2-Alkyl(aryl)-quinazolin-4(3 H)-thiones, 2-R-(quinazolin-4(3 H)-ylthio)carboxylic acids and amides: Synthesis, molecular docking, antimicrobial and anticancer properties

Article abstract of DOI:10.3109/14756366.2015.1018243

In this study, a series of novel 2-alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides were synthesized and evaluated for antimicrobial and anticancer activities. Their structure was confirmed by elemental analys

Full text of DOI:10.3109/14756366.2015.1018243

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ISSN: 1475-6366 (print), 1475-6374 (electronic)
J Enzyme Inhib Med Chem, Early Online: 1–13
2015 Informa UK Ltd. DOI: 10.3109/14756366.2015.1018243
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RESEARCH ARTICLE
2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)car-
boxylic acids and amides: synthesis, molecular docking, antimicrobial
and anticancer properties
Lyudmyla Antypenko1, Sergiy Kovalenko1, Yulia Posylkina1, Vladyslav Nikitin2, Natalia Fedyunina3, and
Vitalii Ivchuk4
2
1Department of Organic and Bioorganic Chemistry, Zaporizhzya State Medical University, Zaporizhzhya, Ukraine, Enamine Ltd., Kyiv, Ukraine,
3Bacterial Laboratory, Zaporizhzhya Regional Hospital, Zaporizhzhya, Ukraine, and 4Department of Chemistry, Kryvyi Rih National University, Kryvyi
Rih, Ukraine
Abstract
Keywords
In this study, a series of novel 2-alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-
ylthio)carboxylic acids and amides were synthesized and evaluated for antimicrobial and
anticancer activities. Their structure was confirmed by elemental analysis and spectral data
(FT-IR, LC-MS, 1H-NMR). Antimicrobial activity was tested in vitro against Staphylococcus aureus,
Enterococcus faecalis, Enterobacter aerogenes, Pseudomonas aeruginosa, Escherichia coli,
Klebsiella pneumonia, Candida albicans and NCI in vitro preliminary anticancer activity against
nine different cancer types. The most active antibacterial and antifungal compounds were: 2.1,
2.2 and 2.4. The introduction of the carboxylic acid or amide residue into the fourth position of
quinazolin-4(3H)-thione resulted in the absence of antimicrobial activity. Substance 3.8
inhibited renal cancer UO-31 line and 2.18 – leukemia CCRF-CEM. The results of in silico
molecular docking for DHFR and CK2 kinase had no correlation with in vitro properties,
proposing the presence of other biological activity pathways.
2-Alkyl(aryl)-quinazolin-4(3H)-thiones,
antibiotic, anticancer, antifungal,
molecular docking
History
Received 12 December 2014
Revised 13 January 2015
Accepted 15 January 2015
Published online 1 April 2015
Introduction
sclerotiorum, Botrytis cinerea, Colletotrichum gloeosporioides)
and showed a broad-spectrum bioactivity9. Also quinazoline-
4(3H)-thione’s derivatives possessed antifungal properties against
Sclerotium cepivorum and Botrytis allii10. Even bis-quinazolines
showed antimicrobial activity11.
Taking into consideration the above facts, we aimed to
synthesize a series of novel 2-R-quinazolin-4(3H)-thiones in
order to obtain the compounds with high antimicrobial and
antifungal activity. Modification of thion pharmacophore with
carboxyl or amide residue could influence the manifestation of
pharmacological action of the synthesized compounds; especially
According to literature data, substituted quinazolines, i.e.
condensed benzene–pyrimidine system, are intensively investi-
gated for biological activities during several decades. In this
paper, quinazoline-4(3H)-thione was chosen as the main structural
fragment, as its derivatives have proven to show a broad spectrum
of biological effects, such as anticonvulsant1, antidiabetic2,
insecticidal3, cardiotonic with myofibrillar Ca2+ sensitizing
effect4, inhibition of thymidylate synthase5, of tyrosine kinase
domain of c-Src Ple6 and of phosphodiesterase7.
Given the constant and increasing threat of drug resistance,
we were particularly interested in antimicrobial properties
of quinazoline-4(3H)-thione’s derivatives. It was found that
4-(S-butylthio)quinazoline was more active than isoniazide,
against atypical strains of mycobacteria, when investigated for
antitubercular activity against Mycobacterium tuberculosis,
M. kansasii, M. fortuitum, M. avium and M. intracellulare8. The
4-ethylthio-6-fluoroquinazoline had potent antifungal activities
against practically all the tested fungi (Gibberella zeae, Fusarium
since
the
7-oxo-2-(trifluoromethyl)-4,7-dihydro-[1,2,4]tria-
zolo[5,1-a]pyrimidine-6-carboxylic acids were reported to inhibit
the growth of M. tuberculosis to 92%12. Substituted 1-ethyl-6-
fluorine-hydro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-quinoline-3-
carboxylic acid had better antimicrobial properties against
Xanthomonas oryzae, than norfloxacin and against
Xanthomonas axonopodis, Erwinia aroideae and Rhizoctonia
solan, than streptomycin sulfate13. It was found that 2-(2-(4-
(trifluoromethyl)benzylidene)hydrazinyl)-N-(4-(2-methyl-4-oxo-
quinazolin-3(4H)-yl)-phenyl)acetamide was the most active com-
pound in its series, when investigated for analgesic, anti-
inflammatory and in vitro antimicrobial activities14. Moreover,
it is known that quinazoline derivatives are used in medicine as an
effective anticancer agents15,16. For example, Afatinib is a
tyrosine kinase inhibitor (TKI) that also irreversibly inhibits
human epidermal growth factor receptors (HER2 and HER4) and
epidermal growth factor receptor (EGFR)17.
oxysporum, Cardamine mandshurica, Rhizoctonia solani,
Thanatephorus cucumeris, Phytophthora infestans, Sclerotinia
Address for correspondence: Dr. Lyudmyla Antypenko, PhD, Department
of Organic and Bioorganic Chemistry, Zaporizhzya State Medical
University, Mayakovsky Ave. 26, Zaporizhzhya 69035, Ukraine.
E-mail: antypenkol@gmail.com

2
L. Antypenko et al.
J Enzyme Inhib Med Chem, Early Online: 1–13
Hence, the synthesis of (2-R-quinazolin-4(3H)-ylthio)car- 2568, 2508, 1959, 1855, 1770, 1743, 1714, 1660, 1617, 1603,
boxylic acids and amides was of undoubted interest from a 1566, 1505, 1464, 1452, 1417, 1371, 1343, 1312, 1259, 1227,
synthetic and biological activity point of view.
1185, 1148, 1124, 1076, 1034, 1013, 971, 917, 886, 854, 837,
1
802, 768, 642. H NMR: d (ppm) 13.74 (br s, 1H, NM), 8.56
(d, J ¼ 8.1 Hz, 1H, M5q.), 7.87 (t, J ¼ 7.6 Hz, 1H, M7q.), 7.67
(d, J ¼ 8.1 Hz, 1H, M8q.), 7.55 (t, J ¼ 7.6 Hz, 1H, M6q.), 2.77
(q, J ¼ 7.5 Hz, 2H, QM2QM3), 1.27 (t, J ¼ 7.5 Hz, 3H, QM2QM3).
LC-MS: m/z ¼ 191 [M + H]+. Anal. Calcd. for C10H10N2S
C, 63.13; H, 5.30; N, 14.72; S, 16.85. Found: C, 63.12; H, 5.34;
N, 14.73; S, 16.82.
Experimental
Chemistry
General
Melting points were determined in open capillary tubes in a
Thiele’s apparatus and were uncorrected. The elemental analyses
(C, H, N, S) were performed using the ELEMENTAR vario EL cube
analyzer (Elementar Analysensysteme GmbH, Hanau, Germany).
IR spectra (4000–600 cmꢀ1) were recorded on a Bruker ALPHA
FT-IR spectrometer (Bruker Bioscience, Germany) using a module
2-Phenyl-3H-quinazoline-4-thione (2.4). Yellow solid. Yield:
53.6%, m.p. 200–202 ꢁC. IR (cmꢀ1): 3140, 3115, 3029, 2975,
2905, 1662, 1599, 1565, 1492, 1463, 1447, 1429, 1345, 1316,
1299, 1284, 1252, 1241, 1220, 1145, 1132, 1080, 1029, 959, 945,
1
ATR eco ZnSe. H NMR spectra (400 MHz) were recorded on a
1
928, 889, 857, 808, 758, 701, 689, 658, 614. H NMR: d (ppm)
Varian-Mercury 400 spectrometer (Varian, Palo Alto, CA) with
SiMe4 as internal standard in DMSO-d6 solution. LC-MS were
recorded using chromatography/mass spectrometric system, which
consists of high-performed liquid chromatograph ‘‘Agi1ent 1100
Series’’ (Agilent, Palo Alto, CA) equipped with diode-matrix and
mass-selective detector ‘‘Agi1ent LC/MSD SL’’ (atmospheric
pressure chemical ionization – APCI). The purity of all obtained
compounds was checked by lH NMR and LC-MS.
13.93 (br s, 1H, NM), 8.64 (d, J ¼ 7.6 Hz, 1H, M5q.), 8.20
(d, J ¼ 7.5 Hz, 2H, M2, M6ph.), 7.93 (t, J ¼ 8.0 Hz, 1H, M7q.), 7.79
(d, J ¼ 7.5 Hz, 1H, M8q.), 7.67–7.54 (m, 4H, M6q., M3–5ph.).
LC-MS: m/z ¼ 239 [M + H]+. Anal. Calcd. for C14H10N2S
C, 70.56; H, 4.23; N, 11.75; S, 13.45. Found: C, 70.54; H, 4.23;
N, 11.74; S, 13.43.
2-Benzyl-3H-quinazoline-4-thione (2.5). Orange solid. Yield:
64.0%, m.p. 200–202 ꢁC. IR (cmꢀ1): 3139, 3117, 3087, 3062,
3031, 2969, 2915, 2892, 2875, 2497, 1674, 1651, 1618, 1598,
1572, 1507, 1494, 1464, 1454, 1435, 1414, 1342, 1318, 1254,
1232, 1181, 1155, 1122, 1072, 1028, 958, 919, 893, 865, 838,
2-R-4(3H)-Quinazolone derivatives were obtained as reported
in literature18. Other starting materials and solvents were obtained
from commercially available sources and used without additional
purification.
1
Materials and methods
827, 763, 729, 717, 695, 667, 658, 642, 610. H NMR: d (ppm)
13.98 (br s, 1H, NM), 8.56 (d, J ¼ 8.1 Hz, 1H, M5q.), 7.87
(t, J ¼ 7.5 Hz, 1H, M7q.), 7.68 (d, J ¼ 8.1 Hz, 1H, M8q.), 7.57
(t, J ¼ 7.6 Hz, 1H, M6q.), 7.41 (d, J ¼ 7.4 Hz, 2H, M2, M6ph.), 7.35
(t, J ¼ 7.4 Hz, 2H, M3, M5ph.), 7.27 (t, J ¼ 7.0 Hz, 1H, M4ph.), 4.11
(s, 2H, QM2). LC-MS: m/z ¼ 253 [M + H]+. Anal. Calcd. for
C15H12N2S C, 71.40; H, 4.79; N, 11.10; S, 12.71. Found: C,
71.42; H, 4.80; N, 12.69; S, 11.12.
Preparation of 2-alkyl(aryl)-quinazolin-4-thiones (2.1–2.18). 2-
Alkyl(aryl)-quinazolin-4(3H)-one (5 mmol) was added to the
solution of 2,4-bis-(4-methoxyphenyl)-1,3-dithia-2,4-diphosphe-
tane-2,4-disulfide (5 mmol, Lawesson’s reagent) in dioxane
(20 ml) and refluxed for 1–2 h. The mixture was poured into the
cold water. The precipitate was filtered and dried. Substances
were recrystallized from a mixture of dioxane–water (2:1) (2.7,
2.9), 2-propanol–water (1:3) (2.4, 2.10), DMF–water (2.8, 2.12–
2.14, 2.16, 2.17), acetone (2.5, 2.11), acetic acid (2.3, 2.6, 2.15,
2.18) or reprecipitated (2.2).
2-Phenethyl-3H-quinazoline-4-thione (2.6). Yellow solid. Yield:
89.0%, m.p. 185–187 ꢁC. IR (cmꢀ1): 3138, 3079, 3026, 2971,
2919, 2723, 2502, 1977, 1955, 1938, 1850, 1738, 1714, 1654,
1603, 1567, 1505, 1494, 1464, 1449, 1430, 1346, 1322, 1270,
1231, 1212, 1146, 1073, 1031, 1020, 994, 969, 955, 902, 847,
766, 737, 691, 645, 619. 1H NMR: d (ppm) 13.82 (br s, 1H, NM),
8.57 (d, J ¼ 8.1 Hz, 1H, M5q.), 7.88 (t, J ¼ 7.6 Hz, 1H, M7q.), 7.70
(d, J ¼ 8.1 Hz, 1H, M8q.), 7.57 (t, J ¼ 7.6 Hz, 1H, M6q.), 7.31
(d, J ¼ 5.0 Hz, 4H, M2, M3, M5, M6ph), 7.21 (t, J ¼ 5.1 Hz, 1H,
M4ph.), 3.13–3.01 (m, 4H, QM2QM2). LC-MS: m/z ¼ 267
[M + H]+. Anal. Calcd. for C16H14N2S C, 72.15; H, 5.30; N,
10.52; S, 12.04. Found: C, 72.37; H, 5.28; N, 10.48; S, 12.01.
3H-Quinazoline-4-thione (2.1). Yellow solid. Yield: 90.0%,
m.p. 302–304 ꢁC. IR (cmꢀ1): 3039, 3010, 2982, 2830, 2792,
2735, 2699, 2662, 2626, 2489, 1815, 1685, 1621, 1595, 1566,
1517, 1463, 1441, 1396, 1341, 1302, 1261, 1243, 1197, 1107,
1026, 987, 954, 906, 864, 809, 771, 760, 682, 669, 639. 1H NMR:
d (ppm) 13.86 (br s, 1H, NH), 8.59 (d, J ¼ 8.0 Hz, 1H, H5q.), 8.19
(s, 1H, M2q.), 7.90 (t, J ¼ 7.5 Hz, 1H, M7q.), 7.74 (d, J ¼ 8.0 Hz,
1H, M8q.), 7.62 (t, J ¼ 7.1 Hz, 1H, M6q.). LC-MS: m/z ¼ 163
[M + H]+. Anal. Calcd. for C8H6N2S C, 59.24; H, 3.73; N, 17.27;
S, 19.77. Found: C, 59.22; H, 3.75; N, 17.26; S, 19.78.
2-Styryl-3H-quinazoline-4-thione (2.7). Yellow solid. Yield:
68.2%, m.p. 246–248 ꢁC. IR (cmꢀ1): 3158, 3100, 3025, 2966,
2917, 2849, 2505, 1739, 1666, 1643, 1608, 1568, 1503, 1469,
1446, 1434, 1346, 1328, 1255, 1222, 1192, 1161, 1148, 1069,
1033, 1016, 981, 962, 871, 842, 830, 779, 766, 747, 690, 676,
604. 1H NMR: d (ppm) 13.83 (br s, 1H, NM), 8.58 (d, J ¼ 8.0 Hz,
1H, M5q.), 8.05 (d, J ¼ 6.1 Hz, 1H, HetQM ¼ ), 7.90 (t, J ¼ 7.5 Hz,
1H, M7q.), 7.76 (d, J ¼ 8.2 Hz, 1H, M8q.), 7.70 (d, J ¼ 7.6 Hz, 2H,
M2, M6ph.), 7.58 (t, J ¼ 7.6 Hz, 1H, M6q.), 7.54–7.42 (m, 3H,
M3–5ph.), 7.29 (d, J ¼ 6.0 Hz, 1H, ¼ QMC6H5). LC-MS: m/z ¼ 219
[M + H]+. Anal. Calcd. for C16H12N2S C, 72.70; H, 4.58; N,
10.60; S, 12.13. Found: C, 72.69; H, 4.56; N, 10.64; S, 12.17.
2-Methyl-3H-quinazoline-4-thione (2.2). Yellow solid. Yield:
73.9%, m.p. 218–220 ꢁC. IR (cmꢀ1): 3167, 3116, 3029, 2977,
2899, 2862, 2784, 2691, 2649, 1667, 1607, 1568, 1504, 1467,
1454, 1419, 1378, 1342, 1292, 1251, 1234, 1213, 1201, 1164,
1142, 1111, 1098, 1040, 1025, 999, 964, 880, 870, 805, 774, 762,
1
692, 660, 642. H NMR: d (ppm) 13.72 (br s, 1H, NM), 8.55
(d, J ¼ 8.1 Hz, 1H, M5q.), 7.87 (t, J ¼ 7.6 Hz, 1H, M7q.), 7.64
(d, J ¼ 8.0 Hz, 1H, M8q.), 7.54 (t, J ¼ 7.6 Hz, 1H, M6q.), 2.48
(s, 3H, QM3). LC-MS: m/z ¼ 177 [M + H]+. Anal. Calcd. for
C9H8N2S C, 61.34; H, 4.58; N, 15.89; S, 18.19. Found: C, 61.38;
H, 4.60; N, 15.84; S, 18.18.
2-Ethyl-3H-quinazoline-4-thione (2.3). Yellow solid. Yield:
77.2%, m.p. 185–187 ꢁC. IR (cmꢀ1): 3187, 3138, 3094, 3073, 2-Trifluoromethyl-3H-quinazoline-4-thione (2.8). Yellow solid.
3042, 2979, 2918, 2875, 2848, 2729, 2693, 2660, 2629, 2598, Yield: 96.2%, m.p. 210–212 ꢁC. IR (cmꢀ1): 3152, 3112, 3085,

