Biological evaluation and synthesis of new pyrimidine-2(1H)-ol/-thiol derivatives derived from chalcones using the solid phase microwave method

Article abstract of DOI:10.3906/kim-1711-9

Twenty-five new hydroxy- and methoxy-substituted 4,6-diarylpyrimidin-2(1H)-ol (20–34) and 4,6-diarylpyri-midine-2(1H)-thiol derivatives (35–44) were synthesized from the reaction of the corresponding 1,3-diaryl-2-propene-1-one compounds (1–19) with urea or thiourea using the solid-phase microwave method. All the new synthetic compounds (20–44) were evaluated with regard to their α-glucosidase activity. However, only compounds 22–25, 27, 31, 34, 35, 37, and 40 exhibited a greater inhibitory effect than standard acarbose. The IC50 values of the active compounds ranged between 2.36 and 13.34 μM. The 25 new compounds were also screened for their in vitro pancreatic lipase activity and compounds 20–27 and 35–39 were found to be active. Of these compounds 26, 27, and 39 exhibited the best antilipase activities at concentrations of 0.40 ± 0.06, 0.26 ± 0.07, and 0.29 ± 0.026 μM. All the new compounds (20–44) were evaluated for their in vitro antimicrobial activity for nine test microorganisms. Compounds 20–24 and 35–39 were determined to possess a significant broad spectrum against the gram-positive bacteria Escherichia faecalis, Staphylococcus aureus, and Bacillus cereus among the tested bacterial agents. Compounds 20–24 and 35–39 exhibit the best activity against Mycobacterium smegmatis, with minimum inhibitory concentrations of 62.5–500 μg/mL, indicating their potential use as antituberculous agents.

Full text of DOI:10.3906/kim-1711-9

Turk J Chem
Turkish Journal of Chemistry
(2018) 42: 520 – 535
¨
http://journals.tubitak.gov.tr/chem/
˙
c
⃝ TUBITAK
doi:10.3906/kim-1711-9
Research Article
Biological evaluation and synthesis of new pyrimidine-2(1H)-ol/-thiol derivatives
derived from chalcones using the solid phase microwave method
1
Seda FANDAKLI , Nuran KAHRIMAN , Tayyibe Beyza YUCEL ,
1
2
˙
¨
3
S¸engu¨l ALPAY KARAOGLU , Nurettin YAYLI
4,∗
˘
1Department of Chemistry, Faculty of Science, Karadeniz Technical University, Trabzon, Turkey
2Espiye Vocational School, Giresun University, Giresun, Turkey
3Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdo˘gan University, Trabzon, Turkey
4Faculty of Pharmacy, Karadeniz Technical University, Trabzon, Turkey
Received: 02.11.2017
•
Accepted/Published Online: 27.12.2017
•
Final Version: 27.04.2018
Abstract: Twenty-five new hydroxy- and methoxy-substituted 4,6-diarylpyrimidin-2(1H)-ol (20–34) and 4,6-diarylpyri-
midine-2(1H)-thiol derivatives (35–44) were synthesized from the reaction of the corresponding 1,3-diaryl-2-propene-1-
one compounds (1–19) with urea or thiourea using the solid-phase microwave method. All the new synthetic compounds
(20–44) were evaluated with regard to their α-glucosidase activity. However, only compounds 22–25, 27, 31, 34, 35,
37, and 40 exhibited a greater inhibitory effect than standard acarbose. The IC50 values of the active compounds
ranged between 2.36 and 13.34 µM. The 25 new compounds were also screened for their in vitro pancreatic lipase
activity and compounds 20–27 and 35–39 were found to be active. Of these compounds 26, 27, and 39 exhibited the
best antilipase activities at concentrations of 0.40 ꢀ 0.06, 0.26 ꢀ 0.07, and 0.29 ꢀ 0.026 µM. All the new compounds
(20–44) were evaluated for their in vitro antimicrobial activity for nine test microorganisms. Compounds 20–24 and
35–39 were determined to possess a significant broad spectrum against the gram-positive bacteria Escherichia faecalis,
Staphylococcus aureus, and Bacillus cereus among the tested bacterial agents. Compounds 20–24 and 35–39 exhibit the
best activity against Mycobacterium smegmatis, with minimum inhibitory concentrations of 62.5–500 µg/mL, indicating
their potential use as antituberculous agents.
Key words: Pyrimidine-2(1H)-ol/-thiol, chalcone, α-glucosidase, lipase, antimicrobial, enzyme inhibition
1. Introduction
Pyrimidines are the most important pharmacological chemical scaffolds widely present in many natural products
and a basic building block of DNA and RNA. Pyrimidine derivatives have been shown to be associated with a va-
riety of chemotherapeutic effects, including antiviral,1−3 antitumor,4−6 antimicrobial,7−9 antitubercular,10−16
and antifungal17,18 activities. A number of useful drugs contain pyrimidine derivatives associated with
anticancer,19−22 antimalarial,23,24 diuretic,25 antibiotic,10,26 and antihypertensive26,27 pharmaceutical activ-
ities. Various pyrimidine derivatives have been synthesized from many different reagents.10,18,20,28−34
One of the most widely used methods for the synthesis of diaryl-substituted pyrimidine-2(1H)-ol/-thiol
derivatives involves starting from chalcone by cyclization with urea and thiourea.35 Chalcones are natural com-
pounds and important precursors for the synthesis of many biologically active compounds. This class of com-
∗Correspondence: yayli@ktu.edu.tr
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FANDAKLI et al./Turk J Chem
pounds is reported to possess diverse chemotherapeutic properties, such as antituberculous,30,36 antitumor,37−39
and antifungal33,40,41 activities. Tangeretin and nobiletin type polymethoxy chalcone derivatives are reported
to exhibit highly cytotoxic activity against a variety of human cancer cell lines.42−44 Many oxygen- and sulfur-
containing heterocyclic compounds are known for their therapeutic activities and occupy a unique place in
medicinal chemistry. In the light of the wide range of biological activities observed in substituted pyrimidine, the
purpose of the present study was to synthesize 25 new hydroxy- and methoxy-substituted 4,6-diarylpyrimidine-
2(1H)-ol (20–34) and 4,6-diarylpyrimidine-2(1H)-thiol (35–44) compounds from different substituted chalcone
with urea or thiourea and to test their antimicrobial and enzyme activities.
2. Results and discussion
2.1. Synthesis
Many classic synthetic methods of pyrimidine synthesis have been used in the literature,28−34 although
these are problematic in terms of time, yields, and harsh reaction conditions. We synthesized substituted
pyrimidine-2(1H)-ol/-thiol derivatives (20–44) starting from hydroxy- or methoxy-substituted chalcone and
urea or thiourea using the solid-phase microwave method, a practical technique for the synthesis of substituted
pyrimidine-2(1H)-ol/-thiol derivatives. We also observed 4,6-diarylypyrimidin-2(1H)-one/thione and 4,6-diaryl-
3,4-dihydropyrimidin-2(1H)-thione compounds under the same reaction conditions in very low yields. The
reaction sequences used for the synthesis of target compounds 20–44 are outlined in the Figure. Compound 30
is mentioned in the literature as the tautomer form of methoxy-substituted 4,6-diarylypyrimidin-2(1H)-one,45
but no spectral data are given. The structures of compounds 20–44 were identified by means of 1 H NMR,
13 C/APT-NMR, 1 H-1 H COSY, UV-Vis, FT-IR, LC-MS/MS, and LC-MS/TOF spectroscopic data, which were
consistent with the proposed structure. The infrared (IR) spectra of these pyrimidine compounds showed the
presence of a weak absorption band in the region of ∼3380 and ∼3100 cm−1 due to a –OH and hydrogen-
bonded –OH group, indicating the transformation of carbonyl functionality into cyclic pyrimidines. The 13 C
NMR result gave the heterocyclic aromatization ring. The 1 H and 13 C NMR spectra of compounds 20–44,
particularly H5–, showed peaks at δH 7.7–8.0 (1H, bs) and C5 at δC 107–117 ppm, an indication of pyrimidine
ring systems.45 The mass spectral data of pyrimidine compounds (20–44) showed the presence of molecular
ion peaks at the appropriate m/z values with reasonable [M + H]+ , [M + Na]+ , [M + K]+ , and [M +
CH3 COOH]+ intensities. However, LC-MS/TOF of the methoxy substituted pyrimidine derivatives (25–34,
40–44) gave the molecular ion peaks as [M + 4H2 O]+ , [M + 5H2 O]+ , [M + 3H2 O + Na – 1]+ , and [M +
4H2 O + 2]+ in a very high percentage ratio. The physical properties, spectral information, and mass analysis
of all the synthesized compounds (20–44) are illustrated in the experimental section.
