3ꢁ
/
H); IR (KBr): n 1724 (C4ꢀ
/
O), 1651
), 1597, 1475, 1257, 1174, 959, 822, 539 cmꢁ1
6.51 (s, 1H, ArCHꢀ
8.00 (d, Jꢀ
(br.s, 2H, N1ꢁ
/
), 7.58Á
/
7.70 (m, 2H, H-4?, H-5?),
(ArCHꢀ
/
.
/
7.50 Hz, 1H, H-6?), 8.08 (s, 1H, H-2?), 12.33
H, N3ꢁH); IR (KBr): n 3443, 3247 (Nꢁ
H), 2849 (CH2), 1728 (C4ꢀ
Anal. (C13H14N2O2S): C, H, N.
/
/
/
/
O), 1653 (ArCHꢀ
/), 1503,
1332, 1194, 1125, 912, 692 cmꢁ1. Anal. (C11H7F3N2OS):
C, H, N.
4.1.2.5. Z-5-(3-Trifluoromethylbenzylidene)-2-
thiohydantoin (25). Obtained as described in Ref. [9],
the reaction mixture was refluxed for 2.0 h, m.p. 213Á
/
216 8C (cream coloured crystals from AcOH), yield
87%; Rf (A) 0.41; Rf (B) 0.87; H NMR (300 MHz): d
4.1.2.6. Z-5-(2,5-Dimethylbenzylidene)-2-thiohydantoin
(28). Obtained as described in Ref. [9], the reaction
1

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K. Kiec-Kononowicz, E. Szymanska / Il Farmaco 57 (2002) 909Á916
/
mixture was refluxed for 1.0 h, m.p. 255Á
crystals from AcOH), yield 90%, raw product was
1
analytically pure; Rf (A) 0.52; Rf (B) 0.82; H NMR
/
256 8C (yellow
(C4ꢀ
/
O), 1640 (ArCHꢀ
/
), 1492, 1373, 1339, 1231, 1194,
965, 804, 781, 644 cmꢁ1. Anal. (C14H10N2OS): C, H, N.
(300 MHz): d 2.29 (s, 3H, C5?ꢁ
CH3), 6.52 (s, 1H, ArCHꢀ), 7.06 (d, Jꢀ
3?), 7.12 (d, Jꢀ7.69 Hz, 1H, H-4?), 7.43 (s, 1H, H-6?),
12.15 (s, 1H, N1ꢁH), 12.33 (s, 1H, N3ꢁH); IR (KBr): n
), 1518, 1376,
/
CH3), 2.30 (s, 3H, C2?ꢁ
/
4.1.2.11. Z-5-(2-Naphthylidene)-2-thiohydantoin (38).
Obtained as described in Ref. [9], the reaction mixture
/
/
7.69 Hz, 1H, H-
/
was refluxed for 1.0 h, m.p. 271Á272 8C (lemon
/
/
/
coloured crystals from AcOH), yield 86%; Rf (A) 0.45;
Rf (B) 0.86; 1H NMR (300 MHz): d 6.62 (s, 1H,
3134 (Nꢁ
/
H), 1722 (C4ꢀ
/
O), 1655 (ArCHꢀ
/
1221, 1101, 968, 803, 654 cmꢁ1. Anal. (C12H12N2OS):
ArCHꢀ
1.65, 8.65 Hz, 1H, H-3?), 7.89Á
H-8?), 8.37 (s, 1H, H-1?), 12.30 (s, 1H, N1ꢁ
1H, N3ꢁH); IR (KBr): n 3130 (NꢁH), 1722 (C4ꢀ
/
), 7.52Á
/
7.56 (m, 2H, H-6?, H-7?), 7.77 (dd, Jꢀ
7.98 (m, 3H, H-4?, H-5?,
H), 12.41 (s,
O),
/
C, H, N.
/
/
4.1.2.7. Z-5-(4-Methoxy-2,5-dimethylbenzylidene)-2-
thiohydantoin (29). Obtained as described in Ref. [9],
/
/
/
1641 (ArCHꢀ
/), 1493, 1373, 1339, 1231, 1194, 965, 804,
the reaction mixture was refluxed for 0.5 h, m.p. 292Á
/
781, 644cmꢁ1. Anal. (C14H10N2OS): C, H, N.
