Synthesis and crystal structures of some new 2-(diphenylamino)-4,5-disubstituted thiazole derivatives

Article abstract of DOI:10.3184/174751916X14610676453088

The reactions of diphenylamine and benzoyl isothiocyanates with phenacyl bromide or methyl 2-bromoacetate in the presence of triethylamine yield 2,4,5-trisubstituted thiazole derivatives. The molecular structures of [2-(diphenylamino)-4-phenylthiazol-5-yl

Full text of DOI:10.3184/174751916X14610676453088

326 RESEARCH PAPER
VOL. 40 JUNE, 326–330
JOURNAL OF CHEMICAL RESEARCH 2016
Synthesis and crystal structures of some new 2-(diphenylamino)-4,5-
disubstituted thiazole derivatives
Reza Heydaria*, Fahimeh Shahrekipoura, Claudia Graiffb and Batool Tahamipourc
aDepartment of Chemistry, Faculty of Sciences, University of Sistan and Baluchestan, PO Box 98135-674, Zahedan, Iran
bDipartimento di Chimica, Universitá di Parma, Viale delle Scienze 17/A Campus Universitario 43100, Parma, Italy
cFarhangian University of Kerman, Kerman, Iran
The reactions of diphenylamine and benzoyl isothiocyanates with phenacyl bromide or methyl 2-bromoacetate in the presence of
triethylamine yield 2,4,5-trisubstituted thiazole derivatives. The molecular structures of [2-(diphenylamino)-4-phenylthiazol-5-yl](o-tolyl)
methanone and methyl 4-(4-chlorophenyl)-2-(diphenylamino)thiazole-5-carboxylate have been fully determined by means of single
crystal X-ray diffraction methods.
Keywords: diphenylamine, benzoyl isothiocyanate, phenacyl bromide, methyl 2-bromoacetate, 2,4,5-trisubstituted thiazoles
1
Thiazoles are some of the most commonly encountered
heterocycles amongst compounds of biological interest and
in bioactive natural products of microbial and marine origin.
They exhibit important biological activities such as antitumour,
antifungal, antibiotic, antiviral and antibacterial properties.1–6
In nature, the thiazolium ring is the chemically active centre
in the coenzyme derived from vitamin B1.7 Synthetic thiazoles
also occupy a prominent position in drug discovery processes
and this ring system is found in a number of marketed drugs.8,9
Several methods for the synthesis of thiazole derivatives have
been developed,10–16 of which the most widely used is the
Hantzsch synthesis.17 In recent years, the synthesis of many new
2,4,5-trisubstituted thiazole derivatives with varied biological
activities has been developed.18–22
The H NMR spectrum of compound 5c showed a singlet
at δ 2.39 for the CH3 protons and the protons of the phenyl
rings gave rise to characteristic signals in the aromatic region
of the spectrum (δ 6.80–7.53). The 13C NMR spectrum of
compound 5c showed CH3 and C=O signals at 19.8 and 190.4
ppm respectively. In the IR spectrum of compound 5c, the C=O
stretching band was observed at 1600 cm–1. The mass spectrum
of 5c displayed the molecular ion peak (M+) at m/z 446.
A proposed mechanism for the preparation of 5 is
outlined in Scheme 2. Addition of diphenylamine to the
aroyl isothiocyanates affords intermediate 7. Nucleophilic
substitution on the bromomethyl group of 3 by sulfur produces
8, from which an intramolecular cyclisation reaction results in
intermediate 9. The latter is in equilibrium with intermediate 10
which undergoes cyclisation and dehydration to afford product
5.23
In this paper we have fully characterised some new
2,4,5-trisubstituted thiazole derivatives 5a–c and 6a–c which
were prepared by condensation of diphenylamine and benzoyl
isothiocyanates with phenacyl bromide or with methyl
2-bromoacetate (Scheme 1).
The synthetic route for preparation of compounds 6a–c is
outlined in Scheme 1. These compounds were prepared by a
one-pot condensation of the benzoyl isothiocyanates with
methyl 2-bromoacetate and diphenylamine in the presence of
triethylamine.
Results and discussion
The reactions of diphenylamine and benzoyl isothiocyanates
with phenacyl bromide in refluxing acetonitrile in the presence
of triethylamine furnished 2,4,5-trisubstituted thiazole
derivatives 5a–c. The molecular and crystal structure of
compound 5c has been fully elucidated by means of X-ray
diffraction analysis.