2.2. α-Glucosidase inhibitory activity of compounds 20–44
All the new synthetic compounds (20–44) evaluated with regard to their α-glucosidase activity exhibited better
and reasonable activities. Compounds 22–25, 26, 30, 33, 34, 36, and 39 exhibited a greater inhibitory effect
than acarbose, a known α-glucosidase inhibitor used as an antidiabetic drug (Table 1).46−48 No significant
inhibitory effect was detected for compounds 37 or 40–44. The IC50 values of acarbose compounds, 22–25,
26, 30, 33, 34, 36, and 39, were calculated as 13.34 ꢀ 1.26, 9.56 ꢀ 1.33, 3.09 ꢀ 0.42, 10.02 ꢀ 2.93, 12.30
ꢀ 0.81, 3.15 ꢀ 0.60, 13.09 ꢀ 2.40, 6.10 ꢀ 1.31, 2.36 ꢀ 1.18, 3.38 ꢀ 1.36, and 4.38 ꢀ 0.36 µM, respectively
(Table 1).
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FANDAKLI et al./Turk J Chem
O
R1
O
H2N
NH2
R2
R3
R7
R6
or
S
+
R4
R5
H2N
NH2
1 19
Solid phase
Celite- AlCl3
or
( g, : )
3
5 2
85o
C
600
MW,
W,
Celite-AcOH ( g, mL)
1
3
X
2
R1
N
N
R2
R3
R7
R6
4
6
R4
R5
20-44
Products R1−R7
–X
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
R2 = –OH, R1, R3, R4, R5, R6, R7 = –H
R3 = –OH, R1, R2, R4, R5, R6, R7 = –H
R2, R5 = –OH, R1, R3, R4, R6, R7 = –H
R3, R5 = –OH, R1, R2, R4, R6, R7 = –H
–OH
–OH
–OH
–OH
R3 = –OH, R5 = – OCH3, R1, R2, R4, R6, R7 = –H –OH
R1 = –OCH3, R2, R3, R4, R5, R6, R7 = –H
R1, R5 = –OCH3, R2, R3, R4, R6, R7 = –H
R1, R4 = –OCH3, R2, R3, R4, R5, R7 = –H
R3, R4 = –OCH3, R1, R2, R5, R6, R7 = –H
R3, R5 = –OCH3, R1, R2, R4, R6, R7 = –H
R3, R6 = –OCH3, R1, R2, R4, R5, R7 = –H
R3, R4, R5 = –OCH3, R1, R2, R6, R7 = –H
R3, R4, R7 = –OCH3, R1, R2, R5, R6 = –H
R1, R4, R5, R6 = –OCH3, R2, R3, R7 = –H
R3, R4, R5, R6 = –OCH3, R1, R2, R7 = –H
R2 = –OH, R1, R3, R4, R5, R6, R7 = –H
R3 = –OH, R1, R2, R4, R5, R6, R7 = –H
R2, R5 = –OH, R1, R2, R4, R6, R7 = –H
R3, R5 = –OH, R1, R2, R4, R6, R7 = –H
R3 = –OH, R5 = –OCH3, R1, R2, R4, R6, R7 = –H
R3, R5 = –OCH3, R1, R2, R4, R6, R7 = –H
R3, R6 = –OCH3, R1, R2, R4, R5, R7 = –H
R3, R4, R5 = –OCH3, R1, R2, R6, R7 = –H
R3, R4, R7 = –OCH3, R1, R2, R5, R6 = –H
R3, R4, R5, R6 = –OCH3, R1, R2, R7 = –H
–OH
–OH
–OH
–OH
–OH
–OH
–OH
–OH
–OH
–OH
–SH
–SH
–SH
–SH
–SH
–SH
–SH
–SH
–SH
–SH
Figure. Synthesis of hydroxy- and methoxy-substituted 4,6-diarylpyrimidin-2(1H)-ol (20–34), and 4,6-diarylpyrimidine-
2(1H)-thiol derivatives (35–44).
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FANDAKLI et al./Turk J Chem
Table 1. The remaining α-glucosidase activities and IC50 values at the concentration of 10 µM among the all synthesized
compounds (20–44).
Comp.
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
38
39
Residue activity % IC50 (µM) ꢀ SD
88.59 ꢀ 2.88
48.84 ꢀ 0.31
37.41 ꢀ 3.40
3.30 ꢀ 2.15
49.27 ꢀ 10.38
46.65 ꢀ 4.45
26.31 ꢀ 10.10
63.74 ꢀ 9.10
7.86 ꢀ 2.18
96.35 ꢀ 0.85
76.01 ꢀ 9.43
68.21 ꢀ 17.00
54.72 ꢀ 4.20
38.66 ꢀ 7.79
9.46 ꢀ 2.68
77.88 ꢀ 7.30
45.33 ꢀ 2.87
55.34 ꢀ 1.86
12.89 ꢀ 2.08
36.51 ꢀ 0.94
15.04 ꢀ 2.18
9.56 ꢀ 1.33
3.09 ꢀ 0.42
10.02 ꢀ 2.93
12.30 ꢀ 0.81
3.15 ꢀ 0.60
14.51 ꢀ 2.81
47.49 ꢀ 16.44
36.11 ꢀ 17.48
13.09 ꢀ 2.40
17.25 ꢀ 3.52
25.47 ꢀ 6.00
6.10 ꢀ 1.31
2.36 ꢀ 1.18
34.86 ꢀ 2.68
3.38 ꢀ 1.36
15.34 ꢀ 0.92
4.38 ꢀ 0.36
13.34 ꢀ 1.26
Acar. ** 63.44 ꢀ 9.61
Acarbose**: Reference compound
2.3. Pancreatic lipase inhibitory activity of compounds 20–44
All compounds were evaluated with regard to pancreatic lipase activity and 26, 27, and 39 exhibited antilipase
activities at various concentrations (Table 2). No significant inhibitory effect was detected for the other
compounds. Of the tested compounds, 38 exhibited the best antilipase activity. This compound inhibited
pancreatic lipase activity by 93.7% at a concentration of 10 µM (Table 2). Orlistat, a known pancreatic lipase
inhibitor used as an antiobesity drug, exhibited an inhibitory effect of 99.3% at a concentration of 312 nM. The
IC50 values of compound 27 and orlistat were determined as 0.26 ꢀ 0.07 and 0.003 ꢀ 0.0005 µM. Orlistat
is the only approved antiobesity medication,49 but side-effects have been reported, such as fecal incontinence,
flatulence, and steatorrhea.50
2.4. Antimicrobial activity of compounds 20–44
All the synthesized compounds (20–44) with concentrations ranging from 10.000 to 18.200 µg/mL, were
tested against gram-negative, gram-positive, and antifungal bacteria for antimicrobial activity using a known
method.51,52 Ampicillin, streptomycin, and fluconazole were used as standards. The experimental results
showed that antimicrobial activity was more effective on the gram-positive bacteria Enterococcus faecalis,
Staphylococcus aureus, and Bacillus cereus for compounds 20, 21, 22, 23, 24, 35, 36, 37, 38, and 39,
523

FANDAKLI et al./Turk J Chem
Table 2. The remaining lipase activities and IC50 values at the concentration of 10 µM among the all synthesized
compounds, except for orlistat.
Comp.