293 8C (orange crystals from AcOH), yield 81%, raw
product was analytically pure; Rf (A) 0.49; Rf (B) 0.84;
4.1.2.12. Z-5-[3,4-(Methylenedioxy)benzylidene]-2-
thiohydantoin (39). Obtained as described in Ref. [9],
the reaction mixture was refluxed for 0.5 h, m.p. 298Á
1H NMR (300 MHz): d 2.14 (s, 3H, C5?ꢁ
/
CH3), 2.34 (s,
CH3), 3.80 (s, 3H, OCH3), 6.51 (s, 1H,
), 6.85 (s, 1H, H-3?), 7.48 (s, 1H, H-6?), 12.09
(s, 1H, N1ꢁH), 12.25 (s, 1H, N3ꢁH); IR (KBr): n 1718
3H, C2?ꢁ
/
/
ArCHꢀ
/
300 8C (yellow crystals from AcOH), yield 80%; Rf (A)
0.38; Rf (B) 0.83; H NMR (300 MHz): d 6.08 (s, 2H,
1
/
/
(C4ꢀ
/
O), 1637 (ArCHꢀ
/
), 1597, 1491, 1378, 1258, 1089,
CH2O), 6.42 (s, 1H, ArCHꢀ
H-5?), 7.24 (dd, Jꢀ1.10, 7.44 Hz, 1H, H-6?), 7.43 (d,
Jꢀ1.10 Hz, 1H, H-2?), 12.06 (s, 1H, N1ꢁH), 12.28 (s,
),
/
), 6.95 (d, Jꢀ/8.24 Hz, 1H,
964, 857, 686 cmꢁ1. Anal. (C13H14N2O2S): C, H, N.
/
/
/
4.1.2.8. Z-5-(a-Methyl-trans-cinnamylidene)-2-
thiohydantoin (35). Obtained as described in Ref. [9],
1H, N3ꢁ
/
H); IR (KBr): n 1717 (C4ꢀ
/
O), 1649 (ArCHꢀ
/
1595, 1488, 1344, 1190, 1106, 1033, 968, 922, 799 cmꢁ1
.
the reaction mixture was refluxed for 2.0 h, m.p. 238Á
/
Anal. (C11H8N2O3S): C, H, N.
240 8C (green yellow crystals from AcOH), yield 58%;
Rf (A) 0.44; Rf (B) 0.82; 1H NMR (300 MHz): d 2.19 (s,
4.1.2.13. Z-5-[(3-Benzyloxy)benzylidene]-2-
3H, CH3), 6.23 (s, 1H, ArCHꢀ
7.26Á7.33 (m, 1H, H-4?), 7.39 (d, Jꢀ
H-3?, H-5?, H-6?), 11.72 (s, 1H, N1ꢁ
/
), 7.00 (s, 1H, CHꢀ
4.67 Hz, 4H, H-2?,
H), 12.27 (s, 1H,
), 1583,
/
),
thiohydantoin (40). The mixture of 12.2 g (0.1 mol) 3-
hydroxybenzaldehyde, 17.1 (0.1 mol) benzylbromide
and 6.9 g (0.05 mol) of anhydrous K2CO3 in 100 ml of
EtOH was refluxed for 4.0 h. After cooling the solid was
filtered off, the filtrate was evaporated to the oily
residue, dissolved in CH2Cl2 and washed three times
with 2% NaOH solution till the disappearance of the
starting aldehyde [checked with tlc Rf (C) 0.08]. The
product Rf (C) 0.45 was recrystallized from EtOH, m.p.
/
/
/
N3ꢁ
/
H); IR (KBr): n 1723 (C4ꢀ
/
O), 1628 (ArCHꢀ
/
1494, 1372, 1189, 969, 915, 752, 701 cmꢁ1. Anal.
(C13H12N2OS): C, H, N.
4.1.2.9. Z-5-(4-Phenylbenzylidene)-2-thiohydantoin
(36). Obtained as described in Ref. [9], the reaction
mixture was refluxed for 0.25 h, m.p. 221Á
/
224 8C
(yellow crystals from AcOH), yield 70%; Rf (A) 0.46;
55Á
synthesis of 40 with the method described in Ref. [9]; the
reaction mixture was refluxed for 2.0 h, m.p. 212Á
/
56 8C; yield 75% and used as starting material in the
Rf (B) 0.86; 1H NMR (300 MHz): d 6.52 (s, 1H,
/
ArCHꢀ
3ƒ, H-5ƒ), 7.72 (def. d, 4H, H-3?, H-5?, H-2ƒ, H-6ƒ), 7.84
(d, Jꢀ8.52 Hz, 2H, H-2?, H-6?), 12.20 (s, 1H, N1ꢁH),
12.37 (s, 1H, N3ꢁH); IR (KBr): n 3253 (NꢁH), 1720
(C4ꢀO), 1648 (ArCHꢀ), 1475, 1337, 1171, 1092, 764,
693 cmꢁ1. Anal. (C16H12N2OS): C, H, N.