1
Compounds 6a–c were characterised by means of IR, H
NMR, 13C NMR and mass spectrometric methods together
with elemental analysis. The molecular and crystal structure
of compound 6b has been fully elucidated by means of X-ray
diffraction analysis.
N
N
O
S
N
Br
5a: X = H
O
3
H
N
S
O
5a-c
5b: X = 4-Cl
5c: X = 2-CH3
C
X
N
Et3N
CH3CN, reflux
X= H, 4-Cl, 2-CH3
+
X
X
1
2
N
O
Br
S
OMe
6a: X = H
4
O
OMe
6a-c
6b: X = 4-Cl
6c: X = 2-CH3
Scheme 1 Preparation of 2,4,5-trisubstituted thiazole derivatives 5a–c and 6a–c.
* Correspondent. E-mail: heydari@chem.usb.ac.ir

JOURNAL OF CHEMICAL RESEARCH 2016 327
O
O
S
r
B
H
N
Ph
+
Ar
N
S
C S
+
Ph
Ph
Ar
N
N
H
R
O
2
Ph
1
7
3
R = OMe, Ph
Ph
O
R
R
Ph
N
N
Ph
N
Ph
Ph
O
H
O
R
O
Et3N
=
S
R
Ph
OMe
2O
OMe
S
S
N
Ph
Ph
N
-
H
N
Ar
N
Ar
N
Ar
Ar
O
H
6
8
9
O
O
=
R
Ph
O
H
O
O
H
Ph
H
2O
NH
NH
Ph
Ph
Ph
Ph
N
S
N
r
A
N
Ar
S
r
N Ph
A
Ph
S
Ph
O
Ph
10
O
-
H
2O
Ph
N
Ph
N
Ph
Ar
S
O
5
Scheme 2 Proposed mechanism for the formation of 5 and 6.
1
the substituted benzoyl isothiocyanate (1 mmol) and phenacyl bromide
(0.20 g, 1 mmol) or methyl 2-bromoacetate (0.15 g, 1 mmol) in
acetonitrile (5 mL) and the mixture was refluxed for 2 h. After
completion of the reaction, which was monitored by TLC, the product
was filtered off and recrystallised from ethanol.
[2-(Diphenylamino)-4-phenylthiazol-5-yl](phenyl)methanone
(5a): Orange crystals; yield 80% (0.35 g); m.p. 212–214 °C (lit.25
214–215 °C); IR (KBr) (νmax cm–1): 3050 (CHaromatic), 1599 (C=O),
1334 (C–N); 1H NMR (400 MHz, CDCl3): δ 7.06–7.17 (m, 5H, ArH),
7.26–7.37 (m, 5H, ArH), 7.43–7.48 (m, 4H, ArH), 7.51–7.55 (m, 6H,
ArH); 13C NMR (100 MHz, CDCl3): δ 124.3 (C), 126.2 (4CH), 126.9
(2CH), 127.6 (2CH), 127.7 (2CH), 128.6 (CH), 129.3 (2CH), 129.8
(4CH), 130.0 (2CH), 131.7 (CH), 134.7 (C), 137.9 (CH), 144.2 (2C),
158.1 (C4thiazole), 170.6 (C2thiazole), 189.1 (C=O); MS m/z (%): 432 (M+,
100), 431 ([M – 1]+, 78), 385 (18), 355 (13), 225 (16), 133 (24), 105 (35),
77 (62). Anal. calcd for C28H20N2OS (432.54): C, 77.75; H, 4.66; N,
6.48; found: C, 77.80; H, 4.61; N, 6.44%.
(4-Chlorophenyl)[2- (diphenylamino) -4-phenylthiazol-5-
yl]methanone (5b): Orange crystals; yield 90% (0.42 g); m.p.