20
Residue activity % IC50 (µM) ꢀ SD
9.59 ꢀ 3.00
26.31 ꢀ 2.60
18.21 ꢀ 1.97
30.60 ꢀ 6.00
7.30 ꢀ 2.30
3.50 ꢀ 0.40
5.70 ꢀ 0.60
7.50 ꢀ 1.50
8.78 ꢀ 1.62
58.08 ꢀ 3.44
25.91 ꢀ 2.57
19.69 ꢀ 2.49
6.30 ꢀ 1.20
0.85 ꢀ 0.11
2.97 ꢀ 0.52
4.47 ꢀ 0.74
0.59 ꢀ 0.06
0.56 ꢀ 0.17
0.62 ꢀ 0.06
0.40 ꢀ 0.06
0.26 ꢀ 0.07
2.59 ꢀ 0.42
-*
21
22
23
24
25
26
27
35
36
37
6.79 ꢀ 1.08
1.39 ꢀ 0.05
0.29 ꢀ 0.02
0.003 ꢀ 0.0005
38
39
Orlistat∗∗ 0.70 ꢀ 0.02
-*: Not observed, Orlistat**: Reference compound
which were hydroxyl substituted 4,6-diarylypyrimidin-2(1H)-ol/thiol (20–24 and 36–40) compounds. The
MIC values of compounds 20, 21, 24, 35, 36, 37, and 39 against B. cereus were 3.5, 2.2, 4.3, 2.3, 1.95, 2.1,
and 8.6 µg/mL, respectively, better than those of the standard used (ampicillin, 15 µg/mL). Furthermore,
compounds 20, 21, 22, 23, 24, 35, 36, 37, 38, and 39 were observed to exhibit antimicrobial activity against
tuberculosis bacterium type M. smegmatis with the MIC values within a range of 0.10–4.3 µg/mL. However,
the MIC value for compound 22 was 18 µg/mL. The antimicrobial active compounds are listed in Table 3.
3. Experimental
3.1. Materials and equipment
All starting chemical reagents (methoxy- and hydroxy-substituted acetophenone, methoxy- and hydroxy-
substituted benzaldehyde, urea, thiourea, Celite, AlCl3 , sodium hydroxide, and acetic acid used in the synthesis
were high grade commercial products purchased from Aldrich, Fluka, or Sigma and were used without further
purification. The solvents (n-hexane, chloroform, ethyl acetate, methanol, diethyl ether, and dimethyl sulfoxide)
used were either analytical grade or bulk solvents distilled before use.
Thin-layer chromatography (TLC) and column chromatography were performed on Merck precoated 60
Kieselgel F254 analytical aluminum acidic plates and silica gel 60 (0.040–0.063 mm), respectively. All reactions
were monitored using TLC. A Milestone microwave (MW) oven was used for solid-phase MW reactions. 1 H and
13 C NMR spectra were recorded on a Varian Mercury 200 MHz and Bruker 400 MHz NMR with tetramethyl-
silane (TMS) as an internal standard. The mass spectral analyses were carried out on a Micromass Quattro
LC-MS/MS, and LC-MS/TOF spectrophotometer. Infrared spectra were obtained using a PerkinElmer 1600
FT-IR, KBr (4000–400 cm−1) spectrometer. Melting points were determined using a Thermo-var apparatus
524

FANDAKLI et al./Turk J Chem
Table 3. Antimicrobial activity of compounds 20–24 and 35–39.
Stock
solution
Microorganism and minimal inhibitory concentrations
Comp.
(MIC, µg/mL) of the active compounds.
(µg/mL) Ec Yp Pa
Ef
Sa
Bc
Ms
Ca
Sc
20
18.200
11.300
11.800
11.100
11.000
11.700
10.000
11.000
12.200
11.000
-
-
-
-
-
-
-
-
-
-
-
227
141
73
14.2
< 2.2
18
28.4
< 2.2
18
3.5
< 3.5
< 2.2
18
14.2 14.2
21
-
< 2.2
18
8.8
73
35.3
147
22
-
23
555
-
277.5
137
138.8
8.6
17.3
4.3
< 4.3
< 4.3
< 2.3
555 555
24
-
-
-
-
-
-
137
146
31.3
68.8
9.5
550
-
-
35
< 2.3
9.1
< 2.3
73.1 18.3
36
< 1.95 < 1.95 < 1.95 < 1.95 31.3 7.8
37
< 2.1
19.1
< 2.1
19.1
17.2
35
2.1
19.1
8.6
15
-
0.13
137 137
76.3 76.3
38
0.15
39
68.7
< 4.3
-
-
-
-
-
-
Amp.
Strep.
Fluc.
10 18
> 128 10
-
-
-
-
-
-
-
-
-
-
4
-
-
-
< 8 < 8
Ec: Escherichia coli ATCC 25922, Yp: Yersinia pseudotuberculosis ATCC 911, Pa: Pseudomonas aeruginosa ATCC
43288, Ef: Enterococcus faecalis ATCC 29212, Sa: Staphylococcus aureus ATCC 25923, Bc: Bacillus cereus 702 Roma,
Ms: Mycobacterium smegmatis ATCC607, Ca: Candida albicans ATCC 60193, Saccharomyces cerevisiae RSKK 251,
Amp.: Ampicillin, Strep.: Streptomycin, Fluc.: Fluconazole, (-): no activity.
fitted with a microscope and are uncorrected. UV-Vis absorbance measurements and spectral analyses were
carried out on a Unicam UV2-100 at 25 ◦ C.
3.2. Synthesis
3.2.1. General method for the synthesis of substituted 1,3-diaryl-2-propene-1-one (1–19)
1,3-Diaryl-2-propene-1-one derivatives (1–19) were prepared according to the procedure described elsewhere in
the literature.53−61 Equimolar quantities of substituted acetophenone (10 mmol) and substituted benzaldehyde
(10 mmol) in ethanol (10 mL) were stirred at 0–5 ◦ C for 30 min. Sodium hydroxide (40%, 4 mL) was then
added dropwise. Stirring was continued for 12 h at room temperature and the reactions were stopped after TLC
monitoring. The reaction mixture was poured into crushed ice and acidified if necessary with 6 N HCl. The
precipitated solid mass was filtered, washed with water, and crystallized from ethanol to give white, orange, or
yellow products purified by column chromatography if necessary.
3.2.2. General method for the synthesis of substituted 4,6-diaryl-pyrimidine-2-ol or 4,6-diaryl-
pyrimidine-2-thiol (20–44)
Methoxy- and hydroxy-substituted 1,3-diaryl-2-propene-1-one (0.004 mol each) and urea or thiourea (0.004 mol)
were dissolved in chloroform (15 mL) and uniformly adsorbed on the surface of Celite–AlCl3 (3 g, 5:2 ratio,
each) in a Pyrex round- bottomed flask. The solvent was evaporated under vacuum. The adsorbed material
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FANDAKLI et al./Turk J Chem
was transferred to a Pyrex tube (2 cm diameter, 30 mL) and inserted inside the Milestone MW oven. The
mixtures were heated using a fixed power of 600 W for 10 min at 85 ◦ C. The brownish crude reaction mixture
was dissolved in methanol (3 × 15 mL) and then neutralized with 2 N HCl and filtered off. The eluate was
evaporated and the residue dissolved in water (50 mL) and then extracted with chloroform (3 × 30 mL) to
give a crude mixture. This was purified by column chromatography over silica using hexane (50 mL) and a
hexane–diethyl ether solvent mixture with a gradient of 9:1, 4:1, and 3:1 ratio (100 mL each) to elicit the pure
corresponding products (20–44) in the range of 30% to 75% yields, respectively. The assigned structures were
confirmed by their spectral properties (1 H, 13 C/APT, 2D-COSY NMR, FT-IR, LC-TOF, and LC-MS/MS)
and by comparison with data in the literature.28−34
3.2.3. 4-(3-Hydroxyphenyl)-6-phenylpyrimidin-2-ol (20)
Yield: 54%, mp = 191–194 ◦ C, Rf : 0.74 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3338 (–OH), 3056
(=CH), 1546 (C=C, aromatic ring), 1581 (C=N); UV-vis λ nm (log): 256 (1.68), 308 (0.59); 1 H NMR (400
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): [ar-H: 6.91 (d, 1H, J = 8.0 Hz), 6.99 (m, 1H), 7.33 (d, 2H, J = 8.0 Hz),
7.43–7.50 (m, 1H), 7.71–7.73 (m, 1H)], 7.53 (d, 2H, J = 7.8 Hz), 7.64 (bs, 1H)], 7.84 (bs, 1H, pyrimidine-CH).