DOI: 10.3109/14756366.2015.1018243 2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides
3
3056, 2983, 2922, 1668, 1631, 1596, 1573, 1516, 1464, 1360, 2-(3-Chlorophenyl)-3H-quinazoline-4-thione (2.14). Yellow
1317, 1218, 1206, 1161, 1130, 1034, 899, 846, 800, 765, 692, solid. Yield: 62.5%, m.p. 223–224 ꢁC. IR (cmꢀ1): 3141, 3107,
624. 1H NMR: d (ppm) 12.44 (br s, 1H, NM), 8.63 (d, J ¼ 8.0 Hz, 3078, 3033, 2979, 2920, 1985, 1955, 1923, 1889, 1834, 1770,
1H, M5q.), 7.99 (t, 1H, J ¼ 6.7 Hz, M7q.), 7.86 (d, J ¼ 8.0 Hz, 1H, 1723, 1681, 1615, 1589, 1567, 1504, 1475, 1438, 1423, 1348,
M8q.), 7.76 (t, J ¼ 6.9 Hz, 1H, M6q.). LC-MS: m/z ¼ 230 1299, 1253, 1221, 1155, 1136, 1097, 1082, 1028, 998, 958, 908,
1
[M + H]+. Anal. Calcd. for C9H5F3N2S C, 46.96; H, 2.19; N, 890, 883, 861, 800, 785, 765, 717, 696, 678, 650. H NMR: d
12.17; S, 13.93. Found: C, 47.01; H, 2.22; N, 12.14; S, 13.93.
(ppm) 8.74 (d, J ¼ 8.2 Hz, 1H, M5q.), 8.10 (t, J ¼ 8.3 Hz, 1H,
M7q.), 7.94 (d, J ¼ 7.9 Hz, 1H, M8q.), 7.84–7.76 (m, 2H, H2,
2-Morpholin-4-yl-3H-quinazoline-4-thione (2.9). Yellow solid. M5ph.), 7.70 (d, J ¼ 8.0 Hz, 1H, M6ph.), 7.65 (t, J ¼ 6.9 Hz, 1H,
Yield: 86.5%, m.p. 202–204 ꢁC. IR (cmꢀ1): 3245, 3197, 3137, M4ph.), 7.58 (t, J ¼ 7.5 Hz, 1H, M6q.). LC-MS: m/z ¼ 373
3055, 2959, 2900, 2851, 2571, 1620, 1573, 1490, 1456, 1434, [M + H]+. Anal. Calcd. for C14H9ClN2S C, 61.65; H, 3.33; N,
1406, 1369, 1336, 1303, 1279, 1254, 1227, 1178, 1153, 1131, 10.27; S, 11.76. Found: C, 61.64; H, 3.32; N, 10.25; S, 11.74.
1109, 1063, 1028, 1019, 1000, 982, 918, 873, 859, 779, 755, 732,
1
713, 693, 633. H NMR: d (ppm) 12.88 (br s, 1H, NM), 8.44
2-(4-Chlorophenyl)-3H-quinazoline-4-thione
(2.15). Yellow
(d, J ¼ 7.6 Hz, 1H, M5q.), 7.67 (t, J ¼ 6.4 Hz, 1H, M7q.), 7.44
(d, J ¼ 8.1 Hz, 1H, M8q.), 7.26 (t, J ¼ 6.6 Hz, 1H, M6q.), 3.76–3.64
(m, 8H, morph.). LC-MS: m/z ¼ 247 [M + H]+. Anal. Calcd.
for C12H13N3OS C, 58.28; H, 5.30; N, 16.99; S, 12.96. Found: C,
58.31; H, 5.28; N, 17.01; S, 12.99.
solid. Yield: 17.8%, m.p. 239–247 ꢁC. IR (cm–1): 3139, 3110,
3079, 3048, 3029, 2980, 2913, 2850, 2497, 1963, 1935, 1909,
1709, 1596, 1571, 1563, 1504, 1488, 1464, 1433, 1400, 1345,
1316, 1298, 1276, 1251, 1221, 1181, 1152, 1131, 1115, 1090,
1075, 1027, 1011, 955, 888, 861, 828, 798, 770, 759, 747, 726,
694, 685, 665, 629. 1H NMR: d (ppm) 10.24 (br s, 1H, NM), 8.73
(d, J ¼ 8.1 Hz, 1H, M5q.), 8.08 (t, 1H, J ¼ 7.8 Hz, M7q.), 7.93
(d, J ¼ 8.0 Hz, 1H, M8q.), 7.78 (d, J ¼ 8.0 Hz, 2H, H2, H6ph.),
7.72–7.65 (m, 2H, H3, H5ph.), 7.60 (t, J ¼ 7.5 Hz, 1H, M6q.).
LC-MS: m/z ¼ 273 [M + H]+. Anal. Calcd. for C14H9ClN2S C,
61.65; H, 3.33; N, 10.27; S, 11.76. Found: C, 61.69; H, 3.35; N,
10.22; S, 11.76.
2-(Morpholin-4-yl-methyl)-3H-quinazoline-4-thione
(2.10).
Yellow solid. Yield: 58.5%, m.p. 180–182 ꢁC. IR (cmꢀ1): 3120,
3082, 3050, 2981, 2965, 2949, 2916, 2848, 2818, 2767, 2693,
2509, 1598, 1568, 1497, 1464, 1448, 1424, 1352, 1335, 1306,
1294, 1270, 1226, 1197, 1164, 1141, 1111, 1076, 1034, 1011,
987, 949, 910, 892, 870, 856, 839, 808, 782, 764, 683, 651, 604.
1H NMR:
d (ppm) 13.99–13.35 (br s, 1H, NM), 8.57
(d, J ¼ 8.0 Hz, 1H, M5q.), 7.87 (t, J ¼ 7.4 Hz, 1H, M7q.), 7.71
(d, J ¼ 8.0 Hz, 1H, M8q.), 7.58 (t, J ¼ 7.5 Hz, 1H, M6q.), 3.59
(s, 4H, N(CH2)2), 3.57 (s, 2H, QM2), 2.60–2.53 (m, 4H, O(CH2)2).
LC-MS: m/z ¼ 261 [M + H]+. Anal. Calcd. for C13H15N3OS
C, 59.75; H, 5.79; N, 16.08; S, 12.27. Found: C, 59.72; H, 5.81;
N, 16.07; S, 12.24.
2-(3-Fluorophenyl)-3H-quinazoline-4-thione
(2.16). Yellow
solid. Yield: 31.03%, m.p. 143–145 ꢁC. IR (cmꢀ1): 3082, 3061,
3012, 2954, 2918, 2850, 2497, 1940, 1868, 1799, 1746, 1682,
1655, 1601, 1589, 1563, 1533, 1482, 1456, 1441, 1325, 1312,
1297, 1266, 1238, 1214, 1169, 1159, 1087, 1040, 1021, 998, 972,
1
957, 918, 885, 866, 796, 781, 759, 679, 640. H NMR: d (ppm)
13.95 (br s, 1H, NH), 8.68 (d, J ¼ 8.1 Hz, 1H, M5q.), 8.17 (m, 2H,
M2, M5ph.), 8.06 (t, J ¼ 7.1 Hz, 1H, M7q.), 7.94 (d, J ¼ 7.4 Hz, 1H,
M8q.), 7.73 (d, J ¼ 7.2 Hz, 1H, M6q.), 7.46 (dd, J1 ¼ 17.7,
J2 ¼ 9.0 Hz, M4, M6ph.). LC-MS: m/z ¼ 256 [M + H]+. Anal.
Calcd. for C14H9FN2S C, 65.61; H, 3.54; N, 10.93; S, 12.51.
Found: C, 65.65; H, 3.57; N, 11.01; S, 12.46.
2-(Thiophen-3-yl)-3H-quinazoline-4-thione
(2.11). Yellow
solid. Yield: 80.3%, m.p. 215–219 ꢁC. IR (cmꢀ1): 3239, 3093,
3064, 2914, 2847, 1609, 1586, 1557, 1487, 1461, 1430, 1415,
1345, 1312, 1288, 1250, 1220, 1187, 1143, 1068, 1027, 1015,
1
968, 942, 884, 865, 843, 801, 765, 717, 686, 622. H NMR: d
(ppm) 13.80 (br s, 1H, NM), 8.80 (s, 1H, H2thioph.), 8.61
(d, J ¼ 7.7 Hz, 1H, M5q.), 7.96–7.86 (m, 2H, H5thioph., M7q.),
7.75 (d, J ¼ 8.0 Hz, 2H, H4thioph., M8q.), 7.59 (t, J ¼ 7.1 Hz, 1H,
M6q.). LC-MS: m/z ¼ 246 [M + H]+. Anal. Calcd. for C12H8N2S2
C, 58.99; H, 3.30; N, 11.46; S, 26.25. Found: C, 59.07; H, 3.26;
N, 11.43; S, 26.22.
2-(4-Trifluoromethylphenyl)-3H-quinazoline-4-thione (2.17).
Red solid. Yield: 46.7%, m.p. 122–123 ꢁC. IR (cmꢀ1): 3043,
3029, 3000, 2917, 2848, 2516, 1987, 1947, 1928, 1907, 1870,
1839, 1651, 1613, 1599, 1558, 1534, 1448, 1406, 1319, 1308,
1247, 1205, 1159, 1103, 1064, 1009, 936, 909, 839, 826, 769,
676, 644, 629, 615. 1H NMR: d (ppm) 13.74 (br s, 1H, NM), 8.73
(d, J ¼ 8.1 Hz, 1H, M5q.), 8.30 (d, J ¼ 8.1 Hz, 2H, H2, H6ph.), 8.00
(t, 1H, J ¼ 7.5 Hz, M7q.), 7.93 (d, J ¼ 8.0 Hz, 1H, M8q.), 7.89 (d,
J ¼ 8.2 Hz, 2H, H3, H5ph.), 7.68 (t, J ¼ 7.5 Hz, 1H, M6q.). LC-MS:
m/z ¼ 306 [M + H]+. Anal. Calcd. for C15H9F3N2S C, 58.82; H,
2.96; N, 9.15; S, 10.47. Found: C, 58.84; H, 3.01; N, 9.13; S,
10.44.
2-(1H-Imidazol-1-yl)-3H-quinazoline-4-thione (2.12). Yellow
solid. Yield: 54.0%, m.p. 235–237 ꢁC. IR (cmꢀ1): 3111, 3065,
2980, 2921, 2853, 2760, 2638, 1677, 1626, 1604, 1580, 1516,
1465, 1431, 1396, 1356, 1340, 1317, 1288, 1255, 1227, 1183,
1121, 1102, 1074, 1034, 958, 920, 875, 862, 831, 761, 734, 690,
665, 646, 627, 604. LC-MS: m/z ¼ 242 [M + H]+. Anal. Calcd. for
C11H8N4S C, 57.88; H, 3.53; N, 24.54; S, 14.05. Found: C, 57.83;
H, 3.52; N, 24.57; S, 14.00.
2-(3,4-Dimethoxyphenyl)-3H-quinazoline-4-thione
(2.18).
2-(2-Chlorophenyl)-3H-quinazoline-4-thione (2.13). Red solid. Yellow solid. Yield: 75.5%, m.p. 216–217 ꢁC. IR (cmꢀ1): 3212,
Yield: 65.1%, m.p. 145–146 ꢁC. IR (cmꢀ1): 2501, 1597, 1585, 3119, 3065, 2999, 2974, 2929, 2840, 2501, 1741, 1597, 1566,
1557, 1533, 1467, 1446, 1425, 1319, 1288, 1268, 1238, 1198, 1513, 1497, 1470, 1451, 1434, 1415, 1356, 1283, 1259, 1244,
1152, 1059, 1018, 966, 946, 936, 910, 876, 860, 838, 767, 754, 1226, 1207, 1174, 151, 1076, 1022, 965, 935, 872, 861, 818, 770,
723, 707, 650, 635. 1H NMR: d (ppm) 10.04 (br s, 1H, NH), 8.74 756, 711, 634, 616. 1H NMR: d (ppm) 13.76 (br s, 1H, NH), 8.61
(d, J ¼ 8.2 Hz, 1H, M5q.), 8.10 (t, J ¼ 7.5 Hz, 1H, M7q.), 7.94 (d, J ¼ 7.9 Hz, 1H, M5q.), 7.93–7.83 (m, 3H, M2, M6ph., M7q.),
(d, J ¼ 7.2 Hz, 1H, M8q.), 7.84–7.76 (m, 2H, M3, M5ph.), 7.70 7.76 (d, J ¼ 8.0 Hz, 1H, M8q.), 7.57 (t, J ¼ 7.5 Hz, 1H, M6q.), 7.14
(d, J ¼ 8.0 Hz, 1H, M6ph.), 7.65 (t, J ¼ 7.6 Hz, 1H, M4ph.), 7.58 (d, J ¼ 8.5 Hz, 1H, M5ph.), 3.92 (s, 3H, 3-NQM3), 3.87 (s, 3H, 4-
(t, J ¼ 7.5 Hz, 1H, M6q.). LC-MS: m/z ¼ 273 [M + H]+. Anal. NQM3). LC-MS: m/z ¼ 299 [M + H]+. Anal. Calcd. for
Calcd. for C14H9ClN2S C, 61.65; H, 3.33; N, 10.27; S, 11.76. C16H14N2O2S C, 64.41; H, 4.73; N, 9.39; S, 10.75. Found: C,
Found: C, 61.67; H, 3.31; N, 10.26; S, 11.73.
64.43; H, 4.75; N. 9.37; S, 10.72.