185–187 °C; IR (KBr) (νmax cm–1): 3060 (CHaromatic), 1610 (C=O),
1331 (C–N); 1H NMR (400 MHz, CDCl3): δ 7.07 (dt, 2H, 3J = 7.6 Hz,
4J = 2 Hz, ArH), 7.18 (t, 2H, 3J = 8.0 Hz, ArH), 7.28–7.37 (m, 5H, ArH),
7.43–7.56 (m, 10H, ArH); 13C NMR (100 MHz, CDCl3): δ 124.2 (C),
126.2 (4CH), 127.0 (2CH), 127.8 (2CH), 127.9 (2CH), 129.3 (2CH),
129.8 (4CH), 131.2 (2CH), 131.9 (CH), 133.2 (C), 134.6 (C), 137.9
(C), 144.1 (2C), 156.7 (C4thiazole), 170.6 (C2thiazole), 188.8 (C=O); MS
m/z (%): 466 (M+, 100), 465 ([M – 1]+, 74), 389 (9), 194 (18), 225 (18),
167 (28), 105 (34), 77 (57). Anal. calcd for C28H19ClN2OS (466.98): C,
72.02; H, 4.10; N, 6.00; found: C, 71.99; H, 4.10; N, 5.84%.
The H NMR spectrum of 6b showed a singlet at δ 3.73
for the OCH3 proton and the phenyl ring protons gave rise to
characteristic signals in the region 7.28–7.79 ppm. The 13C
NMR spectrum of 6b showed OCH3 and C=O carbons at
51.9 and 169.8 ppm respectively. In the IR spectrum of 6b, the
C=O and C–O bands were observed at 1696 and 1247 cm–1
respectively. The mass spectrum of 6b displayed the molecular
ion peak (M+) at m/z 420.
A proposed mechanism for the preparation of 6 is outlined in
Scheme 2. The reaction starts with the formation of 7 by addition
of diphenylamine (1) to the aroyl isothiocyanate 2. Subsequent
nucleophilic alkylation of 7 with methyl bromoacetate yields
intermediate 8. Cyclisation and dehydration of 8 affords
thiazoles 6.
Experimental
All reagents were purchased from Merck and Fluka and were used
without further purification. The structures of the compounds were
determined on the basis of their elemental analyses, IR, 1H NMR and
13C NMR spectroscopy, mass spectra and single-crystal X-ray analysis.
Melting points were measured on an Electrothermal 9100 apparatus.
IR spectra were measured on a Shimadzu IR-460 spectrophotometer.
The H and 13C NMR spectra were recorded at 400.1 and 100.6 MHz
1
respectively on a Bruker Ultrashield 400 Avance III with CDCl3 as
solvent and TMS as internal standard. Mass spectra were recorded
on an Agilent Technology (HP) 5973 mass spectrometer operating
at an ionisation potential of 70 eV. Elemental analysis for C, H and N
were performed using a PerkinElmer CHNS-O Elemental Analyser.
Benzoyl isothiocyanates were prepared according to the reported
procedure.24
[2-(Diphenylamino)-4-phenylthiazol-5-yl](o-tolyl)methanone
(5c): Orange crystals; yield 78% (0.35 g); m.p. 180–182 °C; IR (KBr)
(νmax cm–1): 3050 (CHaromatic), 1600 (C=O), 1331 (C–N); 1H NMR (400
Synthesis of 2-(diphenylamino)-4,5-disubstituted-thiazole derivatives;
general procedure
3
MHz, CDCl3): δ 2.39 (s, 3H, CH3), 6.82 (t, 1H, J = 7.6 Hz, ArH),
6.99–7.14 (m, 6H, ArH), 7.27–7.33 (m, 4H, ArH), 7.44 (t, 4H,
3J = 7.6
A solution of triethylamine (0.10 g, 1 mmol) in acetonitrile (1 mL) was
added dropwise to a stirred solution of diphenylamine (0.17 g, 1 mmol),
Hz, ArH), 7.51 (m, 4H, ArH); 13C NMR (100 MHz, CDCl3): δ 19.8

328 JOURNAL OF CHEMICAL RESEARCH 2016
Table 1 Crystal data, collection and refinement details for compounds
5c and 6b
(CH3), 124.9 (CH), 126.2 (4CH), 126.9 (2CH), 127.3 (2CH), 128.5
(CH), 128.7 (2CH), 129.5 (2CH), 129.8 (4CH), 129.9 (C), 130.5 (CH),
134.4 (C), 136.3 (C), 138.6 (C), 144.1 (2C), 159.2 (C4thiazole), 171.1
(C2thiazole), 190.4 (C=O); MS m/z (%): 446 (M+, 73), 391 (34), 328
(100), 252 (35), 118 (64), 105 (16), 91 (72), 77 (38). Anal. calcd for
C29H22N2OS (446.56): C, 78.00; H, 4.97; N, 6.27; found: C, 77.93; H,
4.92; N, 6.18%.