/
), 7.36Á
/
7.41 (m, 1H, H-4ƒ), 7.48 (def. t, 2H, H-
215 8C (yellow crystals from AcOH), yield 74%; Rf
(A) 0.41; Rf (B) 0.88; H NMR (200 MHz): d 5.17 (s,
1
/
/
2H, CH2O), 6.46 (s, 1H, ArCHꢀ
5?), 7.31Á7.39 (m, 5H, C6H5), 7.40Á
H-4?, H-6?), 12.24 (br.s, 1H, N1ꢁH), 12.32 (br.s, 1H,
N3ꢁH); IR (KBr): n 3436 (NꢁH), 3248 (NꢁH), 1720
(C4ꢀ
/
), 7.01Á/7.06 (m, 1H, H-
/
/
/
/
7.50 (m, 3H, H-2?,
/
/
/
/
/
/
/
O), 1648 (ArCHꢀ
/
), 1476, 1232, 1052, 896, 776, 684,
4.1.2.10. Z-5-(1-Naphthylidene)-2-thiohydantoin (37).
Obtained as described in Ref. [9], the reaction mixture
544 cmꢁ1. Anal. (C17H14N2O2S): C, H, N.
was refluxed for 0.25 h, m.p. 290Á
/
292 8C (lemon
coloured crystals from AcOH), yield 69%; Rf (A) 0.46;
4.1.2.14. Z-5-[3-(4-Chlorobenzyloxy)benzylidene]-2-
thiohydantoin (41). Obtained as described for 40, m.p.
Rf (B) 0.87; 1H NMR (300 MHz): d 7.06 (s, 1H,
220Á222 8C (lemon coloured crystals from AcOH),
/
ArCHꢀ
Jꢀ7.14 Hz, 1H, H-2?), 7.90Á
8.06 (d, Jꢀ8.79 Hz, 1H, H-8?), 12.22 (s, 1H, N1ꢁ
12.39 (s, 1H, N3ꢁH); IR (KBr): n 3129 (NꢁH), 1721
/
), 7.53Á
/
7.64 (m, 3H, H-3?, H-6?, H-7?), 7.79 (d,
7.99 (m, 2H, H-4?, H-5?),
H),
yield 86%; raw product was analytically pure; Rf (A)
1
0.41; Rf (B) 0.88; H NMR (200 MHz): d 5.17 (s, 2H,
/
/
/
/
CH2O), 6.44 (s, 1H, ArCHꢀ
/
), 7.00Á
/
7.05 (m, 1H, H-5?),
/
/
7.32Á7.36 (m, 3H, H-2?, H-4?, H-6?), 7.43Á
/
/7.53, (m, 4H,

´
´
K. Kiec-Kononowicz, E. Szymanska / Il Farmaco 57 (2002) 909Á
/
916
915
H-2ƒ, H-3ƒ, H-5ƒ, H-6ƒ), 12.28 (s, 2H, N1ꢁ
(KBr): n 3432 (NꢁH), 2876 (CH2), 1722 (C4ꢀ
), 1352, 1306, 1232, 1088, 1012, 668 cmꢁ1
.
/
H, N3ꢁ
/
H); IR
mine the actual MIC in the MABA. The MIC was
defined as the lowest concentration inhibiting 99% of
the inoculum. Rifampin (Sigma Chemical Compound,
St. Louis, MO) or isoniazid were included as a positive
drug control.
/
/
O), 1644
(ArCHꢀ
/
Anal. (C17H13ClN2O2S): C, H, N.
4.1.2.15. Z-5-[3-(2-Phenylethoxy)benzylidene]-2-
Compounds were tested for cytotoxicity (IC50) in
VERO cells at concentrations less than or equal to 10
times the MIC. After 72 h exposure, viability was
assessed on the basis of cellular conversion of 3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
(MTT) into a formazan product using the Promega
CellTiter 96 Non-radioactive Cell Proliferation Assay.
thiohydantoin (43). Obtained as described for 40, m.p.