4
L. Antypenko et al.
J Enzyme Inhib Med Chem, Early Online: 1–13
Preparation of 2-R-(quinazolin-4-ylthio)carboxylic acids (3.1– 2-Phenethyl-(quinazolin-4-ylthio)acetic acid (3.6). Pink solid.
3.8). An appropriate amount of 2-R-quinazolin-4(3H)-thione Yield: 15.0%, m.p. 171–173 ꢁC. IR (cmꢀ1): 3028, 2989, 2927,
(5 mmol) was added to methanol or ethanol (15 ml) with metallic 2858, 2761, 2657, 2499, 1942, 1713, 1614, 1569, 1553, 1488,
potassium (0.39 g, 10 mmol). After the dissolution, the appropri- 1458, 1382, 1358, 1295, 1188, 1162, 1077, 1030, 1011, 998, 937,
ate halogenocarboxylic acid (5 mmol) was added. The resulting 907, 887, 861, 788, 775, 761, 740, 698, 655, 625. 1H NMR:
mixture was refluxed for 1–5 h. After cooling to room temperature d (ppm) 12.97–12.77 (br s, 1H, QNNM), 8.09 (d, J ¼ 8.0 Hz, 1H,
the hydrochloric acid was added to reach pH 4–5. The crystalline M5q.), 7.95 (t, J ¼ 7.1 Hz, 1H, M7q.), 7.89 (d, J ¼ 8.2 Hz, 1H,
precipitate was filtered and reprecipitated.
M8q.), 7.68 (t, J ¼ 6.8 Hz, 1H, M6q.), 7.30–7.19 (m, 4H, M2, M3,
M5, M6ph.), 7.17 (t, J ¼ 6.0 Hz, 1H, M4ph.), 4.18 (s, 2H, SQM2),
3.20 (m, 4H, QM2QM2). LC-MS: m/z ¼ 325 [M + H]+. Anal.
Calcd. for C18H16N2O2S C, 66.65; H, 4.97; N, 8.64; S, 9.88.
Found: C, 66.64; H, 5.00; N, 8.64; S, 9.87.
(Quinazolin-4-ylthio)acetic acid (3.1). Orange solid. Yield:
63.6%, m.p. 192–194 ꢁC. IR (cmꢀ1): 3115, 3059, 2982, 2930,
2786, 2427, 2319, 1865, 1697, 1661, 1610, 1571, 1537, 1489,
1469, 1406, 1373, 1320, 1300, 1263, 1235, 1199, 1165, 1114,
1021, 1001, 970, 921, 907, 895, 880, 858, 815, 766, 681, 654. 1H
NMR: d (ppm) 12.90 (br s, 1M, QNNM), 9.04 (s, 1M, M2q.), 8.13
(d, J ¼ 7.9 Hz, 1M, M5q.), 8.08–7.98 (m, 2M, M7, M8q.),
7.79 (t, J ¼ 7.5 Hz, 1M, M6q.), 4.30 (s, 2M, SQM2). LC-MS:
m/z ¼ 221 [M + H]+. Anal. Calcd. for C10H8N2O2S C, 54.53;
H, 3.66; N, 12.72; S, 14.56. Found: C, 54.52; H, 3.64; N, 12.75;
S, 14.57.
2-Styryl-(quinazolin-4-ylthio)acetic acid (3.7). Red solid. Yield:
63.9%, m.p. 208–210 ꢁC. IR (cmꢀ1): 3062, 3027, 2929, 1714,
1671, 1635, 1609, 1580, 1563, 1536, 1485, 1454, 1382, 1347,
1298, 1263, 1204, 1146, 1105, 1072, 1027, 997, 974, 944, 908,
1
869, 846, 753, 697, 679, 649, 621, 611. H NMR: d (ppm) 12.99
(br s, 1H, QNNM), 8.16 (d, J ¼ 7.6 Hz, 1M, HetQM¼), 8.08
(d, J ¼ 8.0 Hz, 1H, M5q.), 7.98–7.87 (m, 2M, M7, M8q.), 7.80–7.71
(m, 3M, M2, M6ph., M6q.), 7.53–7.42 (m, 3M, M3–5ph.), 7.33
(d, J ¼ 7.6 Hz, 1M, ¼ QMC6H5), 4.23 (s, 2M, SQM2). LC-MS:
m/z ¼ 323 [M + H]+. Anal. Calcd. for C18H14N2O2S C, 67.06; H,
4.38; N, 8.69; S, 9.95. Found: C, 67.05; H, 4.38; N, 8.72; S, 9.99.
2-Methyl-(quinazolin-4-ylthio)acetic acid (3.2). Orange solid.
Yield: 62.8%, m.p. 178–180 ꢁC. IR (cmꢀ1): 3167, 3110, 3030,
2978, 2917, 2850, 2395, 2312, 1909, 1715, 1673, 1611, 1572,
1553, 1500, 1486, 1466, 1393, 1339, 1291, 1252, 1219, 1173,
1158, 1029, 998, 930, 901, 859, 770, 752, 689, 665, 645, 604. 1H
NMR: d (ppm) 12.87 (br s, 1M, QNNM), 8.08 (d, J ¼ 7.9 Hz, 1M,
M5q.), 7.89 (d, J ¼ 7.6 Hz, 1M, M8q.), 7.97 (t, J ¼ 7.6 Hz, 1M,
M7q.), 7.68 (t, J ¼ 7.4 Hz, 1M, M6q.), 4.19 (s, 2M, SQM2), 2.68
(s, 3M, QM3). LC-MS: m/z ¼ 235 [M + H]+. Anal. Calcd. for
C11H10N2O2S C, 56.40; H, 4.30; N, 11.96; S, 13.69. Found: C,
56.39; H, 4.31; N, 12.00; S, 13.64.
2-Trifluoromethyl-(quinazolin-4-ylthio)acetic acid (3.8). White
solid. Yield: 92.6%, m.p. 240–242 ꢁC. IR (cmꢀ1): 2997, 2920,
2712, 2595, 1712, 1612, 1566, 1488, 1416, 1394, 1381, 1352,
1303, 1264, 1248, 1223, 1187, 1149, 1112, 1026, 1003, 963, 915,
883, 850, 801, 769, 756, 734, 693, 673, 629, 610. 1H NMR:
d (ppm) 12.97 (br s, 1H, QNNM), 8.25 (d, J ¼ 8.2 Hz, 1H, M5q.),
8.13–8.04 (m, 2M, M7, M8q.), 7.90 (t, J ¼ 8.1 Hz, 1M, M6q.), 4.23
(s, 2M, SQM2). LC-MS: m/z ¼ 289 [M + H]+. Anal. Calcd. for
C11H7F3N2O2S C, 45.84; H, 2.45; N, 9.72; S, 11.12. Found: C,
45.85; H, 2.43; N, 9.72; S, 11.13.
2-Ethyl-(quinazolin-4-ylthio)acetic acid (3.3). Yellow solid.
Yield: 37.7%, m.p. 175–180 ꢁC. IR (cmꢀ1): 2971, 2928, 2422,
2309, 1916, 1711, 1612, 1567, 1547, 1486, 1468, 1350, 1298,
1260, 1217, 1187, 1164, 1152, 1057, 1028, 988, 904, 889, 856,
763, 706, 668, 642, 624. 1H NMR: d (ppm) 14.72 (br s, 1M,
QNNM), 8.07 (d, J ¼ 8.2 Hz, 1H, M5q.), 7.98–7.91 (m, 1H, M7q.),
7.88 (d, J ¼ 8.2 Hz, 1H, M8q.), 7.66 (t, J ¼ 7.5 Hz, 1H, M6q.), 4.17
(s, 2H, SQM2), 2.93 (q, J ¼ 7.5 Hz, 2H, QM2QM3), 1.38–1.28
(m, 3H, QM2QM3). LC-MS: m/z ¼ 249 [M + H]+. Anal. Calcd. for
C12H12N2O2S C, 58.05; H, 4.87; N, 11.28; S, 12.91. Found: C,
12.91; H, 4.82; N, 11.31; S, 12.93.
2-Morpholin-(quinazolin-4-ylthio)acetic acid (3.9). Yellow
solid. Yield: 29.5%, m.p. 120–121 ꢁC. IR (cmꢀ1): 2965, 2926,
2861, 2836, 1624, 1582, 1559, 1513, 1488, 1472, 1440, 1410,
1374, 1360, 1338, 1303, 1260, 1222, 1162, 1151, 1113, 1101,
1070, 1020, 996, 931, 915, 862, 834, 794, 769, 736, 682, 666,
642. 1H NMR: d (ppm) 12.95 (br s, 1H, QNNM), 8.06
(d, J ¼ 8.2 Hz, 1H, M5q.), 8.00 (d, J ¼ 7.2 Hz, 1H, M8q.), 7.87
(t, J ¼ 7.5 Hz, 1M, M7q.), 7.43 (t, J ¼ 8.0 Hz, 1M, M6q.), 4.23
(s, 2M, SQM2), 4.05 (s, 4M, N(CH2)2), 3.71 (s, 4M, O(CH2)2).
LC-MS: m/z ¼ 306 [M + H]+. Anal. Calcd. for C14H15N3O3S
C, 55.07; H, 4.95; N, 13.76; S, 10.50. Found: C, 55.02; H, 4.96;
N, 13.78; S, 10.51.
2-Phenyl-(quinazolin-4-ylthio)acetic acid (3.4). Yellow solid.
Yield: 59.0%, m.p. 168–170 ꢁC. IR (cmꢀ1): 3117, 3053, 3027,
2953, 2917, 2852, 1667, 1601, 1565, 1540, 1505, 1483, 1469,
1450, 1435, 1345, 1298, 1285, 1253, 1242, 1222, 189, 1147,
1104, 1081, 1030, 944, 926, 889, 858, 812, 760, 699, 687, 659,
619. 1H NMR: d (ppm) 12.95 (br s, 1M, QNNM), 8.55
(d, J ¼ 8.04 Hz, 2M, M2, M6ph.), 8.13 (d, J ¼ 8.15 Hz, 1M, M5q.),
8.03–7.94 (m, 2M, M7, M8q.), 7.71 (t, J ¼ 7.56 Hz, 1M, M6q.), 7.58–
7.51 (m, 3M, M3–5ph.), 4.28 (s, 2M, SQM2). LC-MS: m/z ¼ 297
[M + H]+. Anal. Calcd. for C15H11N2O2S C, 63.59; H, 3.91;
N, 9.89; S, 11.32. Found: C, 63.57; H, 3.94; N, 9.89; S, 11.30.
Preparation of 2-R-(quinazolin-4-ylthio)carboxylic acids amides
(4.1–4.9). An appropriate amount of 2-R-quinazolin-4(3H)-
thione (5 mmol) was added to ethanol or methanol (20 ml) with
metallic potassium (0.39 g, 10 mmol).
Then the appropriate amide of halogenocarboxylic acid
(10 mmol) was added and refluxed for 1–2 h. After cooling to
room temperature the mixture was poured into the cold water. The
crystalline precipitate was filtered. Substances were recrystallized
from a mixture of 2-propanol–water (1:3) or from 2-propanol.
2-Benzyl-(quinazolin-4-ylthio)acetic acid (3.5). White solid.
Yield: 62.1%, m.p. 175–178 ꢁC. IR (cmꢀ1): 3140, 3089, 3060,
3031, 2972, 2914, 2893, 2871, 1672, 1652, 1619, 1599, 1572, N-Phenyl-2-(quinazolin-4-ylthio)acetamide (4.1). Yellow solid.
1508, 1495, 1465, 1453, 1415, 1338, 1319, 1254, 1233, 1183, Yield: 88.0%, m.p. 121–124 ꢁC. IR (cmꢀ1): 3298, 3194, 3144,
1156, 1123, 1073, 1029, 999, 959, 920, 887, 867, 842, 828, 765, 3058, 2954, 2922, 2850, 1662, 1598, 1535, 1497, 1485, 1444,
731, 715, 696, 669, 657, 644, 611. LC-MS: m/z ¼ 311 [M + H]+. 1421, 1358, 1319, 1279, 1242, 1180, 1164, 1147, 1113, 1079,
Anal. Calcd. for C17H14N2O2S C, 65.79; H, 4.55; N, 9.03; S, 1020, 996, 956, 904, 886, 869, 857, 836, 791, 757, 692, 677, 652,
1
10.33. Found: C, 66.01; H, 4.53; N, 9.00; S, 10.35.
616. H NMR: d (ppm) 10.49 (br s, 1H, NH), 8.99 (s, 1H, M2q.),