5c
6b
Formula
C29H22N2OS
446.56
Monoclinic
C2/c
C23H17ClN2O2S
420.90
Triclinic
Formula weight
Crystal system
Space group
P-1
Methyl 2-(diphenylamino)-4-phenylthiazole-5-carboxylate (6a): Yellow
crystals; yield 77% (0.30 g); m.p. 213–215 °C (lit.26 212.1–212.6 °C); IR
(KBr) (νmax cm–1): 1700 (C=O), 1332 (C–N), 1250 (C–O); 1H NMR (400
MHz, CDCl3): δ 3.73 (s, 3H, OCH3), 7.28–7.32 (m, 2H, ArH), 7.41–7.49
(m, 11H, ArH), 7.80–7.82 (m, 2H, ArH); 13C NMR (100 MHz, CDCl3):
δ 51.8 (OCH3), 112.1 (C), 126.2 (4CH), 126.8 (2CH), 127.6 (2CH), 129.1
(CH), 129.8 (4CH), 129.9 (2CH), 134.4 (C), 144.2 (2C), 159.4 (C4thiazole),
162.2 (C2thiazole), 169.7 (C=O); MS m/z (%): 386 (M+, 100), 385 ([M – 1]+,
92), 327 (14), 225 (15), 180 (13), 133 (15), 105 (2), 77 (37). Anal. calcd for
C23H18N2O2S (386.47): C, 71.48; H, 4.69; N, 7.25; found: C, 71.57; H, 4.70;
N, 7.30%.
Unit cell dimensions
a = 24.621(2) Å
b = 10.1400(9) Å
c = 20.4896(19) Å
a = 9.578(2) Å
b = 10.192(3) Å
c = 11.606(3) Å
α = 71.807(4)°
ß = 69.400(4)°
γ = 87.865(4)°
1004.1(4) Å3
2
1.392
436
0.317 mm–1
14371
ß = 114.336(2)°
Volume
Z
4660.8(7) Å3
8
Density (calculated) g cm–3 1.273
F(000)
Absorption coefficient
Data collected
Unique data (Rint)
Observed reflections
1872
Methyl 4-(4-chlorophenyl)-2-(diphenylamino)thiazole-5-carboxylate
(6b): Yellow crystals; yield 83% (0.35 g); m.p. 192–194 °C; IR (KBr)
(νmax cm–1): 1696 (C=O), 1333 (C–N), 1247 (C–O); 1H NMR (400 MHz,
CDCl3): δ 3.73 (s, 3H, OCH3), 7.28–7.34 (m, 2H, ArH), 7.37–7.39 (m,
0.163 mm–1
37204
7135
6091
3838
3
4
2H, ArH), 7.42–7.48 (m, 8H, ArH), 7.78 (dt, 2H, J = 6.8 Hz, J = 2.0
Hz, ArH); 13C NMR (100 MHz, CDCl3): δ 51.9 (OCH3), 112.2 (C), 126.2
(4CH), 126.9 (2CH), 127.8 (2CH), 129.8 (4CH), 131.4 (2CH), 132.7 (C),
135.0 (C), 144.1 (2C), 158.0 (C4thiazole), 162.1 (C2thiazole), 169.8 (C=O). MS
m/z (%): 420 (M+, 100), 419 ([M – 1]+, 90), 361 (15), 225 (22), 194 (22),
167 (33), 123 (22), 77 (45). Anal. calcd for C23H17ClN2O2S (420.91): C,
65.63; H, 4.07; N, 6.66; found: C, 65.72; H, 4.10; N, 6.70%.
4135
Parameters/restraints
299/0
263/0
a
b
Final R1 , wR2 (Obs. data)
0.0486, 0.1170
0.0975, 0.1384
1.016
0.0496, 0.1202
0.0869, 0.1395
1.025
a
b
Final R1 , wR2 (all data)
Goodness of fit on Fꢀ2 (S)
CCDC
990840
989214
Methyl 2-(diphenylamino)-4-(o-tolyl)thiazole-5-carboxylate (6c):
Yellow crystals; yield 70% (0.28 g); m.p. 188–190 °C; IR (KBr)
(νmax cm–1): 1710 (C=O), 1325 (C–N), 1256 (C–O); 1H NMR (400 MHz,
CDCl3): δ 2.43 (s, 3H), 3.73 (s, 3H, OCH3), 7.19–7.25 (m, 2H, ArH),
7.30–7.37 (m, 4H, ArH), 7.40–7.46 (m, 8H, ArH); 13C NMR (100 MHz,
CDCl3): δ 19.9 (CH3), 51.7 (OCH3), 104.8 (C), 125.9 (2CH), 126.9
(4CH), 127.7 (2CH), 128.3 (CH), 129.8 (CH), 130.51 (2CH), 131.1
(2CH), 135.1 (C), 136.7 (C), 142.3 (C), 144.2 (2C), 163.7 (C2thiazole),
166.6 (C=O); MS m/z (%): 400 (M+, 77), 399 ([M – 1]+, 40), 341
(100), 259 (30), 212 (27), 169 (30), 147 (60), 77 (57). Anal. calcd for
C24H20N2O2S (400.49): C, 71.98; H, 5.03; N, 6.99; found: C, 71.89; H,
5.03; N, 7.04%.