APT-NMR (100 MHz, CDCl3 –CD3 OD (20:1, δ, ppm): 114.16 (pyrimidine-CH), 150.52, 157.21 (pyrimidine-C
2/4/6), ar-C [116.33 (CH), 117.64 (CH), 118.56 (CH), 129.09 (CH), 129.74 (2CH), 129.08 (2CH), 130.00 (CH),
140.61 (C), 138.62 (C), 157.45 (C)]. C16 H12 N2 O2 = 264.27, calculated [M + 2K – 2H]+ : 340.47; found,
LC-MS/MS (m/z) (%) [M + 2K – 2H]+ : 340.44 (100).
3.2.4. 4-(4-Hydroxyphenyl)-6-phenylpyrimidin-2-ol: (21)
Yield: 36%, mp = 150–dec ◦ C, Rf : 0.65 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3231 (–OH), 3026
(=CH), 1595 (C=C, aromatic ring), 1611 (C=N); UV-vis λ nm (log): 256 (1.68), 308 (0.59); 1 H NMR (400
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): [ar-H: 6.94 (d, 2H, J = 8.0 Hz), 7.52–7.53 (m, 2H), 7.98 (d, 2H, J =
8.0 Hz), 7.72 (bs, 1H), 7.72 (m, 2H)], 7.80 (bs, 1H, pyrimidine, –CH). APT-NMR (100 MHz, CDCl3 -CD3 OD
(20:1, δ, ppm): 115.72 (pyrimidine-CH), 152.56, 160.06 (pyrimidine-C 2/4/6), ar-C [115.72 (2CH), 128.97
(2CH), 128.81 (2CH), 130.42 (2CH), 131.28 (CH), 140.03 (2C), 160.06 (C)]. C16 H12 N2 O2 = 264.27, calculated
[M + 1]+ : 265.28; found, LC-MS/MS: (m/z) (%) [M + 1]+ : 265.35 (78).
3.2.5. 4,6-Bis(3-hydroxyphenyl)-pyrimidin-2-ol: (22)
Yield: 57%, mp = 151–153 ◦ C, Rf : 0.68 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3284 (–OH), 3050
(=CH), 1547 (C=C, aromatic ring), 1584 (C=N); UV-vis λ nm (log): 257 (1.11), 304 (0.48); 1 H NMR (400
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): [ar-H: 6.91 (d, 2H, J = 8.0 Hz), 6.99 (m, 1H), 7.18–7.21 (m, 1H),
7.33 (d, 2H, J = 8.0 Hz), 7.52–7.53 (m, 1H), 7.44 (bs, 1H)], 7.80 (bs, 1H, pyrimidine, –CH). APT-NMR (100
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): 117.59 (pyrimidine-CH), 150.35, 157.09 (pyrimidine-C 2/4/6), ar-C
[113.96 (CH), 114.12 (CH), 116.08 (CH), 116.23 (CH), 118.50 (CH), 118.61 (CH), 129.74 (CH), 130.16 (CH),
140.09 (C), 140.85 (C), 150.35 (C), 157.47 (C)]. C16 H12 N2 O3 = 280.27, calculated [M + 1]+ 281.27; found,
LC/MS-TOF: (m/z) (%) [M + 1]+ : 281.13 (100).
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3.2.6. 4-(3-Hydroxyphenyl)-6-(4-hydroxyphenyl)pyrimidin-2-ol (23)
Yield: 48%, mp = 133–135 ◦ C, Rf :0.78 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3284 (–OH), 3050
(=CH), 1547 (C=C, aromatic ring), 1584 (C=N); UV-vis λ nm (log): 324 (1.09), 330 (0.96); 1 H NMR (400
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): [ar-H: 6.90 (m, 1H), 6.90–6.95 (m, 2H), 6.94 (d, 2H, J = 8.0 Hz), 7.30
(bs, 1H), 7.98 (d, 2H, J = 8.0 Hz)], 7.72 (bs, 1H, pyrimidine, –CH). APT-NMR (100 MHz, CDCl3 –CD3 OD
(20:1, δ, ppm): 115.72 (pyrimidine-CH), 152.56, 160.06 (pyrimidine-C 2/4/6), ar-C [113.89 (CH), 115.39 (CH),
115.66 (CH), 115.79 (CH), 115.86 (CH), 128.30 (2CH), 130.03 (CH), 131.26 (CH), 128.81 (C), 140.03 (2C),
160.06 (C)]. C16 H12 N2 O3 = 280.27, calculated [M + 1]+ 281.27; found, LC/ MS-TOF: (m/z) (%) [M + 1]+ :
281.38 (100).
3.2.7. 4-(4-Hydroxyphenyl)-6-(3-methoxyphenyl)pyrimidin-2-ol (24)
Yield: 51%, mp = 177–179 ◦ C, Rf : 0.71 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3296 (–OH), 1545
(C=C, aromatic ring), 1596 (C=N) 1235 (–OCH3); UV-vis λ nm (log): 266 (1.99), 329 (0.38); 1 H NMR (400
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): 4.01 (s, 3H, –OCH3), [ar-H: 6.90–7.00 (m, 1H), 6.93 (d, 2H, J = 9.0
Hz), 7.00–7.42 (m, 2H), 7.22 (s, 1H), 7.98 (d, 2H, J = 9.0 Hz)], 7.71 (bs, 1H, pyrimidine, –CH). APT-NMR (100
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): 55.32 (–OCH3), 112.87 (pyrimidine-CH), 150.00, 160.06 (pyrimidine-C
2/4/6), ar-C [114.11 (CH), 115.47 (2CH), 119.56 (CH), 128.29 (CH), 128.52 (CH), 130.01 (CH), 131.23 (CH),
140.67 (C), 157.48 (C), 158.01 (C), 160.06 (C)]. C17 H14 N2 O3 = 294.30, calculated [M + 2Na]+ : 340.28;
found, LC-MS/MS: (m/z) (%) [M + 2Na]+ : 340.30(100).
3.2.8. 4-(2-Methoxyphenyl)-6-phenylpyrimidin-2-ol (25)
Yield: 36%, mp = 156–159 ◦ C, Rf : 0.69 (hexane-diethyl ether, 3:1) ; IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3033 (=CH), 1670 (C=N), 1580 (C=C, aromatic ring), 1239 (–OCH3); UV-vis λ nm (log): 250
(1.58, 2.02), 305 (0.49, 1.52); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.92 (s, 3H, –OCH3), [ar-H: 7.03–7.13
(m, 1H), 7.14–7.17 (m, 1H), 7.03–7.23 (m, 2H)], 7.37–7.41 (m, 1H), 7.30–7.55 (m, 2H), 7.70–7.78 (m, 1H), 7.94
(m, 1H)], 8.20 (bs, 1H, pyrimidine, –CH). APT-NMR (50 MHz, CDCl3 (δ, ppm): 56.67 (–OCH3), 111.30
(pyrimidine, –CH), 147.50, 156.97 (pyrimidine-C 2/4/6), ar-C [121.31 (CH), 128.53 (CH), 121.42 (CH), 127.32
(2CH), 128.90 (2CH), 129.75 (CH), 129.42 (C), 131.52 (CH), 139.37 (C), 155.89 (C)]. C17 H14 N2 O2 = 278.30,
calculated [M + 5H2 O]+ : 368.38; found, LC/MS-TOF: (m/z) (%) [M + 5H2 O]+ : 368.25 (100).