DOI: 10.3109/14756366.2015.1018243 2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides
5
8.19 (d, J ¼ 8.1 Hz, 1H, M5q.), 8.01 (t, J ¼ 7.4 Hz, 2H, M7, M8q.), 3260, 3199, 3139, 3083, 3030, 2978, 2928, 2869, 1669, 1623,
7.77 (d, J ¼ 7.4 Hz, 1H, M6q.), 7.67–7.57 (m, 2H, M2, M4ph.), 7.31 1600, 1550, 1503, 1482, 1444, 1375, 1339, 1325, 1294, 1251,
(t, J ¼ 7.2 Hz, 2H, M3, M5ph.), 7.25–7.19 (m, 1H, M4ph.), 4.41 1229, 1210, 1186, 1155, 1076, 1057, 1029, 991, 919, 869, 844,
1
(s, 2H, SCH2). LC-MS: m/z ¼ 296 [M + H]+. Anal. Calcd. for 799, 755, 716, 694, 669, 641. H NMR: d (ppm) 10.41 (br s, 1H,
C16H13N3OS C, 65.06; H, 4.44; N, 14.23; S, 10.86. Found: C, NH), 8.06 (d, J ¼ 8.1 Hz, 1H, M5q.), 7.95 (t, J ¼ 7.9 Hz, 1H, M7q.),
65.03; H, 4.45; N, 14.23; S, 10.81.
7.86 (d, J ¼ 8.2 Hz, 1H, M8q.), 7.72–7.60 (m, 3H, M6q., M2,
M6ph.), 7.33 (t, J ¼ 7.8 Hz, 2H, M3, M5ph.), 7.08 (t, J ¼ 7.3 Hz, 1H,
M4ph.), 4.93 (q, J ¼ 6.9 Hz, 1H, SCH), 2.68 (s, 3H, CH3), 1.68
(d, J ¼ 6.0 Hz, 3H, SCHCH3). LC-MS: m/z ¼ 368 [M + H]+. Anal.
Calcd. for C18H17N3OS C, 66.85; H, 5.30; N, 12.99; S, 9.91.
Found: C, 66.83; H, 5.32; N, 13.00; S, 9.91.
N-Phenyl-2-(quinazolin-4-ylthio)propionamide
(4.2). Yellow
solid. Yield: 80.8%, m.p. 138–140 ꢁC. IR (cmꢀ1): 3237, 3191,
3131, 3061, 3043, 2979, 2928, 2871, 2854, 1658, 1602, 1560,
1545, 1485, 1445, 1376, 1334, 1320, 1294, 1280, 1254, 1229,
1188, 1163, 1089, 1075, 1029, 990, 958, 931, 900, 869, 835, 790,
758, 713, 696, 679, 652. 1H NMR: d (ppm) 10.47 (br s, 1H, NH), 2-(2-Morpholin-4-ylmethyl-quinazolin-4-ylthio)-N-phenylaceta-
9.05 (s, 1H, M2q.), 8.14 (d, J ¼ 8.2 Hz, 1H, M5q.), 8.06–7.95 mide (4.7). Yellow solid. Yield: 73.5%, m.p. 184–185 ꢁC. IR
(m, 2H, M7, M8q.), 7.75 (t, J ¼ 7.4 Hz, 1H, M6q.), 7.63 (d, (cmꢀ1): 3306, 3053, 2964, 2952, 2941, 2921, 2883, 2840, 2826,
J ¼ 8.2 Hz, 2H, M2, M6ph.), 7.33 (t, J ¼ 7.5 Hz, 2H, M3, M5ph.), 1676, 1597, 1561, 1547, 1525, 1497, 1481, 1452, 1439, 1419,
7.08 (t, J ¼ 7.0 Hz, 1H, M4ph.), 5.06 (q, J ¼ 6.6 Hz, 1H, SQM), 1366, 1353, 1325, 1308, 1284, 1258, 1240, 1189, 1170, 1135,
1.69 (d, J ¼ 6.9 Hz, 3H, SQMQM3). LC-MS: m/z ¼ 310 [M + H]+. 1112, 1079, 1069, 1030, 1005, 984, 969, 957, 922, 896, 887, 874,
Anal. Calcd. for C17H15N3OS C, 66.00; H, 4.89; N, 13.58; 858, 837, 821, 774, 758, 704, 691, 650, 637, 605. 1H NMR:
S, 10.36. Found: C, 66.01; H, 4.87; N, 13.57; S, 10.38.
d (ppm) 10.38 (br s, 1H, NH), 8.15 (d, J ¼ 8.1 Hz, 1H, M5q.),
8.04–7.92 (m, 2H, M7, M8q.), 7.76 (t, J ¼ 7.8 Hz, 1H, M6q.), 7.61
(d, J ¼ 7.6 Hz, 2H, M2, M6ph.), 7.32 (d, J ¼ 6.0 Hz, 2H, M3, M5ph.),
7.06 (t, J ¼ 6.3 Hz, 1H, M4ph.), 4.32 (s, 2H, SCH2), 3.75 (s, 2H,
QM2N), 3.40 (s, 4H, N(CH2)2), 2.55 (s, 4H, O(CH2)2). LC-MS:
m/z ¼ 395 [M + H]+. Anal. Calcd. for C21H22N4O2S C, 63.94;
H, 5.62; N, 14.20; S, 8.13. Found: C, 63.94; H, 5.60; N, 14.27;
S, 8.11.
N-Benzyl-2-(quinazolin-4-ylthio)propionamide
(4.3). Yellow
solid. Yield: 74.2%, m.p. 100–160 ꢁC. IR (cmꢀ1): 3320, 3270,
3063, 3032, 2972, 2921, 2853, 1645, 1615, 1597, 1551, 1496,
1483, 1451, 1420, 1396, 1375, 1360, 1331, 1319, 1303, 1278,
1257, 1237, 1219, 1187, 1162, 1150, 1099, 1078, 1045, 1022,
995, 959, 909, 867, 835, 810, 790, 758, 732, 695, 679, 651, 618.
1H NMR: d (ppm) 8.98 (s, 1H, M2q.), 8.80 (br s, 1H, NH), 8.12
(d, J ¼ 8.2 Hz, 1H, M5q.), 8.06–7.95 (m, 2H, M7, M8q.), 7.74 N-(2-Chlorophenyl)-2-(2-methyl-quinazolin-4-ylthio)acetamide
(t, J ¼ 7.8 Hz, 1H, M6q.), 7.38–7.20 (m, 5H, M2–6ph.), 4.97–4.88 (4.8). Yellow solid. Yield: 85.5%, m.p. 188–190 ꢁC. IR (cmꢀ1):
(m, 1H, SQM), 4.33 (d, J ¼ 5.8 Hz, 2H, QM2), 1.63 (d, J ¼ 7.0 Hz, 3329, 2895, 1680, 1611, 1585, 1552, 1530, 1479, 1470, 1456,
3H, SQMQM3). LC-MS: m/z ¼ 324 [M + H]+. Anal. Calcd. for 1436, 1417, 1380, 1318, 294, 1281, 1255, 1241, 1197, 1149,
C18H17N3OS C, 66.85; H, 5.30; N, 12.99; S, 9.91. Found: C, 1055, 1032, 989, 960, 935, 917, 898, 871, 857, 839, 789, 765,
1
66.85; H, 5.32; N, 12.96; S, 9.87.
753, 735, 680, 667, 640. H NMR: d (ppm) 9.89 (br s, 1H, NH),
8.12 (d, J ¼ 8.1 Hz, 1H, M5q.), 7.97 (t, J ¼ 7.3 Hz, 1H, M7q.), 7.88
(d, J ¼ 8.3 Hz, 1H, M8q.), 7.76 (d, J ¼ 7.8 Hz, 1H, M6ph.), 7.68
(t, J ¼ 7.5 Hz, 1H, M6q.), 7.50 (d, J ¼ 7.9 Hz, 1H, M3ph.), 7.34
(t, J ¼ 7.6 Hz, 1H, M4ph.), 7.20 (t, J ¼ 7.3 Hz, 1H, M5ph.), 4.39
(s, 2H, SCH2), 2.70 (s, 3H, CH3). LC-MS: m/z ¼ 344 [M + H]+.
Anal. Calcd. for C17H14ClN3OS C, 59.39; H, 4.10; N, 12.22; S,
9.33. Found: C, 59.38; H, 4.13; N, 12.21; S, 9.36.
2-(2-Methyl-quinazolin-4-ylthio)-N-phenylacetamide
(4.4).
Yellow solid. Yield: 64.6%, m.p. 178–180 ꢁC. IR (cmꢀ1): 3271,
3189, 3130, 3055, 3030, 2977, 2907, 2849, 1652, 1597, 1548,
1531, 1495, 1479, 1443, 1396, 1382, 1365, 1330, 1318, 1292,
1244, 1208, 1162, 1148, 1075, 1027, 1015, 991, 972, 921, 906,
1
872, 842, 775, 752, 719, 687, 666, 638. H NMR: d (ppm) 10.43
(br s, 1H, NH), 8.11 (d, J ¼ 8.1 Hz, 1H, M5q.), 7.95 (t, J ¼ 7.6 Hz,
1H, M7q.), 7.86 (d, J ¼ 8.2 Hz, 1H, M8q.), 7.67 (t, J ¼ 7.5 Hz, 1H,
M6q.), 7.61 (d, J ¼ 7.8 Hz, 2H, M2, M6ph.), 7.33 (t, J ¼ 7.8 Hz, 2H,
M3, M5ph.), 7.07 (t, J ¼ 7.3 Hz, 1H, M4ph.), 4.32 (s, 2H, SQM2),
2.67 (s, 3H, CH3). LC-MS: m/z ¼ 310 [M + H]+. Anal. Calcd. for
C17H15N3OS C, 66.00; H, 4.89; N, 13.58; S, 10.36. Found: C,
66.03; H, 4.91; N, 13.64; S, 10.32.
N-(4-Chlorophenyl)-2-(2-methyl-quinazolin-4-ylthio)acetamide
(4.9). Yellow solid. Yield: 52.5%, m.p. 162–164 ꢁC. IR (cmꢀ1):
3264, 3186, 3119, 3054, 2920, 2889, 2850, 1660, 1612, 1594,
1549, 1521, 1491, 1481, 1457, 1400, 1379, 1330, 1293, 1274,
1245, 1207, 1168, 1151, 1094, 1076, 1014, 991, 970, 920, 892,
1
841, 823, 765, 755, 734, 708, 697, 667, 639. H NMR: d (ppm)
10.57 (br s, 1H, NH), 8.11 (d, J ¼ 8.1 Hz, 1H, M5q.), 7.96
(t, J ¼ 7.6 Hz, 1H, M7q.), 7.87 (d, J ¼ 8.2 Hz, 1H, M8q.), 7.71–7.60
(m, 3H, M6q., M2, M6ph.), 7.39 (t, J ¼ 6.8 Hz, 2H, M3, M5ph.), 4.31
(s, 2H, SCH2), 2.62 (s, 3H, CH3). LC-MS: m/z ¼ 344 [M + H]+.
Anal. Calcd. for C17H14ClN3OS C, 59.39; H, 4.10; N, 12.22; S,
9.33. Found: C, 58.41; H, 4.11; N, 12.25; S, 9.33.
3-(2-Methyl-quinazolin-4-ylthio)-N-phenylpropionamide (4.5).
Yellow solid. Yield: 46.4%, m.p. 199–201 ꢁC. IR (cmꢀ1): 3246,
3186, 3121, 3060, 3023, 2971, 2917, 2849, 1682, 1605, 1546,
1480, 1443, 1370, 1336, 1306, 1282, 1253, 1209, 1175, 1146,
1080, 1029, 993, 965, 921, 906, 866, 846, 787, 753, 695, 667,
640. 1H NMR: d (ppm) 10.00 (br s, 1H, NH), 8.04 (d, J ¼ 8.2 Hz,
1H, M5q.), 7.96–7.89 (m, 1H, M7q.), 7.86 (d, J ¼ 8.3 Hz, 1H,
M8q.), 7.68–7.57 (m, 3H, M2, M6ph., M6q.), 7.30 (t, J ¼ 7.3 Hz,
2H, M3, M5ph.), 7.04 (t, J ¼ 7.0 Hz, 1H, M4ph.), 3.63 (t, J ¼ 6.2 Hz,
2H, SCH2), 2.89 (t, J ¼ 6.2 Hz, 2H, SCH2CH2), 2.70 (s, 3H, QM3).
LC-MS: m/z ¼ 324 [M + H]+. Anal. Calcd. for C18H17N3OS
C, 66.85; H, 5.30; N, 12.99; S, 9.91. Found: C, 66.84; H, 5.31;
N, 13.02; S, 9.94.
Docking, scoring and visual inspection of synthesized
substances into the enzymes binding site
Flexible molecular docking was carried out using the software
package OpenEye, including related utilities: Fred Receptor2.2.5,
Vida4.1.1, Flipper, Babel3, Omega2.4.3 and Fred2.2.519,20. The
crystal structures of the enzymes were obtained from the protein
data bank21.
The methodology of research consisted of the following steps:
generation of R-, S- and cis-, trans-isomers of ligands (the
studied compounds and relevant drugs, program Flipper),
2-(2-Methyl-quinazolin-4-ylthio)-N-phenylpropionamide (4.6).
Yellow solid. Yield: 72.4%, m.p. 119–130 ꢁC. IR (cmꢀ1): 3455,
–