aR1 = S||F o|-|Fc||/ S|Fo|.
bwR2 = [S[w(Fo2-Fc )2]/S[w(Fo )2]].
2
2
Crystal structure analysis
The X-ray diffraction measurements of 5c and 6b were made
at room temperature on a Bruker APEX II27 single crystal
diffractometer equipped with an area detector using graphite
monochromated Mo-Kα radiation (λ = 0.71073 Å). Orange
and yellow prismatic crystals of 5c and 6b were mounted on
glass fibres and used for data collection. Cell constants and
orientation matrices for data collection were obtained by least-
squares refinement of diffraction data from 999 reflections.
The structures were solved by direct methods and refined by
full-matrix least-squares procedures (based on Fo2),28–30 first
with isotropic thermal parameters and then with anisotropic
thermal parameters in the last cycles of refinement for all the
non-hydrogen atoms for both structures. The hydrogen atoms
were introduced into the geometrically calculated positions and
refined riding on the corresponding parent atoms. CCDC990840
for compound 5c and CCDC989214 for compound 6b contain
the supplementary crystallographic data for this paper. These
data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via
Fig. 1 ORTEP view and atom-numbering scheme of compound 5c. The
ellipsoids are drawn at the 30% probability level.
bond distances and angles is reported in Table 2. The molecule
consists of five rings, A (C1, C2, C3, N1, S) for the thiazole, B
(C5, C6, C7, C8, C9, C10, C11) for the tolyl and C (C12, C13,
C14, C15, C16, C17), D (C18, C19, C20, C21, C22, C23) and E
(C24, C25, C26, C27, C28, C29) for the phenyl groups, which
are nearly planar and are twisted with respect to the mean plane
of the thiazole unit with dihedral angles of 58.94(1)°, 42.00(1)°,
35.16(1)° and 77.71(1)° respectively for A^B, A^C, A^D and
A^E. The part of the molecule consisting of the thiazole ring
and atoms C4, N2, C18 and C24 is nearly planar and the atom O
deviates from it by 0.2910(1) Å. The N–C24 and N2–C18 bond
distances are similar [1.444(2) Å and 1.434(2) Å respectively]
https://summary.ccdc.cam.ac.uk/structure-summary-form
A summary of the crystal data, experimental details and
refinement results for 5c and 6b is given in Table 1.
