Synthesis of 2-[4-aryl(hetaryl, cyclopropyl)thiazol-2-yl]-3-hetarylacrylonitriles by recyclizations of 2,6-diamino-4-hetaryl-4H-thiopyran-3,5-dicarbonitriles with α-bromoketones

Article abstract of DOI:10.1134/S1070363215040167

Abstract Recyclization of 2,6-diamino-4-hetaryl-4H-thiopyran-3,5-dicarbonitriles with α-bromoketones afforded 2-[4-aryl(hetaryl, cyclopropyl)thiazol-2-yl]-3-hetarylacrylonitriles.

Full text of DOI:10.1134/S1070363215040167

ISSN 1070-3632, Russian Journal of General Chemistry, 2015, Vol. 85, No. 4, pp. 861–865. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © V.D. Dyachenko, 2015, published in Zhurnal Obshchei Khimii, 2015, Vol. 85, No. 4, pp. 618–623.
Synthesis of
2-[4-Aryl(hetaryl, cyclopropyl)thiazol-2-yl]-3-hetarylacrylonitriles
by Recyclizations
of 2,6-Diamino-4-hetaryl-4H-thiopyran-3,5-dicarbonitriles
with α-Bromoketones
V. D. Dyachenko
Shevchenko Lugansk National University, ul. Oboronnaya 2, Lugansk, 91011 Ukraine
e-mail: dyachvd@mail.ru
Received January 19, 2015
Abstract—Recyclization of 2,6-diamino-4-hetaryl-4H-thiopyran-3,5-dicarbonitriles with α-bromoketones afforded
2-[4-aryl(hetaryl, cyclopropyl)thiazol-2-yl]-3-hetarylacrylonitriles.
Keywords: 4H-thiopyranes, α-bromoketone, 3-hetaryl-2-(thiazol-2-yl)acrylonitriles, recyclization
DOI: 10.1134/S1070363215040167
2,6-Diamino-4-aryl(hetaryl)-3,5-dicyano-4H-thio-
pyrans synthesized by reacting aryl(hetaryl)methylidene-
malononitriles with cyanothioacetamide are known to
transform into 6-amino-4-aryl(hetaryl)-3,5-dicyano-
pyridine-2(1H)-thiones when refluxing in ethanol in
the presence of amine [1–4]. In an aqueous ethanol this
reaction resulted in the formation of 4-aryl-6-hydroxy-
3,5-dicyanopyridine-2(1H)-thiones [5–7]. Cross-recycliza-
tion of these thiopyrans afforded 4-aryl-2,6-dihyd-
razino-3,5-dicyanopyridines (in the presence of two-
fold excess of hydrazine) [8], substituted 3-(1-pyr-
idinium)-5-cyano-3,4-trans-1,2,3,4-tetrahydropyridine-
6-thiolates (in the presence of an equimolar amount of
pyridinium ylides) [9], substituted 2-amino-4-aryl-7,7-
dimethyl-5-oxo-3-cyano-5,6,7,8-tetrahydro-4Н-benzo[b]-
pyrans (in the presence of dimedone) [10], and 4-aryl-
5,6-tri(tetra)methylene-3-cyanopyridine-2(1H)-thiones (in
the presence of cycloalkanones enamines) [11, 12].
The reaction probably comprises the thiopyran ring
opening under the action of temperature and a catalyst
to form the corresponding intermediates IV, which
were regioselectively alkylated with α-bromoketones
IIa–IIo to yield compounds V. The latter underwent
intramolecular condensation to the Hantzsch thiazoles
VI followed by malonodinitrile elimination and the
formation of substituted acrylonitriles IIIa–IIIv
(method a). This reaction pathway was proved by
replacing α-bromo ketones II with alkyl halides
without carbonyl function, which led to the retention
of malonodinitrile moiety in the molecules of
intermediates V and to pyridine ring formation [15]
(Scheme 1).
The structures of compounds IIIa–IIIv were
1
confirmed by IR and H NMR spectroscopy data
(Table 2) as well as by authentic Hantzsch synthesis
starting from acrylic acid thioamides VIIa–VIIc and
α-bromo ketones IIa–IIo (method b). For example, in
the IR spectra of acrylonitriles IIIa–IIIv there were
characteristic absorption bands of the stretching
vibrations of the conjugated cyano group in the range
Further developing our previous studies on the
chemistry 4H-thiopyrans [13–16], here we report on
the recyclization of substituted 2,6-diamino-4-[2-furyl-
(thienyl)]-4Н-thiopyran-3,5-dicarbonitriles Ia–Ic with
α-bromoketones IIa–IIo in boiling 2-propanol in the
presence of triethylamine.
1
of 2202–2229 cm–1. H NMR spectra contained the
signals of the vinyl moiety and H5 of the thiazole ring,
which is typical for this class of compounds [17] as
well as the proton signals of aromatic substituents. The
value of the molecular ion peak in the mass spectrum
The products of this transformation were 2-[4-aryl-
(hetaryl, cyclopropyl)thiazol-2-yl]-3-hetarylakrylonitriles
IIIa–IIIv (Tables 1, 2).
861