6
–
L. Antypenko et al.
J Enzyme Inhib Med Chem, Early Online: 1–13
R
R
which allowed the production of studied compounds’
isomer’s range;
N
O
N
P S
2
5
molecular modeling (Hyper Chem 7.5) by generation of the
obtained isomeric forms’ 3D-structures – using the method of
molecular mechanics (MM +) and semi-empirical quantum
mechanical method with Polak–Ribiere algorithm (PM3);
generation of ligands conformations (Omega2.4.3). The
number of obtained conformations was not significant due
to the further selection of the most optimal conformers using
the program Fred2.2.5;
NH
NH
pyridine
1.1
S
1.2
–
–
R Cl KOH
1
R
N
R
N
SR
1
carrying out molecular docking (Fred2.2.5).
Scoring functions (Shapegauss, PLP, Chemgauss2,
N
acetone
N
SR1
Chemgauss3, Chemscore, OEChemscore, Screenscore, CGO,
CGT, Zapbind, Consensus Score) were obtained as a result of
studies, the values of which assess specific characteristics of the
ligand–protein complex, indicating the possibility of their
matching.
1.3
Cl
1.4
R= Alk, Aryl, Ph, Het R =H, Alk, Aryl
1
Scheme 1. Synthesis of 2-R-quinazolin-4(3H)-thiones and their
derivatives.
Antimicrobial and antifungal activity in vitro testing
Results and discussion
Materials and methods
Chemistry
The in vitro antibacterial activity of all newly synthesized
compounds were tested in the Zaporozhye Regional Hospital
Bacterial Laboratory against Gram positive bacteria
(Staphylococcus aureus ATCC 25923, Enterococcus faecalis
ATCC 29212), Gram negative bacteria (Enterobacter aerogenes
12, Pseudomonas aeruginosa ATCC 27853, Escherichia coli
ATCC 25922, Klebsiella pneumonia 68) and antifungal properties
against Candida albicans ATCC 885653. The amount of micro-
bial cells was 1.5 ꢂ 108 c.f.u./mL. Incubation period of bacteria
was 24 h at 35 ꢁC, yeast – 48–72 h at 28–30 ꢁQ. The agar-diffusion
method was used for determination of the preliminary antibac-
terial and antifungal activity. Standard sterilized filter paper discs
(6 mm diameter) were impregnated with a solution of the test
compound in DMSO (100 mg/disk) and placed it on an agar
(Mu¨ller–Hinton Broth (Oxoid)) plate seeded with the appropriate
test organism in triplicates. DMSO alone was used as a control
at the same above-mentioned concentration. Gatifloxacin,
Gemifloxacin, Moxifloxacin, Ceftriaxone and Nystatin were
used as reference drugs. The results were recorded for each
of the tested compound as the average diameter of inhibition
zones diameters (IZD) of bacterial or fungal growth around the
discs in mm.
Among known methods of 2-R-quinazolin-4(3H)-thiones (1.2)
synthesis are thionation of 2-R-quinazolin-4(3H)-ones (1.1) by
phosphorus pentasulfide in acetone in the presence of potassium
acetate or the alkylation of 4-chloroquinazoline (1.3) with
appropriate thions (Scheme 1)9.
Alkylation of 2-R-quinazolin-4(3H)-thiones (1.2) by the
halogenoalkanes in an alkaline medium with the presence of
tetrabutylammonium bromide leads to the corresponding
S-derivatives (1.4) (Scheme 1)23.
When isothiocyanates were used as electrophiles to react with
ortho-bromophenyl isocyanides (1.5), appropriate cyclic 2-R-
quinazolin-4(3H)-thiones (1.7) were formed in high yields
(Scheme 2)24. The reaction mixture with isothiocyanates was
gradually warmed to 40 ꢁC before quenching with water to form
intermediate 1.6.
Thus, the variety of the known 2-R-quinazolin-4(3H)-thiones
is quite narrow, so synthetic and biological investigation in this
field is still novel and promising.
Synthesis of novel 2-R-quinazolin-4(3H)-thiones
Thionation of 2-R-4(3H)-quinazolones was carried out with the
help of a known reagent, namely Lawesson’s (2,4-bis(p-methox-
yphenyl)-1,3-dithiadiphosphetane-2,4-disulfide)25,26
,
which
Anticancer activity testing
reduced the reaction time and increased the yield of the required
2-R-quinazolin-4(3H)-thiones (2.1–2.18) (Scheme 3).
The structure of all synthesized compounds was evaluated by
elemental analysis and their spectral data (IR, LC-MS, H-NMR
spectra).
The data obtained by LC-MS spectra confirmed the purity of
all obtained substances, demonstrating their appropriately proto-
nated molecular ions [M + H]+.
Materials and methods
Primary anticancer assay was performed against human tumor cell
lines panel derived from nine neoplastic diseases, in accordance
with the protocol of the Drug Evaluation Branch, National Cancer
Institute, Bethesda22. The human tumor cell lines of the cancer
screening panel were grown in RPMI 1640 medium containing
5% fetal bovine serum and 2 mM L-glutamine. For a typical
screening experiment, cells were inoculated in 96-well microtiter
plates in 100 mL assay volume, at plating densities ranging from
5000 to 40 000 cell/well. After cell inoculation, the microtiter
plates were incubated at 37 ꢁC, under an atmosphere of 5:95
CO2:air (v/v) at 100% relative humidity, for 24 h prior to addition
of drugs under assessment. Following drug additions (1 mM), the
plates were incubated for an additional 48 h, under the same
conditions. Sulforhodamine B (SRB) solution (100 mL, 0–4% w/v
in 1% aq. acetic acid) was added to each well and plates were
incubated for 10 min at room temperature. The percentage growth
was evaluated spectrophotometrically versus controls not treated
with test agents.
1
In the IR-spectra of compounds 2.1–2.18, the aromatic rings’
stretchings were presented as the peaks of the weak and medium
intensity absorption at 1620–1428 cmꢀ1. Furthermore, the exist-
ence of aromatic system was confirmed by C–H stretchings at
3025–3148 cmꢀ1. Out-of-plane vibrations of ¼C–H bond were
observed in the range from 871 to 690 cmꢀ1. Methylene groups of
2.3, 2.5, 2.6, 2.9, 2.10, 2.12 were characterized by deformational
vibrations at 1465–1456 cmꢀ1, and methyl groups of 2.2, 2.3, 2.18
at 1378–1356 cmꢀ1. Methoxy group of compound 2.18 resonated
as two intense stretchings: asymmetric at 1258–1243 cmꢀ1 and
symmetric at 1021 cmꢀ1. Signals of aliphatic C–N bond (2.9,
2.10) were presented in the range from 1369 to 1000 cmꢀ1
,

DOI: 10.3109/14756366.2015.1018243 2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides
7
1) n-BuLi, -78 °C,
Scheme 2. Synthesis of 3-R-quinazolin-
4(3H)-thiones.
N
Li
R
NC
Br
N
H O
THF, 10 min
2
N
N
2) RNCS, -78 °C, 3h
R
S
1.5
1.6
S
1.7
R=cPr, cHex
S
S
S
double bonds and aromatic ring of compounds. Aromatic and
vinyl CH group vibrations were observed at 3167–2965 cmꢀ1
Methylene groups of 3.1–3.9 had characteristic absorption peak at
1488–1458 cmꢀ1, and methyl groups of 3.2, 3.3 absorbed at
N
R
N
S
R
OMe
P
P
OMe
.
S
NH
NH
dioxane
1392–1345 cmꢀ1
.
The stretching vibrations of ¼CH group
2.0 O
2.1-2.18
appeared at 3062–3027 cmꢀ1 and out-of-plane vibrations from
908 to 697 cmꢀ1. In compound 3.8, the CF bond had a
characteristic multiplet with strong bands in the range from
1352 to 1112 cmꢀ1. The C¼N bond was characterized by
2.1
H
2.7
2.8 CF
2.13
2-Cl-C H
CH=CH-C H
6
5
6
6
4
4
2.2 CH
2.14 3-Cl-C H
3
3
2.3 C H
2.9 morpholin-4-yl
2.10 CH -morpholin-4-yl 2.16 3-F-C H
2.11 thiophen-3-yl
2.12 1H-imidazol-1-yl
2.15 4-Cl-C H
6
2
6
5
5
4
4
2.4 C H
2
6
broadened vibrations of variable intensity at 1667–1610 cmꢀ1
.
2.5 CH -C H
2.17 4-CF -C H
2
6
5
6
3 6 4
In the 1H NMR spectra, the substances 3.1–3.9 were
characterized by broadened one-proton singlet of carboxylic
group proton at 14.72–12.87 ppm. For 3.1, the H2-quin. signal was
found at 9.04 ppm. The one-proton doublets of H5-quin. and H8-
quin. appeared at 8.25–8.06 and 8.13–7.97 ppm; one-proton
2.6 (CH ) -C H
2.18 3,4-(OCH )-C H
3 6 3
2 2
5
Scheme 3. Synthesis of 2-R-quinazolin-4(3H)-thiones.
whereas the C¼N bond (2.1–2.18) absorbed approximately at the signals H7-quin. and H6-quin. were shown as triplets at 8.09–
same frequencies as the C¼C bond at 1685 to 1613 cmꢀ1, but 7.89 and 7.90–7.43 ppm, respectively. The signals of phenyl
broadened and more intensive. The vibration of chlorine protons were also observed in the low field at 8.55–7.15 ppm. The
substituent of compounds 2.13–2.15 was observed between cis CH¼CH fragment of 3.7 was detected at 7.33 and 8.16 ppm,
1097 and 1027 cmꢀ1, and the vibrations of fluorine substituents deshielded by substituents. Characteristic two-proton singlet of
(2.16) were observed at 1266 to 1087 cmꢀ1. Multiplet of strong SCH2-group was detected at 4.30–4.17 ppm. Aliphatic morpholyl
peaks in the range from 1360 to 1103 cmꢀ1 was typical for CF3- protons of 3.9 were observed at 4.05–3.71 ppm as singlets, and
group for compounds 2.8 and 2.17. The broadened and very weak protons of alkyl substituents of compounds 3.2–3.3, 3.5–3.6, 3.9
absorption at 2571–2489 cmꢀ1 only partially confirmed the were observed in a strong field at 3.20–1.28 ppm with corres-
presence of SH-groups of compounds, as vibrations overlapped ponding multiplicity.
with signals of other groups. The stretching of C¼S bond of
compound 2.11 was observed at 1250–1015 cmꢀ1
.
Synthesis of (2-R-quinazolin-4 (3H)-ylthio)carboxylic acids
amides
1H NMR-spectra data characterized substances 2.1–2.18
according to their proposed structures, and quinazoline’s signals
were found in the next range of ppm: one-proton doublets of H5-
quin. and H8-quin. at the 8.74–8.44 and at the 7.94–7.44
respectively; H7-quin. and H6-quin. as one-proton triplets at the
8.10–7.67 and at the 7.76–7.26, and for unsubstituted quinazolin-
4-(3H)-thione (2.1) H2-quin. was observed at 8.19 ppm. The one-
proton broadened singlet of the NH-group was detected at the
13.98–13.72 ppm, and for compounds 2.8, 2.9 2.13 it was shifted
to stronger field – the 12.44 ppm, the 12.88 ppm and the
10.04 ppm, respectively. Signals of phenyl protons were presented
at 8.30–7.14 ppm with proper multiplicity. The SCH ¼ CH signal
of compound 2.7 was recorded at 7.29 ppm. Aliphatic morpholyl
protons for 2.9 and 2.10 were observed in strong field at 3.76–
2.53 ppm. The alkyl and methoxy groups were found at 3.92–
1.27 ppm.
The next step of synthesis was refluxing the 2-R-quinazolin-
4(3H)-thiones (2.1, 2.2, 2.10) with halogenocarboxylic acids
amides in potassium methylate to obtain the appropriate (2-R-
quinazolin-4(3H)-ylthio)carboxylic acids amides (4.1–4.9)
(Scheme 5).
In the IR-spectra, the amide NH-proton of compounds 4.1–4.9
was characterized by broadened and medium intensive signal
at 3245–3455 cmꢀ1. The carbonyl vibrations were observed
at 1682–1645 cmꢀ1. Double bonds of aromatic rings showed
medium strength absorption peaks at 1615–1439 cmꢀ1. Aromatic
and vinyl CH-groups occurred at 3329–3023 cmꢀ1, and aliphatic
CH for compounds 4.2, 4.3, 4.6 at 2979–2853 cmꢀ1. Methylene
groups of compounds 4.1, 4.3–4.5, 4.7–4.9 had characteristic
absorption peak at 1485–1479 cmꢀ1, and methyl groups of
compounds 4.2–4.6, 4.8, 4.9 at 1380–1370 cmꢀ1. The signals of
CN-bond appeared in the range from 1353 to 1005 cmꢀ1
and C¼N bond at 1682–1611 cmꢀ1. Chlorine substituted phenyls
,
Synthesis of (2-R-quinazolin-4(3H)-ylthio)acetic acids
The (2-R-quinazolin-4(3H)-ylthio)acetic acids (3.1–3.9) were 4.8 and 4.9 had a characteristic valence vibrations at 1094–
.
obtained by refluxing the appropriate 2-R-quinazolin-4(3H)- 1032 cmꢀ1
1
In the H NMR spectra of (2-R-quinazolin-4(3H)-ylthio)car-
boxylic acids amides (4.1–4.9), NH-proton was shown almost for
thiones (2.1–2.9) with chloroacetic acid in potassium alkoxide
(Scheme 4).
The IR spectra of (2-R-quinazolin-4(3H)-ylthio)acetic acids all amides as broadened one-proton singlet at 10.57–9.89 ppm,
(3.1–3.9) were characterized by high intensity bands of carbonyl except the compound 4.3 (8.80 ppm). The H5 and H8 quin. signals
group stretchings at 1715–1624 cmꢀ1, and for compounds 3.1, 3.2 were found at 8.06–7.89 and 8.01–7.90 ppm, H7 and H6 at 8.01–
and 3.5 the signal was observed as a doublet. The hydroxy group 7.90 and 7.77–7.62 ppm; H2 quin. for 4.1–4.3 at 9.05–8.98 ppm.
was characterized by a broad peak at 2964–2914 cmꢀ1 (over- The SCH- of 4.2, 4.3, 4.6 resonated as one-proton quadruplet at
lapping with CH vibrations). The weak intensity absorption band 5.06–4.85 ppm. The SCH2-group appeared as a triplet for 4.5 at
at 1635 cmꢀ1 and medium at 1614–1416 cmꢀ1 corresponds to 3.63 ppm and two-proton singlet at 4.41–4.31 ppm for all other