An ORTEP view of compound 5c is shown in Fig. 1 together
with the atomic labelling scheme. A list of the most important

JOURNAL OF CHEMICAL RESEARCH 2016 329
Table 2 Selected bond distances and bond angles for compound 5c
Table 3 Selected bond lengths and bond angles for compound 6b
Bond lengths/Å
Bond lengths/Å
C1–C2
C1–C4
C1–S
C2–N1
C2–C12
C3–N1
C3–N2
C3–S
C4–O
C4–C5
C18–N2
C24–N2
1.380(2)
1.462(2)
C1–C2
C1–C4
C1–S
C2–N1
C2–C6
C3–N1
C3–N2
C3–S
C4–O1
C4–O2
C5–O2
C12–N2
1.378(2)
1.467(2)
1.7364(17)
1.372(2)
1.475(2)
1.312(2)
1.373(2)
1.7443(17)
1.201(2)
1.341(2)
1.444(2)
1.430(2)
1.441(2
1.7381(14)
1.3757(19)
1.4805(19)
1.3142(18)
1.3667(18)
1.7394(15)
1.2294(19)
1.490(2)
1.434(2)
1.4436(19)
C18–N2
Bond angles/°
C2–C1–C4
C2–C1–S
C4–C1–S
N1–C2–C1
N1–C2–C12
C1–C2–C12
N1–C3–N2
N1–C3–S
N2–C3–S
O–C4–C1
O–C4–C5
C1–C4–C5
C3–N1–C2
C3–N2–C18
C3–N2–C24
C18–N2–C24
C1–S–C3
Bond angles/°
C2–C1–C4
C2–C1–S
C4–C1–S
N1–C2–C1
N1–C2–C6
C1–C2–C6
N1–C3–N2
N1–C3–S
N2–C3–S
O1–C4–O2
O1–C4–C1
O2–C4–C1
C3–N1–C2
C3–N2–C12
C3–N2–C18
C12–N2–C18
C4–O2–C5
C1–S–C3
134.66(13)
109.85(11)
115.46(11)
115.63(12)
117.06(13)
127.29(13)
125.52(13)
115.76(11)
118.72(11)
119.14(15)
121.01(15)
119.66(14)
110.20(12)
124.77(12)
116.76(12)
118.47(11)
88.49(7)
128.25(15)
109.82(12)
121.75(13)
115.58(15)
116.51(15)
127.73(15)
124.43(15)
115.12(12)
120.40(13)
123.04(16)
125.50(17)
111.44(15)
110.74(14)
123.33(14)
118.27(13)
118.40(13)
115.51(15)
88.66(8)
molecular structure of compound 6b, the COOMe group is
nearly planar and it shows a dihedral angle of 6.59(1)° with
the plane of the thiazole ring. As seen from the value of the
torsion angle S–C1–C4–O1 [172.70(5)°], the molecule has the
C=O and S in an anti-periplanar conformation. Similarly, the
exocyclic N2 atom and C12 and C18 attached to it, which form
a planar moiety, are almost coplanar with the thiazole ring, due
to the conjugation of the N-atom lone pair with the thiazole
system. The dihedral angle between this mean plane and
that of the thiazole system is 4.67(1)°. The mean plane of the
4-chlorophenyl moiety has a dihedral angle of 48.21(1)° with
the thiazole-ring plane. In the crystal packing of the molecule
there are no strong intermolecular contacts.
Conclusion
Fig. 2 ORTEP view and atom-numbering scheme of compound 6b. The
The present study reports the synthesis of 2,4,5-trisubstituted
thiazole derivatives by condensation of diphenylamine and
benzoyl isothiocyanates with phenacyl bromide or with methyl
2-bromoacetate. Single crystal X-ray diffraction analysis
confirms the identity of the compounds.
ellipsoids are drawn at the 50% probability level.
and are longer than N2–C3 [1.367(2) Å]. Considering the crystal
packing of the molecule no notable intermolecular contacts are
present.
An ORTEP view of the molecular structure of compound 6b
is shown in Fig. 2 together with the atomic labelling scheme.
A list of the most important bond distances and angles is
reported in Table 3. The molecular structure of compound
6b strongly resembles that reported in the literature.31 In the
We are grateful to the University of Sistan and Baluchestan
Research Council for the partial support of this research.
Received 15 November 2015; accepted 28 February 2016
Paper 1503715 doi: 10.3184/174751916X14610676453088
Published online: 13 May 2016

330 JOURNAL OF CHEMICAL RESEARCH 2016
17 M. Ochiai, Y. Nishi, S. Hashimoto, Y. Tsuchimoto and D.W. Chen, J. Org.
Chem., 2003, 68, 7887.
18 L. Wang, F.-y. Dai, J. Zhu, K.-k. Dong, Y.-l. Wang and T. Chen, J. Chem.
Res., 2011, 35, 313.
References
1
B. Chen and W. Heal, Comprehensive heterocyclic chemistry III, eds A.R.
Katritzky, C.A. Ramsden, E.F.V. Scriven and R.J.K. Taylor. Elsevier, Oxford,
2008. Vol. 4, p. 635.
19 R. Romagnoli, P.G. Baraldi, C.L. Cara, M.K. Salvador, R. Bortolozzi, G.
Basso, G. Viola, J. Balzarini, A. Brancale, X.-H. Fu, J. Li, S.-Z. Zhang and
E. Hamel, Eur. J. Med. Chem., 2011, 46, 6015.
20 A. Gallardo-Godoy, J. Gever, K.L. Fife, B.M. Silber, S.B. Prusiner and
A.R. Renslo, J. Med. Chem., 2011, 54, 1010.