862
DYACHENKO
Scheme 1.
R
R
R
X
X
X
O
Br
R1
NC
CN
NC
NC
CN
S
NC
CN
а
IIа−IIm
−HBr
NC
H2N
H2N
S
NH2
HN
O
S
R1
Iа−Ic
IV
V
R
R
X
R
X
X
IIа−IIm
−H2O
CN
S
CN
S
NC
NC
CN
S
−CH2(CN)2
b
H2N
N
N
R1
R1
VI
VIIа−VIIc
IIIа−IIIv
I, VII, R = H, X = O (a), Me, O (b), H, S (c); II, R1 = cyclopropyl (a), 6,8-dibromocoumarin-3-yl (b), 4-BuC6H4 (c);
4-PhC6H4 (d), coumarin-3-yl (e), 4-MeC6H4 (f), 3,4-Cl2C6H3 (g), 2-HOC6H4 (h), Ph (i), 2,4-Me2C6H3 (j), 4-ClC6H4 (k),
4-BrC6H4 (l), 4-MeOC6H4 (m); III, R = Н, X = О, R1 = cyclopropyl (a), 6,8-dibromocoumarin-3-yl (b), 4-BuC6H4 (c),
4-PhC6H4 (d), coumarin-3-yl (e), 4-MeC6H4 (f), 3,4-Cl2C6H3 (g), 2-HOC6H4 (h); R = Me, X = О, R1 = 4-BuC6H4 (i), Ph (j),
cyclopropyl (k), 4-PhC6H4 (l), 2,4-Me2C6H3 (m), coumarin-3-yl (n), 4-MeC6H4 (o), 3,4-Cl2C6H3 (p), 4-ClC6H4 (q),
4-BrC6H4 (r); R = Н, X = S, R1 = cyclopropyl (s), 4-PhC6H4 (t), coumarin-3-yl (u), 4-MeOC6H4 (v).
of compound IIIh corresponded to the “nitrogen
rule” [18], and the existence of the ion [M + 2]+
indicated the presence of the sulfur atom in the
molecule [19].
marinyl)thiazoles are known as phosphors [22], and 5-
arylthiazoles show fungicidal [23], antiviral [24, 25]
and anti-enzymatic [26, 27] activity.
EXPERIMENTAL
When comparing the yields of the compounds III
prepared according to the methods a and b it is seen
(Table 1) that in the first case they are smaller
obviously due to occurrence of the side reactions. The
method a possesses a special synthetic importance
because in some cases the aryl(hetaryl)methylidene-
cyanothioacetamides, which are necessary for the
Hantzsch method implementing, failed to be isolated
because of their easy dimerization [20], and alkyl-
methylidenecyanothioacetamides are hitherto un-
known. Note that the organic compounds containing
thiazole moiety are of special interest due to their wide
occurrence in nature [21]. In particular, 4-(3-cou-
IR spectra were recorded on a X-29 spectrometer
(from mulls in mineral oil). H NMR spectra of the
1
DMSO-d6 or CDCl3 solutions were registered on a
Bruker WP-100SY (100 MHz, IIIa, IIIc–IIIf, IIIk–
IIIu), Gemini-200 (200 MHz, IIIv), Bruker AM-300
(300 MHz, IIIb), Varian Mercury-400 (400 MHz, IIIi,
IIIj), Bruker DR-500 (500 MHz, IIIh), and Bruker
AM-300 (300 MHz, IIIg) spectrometers, internal
reference TMS. Mass spectra were taken on a Kratos
MS-890 spectrometer (EI, 70 eV) with a direct input of
the sample into the ion source. Melting points were
determined on a Koeffler heating block. The reaction