159Á161 8C (yellow crystals from AcOH), yield 45%; Rf
(A) 0.45; Rf (B) 0.88; H NMR (200 MHz): d 3.05 (t,
Jꢀ6.86 Hz, 2H, C6H5CH2), 4.26 (t, Jꢀ6.88 Hz, 2H,
CH2O), 6.46 (s, 1H, ArCHꢀ), 6.92Á6.98 (m, 1H, H-5?),
7.22Á7.36 (m, 8H, C6H5, H-2?, H-4?, H-6?), 12.29 (br.s,
2H, N1ꢁH, N3ꢁH); IR (KBr): n 3164 (NꢁH), 2856
/
1
/
/
/
/
/
/
/
/
Compounds for which the selectivity index SI (ꢀ
/IC50/
(CH2), 1722 (C4ꢀ
/
O), 1640 (ArCHꢀ
/
), 1572, 1480, 1364,
MIC)ꢀ10 were considered as active and classified to
/
1240, 900, 764, 702, 500 cmꢁ1. Anal. (C18H16N2O2S): C,
H, N.
further tests.
4.1.2.16. Z-5-[(3-Allyloxy)benzylidene]-2-
thiohydantoin (44). Obtained as described for 40, m.p.
Acknowledgements
184Á
(A) 0.42; Rf (B) 0.88; H NMR (200 MHz): d 4.59 (s,
2H, OCH2), 5.25 (d, Jꢀ10.71 Hz, 1H, Hc), 5.40 (d, Jꢀ
17.00 Hz, 1H, Hb), 5.97Á6.10 (m, 1H, Ha), 6.91 (t, Jꢀ
8.52 Hz, 1H, H-5?), 7.02 (s, 1H, ArCHꢀ), 7.07 (def. t,
1H, H-4?), 7.27Á7.32 (m, 1H, H-2?), 7.58 (d, Jꢀ15.65
Hz, 0.5H, H-6?), 8.40 (d, Jꢀ16.20 Hz, 0.5H, H-6?),
11.88 (s, 0.5H, N1ꢁH), 12.13 (s, 1.5H, N3ꢁH, N1ꢁH),
12.18 (s, 0.5H, N3ꢁH); IR (KBr): n 3115 (NH), 2869
/
187 8C (yellow crystals from AcOH), yield 69%; Rf
1
The authors are grateful for the antimycobacterial
data provided by the Tuberculosis Antimicrobial Ac-
quisition and Coordinating Facility (TAACF) through a
research and development contract with US National
Institute of Allergy and Infectious Diseases. We also
thank Maria Kaleta for the help in synthetic part of this
work. Financial support from the Polish State Commit-
tee for Scientific Research (project BBN 501/P/136/F) is
gratefully acknowledged.
/
/
/
/
/
/
/
/
/
/
/
/
(CH2), 1707 (C4ꢀ
/
O), 1606 (ArCHꢀ/), 1513, 1208, 947,
770, 685 cmꢁ1. Anal. (C13H12N2O2S): C, H, N.
4.1.2.17. Z-5-[(4-Allyloxy)benzylidene]-2-
thiohydantoin (45). Obtained as described for 40, m.p.
References
219Á
(A) 0.28; Rf (B) 0.77; H NMR (200 MHz): d 4.61 (d,
Jꢀ5.21 Hz, 2H, CH2O), 5.27 (d, Jꢀ10.50 Hz, 1H, Hc),
5.39 (dd, Jꢀ17.27, 1.46 Hz, 1H, Hb), 5.97Á6.06 (m, 1H,
Ha), 6.46 (s, 1H, ArCHꢀ), 6.98 (d, Jꢀ8.64 Hz, 2H, H-
3?, H-5?), 7.72 (d, Jꢀ8.69 Hz, 2H, H-2?, H-6?), 12.09 (s,
1H, N1ꢁH), 12.26 (s, 1H, N3ꢁH); IR (KBr): n 3231,
3124 (NꢁH), 2920, 2854, 2831 (CꢁH), 1724 (C4ꢀO),
), 1598, 1514, 1486, 1375, 1252, 1177, 963,
/
221 8C (yellow crystals from AcOH), yield 80%; Rf
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