8
L. Antypenko et al.
J Enzyme Inhib Med Chem, Early Online: 1–13
N
S
R
O
Scheme 4. Synthesis of (2-R-quinazolin-
4(3H)-ylthio)acetic acids.
R
N
Cl
H
CH
3.1
3.2
3.3
3.4
3.5
3.6
OH
3
NH
C H
2
5
N
CH OK
C H
3
6
5
CH -C H
(CH ) -C H
2
6 5
S
2 2
6 5
2.1-2.9
3.1-3.9
3.7 CH=-CH- H
6
5
CF
3.8
3.9 morpholin-4-yl
3
HO
O
R
R2NH
O
(Figure 1). Also, the Consensus Score of 2-(2-morpholin-4-
ylmethylquinazolin-4-ylthio)-N-phenylacetamide (4.7) was at the
same level as the reference (Table 1).
By generalizing obtained results, amides had better affinity to
DHFR. The more planar substituents the molecules had the better
was the affinity. Introduction of simple alkyl radicals worsens it.
Therefore, to prove the presence of antimicrobial activity, the next
step of investigation was in vitro screening.
(CH2)n
R
N
S
N
S
R
Cl
N
NH
CH3OK
4.1-4.9
2.1, 2.2, 2.10
(CH )n
2
R
1
n
0
0
0
0
1
0
R
H
H
R
H
CH
R
2
1
O
4.1
4.2
4.3
4.4
4.5
4.6
C H
6
5
5
Antimicrobial and antifungal activity study. All the newly
synthesized compounds were evaluated for in vitro antibacterial
activity against Gram positive bacteria (Staphylococcus aureus
ATCC 25923, Enterococcus faecalis ATCC 29212), Gram
negative bacteria (Enterobacter aerogenes 12, Pseudomonas
aeruginosa ATCC 27853, Escherichia coli ATCC 25922,
Klebsiella pneumonia 68) and antifungal properties against
Candida albicans ATCC 885653 (Table 2).
R HN
C H
6
2
3
H
CH CH C H
H
H
3
2
6
5
5
5
5
C H
CH
CH
CH
6
3
3
3
C H
6
CH
C H
3
6
4.7 0 CH -mor-
2
pholin-4-yl
0
0
H
H
H
C H
6
4-C1-C H
2-C1-C H
6
5
6
4.8
4.9
CH
CH
3
3
5
5
As a result, it was found that Escherichia coli, Enterococcus
faecalis and Pseudomonas aeruginosa were insensitive to all the
synthesized compounds. Moreover, compounds 2.5–2.7, 2.12–
2.14, 2.16–2.18, 3.1–3.9, 4.1–4.9 had no antimicrobial and
antifungal effects on all studied microorganisms.
Scheme 5. Synthesis of the (2-R-quinazolin-4(3H)-ylthio)carboxylic
acids amides.
compounds. The signals of phenyl protons were presented at
7.61–7.04 ppm. Aliphatic signals were observed in the strong field
(2.89–1.63 ppm).
Substances 2.2–2.4, 2.9–2.11, 2.15 had the most significant
influence on the growth of C. albicans, showing the antifungal
activity. 2-Methylquinazolin-4-(3H)-thione (2.2) possessed the
best results of inhibition zone diameter, 23 mm, exceeding 21 mm
of Nystatin (Table 1). The growth of S. aureus and E. aeruginosa
were slightly suppressed by compounds 2.1, 2.4, 2.8 and 2.9.
Interestingly, the most active among them appeared to be
unsubstituted quinazolin-4(3H)-thione (2.1), which delayed their
growth at 15 and 11 mm, respectively. The latter one (2.1) and
2-phenylquinazolin-4(3H)-thione (2.4) also moderately inhibited
the growth of K. pneumonia at 11 and 10 mm. But, unfortunately,
they did not suppress the level of any of the references even at a
concentration of 100 mg/disk.
Pharmacology
Docking studies to Candida albicans dihydrofolate reductase. In
continuation of our potential antimicrobials investigation, the
dihydrofolate reductase (DHFR) was used as a model to study
compounds’ affinity to it. DHFR is an enzyme that reduces
dihydrofolic acid to tetrahydrofolic acid, using NADPH as
electron donor27. A variety of drugs act as its inhibitors: the
antibiotic trimethoprim and its derivatives, the antimalarial drugs
pyrimethamine and proguanil, the chemotherapeutic agent metho-
trexate28. Thus, we were aimed to perform the docking studies,
as an approach to find the molecules with affinity to a
specific biological target, namely, synthesized compounds into
the active site of DHFR to predict the possible presence of the
antimicrobial activity.
Hence, the studies have shown that the most active antimicro-
bial and antifungal compounds were: unsubstituted (2.1),
2-methyl-(2.2) and 2-phenylquinazolin-4(3H)-thione (2.4).
Structure–antimicrobial activity correlation. Some regularity
in the appearance of biological activity could be traced. The
introduction of larger substituent in the second position of
quinazolin-4(3H)-thione gives a significant weakening of the
antibacterial action against S. aureus, E. faecalis, K. pneumoniae
and results in a moderate antifungal action against C. albicans.
The modification of forth position with carboxylic acids and
amides residues surprisingly leads to the disappearance of any
antimicrobial activity. Analyzing the molecular docking results,
there was no correlation between affinity to DHFR and
antimicrobial data. Thus, we could suppose that synthesized
compounds had other mechanism of antimicrobial activity.
Investigation was conducted by flexible molecular docking
using the software package ‘‘OpenEye’’, including related
utilities: Fred Receptor2.2.5, Vida4.1.1, Flipper, Babel3,
Omega2.4.3 and Fred2.2.519,20. The crystal structure of the
enzyme DHFR (1AOE.pdb) was obtained from the protein data
bank21. The 7-(pentan-3-yl)-7H-pyrrolo[3,2-f]quinazoline-1,3-
diamine (GW345) was used as a reference (Figure 1)27.
The obtained scoring functions (Shapegauss, PLP,
Chemgauss2,
Chemgauss3,
Chemscore,
OEChemscore,
Screenscore, CGO, CGT, Zapbind, Consensus Score) indicate
the best possibility of the matching into the ligand–protein
complex.
The
DHFR and investigated compounds revealed the best results
for 2-(2-methylquinazolin-4-ylthio)-N-phenylacetamide (4.6)
analysis
of
docking
interactions
between
Docking studies of CK2 kinase. Most interesting target for
anticancer investigations is protein kinase CK2 (casein kinase II),

DOI: 10.3109/14756366.2015.1018243 2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides
9
Figure 1. Interaction of 2-(2-methyl-quinazolin-4-ylthio)-N-phenylpropionamide (4.6) (A) and reference (7-(pentan-3-yl)-7H-pyrrolo[3,2-f]quinazo-
line-1,3-diamine) (B) into the DHFR binding site.
Table 1. The obtained scoring functions of the investigated compounds and (7-(pentan-3-yl)-7H-pyrrolo[3,2-f]quinazoline-1,3-diamine) into DHFR
binding site.
Consensus
Score Shapegauss
Cmpd
PLP
Chemgauss2 Chemgauss3 Chemscore OEChemscore Screenscore
CGO
CGT
Zapbind
4.6
4.7
Reference
4.3
4.5
3.6
4.4
3.4
4.2
4.8
2.6
4.1
3.5
2.5
2.13
3.9
2.17
2.14
2.15
4.9
2.16
2.12
2.18
2.4
2.9
3.2
2.7
2.11
3.7
2.10
3.8
82
86
86
92
ꢀ378.765 ꢀ49.6334 ꢀ44.7116 ꢀ60.8656 ꢀ20.527
ꢀ33.3789 ꢀ116.047 ꢀ218.186 ꢀ0.43637 ꢀ22.6468
ꢀ34.9882 ꢀ121.381 ꢀ190.051 ꢀ0.32638 ꢀ26.0352
ꢀ444.152 ꢀ50.459
ꢀ49.3208 ꢀ60.7651 ꢀ20.6596
ꢀ308.194 ꢀ51.2794 ꢀ46.1962 ꢀ64.3525 ꢀ21.2196
ꢀ381.148 ꢀ49.2852 ꢀ46.3099 ꢀ59.078 ꢀ22.1063
ꢀ381.592 ꢀ47.7807 ꢀ45.2465 ꢀ68.0848 ꢀ18.4502
ꢀ28.2021 ꢀ120.31
ꢀ351.28 ꢀ0.95831 ꢀ8.45465
ꢀ34.3712 ꢀ109.501 ꢀ208.71 ꢀ0.40294 ꢀ22.3413
ꢀ34.1904 ꢀ120.006 ꢀ197.684 ꢀ0.42593 ꢀ22.6365
ꢀ30.9478 ꢀ102.223 ꢀ226.669 ꢀ0.49999 ꢀ19.3994
97
108
114
137
137
139
145
147
157
197
200
215
220
223
225
234
239
242
250
253
256
276
281
282
284
288
307
307
311
347
364
393
ꢀ383.317 ꢀ46.208
ꢀ44.6148 ꢀ62.5484 ꢀ17.9078
ꢀ365.394 ꢀ46.6807 ꢀ42.1459 ꢀ57.7325 ꢀ18.6133
ꢀ354.584 ꢀ43.5951 ꢀ40.4575 ꢀ57.537 ꢀ17.6772
ꢀ331.913 ꢀ44.9021 ꢀ37.9129 ꢀ46.694 ꢀ18.226
ꢀ360.515 ꢀ49.4909 ꢀ44.2391 ꢀ57.8334 ꢀ17.6949
ꢀ348.186 ꢀ49.9596 ꢀ40.3333 ꢀ53.3965 ꢀ20.8559
ꢀ345.766 ꢀ51.1229 ꢀ42.2129 ꢀ53.5865 ꢀ20.8751
ꢀ30.0201 ꢀ114.61
ꢀ209.083 ꢀ0.47499 ꢀ23.6368
ꢀ30.2581 ꢀ114.387 ꢀ227.122 ꢀ0.53644 ꢀ17.5635
ꢀ27.8546 ꢀ109.7 ꢀ245.288 ꢀ0.56868 ꢀ19.1514
ꢀ29.1051 ꢀ108.545 ꢀ235.902 ꢀ0.46207 ꢀ16.0701
ꢀ32.1831 ꢀ120.94
ꢀ186.402 ꢀ0.44206 ꢀ17.7927
ꢀ31.1928 ꢀ127.393 ꢀ195.133 ꢀ0.43923 ꢀ14.7374
ꢀ32.4152 ꢀ122.376 ꢀ200.883 ꢀ0.41885 ꢀ10.7625
ꢀ25.8349 ꢀ111.403 ꢀ198.767 ꢀ0.45301 ꢀ19.2544
ꢀ356.475 ꢀ48.9562 ꢀ44.038
ꢀ58.2667 ꢀ18.0081
ꢀ289.134 ꢀ41.4663 ꢀ35.6895 ꢀ52.4105 ꢀ15.6978
ꢀ259.853 ꢀ40.9669 ꢀ33.8891 ꢀ42.4025 ꢀ16.9804
ꢀ300.149 ꢀ38.0297 ꢀ36.7167 ꢀ42.1042 ꢀ13.8311
ꢀ347.948 ꢀ40.6094 ꢀ41.0362 ꢀ58.406 ꢀ15.1547
ꢀ299.186 ꢀ41.2863 ꢀ34.2701 ꢀ46.2202 ꢀ16.6175
ꢀ24.039
ꢀ27.2424
ꢀ27.4
ꢀ96.9218 ꢀ272.537 ꢀ0.73395 ꢀ18.7643
ꢀ95.5493 ꢀ240.888 ꢀ0.59124 ꢀ17.0203
ꢀ93.372 ꢀ101.988 ꢀ0.21461 ꢀ22.1789
ꢀ25.0826 ꢀ101.669 ꢀ195.767 ꢀ0.45753 ꢀ17.8969
ꢀ293.334 ꢀ40.2826 ꢀ33.639
ꢀ47.1476 ꢀ16.0805
ꢀ24.8425 ꢀ103.112 ꢀ197
ꢀ28.1221 ꢀ26.1088 ꢀ160.542 ꢀ0.35169 ꢀ20.3654
ꢀ0.46266 ꢀ17.6947
ꢀ372.463 24.61172 ꢀ45.7289 ꢀ55.1096 ꢀ15.4709
ꢀ286.71 ꢀ40.4509 ꢀ33.5012 ꢀ46.304 ꢀ15.0294
ꢀ264.66 ꢀ37.1178 ꢀ34.8203 ꢀ52.7886 ꢀ14.3724
ꢀ282.787 ꢀ32.8939 ꢀ33.8284 ꢀ39.9133 ꢀ14.785
ꢀ282.489 ꢀ39.6817 ꢀ32.4522 ꢀ45.3545 ꢀ15.2888
ꢀ24.6116 ꢀ102.597 ꢀ197.935 ꢀ0.46985 ꢀ17.4272
ꢀ22.2174
ꢀ92.4593 ꢀ227.895 ꢀ0.70836 ꢀ13.4663
ꢀ89.7601 ꢀ218.89 ꢀ0.49911 ꢀ19.1477
ꢀꢀ25.2986
ꢀ24.9071 ꢀ102.492 ꢀ189.837 ꢀ0.46683 ꢀ17.0605
ꢀ279.662 ꢀ37.329
ꢀ34.5317 ꢀ40.7148 ꢀ15.3446
ꢀ24.0937
ꢀ21.1586
ꢀ22.9476
ꢀ23.472
ꢀ24.506
ꢀ22.2012
ꢀ19.2077
ꢀ20.9541
ꢀ22.906
ꢀ86.958 ꢀ212.897 ꢀ0.61779 ꢀ14.6992
ꢀ94.9782 ꢀ225.681 ꢀ0.66529 ꢀ16.4408
ꢀ82.0469 ꢀ226.679 ꢀ0.53643 ꢀ19.9704
ꢀ96.1665 ꢀ180.632 ꢀ0.46416 ꢀ17.242
ꢀ64.3374 ꢀ218.546 ꢀ0.36965 ꢀ22.1967
ꢀ256.281 ꢀ37.0266 ꢀ30.4889 ꢀ39.6976 ꢀ13.9405
ꢀ245.564 ꢀ33.1216 ꢀ29.8359 ꢀ35.8302 ꢀ14.2575
ꢀ276.842 ꢀ38.6947 ꢀ31.4477 ꢀ42.7806 ꢀ14.258
ꢀ286.732 ꢀ28.7227 ꢀ32.8977 ꢀ29.3642 ꢀ15.1515
ꢀ263.681 ꢀ32.4705 ꢀ31.9649 ꢀ37.644 ꢀ13.4627
ꢀ307.998 ꢀ33.4153 ꢀ39.6585 ꢀ44.5068 ꢀ10.1369
ꢀ238.767 ꢀ34.8311 ꢀ28.7247 ꢀ37.8476 ꢀ12.8009
ꢀ268.889 ꢀ32.1917 ꢀ38.5509 ꢀ41.7444 ꢀ12.482
ꢀ84.7462 ꢀ232.8
ꢀ0.59302 ꢀ15.9064
ꢀ86.2238 ꢀ149.599 ꢀ0.37068 ꢀ16.8518
ꢀ90.6225 ꢀ216.915 ꢀ0.66458 ꢀ15.8733
ꢀ78.2142 ꢀ194.199 ꢀ0.5021 ꢀ7.9952
ꢀ85.5844 ꢀ185.563 ꢀ0.56516 ꢀ13.4571
ꢀ82.2969 ꢀ99.7401 ꢀ0.28716 ꢀ14.1796
ꢀ70.2144 ꢀ107.419 ꢀ0.29593 ꢀ16.2219
3.1
3.3
2.8
2.3
ꢀ231.165 ꢀ34.8882 ꢀ29.3037 ꢀ36.1957 ꢀ9.09227 ꢀ16.0344
ꢀ260.234 ꢀ33.4146 ꢀ29.595
ꢀ42.376 ꢀ12.449
ꢀ21.6917
ꢀ16.4791
2.2
ꢀ196.074 ꢀ24.9307 ꢀ22.9715 ꢀ35.0098 ꢀ9.1122