2
3
Y.J. Wu and B.V. Yang, Progress in heterocyclic chemistry, eds G.W. Gribble
and J.A. Joule. Elsevier, Oxford, 2007, Vol. 18, p. 247.
N. Desroy, F. Moreau, S. Briet, G. Le Fralliec, S. Floquet, L. Durant, V.
Vongsouthi, V. Gerusz, A. Denis and S. Escaich, Biorg. Med. Chem., 2009,
17, 1276.
4
5
S. Heng, K.R. Gryncel and E.R. Kantrowitz, Biorg. Med. Chem., 2009, 17,
3916.
E. Bey, S. Marchais-Oberwinkler, R. Werth, M. Negri, Y.A. Al-Soud,
P. Kruchten, A. Oster, M. Frotscher, B. Birk and R.W. Hartmann, J. Med.
Chem., 2008, 51, 6725.
T.A. Farghaly and E.M.H. Abbas, J. Chem. Res., 2012, 36, 660.
R. Breslow, J. Am. Chem. Soc., 1958, 80, 3719.
J.B. Sperry and D.L. Wright, Curr. Opin. Drug Discov. Devel., 2005, 8, 723.
D. Thomae, E. Perspicace, Z. Xu, D. Henryon, S. Schnieder, S. Hesse, G.
Kirsch and P. Seck, Tetrahedron, 2009, 65, 2982.
21 D.N. Darji, T.Y. Pasha, A. Bhandari, K.I. Molvi, S.A. Desai and M.V.
Makwana, Pharma Chem., 2012, 4, 808.
22 D.N. Darji, T.Y. Pasha, A. Bhandari, K.I. Molvi, S.A. Desai and M.V.
Makwana, J. Chem. Pharm. Res., 2012, 4, 2148.
23 K. Challacombe, S.E. Leach, S.J. Plackett and G.D.J. Meakins, J. Chem.
Soc., Perkin. Trans. 1, 1988, 221.
24 A. Saeed, U. Shaheen and M. Bolte, Crystals, 2011, 1, 34.
25 E. Gudriniece, E.K. Matseevskaya and K. Ziemelis, Latv. PSR Zinat.
Akad. Vestis, Kim. Ser., 1967, 5, 559.
26 A. Souldozi, S.H.R. Shojaei, A. Ramazani, K. Slepokura and T. Lis, Chin.
J. Struct. Chem., 2013, 32, 82.
27 Bruker, SMART Software users guide, Version 5.1. Bruker Analytical
X-ray Systems, Madison, WI, 1999.
28 Bruker, SAINT Software users guide, Version 6.0. Bruker Analytical X-ray
Systems, Madison, WI, 1999.
29 G.M. Sheldrick, SADABS. Bruker Analytical X-ray Systems, Madison, WI,
1999.
6
7
8
9
10 S.K. Anandan, J.S. Ward, R.D. Brokx, T. Denny, M.R. Bray, D.V. Patel and
X.Y. Xiao, Bioorg. Med. Chem. Lett., 2007, 17, 5995.
11 T.M. Potewar, S.A. Ingale and K.V. Srinivasan, Tetrahedron, 2007, 63, 11066.
12 A. Zambon, G. Borsato, S. Brussolo, P. Frascella and V. Lucchini,
Tetrahedron Lett., 2008, 49, 66.
13 P.X. Franklin, A.D. Pillai, P.D. Rathod, S. Yerande, M. Nivsarkar, H. Padh,
K.K. Vasu and V. Sudarsanam, Eur. J. Med. Chem., 2008, 43, 129.
14 P. Karegoudar, M.S. Karthikeyan, D.J. Prasad, M. Mahalinga, B.S. Holla
and N.S. Kumari, Eur. J. Med. Chem., 2008, 43, 261.
15 A. Hantzsch and J.H. Weber, Ber. Dtsch. Chem. Ges., 1887, 20, 3118.
16 T. Eicher and S. Hauptmann, The chemistry of heterocycles: structure,
reactions, syntheses and applications, 2nd edn. Wiley-VCH, Weinheim, 2003.
30 G.M. Sheldrick, SHELXL-97, Program for crystal structure refinement.
University of Göttingen, Germany, 1997.
31 A. Souldozi, A. Ramazani, A.R. Dadrass, K. Slepokura and T. Lis, Helv.
Chim. Acta, 2012, 95, 339.