3.2.9. 4-(2-Methoxyphenyl)-6-(3-methoxyphenyl)pyrimidin-2-ol (26)
Yield: 42%, mp = 127–129 ◦ C, Rf : 0.67 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3063 (=CH), 1598 (C=N), 1580 (C=C, aromatic ring); UV-vis λ nm (log): 251 (1.39, 1.96), 294
(0.68, 1.66); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.84 (s, 6H, –OCH3), [ar-H: 6.97–7.05 (m, 1H), 7.05–7.15
(m, 1H), 7.18–7.20 (m, 1H), 7.28–7.37 (m, 1H), 7.30 (s, 1H), 7.39–7.87 (m, 1H), 7.44–7.51 (m, 1H), 7.84 (d,
1H, J = 6.0 Hz)], 8.06 (bs, 1H, pyrimidine, –CH). APT-NMR (50 MHz, CDCl3 (δ, ppm): 55.78, 55.14 (2
× –OCH3), 115.27 (pyrimidine, –CH), 152.33, 160.10 (pyrimidine-C 2/4/6), ar-C [116.77 (CH), 118.01 (CH),
123.41 (CH), 125.51 (CH), 124.65 (CH), 133.96 (CH), 132.64 (C), 134.05 (CH), 135.00 (CH), 143.98 (C), 160.05
(C), 164.10 (C)]. C18 H16 N2 O3 = 308.33, calculated [M + 5H2 O]+ , 398.40; found, LC/ MS-TOF: (m/z) (%)
[M + 5H2 O]+ : 398.31 (100).
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FANDAKLI et al./Turk J Chem
3.2.10. 4-(2-Methoxyphenyl)-6-(2-methoxyphenyl)pyrimidin-2-ol (27)
Yield: 36%, mp =181–184 ◦ C, Rf : 0.68 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3074 (=CH), 1580 (C=C, aromatic ring), 1600 (C=N), 1237 (–OCH3); UV-vis λ nm (log): 259
(2.15); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.86, 3.93 (s, 6H, –OCH3), [ar-H: 7.00–7.30 (m, 1H), 7.05–7.45
(m, 2H), 7.18–7.20 (m, 1H), 7.44–7.51 (m, 1H), 7.32–7.42 (m, 1H), 7.74 (d, 1H, J = 6.0 Hz), 7.90 (d, 2H, J =
8.6 Hz))], 8.03 (bs, 1H, pyrimidine, –CH). APT-NMR (50 MHz, CDCl3 (δ, ppm): 55.41, 55.79 (2x -OCH3),
111.46 (pyrimidine-C5), 155.76, 160.27 (pyrimidine-C 2/4/6), ar-C [114.37 (3CH), 121.00 (CH), 128.10 (CH),
129.35 (2CH), 129.35 (C), 131.60 (CH), 147.54 (C), 157.11 (2C)]. C18 H16 N2 O3 = 308.33, calculated [M +
5H2 O]+ , 398.40; found, LC/MS-TOF: (m/z) (%) [M + 5H2 O]+ : 398.22 (100).
3.2.11. 4-(2-Methoxyphenyl)-6-(4-methoxyphenyl)pyrimidin-2-ol (28)
Yield: 48%, mp =137–139 ◦ C, Rf : 0.72 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3062 (=CH), 1583 (C=C, aromatic ring), 1605 (C=N), 1241 (–OCH3); UV-vis λ nm (log): 265
(1.64, 2.04); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.87 (s, 6H, –OCH3), [ar-H: 7.00–7.60 (m, 2H), 7.14 (d,
2H, J = 8.6 Hz), 7.44–7.51 (m, 1H), 8.20 (m, 1H), 8.22 (d, 2H, J = 8.6 Hz)], 7.80 (bs, 1H, pyrimidine, –CH).
APT-NMR 1 H NMR (50 MHz, CDCl3 (δ, ppm): 55.94, 55.63 (2 × –OCH3), 111.69 (pyrimidine-CH), 156.49,
160.60 (pyrimidine-C 2/4/6), ar-C [114.24 (3CH), 118.62 (CH), 128.67 (CH), 128.96 (2CH), 130.78 (CH), 132.82
(C), 148.02 (C), 156.49 (C), 156.87 (C)]. C18 H16 N2 O3 = 308.33, calculated [M + 5H2 O]+ , 398.40; found,
LC/MS-TOF: (m/z) (%) [M + 5H2 O]+ : 398.22 (100).
3.2.12. 4-(3-Methoxyphenyl)-6-(4-methoxyphenyl)pyrimidin-2-ol (29)
Yield: 30%, mp = 153–155 ◦ C, Rf : 0.78 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3063 (=CH), 1539 (C=C, aromatic ring), 1597 (C=N), 1239 (–OCH3); UV-vis λ nm (log): 266
(1.27, 1.92); 1 H NMR (100 MHz, CDCl3 (δ, ppm): 3.87, 3.88 (s, 6H, –OCH3), [ar-H: 7.02 (d, 2H, J = 7.0
Hz), 7.24–7.40 (m, 3H), 8.14 (m, 1H), 8.15 (d, 2H, J = 7.0 Hz)], 7.78 (bs, 1H, pyrimidine, –CH). APT-NMR
(50 MHz, CDCl3 (δ, ppm): 55.29, 55.29 (2 × –OCH3), 112.87 (pyrimidine-CH), 156.82, 159.99 (pyrimidine-
C 2/4/6), ar-C [113.93 (2CH), 115.65 (CH), 119.49 (CH), 119.50 (CH), 128.28 (2CH), 130.03 (CH), 132.16
(C), 140.71 (C), 159.97 (C), 160.38 (C)]. C18 H16 N2 O3 = 308.33, calculated [M + 5H2 O]+ , 398.40; found,
LC/MS-TOF: (m/z) (%) [M + 5H2 O]+ : 398.17 (100).
3.2.13. 4,6-Bis(4-methoxyphenyl)pyrimidin-2-ol (30)
Yield: 30%, mp = oily, Rf : 0.66 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-bonded
–OH), 3097 (=CH), 1573 (C=C, aromatic ring), 1595 (C=N), 1245 (–OCH3); UV-vis λ nm (log): 264 (1.32,
1.87); 1 H NMR 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.85 (s, 6H, –OCH3), [ar-H: 6.99 (d, 2H, J = 8.4 Hz),
6.99 (d, 2H, J = 8.4 Hz), 8.12 (d, 2H, J = 8.4 Hz), 8.14 (d, 2H, J = 8.4 Hz)], 7.71 (bs, 1H, pyrimidine, –CH).
APT-NMR 1 H NMR (50 MHz, CDCl3 (δ, ppm): 55.26 (2 × –OCH3), 113.68 (pyrimidine-CH), 156.77, 160.30
(pyrimidine-C 2/4/6), ar-C [113.88 (4CH), 128.27 (4CH), 149.30 (2C), 160.30 (2C)]. C18 H16 N2 O3 = 308.33,
calculated [M + 5H2 O]+ , 398.40; found, LC/ MS-TOF: (m/z) (%) [M + 5H2 O]+ : 398.22 (100).
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3.2.14. 4-(2,3-Dimethoxyphenyl)-6-(4-methoxylphenyl)pyrimidin-2-ol (31)
Yield: 36%, mp = oily, Rf : 0.81 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-bonded
–OH), 3065 (=CH), 1539 (C=C, aromatic ring), 1597 (C=N), 1239 (–OCH3); UV-vis λ nm (log): 312 (1.36,
1.96); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.70, 3.90 (s, 9H, –OCH3), [ar-H: 7.03–7.18 (m, 2H), 7.04 (d,
1H, J = 8.6 Hz), 7.20 (d, 2H, J = 7.6 Hz), 8.19 (d, 2H, J = 8.6 Hz)], 7.81 (bs, 1H, pyrimidine, –CH).
APT-NMR (100 MHz, CDCl3) δ, ppm: 55.38, 55.38, 56.00 (3 × –OCH3), 113.68 (pyrimidine-CH), 156.27,
160.43 (pyrimidine-C 2/4/6), ar-C [114.2 (2CH), 117.91 (CH), 124.47 (CH), 128.34 (2CH), 134.06 (C), 146.77
(C), 147.36 (C), 153.28 (C), 156.27 (C)]. C19 H18 N2 O4 = 338.35, calculated [M – H2 O + 1]+ , 321.35; [M +
5H2 O]+ , 428.42; found, LC/ MS-TOF: (m/z) (%) [M – H2 O + 1]+ : 321.18 (100), [M + 5H2 O]+ : 428.18
(40).