10 L. Antypenko et al.
Table 2. Microorganisms’ growth inhibition zones (in mm).
J Enzyme Inhib Med Chem, Early Online: 1–13
Compound
Conc. (mg/disk) Staphylococcus aureus Enterococcus aeruginosa Klebsiella pneumonia Candida albicans
2.1
2.2
2.3
2.4
2.8
2.9
2.10
2.11
100
100
100
100
100
100
100
100
100
5
5
5
30
100
10
15
6
6
15
9
11
6
11
6
6
10
6
6
6
6
6
ꢀ**
ꢀ
ꢀ
ꢀ
ꢀ
16
11
6
6
10
6
6
6
6
6
ꢀ
ꢀ
ꢀ
25
ꢀ
ꢀ
6*
23
16
8
6
18
13
15
10
ꢀ
6
6
2.15
Gatifloxacin
Gemifloxacin
Moxifloxacin
Ceftriaxone
Nystatin
Ampicillin
30
30
31
33
ꢀ
22
ꢀ
ꢀ
ꢀ
21
ꢀ
All statistical analysis of the results was carried out using the ‘‘Biostatistica’’ software (p ꢃ 0.05).
*6 mm ꢀ diameter paper disk.
**Not investigated.
Figure 2. Interaction of 2-styryl-(quinazolin-4-ylthio)acetic acid (3.7) (A) and Silmitasertib (CX-4945) (B) into the binding site of protein kinase CK2.
a constitutively active serine/threonine kinase, that is involved in a Preliminary in vitro anticancer testing. The activity of the
variety of roles essential to the maintenance of cellular homeo- compounds was measured according to a value of 100 that meant
stasis. It regulates multiple processes that play important roles no growth inhibition. A value of 30 would mean 70% growth
in the sensitivity of cancer to epidermal growth factor receptor inhibition. A value of 0 meant no net growth over the course of the
targeting therapeutics, including PI3K-Akt-mTOR signaling, experiment. A value of ꢀ30 would mean 70% lethality. A value of
Hsp90 activity and inhibition of apoptosis27. Hence, we conducted ꢀ100 meant all cells were dead (Table 4).
docking studies of synthesized substances into the active site of
Hence, 2-trifluoromethyl-(quinazolin-4-ylthio)acetic acid (3.8)
protein kinase CK2 (3NSZ)21. Silmitasertib (CX-4945) was used was the most active among all, inhibiting growth of UO-31 of
as the reference (Figure 2)29.
renal cancer to 17.01% and A498 to 54.81%. While it had
According to docking results, 11 substances had better promoted the growth of CNS cancer SF-268 line, leukemia
Consensus Scores than Silmitasertib. Among them, the best CAKI-1 and SR lines, and ovarian cancer OVCAR-3. The best
two were 2-styryl-(quinazolin-4-ylthio)acetic acid (3.7) and anticancer compound against leukemia CCRF-CEM cell line
N-(4-chlorophenyl)-2-(2-methyl-quinazolin-4-ylthio)acetamide (4.9) appeared to be 2-(3,4-dimethoxyphenyl)-3H-quinazoline-4-thione
with Consensus Scores three times less than that of Silmitasertib, (2.18) with 18.75% of cancer line growth. 2-Benzyl-3H-quinazo-
representing their anticancer potential (Figure 2, Table 3).
line-4-thione (2.5) was practically ineffective against all cancer
Thus, introduction of the amide residues again facilitates cell lines, except the light inhibition of UO-31 and A498 of renal
substances affinity. So, substances structures were sent to the cancer with 75.05 and 80.24%.
National Cancer Institute (NCI) to be in vitro investigated for
anticancer properties.
2-Trifluoromethyl-3H-quinazoline-4-thione (2.8) also showed
light anticancer effect against ovarian IGROV1 to 71.97% and

DOI: 10.3109/14756366.2015.1018243 2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides 11
Table 3. The obtained scoring functions of the investigated compounds and Silmitasertib into CK2 kinase binding site.
Consensus
score
Cmpd
Shapegauss
PLP
Chemgauss2 Chemgauss3 Chemscore OEChemscore Screenscore
CGO
CGT
Zapbind
3.7
4.9
3.6
4.4
3.5
4.1
4.7
3.9
46
65
ꢀ465.545 ꢀ57.0443 ꢀ52.0457
ꢀ447.211 ꢀ54.6976 ꢀ47.7201
ꢀ428.575 ꢀ50.8626 ꢀ46.2184
ꢀ442.753 ꢀ56.5359 ꢀ51.9282
ꢀ423.283 ꢀ46.3807 ꢀ45.3975
ꢀ89.526
ꢀ22.8763
ꢀ22.0093
ꢀ19.661
ꢀ38.2368
ꢀ35.6513
ꢀ31.9269
ꢀ38.2661
ꢀ32.312
ꢀ146.183 ꢀ272.397 ꢀ0.5101 ꢀ17.8824
ꢀ134.385 ꢀ263.625 ꢀ0.4875 ꢀ19.4444
ꢀ122.944 ꢀ281.953 ꢀ0.51936 ꢀ15.6018
ꢀ155.028 ꢀ214.612 ꢀ0.38081 ꢀ12.7306
ꢀ119.811 ꢀ269.899 ꢀ0.50498 ꢀ17.9316
ꢀ118.385 ꢀ269.485 ꢀ0.45643 ꢀ21.7419
ꢀ115.513 ꢀ258.918 ꢀ0.39834 ꢀ22.7315
ꢀ125.964 ꢀ244.859 ꢀ0.47028 ꢀ18.7362
ꢀ125.574 ꢀ238.485 ꢀ0.37643 ꢀ19.7773
ꢀ113.403 ꢀ245.244 ꢀ0.45564 ꢀ19.777
ꢀ115.011 ꢀ268.464 ꢀ0.46281 ꢀ23.5911
ꢀ118.674 ꢀ244.346 ꢀ0.37861 ꢀ19.8628
ꢀ115.397 ꢀ267.213 ꢀ0.48533 ꢀ18.925
ꢀ115.153 ꢀ230.579 ꢀ0.46066 ꢀ19.2743
ꢀ112.757 ꢀ253.82 ꢀ0.48786 ꢀ17.8278
ꢀ111.778 ꢀ234.62 ꢀ0.51387 ꢀ18.2424
ꢀ110.607 ꢀ289.325 ꢀ0.48154 ꢀ19.2192
ꢀ96.9218 ꢀ272.537 ꢀ0.73395 ꢀ18.7643
ꢀ113.381 ꢀ247.599 ꢀ0.49254 ꢀ21.8732
ꢀ113.632 ꢀ273.045 ꢀ0.53468 ꢀ17.3226
ꢀ113.392 ꢀ223.74 ꢀ0.44982 ꢀ18.5348
ꢀ114.266 ꢀ220.905 ꢀ0.37854 ꢀ12.3272
ꢀ75.0627
ꢀ84.1132
ꢀ79.1107
ꢀ77.7719
ꢀ66.9817
ꢀ67.022
100
111
113
114
116
125
125
131
137
158
168
174
177
185
187
200
215
225
226
243
250
272
279
287
290
302
306
313
344
348
359
360
366
400
404
ꢀ24.8452
ꢀ19.6203
ꢀ19.5518
ꢀ19.8292
ꢀ19.8355
ꢀ18.5955
ꢀ21.6011
ꢀ18.3473
ꢀ18.7694
ꢀ18.014
ꢀ435.422 ꢀ48.305
ꢀ47.4608
ꢀ35.4336
ꢀ33.0239
ꢀ30.0673
ꢀ33.0863
ꢀ33.7218
ꢀ31.2201
ꢀ32.451
ꢀ452.331 ꢀ48.8969 ꢀ47.4851
ꢀ407.418 ꢀ50.5678 ꢀ43.645
ꢀ438.655 ꢀ47.5173 ꢀ48.4867
ꢀ390.288 ꢀ52.0469 ꢀ46.6193
ꢀ400.893 ꢀ48.0687 ꢀ43.0718
ꢀ424.616 ꢀ44.4712 ꢀ47.3726
ꢀ421.062 ꢀ45.1238 ꢀ45.1304
ꢀ379.789 ꢀ49.9054 ꢀ40.2089
ꢀ388.947 ꢀ46.1489 ꢀ40.0884
ꢀ78.0435
ꢀ73.9937
ꢀ70.9293
ꢀ70.9628
ꢀ69.2785
ꢀ67.259
4.3
3.4
4.6
Silmitasertib
4.8
2.13
2.7
ꢀ30.1503
ꢀ28.2063
ꢀ31.2235
ꢀ31.3653
ꢀ30.0671
ꢀ24.039
ꢀ75.7726
ꢀ71.9881
ꢀ70.1908
ꢀ65.9785
ꢀ42.4025
ꢀ70.7715
ꢀ68.6724
ꢀ71.1119
ꢀ51.2566
ꢀ69.8586
ꢀ59.6429
ꢀ65.4811
ꢀ61.3411
ꢀ65.3822
ꢀ71.1171
ꢀ59.3032
ꢀ58.6646
ꢀ56.3152
ꢀ56.1612
ꢀ56.6993
ꢀ49.0541
ꢀ58.4542
ꢀ51.8065
ꢀ53.8422
ꢀ18.8896
ꢀ19.3879
ꢀ19.7693
ꢀ18.0202
ꢀ16.9804
ꢀ17.1314
ꢀ11.178
2.5
4.2
ꢀ379.177 ꢀ44.743
ꢀ40.5407
ꢀ398.286 ꢀ42.2567 ꢀ43.9281
ꢀ259.853 ꢀ40.9669 ꢀ33.8891
ꢀ359.284 ꢀ41.9247 ꢀ37.9216
ꢀ384.701 ꢀ39.4418 ꢀ44.3643
ꢀ367.321 ꢀ49.5066 ꢀ39.297
ꢀ400.059 ꢀ43.1326 ꢀ44.8307
2.14
2.15
2.17
2.16
4.5
2.11
2.10
2.6
2.9
3.2
3.8
2.4
3.3
2.12
3.1
2.3
2.18
2.8
ꢀ26.9806
ꢀ27.1451
ꢀ28.7606
ꢀ30.6285
ꢀ28.4853
ꢀ29.195
ꢀ17.1016
ꢀ19.4939
ꢀ17.1932
ꢀ16.6666
ꢀ16.9829
ꢀ16.4878
ꢀ15.1261
ꢀ13.3303
ꢀ17.1053
ꢀ15.0863
ꢀ14.9212
ꢀ15.4284
ꢀ14.4478
ꢀ12.8196
ꢀ13.0625
ꢀ12.9322
ꢀ13.4993
ꢀ374.852 ꢀ52.315
ꢀ38.1648
ꢀ109.82
ꢀ203.502 ꢀ0.40935 ꢀ17.2089
ꢀ359.428 ꢀ46.3294 ꢀ40.4289
ꢀ348.078 ꢀ41.9709 ꢀ36.5865
ꢀ344.132 ꢀ42.0194 ꢀ35.3252
ꢀ331.338 ꢀ37.2939 ꢀ33.9678
ꢀ95.8228 ꢀ226.098 ꢀ0.45694 ꢀ16.971
ꢀ104.365 ꢀ205.341 ꢀ0.36445 ꢀ23.0116
ꢀ105.813 ꢀ206.169 ꢀ0.41606 ꢀ20.1194
ꢀ95.9809 ꢀ222.752 ꢀ0.48607 ꢀ20.6174
ꢀ102.169 ꢀ227.065 ꢀ0.43846 ꢀ18.7044
ꢀ106.138 ꢀ186.669 ꢀ0.3445 ꢀ19.1691
ꢀ28.2629
ꢀ25.7006
ꢀ23.7235
ꢀ20.9295
ꢀ27.5289
ꢀ27.1866
ꢀ22.6947
ꢀ26.6064
ꢀ23.0104
ꢀ22.0651
ꢀ21.1519
ꢀ21.0005
ꢀ20.3355
ꢀ330.22
ꢀ38.0283 ꢀ36.3433
ꢀ329.269 ꢀ42.851
ꢀ34.4855
ꢀ340.33 ꢀ39.5097 ꢀ37.3865
ꢀ114.204 ꢀ213.336 ꢀ0.3974
ꢀ3.82986
ꢀ319.216 ꢀ39.4209 ꢀ33.4432
ꢀ100.03
ꢀ171.279 ꢀ0.33309 ꢀ19.5219
ꢀ329.32
ꢀ284.88
ꢀ41.1729 ꢀ37.3324
ꢀ40.0202 ꢀ28.3876
ꢀ105.983 ꢀ170.162 ꢀ0.30434 ꢀ16.2156
ꢀ98.8193 ꢀ161.087 ꢀ0.34059 ꢀ18.7
ꢀ88.9445 ꢀ190.158 ꢀ0.29216 ꢀ22.9582
ꢀ97.3175 ꢀ171.226 ꢀ0.34107 ꢀ17.5733
ꢀ85.8291 ꢀ149.89 ꢀ0.31695 ꢀ17.199
ꢀ90.374 ꢀ124.304 ꢀ0.27049 ꢀ14.629
ꢀ318.385 ꢀ33.8189 ꢀ32.8457
ꢀ287.948 ꢀ40.3914 ꢀ30.1253
2.2
2.1
ꢀ268.66
ꢀ35.0508 ꢀ26.1141
ꢀ268.407 ꢀ35.9859 ꢀ27.4171
Table 4. Percentage of in vitro tumor cell lines growth with investigated
substances in 10 mM.
Table 4. Continued
Compound/Growth percent
Compound/Growth percent
Subpanel tumor cell lines
2.5
2.8
2.18
3.8
Subpanel tumor cell lines
2.5
2.8
2.18
3.8
HCT-15
HT29
KM12
SW-620
Renal cancer
786-0
A498
ACHN
CAKI-1
RXF 393
SN12C
TK-10
105 to
Prostate cancer
PC-3
DU-145
Breast cancer
MCF7
MDA-MB-231/ATCC
HS 578T
BT-549
110.56
107.08
117.43
113.17
103.04
106.35
114.67
110.06
107.44
nt
106.26
105.87
102.97
104.49
113.99
102.53
Leukemia
CCRF-CEM
HL-60(TB)
K-562
MOLT-4
RPMI-8226
SR
Non-small cell lung
A549/ATCC
EKVX
HOP-62
HOP-92
95.86
98.58
nt
105.14
nt
95.49
102.64
97.17
110.42
117.38
89.50
18.75
97.02
98.36
90.50
99.12
91.75
102.67
108.99
107.52
116.67
89.67
105.32
80.24
105.30
87.12
120.11
104.86
109.08
nt
106.86
84.51
98.83
73.23
108.49
111.03
111.71
nt
103.03
96.78
94.67
87.51
105.43
101.68
143.35
nt
100.27
54.81
102.70
160.10
112.15
95.31
102.22
nt
108.57
150.08
104.38
105.26
106.59
90.95
102.59
nt
103.03
110.50
92.96
95.59
109.52
101.31
97.95
113.93
96.66
107.47
107.59
88.20
96.01
91.75
85.56
97.09
114.06
99.19
114.93
106.45
87.26
96.80
112.46
99.07
108.30
101.31
89.87
96.83
106.90
92.36
NCI-H226
NCI-H23
96.85
nt
103.10
146.23
89.33
123.87
98.05
147.82
NCI-H322M
NCI-H460
NCI-H522
Colon cancer
COLO 205
HCC-2998
HCT-116
102.97
95.11
103.99
98.85
101.89
99.89
123.36
111.23
106.65
102.96
92.18
89.18
85.79
100.39
92.97
100.24
107.68
109.87
94.03
131.96
97.13
106.59
101.98
102.03
100.25
111.56
104.46
101.75
113.19
77.72
100.03
T-47D
107.69
(continued )
(continued )

12 L. Antypenko et al.
J Enzyme Inhib Med Chem, Early Online: 1–13
Table 4. Continued
Compound/Growth percent
molecular docking for DHFR and CK2 kinase inhibition and
in vitro biological activities speculatively had proven other
antimicrobial and anticancer action mechanisms for synthesized
substances. Thus, library of the antimicrobial and anticancer
substances among 2-R-quinazolin-4(3H)-thione derivatives was
enlarged to be used for future effective drug modifications. And,
taking into the account their other non-investigated biological
activities, studies of the novel synthesized compounds will be
continued.
Subpanel tumor cell lines
2.5
2.8
2.18
3.8
MDA-MB-468
MDA-MB-435
NCl/ADR-RES
Ovarian cancer
IGROV1
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
NCI/ADR-RES
SK-OV-3
Melanoma
LOX IMVI
MALME-3M
M14
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
MDA-MB-435
CNS cancer
SF-268
SF-295
SF-539
SNB-19
SNB-75
U251
Mean of data
Delta of data
Range of data
116.17
107.35
106.74
91.46
111.08
102.43
101.97
95.21
103.48
88.95
107.42
91.31
112.61
115.31
109.61
108.40
100.66
106.74
113.26
71.97
140.99
99.33
100.55
96.66
112.81
117.06
103.00
107.94
104.94
103.48
100.75
101.62
146.62
97.45
Declaration of interest
83.61
104.34
91.31
101.22
The authors declare no conflicts of interest. The authors alone are
responsible for the content and writing of this article.
The authors gratefully acknowledge ‘‘Enamine Ltd.’’ (Kiev, Ukraine)
for financial support of this work.
102.43
102.10
nt
97.13
85.15
101.45
102.81
118.36
99.46
94.13
121.79
111.08
109.57
109.47
111.92
125.84
107.66
87.39
99.95
84.18
95.21
97.75
101.16
100.37
104.18
97.34
109.72
99.36
99.53
117.22
97.74
nt
118.60
100.44
107.03
105.96
nt
References
1. Zheng Y, Bian M, Deng X-Q, et al. Synthesis and anticonvulsant
activity evaluation of 5-phenyl-[1,2,4]triazolo[4,3-c]quinazolin-3-
amines. Arch Pharm 2013;346:119–26.
2. Lee NK, Lee JW, LEE S404-904 J Apt., et al. SK Chemicals Co.,
Ltd.; Leadgenex Inc; Industry Academic Cooperation Foundation of
Kyunghee University, Eur Pat EP 1844023 A1, 2007.
3. Wu J, Bai S, Yue M, et al. Synthesis and insecticidal activity of 6,8-
dichloroquinazoline derivatives containing a sulfide substructure.
Chem Pap 2014;68:969–75.
4. Nomoto T, Ohno K. Studies on cardiotonic agents. VII. Potent
cardiotonic agent KF15232 with myofibrillar Ca2+ sensitizing effect.
Chem Pharm Bull 1991;39:900–10.
107.42
109.50
98.53
101.83
106.25
99.55
101.57
104.38
29.33
118.94
123.25
98.21
89.85
89.19
95.33
103.49
31.52
74.26
103.45
108.42
101.33
104.44
84.82
101.21
99.96
81.21
171.12
109.27
102.60
94.12
64.28
102.51
103.00
85.99
5. Thornton TJ, Jones TR, Jackman AL, et al. Quinazoline antifolates
inhibiting thymidylate synthase: 4-thio-substituted analogs. J Med
Chem 1991;34:978–84.
56.91
124.60
154.11
nt – Not tested.
6. Patrick A, Green TP, Hennequin LF, et al. Discovery of a new class
of anilinoquinazoline inhibitors with high affinity and specificity for
the tyrosine kinase domain of c-Src. J Med Chem 2004;47:871–87.
7. Sanchez AI, Martinez-Barrasa V, Burgos C, et al. Synthesis and
evaluation of quinazoline derivatives as phosphodiesterase 7 inhibi-
tors. Bioorg Med Chem 2013;21:2370–8.
8. Kune JI, Jaroslav B, Pour M, et al. Quinazoline derivatives with
antitubercular activity. Farmaco 2000;55:725–9.
9. Xu G-F, Song B-A, Bhadury PS, et al. Synthesis and antifungal
activity of novel s-substituted 6-fluoro-4-alkyl(aryl)thioquinazoline
derivatives. Bioorg Med Chem 2007;15:3768–74.
10. Shalaby AA, El-Khamry AMA, Shiba A, et al. Synthesis and
antifungal activity of some new quinazoline and benzoxazinone
derivatives. Arch Pharm 2000;333:365–72.
11. Shiba SH, El-Rhamry AA, Shaban ME, Atia KS. Synthesis and
antimicrobial activity of some bis-quinazoline derivatives.
Pharmazie 1997;52:189–94.
12. Abdel-Rahman HM, El-Koussi NA, Hassan HY. Fluorinated 1,2,4-
triazolo[1,5-a]pyrimidine-6-carboxylic acid derivatives as antimy-
cobacterial agents. Arch Pharm 2009;342:94–9.
renal cancer CAKI-1 to 73.23%, still promoting the growth of
ovarian OVCAR-3 and prostate DU-145 cancer lines. Therefore,
investigated substances have not undergone the predetermined
threshold inhibition criteria to be progressed to the next 5-dose
screen.
Structure–anticancer activity correlation. The best anticancer
modification was synthesis of 2-(3,4-dimethoxyphenyl)-substi-
tuted 3H-quinazoline-4-thione, because introduction of carboxylic
acid fragment and the halogen not only increased the anticancer
properties, but procancer as well. Comparing docking results with
in vitro one, substances 2.5, 2.8 and 2.18 had low affinity to CK2
kinase. So, their anticancer activity mechanism should be of other
inhibition pathway.
13. Yu Z, Shi G, Sun Q, et al. Design, synthesis and in vitro
antibacterial/antifungal evaluation of novel 1-ethyl-6-fluoro-1,4-
dihydro-4-oxo-7(1-piperazinyl)quinoline-3-carboxylic acid deriva-
tives. Eur J Med Chem 2009;44:4726–33.
14. Saravanan G, Alagarsamy V, Prakash CR. Synthesis, analgesic, anti-
inflammatory and in vitro antimicrobial activities of some novel
isoxazole coupled quinazolin-4(3H)-one derivatives. Med Chem Res
2013;22:340–50.
15. El-Azab AS, Al-Omar MA, Abdel-Aziz Al A-M, et al. Design,
synthesis and biological evaluation of novel quinazoline derivatives
as potential antitumor agents: molecular docking study. Eur J Med
Chem 2010;45:4188–98.
16. Alanazi AM, Abdel-Aziz Al A-M, Al-Suwaidan IA, et al.
Design, synthesis and biological evaluation of some novel
substituted quinazolines as antitumor agents. Eur J Med Chem
2014;79:446–54.
Conclusions
A number of novel 2-alkyl(aryl)-quinazolin-4-thiones, 2-R-
(quinazolin-4-ylthio)carboxylic acids and amides were synthe-
sized and characterized by their structure, in silico DHFR and
CK2 affinity and in vitro biological activity. The antibacterial and
antifungal screening against S. aureus, E. faecalis, E. aerogenes,
P. aeruginosa, E. coli, K. pneumonia and C. albicans has found
the most active unsubstituted (2.1), 2-methyl-(2.2) and 2-
phenylquinazolin-4(3H)-thione (2.4). The modification of forth
position with carboxylic acids and amides residues resulted in
disappearance of any antimicrobial activity. The NCI anticancer
study revealed 2-trifluoromethyl-(quinazolin-4-ylthio)acetic acid
(3.8) and 2-(3,4-dimethoxyphenyl)-3H-quinazoline-4-thione
(2.18) to have anticancer properties against renal cancer UO-31
and leukemia CCRF-CEM cell lines. Comparison of the in silico
17. Kumar S, Agrawal R. Next generation tyrosine kinase inhibitor
(TKI): Afatinib. Recent Pat Anticancer Drug Discov 2014;9:382–93.

DOI: 10.3109/14756366.2015.1018243 2-Alkyl(aryl)-quinazolin-4(3H)-thiones, 2-R-(quinazolin-4(3H)-ylthio)carboxylic acids and amides 13
18. Tomisek AJ, Christensen BT. Quinazolines. VI. Syntheses of certain 25. Kovalenko SM, Vlasov SV, Silin OV, Chernykh VP. Recyclization of
2-methyl-4-substituted quinazolines. J Am Chem Soc 1948;70:
2423–5.
19. Alvarez J, Shoichet B. Virtual screening in drug discovery. Boca
Raton, FL: CRC Press, Taylor & Francis; 2005.
20. Fred Receptor2.2.5, Vida4.1.1, Flipper, Babel3, Omega2.4.3 and
Fred2.2.5: OpenEye Sci. Soft Inc Santa Fe, NM, USA, 2011.
Available from: http://www.eyesopen.com.
21. Protein Data Bank, pdb. Available from: http://www.pdb.org.
22. Boyd MR. The NCI in vitro anticancer drug discovery screen:
concept, implementation and operation. Totowa, NJ: Humana Press;
1997.
23. Kunes J, Bazant J, Pour M, et al. Quinazoline derivatives with
antitubercular activity. Farmaco 2000;55:725–9.
24. Lygin AV, Meijere A. Ortho-lithiophenyl isocyanide: a versatile
precursor for 3H-quinazolin-4-ones and 3H-quinazolin-4-thiones.
Org Lett 2009;11:389–92.
2-imino-2H-1-benzopyrans under the action of nucleophilic
reagents: the novel approach for 2-(coumarin-3-yl)-3H-quinazolin-
4-thiones. J Sulf Chem 2009;30:53–63.
26. Salah SI, Ali MA-H, Yassien G, et al. Synthesis and biological
evaluation of some new fused quinazoline derivatives. J Chem Res
1997:154–5.
27. Whitlow W, Howard AJ, Stewart D, et al. X-ray crystallographic
studies of Candida albicans dihydrofolate reductase. High resolution
structures of the holoenzyme and an inhibited ternary complex.
J Biol Chem 1997;272:30289–98.
28. Hawser S, Lociuro S, Islam K. Dihydrofolate reductase inhibitors as
antibacterial agents. Biochem Pharmacol 2006;71:941–8.
29. Bliesath J, Huser N, Omoric M, et al. Combined inhibition of
EGFR and CK2 augments the attenuation of PI3K-Akt-mTOR
signaling and the killing of cancer cells. Cancer Lett 2012;322:
113–18.
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