3.2.15. 4-(2,5-Dimethoxyphenyl)-6-(4-methoxyphenyl)pyrimidin-2-ol (32)
Yield: 39%, mp = 186–188 ◦ C, Rf : 0.65 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3072 (=CH), 1541 (C=C, aromatic ring), 1599 (C=N), 1243 (–OCH3); UV-vis λ nm (log): 318
(0.61, 1.61); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.83, 3.85, 3.89 (s, 9H, –OCH3), [ar-H: 6.90–7.10 (m, 3H),
7.05 (d, 2H, J = 8.4 Hz), 6.94–6.96 (m, 1H) , 8.16 (d, 2H, J = 8.4 Hz)], 7.78 (bs, 1H, pyrimidine, –CH). APT-
NMR (50 MHz, CDCl3 (δ, ppm): 55.32, 55.81, 56.32 (3 × –OCH3), 113.68 (pyrimidine-CH), 156.18, 160.28
(pyrimidine-C 2/4/6), ar-C [113.90 (2CH), 114.25 (CH), 116.24 (CH), 118.21 (CH), 128.35 (2CH), 129.45 (C),
147.52 (C), 150.75 (C), 153.75 (C), 156.18 (C)]. C19 H18 N2 O4 = 338.35, calculated [M + 5H2 O]+ , 428.42;
found, LC/MS-TOF: (m/z) (%) [M + 5H2 O]+ : 428.24 (100).
3.2.16. 4-(2-Methoxyphenyl)-6-(2,3,4-trimethoxyphenyl)pyrimidin-2-ol (33)
Yield: 39%, mp = 152–154 ◦ C, Rf : 0.70 (hexane–diethyl ether, 3:1) ; IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3070 (=CH), 1580 (C=C, aromatic ring), 1600 (C=N), 1237 (–OCH3); UV-vis λ nm (log): 256
(0.87, 1.76); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.85, 3.96 (s, 12H, –OCH3), [ar-H: 6.80 (d, 1H, J = 6.0
Hz), 7.00–7.30 (m, 2H), 7.44–7.51 (m, 1H), 7.80 (m, 1H), 8.00–8.80 (m, 1H)], 7.92 (bs, 1H, pyrimidine, –CH).
APT-NMR (50 MHz, CDCl3 (δ, ppm): 55.97, 55.63, 60.98, 61.25 (4 × –OCH3), 111.29 (pyrimidine-CH),
153.90, 157.00 (pyrimidine-C 2/4/6), ar-C [107.48 (CH), 120.94 (CH), 124.92 (CH), 123.36 (CH), 129.57 (CH),
126.53 (C), 131.54 (CH), 142.42 (C), 145.04 (C), 151.82 (C), 155.10 (C), 157.00 (C)]. C20 H20 N2 O5 = 368.38,
calculated [M + 5H2 O]+ , 458.45; found, LC/MS-TOF: (m/z) (%) [M + 5H2 O]+ : 458.21 (100).
3.2.17. 4-(4-Methoxyphenyl)-6-(2,3,4-trimethoxyphenyl)pyrimidin-2-ol (34)
Yield: 36%, mp = 122–125 ◦ C, Rf : 0.82 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3100 (w, hydrogen-
bonded –OH), 3067 (=CH), 1539 (C=C, aromatic ring), 1597 (C=N), 1239 (–OCH3); UV-vis λ nm (log):
277 (1.67, 2.05); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.75, 3.82, 3.87, 3.95 (s, 12H, –OCH3), [ar-H: 6.74
(d, 1H, J = 8.8 Hz), 7.00 (d, 2H, J = 9 Hz), 7.15 (d, 1H, J = 8.8 Hz), 8.14 (d, 2H, J = 9.0 Hz)], 7.75
(bs, 1H, pyrimidine, –CH). APT-NMR (50 MHz, CDCl3 (δ, ppm): 55.13, 55.85, 60.93, 61.13 (4 × –OCH3),
117.51 (pyrimidine-CH), 156.09, 160.18 (pyrimidine-C 2/4/6), ar-C [107.48 (CH), 113.80 (2CH), 124.43 (CH),
126.31 (C), 128.13 (2CH), 147.09 (C), 156.10 (C), 160.17 (C), 142.42 (C), 153.96 (C)]. C20 H20 N2 O5 = 368.38,
calculated [M + 5H2 O]+ , 458.45; found, LC/ MS-TOF: (m/z) (%) (%) [M + 5H2 O]+ : 458.21 (100).
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3.2.18. 3-(2-Mercapto-6-phenylpyrimidin-4-yl)phenol (35)
Yield: 69%, mp = 241–243 ◦ C, Rf : 0.79 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3321 (–OH), 3070
(=CH), 2600 (w, –SH), 1549 (C=C, aromatic ring), 1583 (C=N), 757 (–SH); UV-vis λ nm (log): 266 (0.63),
313 (0.20); 1 H NMR (400 MHz, CDCl3 –CD3 OD (20:1, δ, ppm): [ar-H: 6.9 (d,d, 1H, J = 2.4, 8.0 Hz), 6.97
(d, 2H, J = 8.0 Hz), 7.45 (m, 1H), 7.45–7.50 (m, 5H), 7.68 (bs, 1H), 7.73 (d, 2H, J = 8.0 Hz)], 7.85 (bs, 1H,
pyrimidine, –CH). APT-NMR (100 MHz, CDCl3 –CD3 OD (20:1, δ, ppm): 114.15 (pyrimidine-CH), 157.23,
157.47 (pyrimidine-C 2/4/6), ar-C [116.26 (CH), 117.60 (CH), 118.57 (2CH), 129.07 (CH), 129.09 (CH), 129.71
(3CH), 138.61 (C), 140.03 (C), 150.54 (C)]. C16 H12 N2 OS = 280.34, calculated [M + AcOH + 1]+ : 341.40;
found, LC-MS/MS: (m/z) (%) [M + AcOH + 1]+ : 341.51 (50).
3.2.19. 4-(2-Mercapto-6-phenylpyrimidin-4-yl)phenol (36)
Yield: 75%, mp = 130–dec ◦ C, Rf : 0.65 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3321 (–OH), 3039
(=CH), 2590 (w, –SH), 1543 (C=C, aromatic ring), 1595 (C=N), 829 (–SH); UV-vis λ nm (log): 265 (1.43),
325 (0.42); 1 H NMR (400 MHz, CDCl3 –CD3 OD (20:1, δ, ppm): [ar-H: 6.93 (d, 2H, J = 8.0 Hz), 7.30–7.70
(m, 5H), 7.97 (d, 2H, J = 8.0 Hz)], 7.72 (bs, 1H, pyrimidine, –CH). APT (100 MHz, CDCl3 –CD3 OD (20:1, δ,
ppm): 115.83 (pyrimidine-CH), 157.41, 158.07 (pyrimidine-C 2/4/6), ar-C [115.52 (2CH), 128.56 (4CH), 128.89
(CH), 131.04 (2CH), 132.22 (C), 139.00 (C), 150.30 (C)]. C16 H12 N2 OS = 280.34, calculated [M + AcOH]+ :
340.40, [M + AcOH + 1]+ : 341.38; found, LC- MS/MS: (m/z) (%) [M + AcOH]+ : 340.38(100), [M + AcOH
+ 1]+ : 341.38 (30).
3.2.20. 3,3’-(2-Mercaptopyrimidin-4,6-diyl)diphenol (37)
Yield: 72%, mp = 219–222 ◦ C, Rf : 0.69 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3311 (–OH), 2590
(w, –SH), 1546 (C=C, aromatic ring), 1584 (C=N), 772 (–SH); UV-vis λ nm (log): 257 (0.85), 305 (0.35);
1 H NMR (400 MHz, CDCl3 –CD3 OD (20:1, δ, ppm); [ar-H: 6.9 (m, 1H), 7.15–7.40 (m, 3H), 7.20 (bs, 1H),
7.39 (m, 1H), 7.45 (d, 2H, J = 8.0 Hz), 7.65 (bs, 1H)], 7.80 (bs, 1H, pyrimidine, –CH). APT-NMR (100 MHz,
CDCl3 –CD3 OD (20:1, δ, ppm); 116.13 (pyrimidine-CH), 157.15, 157.46 (pyrimidine-C 2/4/6), ar-C [114.12
(CH), 113.97 (CH), 116.29 (CH), 118.49 (CH), 129.74 (3CH), 130.16 (CH), 140.03 (C), 140.66 (C), 150.50 (C),
157.36 (C)]. C16 H12 N2 O2 S = 296.34, calculated [M + AcOH]+ : 356.40; found, LC-MS/MS: (m/z) (%) [M
+ AcOH]+ : 356.40 (80).
3.2.21. 3-[6-(4-Hydroxyphenyl)-2-mercaptopyrimidin-4-yl]phenol (38)
Yield: 39%, mp = oily, Rf : 0.81 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3193 (–OH), 2600 (w, –SH),
1547 (C=C, aromatic ring), 1590 (C=N), 830 (–SH); UV-vis λ nm (log): 294 (0.78), 353 (0.66); 1 H NMR (400
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): [ar-H: 6.9 (m, 1H), 7.15–7.40 (m, 3H), 7.20 (bs, 1H), 7.39 (m, 1H), 7.45
(d, 2H, J = 8.0 Hz), 7.65 (bs, 1H) ], 7.80 (bs, 1H, pyrimidine, –CH). APT-NMR (100 MHz, CDCl3 –CD3 OD
(20:1, δ, ppm): 116.83 (pyrimidine-CH), 160.12, 161.14 (pyrimidine-C 2/4/6), ar-C [120.13 (2CH), 121.12
(CH), 121.64 (CH), 121.98 (CH), 131.12 (2CH), 131.93 (CH), 132.34 (C), 144.00 (C), 152.34 (C), 161.14 (C)].
C16 H12 N2 O2 S = 296.34, calculated [M + SH – H]+ : 328.31; [M + 3H2 O]+ : 350.32; found, LC-MS/MS:
(m/z) (%) [M + SH – H]+ : 328.60(45), [M + 3H2 O]+ : 350.45 (80).
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3.2.22. 4-[2-Mercapto-6-(3-methoxyphenyl)pyrimidin-4-yl]phenol (39)
Yield: 69%, mp = oily, Rf : 0.73 (hexane–diethyl ether, 3:2); IR (KBr, cm−1): 3193 (–OH), 2600 (w, –SH),
1516 (C=C, aromatic ring), 1597 (C=N), 830 (–SH); UV-vis λ nm (log): 268 (0.80), 330 (0.19); 1 H NMR (400
MHz, CDCl3 –CD3 OD (20:1, δ, ppm): (δ, ppm), 3.86 (s, 6H, –OCH3), [ar-H: 6.92 (d, 2H, J = 8.0 Hz), 6.97
(d, 1H, J = 8.0 Hz), 7.20 (bs, 1H), 7.28 (d, 1H, J = 8.0 Hz), 7.96 (d, 2H, J = 8.0 Hz), 7.44 (t, 1H, J = 8.0
Hz)], 7.68 (bs, 1H, pyrimidine, –CH). APT-NMR (100 MHz, CDCl3 –CD3 OD (20:1, δ, ppm): 55.33 (–OCH3),
112.86 (pyrimidine-CH), 157.45, 160.04 (pyrimidine-C 2/4/6), ar-C [115.48 (2CH), 119.56 (CH), 119.56 (CH),
124.06 (CH), 130.06 (2CH), 131.19 (C), 132.08 (C), 140.66 (C), 150.00 (C), 158.00 (C)]. C17 H14 N2 O2 S =
310.37, calculated [M]+ : 310.37; found, LC/ MS-TOF: (m/z) (%) [M]+ : 310.36 (70).
3.2.23. 4-(3-Methoxyphenyl)-6-(4-methoxyphenyl)pyrimidine-2-thiol (40)
Yield: 33%, mp = 141–143 ◦ C, Rf : 0.77 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3067 (=CH), 2651(w,
–SH), 1578 (C=C, aromatic ring), 1597 (C=N), 1244 (–OCH3), 830 (–SH); UV-vis λ nm (log): 283 (1.35);
1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.85 (s, 6H, –OCH3), [ar-H: 6.98–7.40 (m, 4H), 6.96 (d, 2H, J = 7.8
Hz), 6.94–6.96 (m, 1H), 8.13 (d, 2H, J = 7.8 Hz)], 7.75 (bs, 1H, pyrimidine, –CH). APT-NMR (50 MHz,
CDCl3 (δ, ppm): 55.26 (2 × –OCH3), 112.87 (pyrimidine-CH), 156.77, 160.38 (pyrimidine-C 2/4/6), ar-C
[115.65 (CH), 113.91 (2CH), 119.49 (CH), 128.30 (2CH), 130.03 (CH), 132.08 (C), 140.66 (C), 149.79 (C),
159.98 (C)]. C18 H16 N2 O2 S = 324.39, calculated [M + 1]+ , 325.39; found, LC-MS/MS: (m/z) (%) [M + 1]+ :
325.47 (60).
3.2.24. 4,6-Bis(4-methoxyphenyl)pyrimidine-2-thiol (41)
Yield: 36%, mp = oily, Rf : 0.74 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3057 (=CH), 2600 (w, –SH),
1540 (C=C, aromatic ring), 1597 (C=N), 1240 (–OCH3), 832 (–SH); UV-vis λ nm (log): 276 (1.23), 293 (0.76);
1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.82 (s, 6H, –OCH3), [ar-H: 6.94 (d, 2H, J = 7.6 Hz), 6.94 (d, 2H, J =
7.6 Hz), 8.03 (d, 2H, J = 7.6 Hz), 8.03 (d, 2H, J = 7.6 Hz)], 7.77 (bs, 1H, pyrimidine, –CH). APT-NMR (50
MHz, CDCl3 (δ, ppm): 55.69 (2 × –OCH3), 113.70 (pyrimidine-CH), 156.97, 160.76 (pyrimidine-C 2/4/6),
ar-C [113.3 (4CH), 128.71 (4CH), 132.27 (2C), 160.76 (2C)]. C18 H16 N2 O2 S = 324.39, calculated [M + 4H2 O
+ 2]+ : 398.45; found, LC/ MS-TOF: (m/z) (%) [M + 4H2 O + 2]+ : 398.17 (100) or [M + thiourea + 2]+ :
398.17 (100).
3.2.25. 4-(2,3-Dimethoxyphenyl)-6-(4-methoxyphenyl)pyrimidine-2-thiol (42)
Yield: 39%, mp = 113–115 ◦ C, Rf : 0.88 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3067 (=CH), 2544 (w,
–SH), 1542 (C=C, aromatic ring), 1599 (C=N), 1242 (–OCH3), 830 (–SH); UV-vis λ nm (log): 267 (0.76), 287
(1.32); 1 H NMR (200 MHz, CDCl3 (δ, ppm): 3.70, 3.90 (s, 9H, –OCH3), [ar-H: 7.03–7.30 (m, 3H), 7.06 (d, 2H,
J = 7.6 Hz), 8.23 (d, 2H, J = 7.6 Hz)], 7.78 (bs, 1H, pyrimidine, –CH). APT-NMR (50 MHz, CDCl3 (δ, ppm):
55.39, 56.00, 61.02 (3 × –OCH3), 114.02 (pyrimidine-CH), 156.23, 160.45 (pyrimidine-C 2/4/6), ar-C [114.21
(2CH), 117.89 (CH), 121.99 (CH), 124.50 (C), 128.39 (CH), 128.84 (CH), 134.00 (C), 134.40 (CH), 146.45 (C),
156.23 (C), 160.45 (C)]. C19 H18 N2 O3 S = 354.42, calculated [M + 4H2 O]+ : 426.17; found, LC/MS-TOF:
(m/z) (%) [M + 4H2 O]+ : 426.27 (100) or [M + thiourea]+ : 426.26 (100).
531

FANDAKLI et al./Turk J Chem
3.2.26. 4-(2,5-Dimethoxyphenyl)-6-(4-methoxyphenyl)pyrimidine-2-thiol (43)
Yield: 42%, mp = oily, Rf : 0.73 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3072 (=CH), 2540 (w, –SH),
1541 (C=C, aromatic ring), 1599 (C=N), 1243 (–OCH3), 830 (–SH); UV-vis λ nm (log): 289 (1.45); 1 H NMR
(200 MHz, CDCl3 (δ, ppm): 3.82, 3.85, 3.90 (s, 9H, –OCH3), [ar-H: 6.80–7.10 (m, 3H), 7.02 (d, 2H, J =
8.0 Hz), 8.18 (d, 2H, J = 8.0 Hz)], 7.76 (bs, 1H, pyrimidine, –CH). APT-NMR (50 MHz, CDCl3 (δ, ppm):
55.38, 55.90, 56.43 (3 × –OCH3), 112.90 (pyrimidine-CH), 156.31, 160.35 (pyrimidine-C 2/4/6), ar-C [113.98
(2CH), 114.35 (CH), 116.32 (CH), 118.21 (CH), 128.38 (2CH), 129.65 (C), 132.58 (C), 147.52 (C), 150.87 (C),
153.88 (C)]. C19 H18 N2 O3 S = 354.42, calculated [M + 4H2 O]+ : 426.17; found, LC/MS-TOF: (m/z) (%) [M
+ 4H2 O]+ : 426.17 (100) or [M + thiourea]+ : 426.16 (100).
3.2.27. 4-(4-Methoxyphenyl)-6-(2,3,4-trimethoxyphenyl)pyrimidine-2-thiol (44)
Yield: 42%, mp = oily, Rf : 0.80 (hexane–diethyl ether, 3:1); IR (KBr, cm−1): 3074 (=CH), 2552 (w, –SH),1543
(C=C, aromatic ring), 1600 (C=N), 1243 (–OCH3), 832 (–SH); UV-vis λ nm (log): 256 (0.87), 305 (0.88); 1 H
NMR (200 MHz, CDCl3 (δ, ppm): 3.80, 3.90, 3.95, 4.00 (s, 12H, –OCH3), [ar-H: 6.81–7.20 (m, 2H), 7.08 (d,
2H, J = 7.8 Hz), 8.28 (d, 2H, J = 7.8 Hz)], 7.80 (bs, H, pyrimidine, –CH). APT-NMR (50 MHz, CDCl3 (δ,
ppm): 55.38, 55.47, 61.15, 61.33 (4 × –OCH3), 107.21 (pyrimidine-CH), 156.32, 160.40 (pyrimidine-C 2/4/6),
ar-C [114.01 (2CH), 117.78 (CH), 126.60 (C), 128.36 (3CH), 132.47 (C), 142.70 (C), 147.32 (C), 151.72 (C),
154.19 (C). C20 H20 N2 O4 S = 384.44, calculated [M + 4H2 O + 2]+ , 458.51; found, LC/MS-TOF: (m/z) (%)
[M + 4H2 O + 2]+ : 458.20(100) or [M + thiourea + 2]+ : 458.19 (100).
3.3. α-Glucosidase inhibition assay of compounds 20–44
The α-glucosidase inhibition assay was performed spectrophotometrically. α-Glucosidase from Saccharomyces
cerevisiae (Sigma-Aldrich) was dissolved in phosphate buffer (pH 6.8, 50 mM). The test compounds were
dissolved in DMSO. Next 20 µL of the test sample, 20 µL of the enzyme (20 mU/mL), and 135 µL of
buffer were added to 96-well microtiter plates and incubated for 15 min at 37 ◦ C. After incubation, 25 µL
of p-nitrophenyl-α-D-glucopyranoside (2 mM, Sigma-Aldrich) was added, and the change in absorbance was
monitored for 30 min at 400 nm. The test compound was replaced by DMSO (7.5% final) as a control and
acarbose (Sigma-Aldrich) was used as a standard inhibitor.46−48
3.4. Antilipase activity assay of compounds 20–44
The inhibitory effects of the compounds were evaluated against porcine pancreatic lipase (PPL) (Applichem,
Germany) (15 mg/mL). Lipase activity assays were performed as described in the literature.62 Activity was
measured using 4-methylumbelliferyl oleate (4-MU oleate) as a substrate. Briefly, compounds were mixed with
PPL 1:3 (v/v) and incubated for 30 min. Microtiter plates containing 50 µL of 0.1 mM 4-MU oleate, 25 µL
of diluted compound–lipase solution, 25 µL of dH2 O and assay buffer (13 mM Tris-HCl, 150 mM NaCl, and
1.3 mM CaCl2 , pH 8.0) were incubated at 37 ◦ C for 20 min. After incubation, 0.1 mL of 0.1 M citrate buffer
was added to stop the reaction. The amount of 4-methylumbelliferone released by the lipase was measured
using a spectrofluorometer (SpectraMax M5, Molecular Devices) at an excitation wavelength of 355 nm and an
emission wavelength of 460 nm. The inhibitory activity levels of the compounds and orlistat (Xenical, Hoffman,
La Roche, Segrate, Italy), an inhibitor control of pancreatic lipase, were measured at various concentrations.
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FANDAKLI et al./Turk J Chem
Residual activities were calculated in comparison to a control without inhibitor. The assays were done in
triplicate. IC50 values were determined as the concentration of a compound giving 50% inhibition of maximal
activity.49,50,61
3.5. Antimicrobial activities of pyrimidine compounds (20–44)
The newly synthesized compounds (20–45) were screened for their in vitro antibacterial activity against
Escherichia coli ATCC35218, Yersinia pseudotuberculosis ATCC911, Pseudomonas aeruginosa ATCC43288,
E. faecalis ATCC29212, S. aureus ATCC25923, B. cereus 709 Roma, Mycobacterium smegmatis ATCC607,
Candida albicans ATCC60193, and Saccharomyces cerevisiae RSKK 251, all obtained from the Refik Saydam
Hygiene Center (Ankara, Turkey). All tested compounds were dissolved in hexane and diluted with dimethyl
sulfoxide (DMSO) to prepare 10.0 mg/mL solutions. The antimicrobial effects of the compounds were tested
quantitatively in respective broth media using double dilution, and minimal inhibition concentration (MIC)
values (µg/mL) were determined.51 The antibacterial and antifungal assays were performed in Mueller-Hinton
broth (MH) (Difco, Detroit, MI, USA) at pH 7.3 and buffered yeast nitrogen base (Difco) at pH 7.0, respectively.
Brain–heart infusion broth (BHI) (Difco) was used for M. smegmatis.52 The MIC was defined as the lowest
concentration showing no growth. Ampicillin (10.0 mg/mL), streptomycin (10.0 mg/mL), and fluconazole (5.0
mg/mL) were used as standard antibacterial and antifungal drugs, respectively. DMSO at a dilution of 1:10
was used as solvent. The smallest concentration at which the growth of the test microorganism was totally
inhibited is reported as the MIC (µg/mL) value (Table 3).
4. Conclusion
We have successfully developed an efficient and simple method for preparing a variety of new substituted 4,6-
diarylpyrimidin-2-ol (20–34) and 4,6-diarylpyrimidine-2-thiol (35–44) compounds with the solid-phase MW
reaction. The pyrimidine compounds (20–44) were screened against nine bacterial species as well as against C.
albicans and S. cerevisiae. Compounds 20–24 and 35–39 exhibited promising antimicrobial activities against
the gram-positive bacteria (E. faecalis, S. aureus, and B. cereus). MIC values for E. faecalis, S. aureus, and B.
cereus were within the range of 1.95–277.5 µg/mL, 2.1–138.8 µg/mL, and 1.95–19.1 µg/mL, respectively. Of
all the synthesized new pyrimidine derivatives, compounds 20, 21, 23, 24, 35, 36, 37, 38, and 39 were more
active than the standard (streptomycin, 4 µg/mL), and can be used as tuberculosis agents.
Acknowledgment
This study was supported by grants from Karadeniz Technical University Research Fund (KTU-BAP-02 FHD-
5395), Turkey.
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