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SYNTHESIS OF 2-[4-ARYL(HETARYL, CYCLOPROPYL)THIAZOL-2-YL]-...
863
Table 1. Yields, melting points, and elemental analysis data of compounds IIIa–IIIv
Found, %
H
Calculated, %
Comp.
no.
Yield, %,
method a/b
mp,
°С
Formula
11.47 C13H10N2OS
C
N
C
H
N
IIIа
IIIb
IIIc
IIId
IIIe
IIIf
IIIg
IIIh
IIIi
61/75
68/74
70/81
75/88
69/76
65/70
78/90
60/72
73/88
64/78
61/70
85/91
62/80
73/84
69/75
61/77
72/84
65/80
79/80
84/93
66/72
64/69
82
64.32
45.01
71.72
74.33
65.77
69.72
55.20
65.14
72.24
69.70
65.57
75.09
71.06
66.48
70.42
56.39
62.37
54.86
60.29
71.28
62.86
62.81
4.08
1.42
5.31
4.11
3.04
3.99
2.11
3.31
5.66
3.96
4.62
4.22
4.91
3.19
4.55
2.84
3.22
3.07
3.77
3.66
2.59
3.62
64.44
45.27
71.83
74.55
65.89
69.84
55.35
65.29
72.38
69.84
65.60
74.98
71.22
66.66
70.56
56.52
62.48
55.00
60.44
71.32
62.97
62.94
4.16
1.60
5.43
3.98
2.91
4.14
2.32
3.42
5.79
4.14
4.72
4.38
5.03
3.36
4.61
2.79
3.39
2.99
3.90
3.81
2.78
3.73
11.56
5.56
8.38
7.90
8.09
9.58
8.07
9.52
8.04
9.58
10.93
7.60
8.74
7.77
9.14
7.75
8.57
7.55
10.84
7.56
7.73
8.63
218–220
70–72
5.45
8.25
7.75
7.96
9.41
7.89
9.37
7.95
9.42
C19H8Br2N2O3S
C20H18N2OS
C22H14N2OS
C19H10N2O3S
C17H12N2OS
C16H8Cl2N2OS
C16H10N2O2S
C21H20N2OS
C17H12N2OS
169–171
219–221
139–141
170–172
169–170
91–93
IIIj
IIIk
IIIl
128–130
70–71
10.80 C14H12N2OS
161–163
110–112
173–175
138–140
145–147
141–143
133–135
105–107
190–191
215–217
153–155
7.48
8.65
7.58
8.97
7.66
8.42
7.38
C23H16N2OS
IIIm
IIIn
IIIo
IIIp
IIIq
IIIr
IIIs
IIIt
IIIu
IIIv
C19H16N2OS
C20H12N2O3S
C18H14N2OS
C17H10Cl2N2OS
C17H11ClN2OS
C17H11BrN2OS
10.71 C13H10N2S2
7.43
7.64
8.54
C22H14N2S2
C19H10N2O2S2
C17H12N2OS2
Table 2. Parameters of IR and 1H NMR spectra of compounds IIIa–IIIv
δН, ppm (J, Hz)
Comp.
ν(C≡N,
no. С=О), cm–1
СН= (1Н, s),
Other signals
Н5thiazole (1Н, s)
IIIа
2211
7.96, 7.38
0.78–1.06 m (4H, 2СН2), 2.11 m (1H, CН), 6.74 d.d (1H, H4, furan, J 2.4, J 3.1),
7.31 d (1H, Н3, furan, J 2.9), 8.09 d (1H, H5, furan, J 1.2)
IIIb 2215, 1718
8.12, 8.05
6.79 d.d (1H, H4, furan, J 2.9, J 2.9), 7.32 d (1H, H3, furan, J 2.9), 7.99 d (1H, H5,
furan, J 1.2), 8.01 s (1H, H7, coumarin), 8.48 s (1Н, H5, coumarin), 8.81 s (1H, H4,
coumarin)
IIIc
IIId
2229
2220
8.16, 8.07
8.27, 8.15
8.44, 8.14
0.89 t (3H, CH3, J 7.2), 1.11–1.72 m (4H, 2СН2), 2.60 t (2H, CH2, J 6.0), 6.83 d.d
(1H, H4, furan, J 2.4, J 2.9), 7.37 d (1H, H3, furan, J 2.9), 7.26 d (2Н, HAr, J 7.0),
7.91 d (2Н, HAr, J 7.0), 8.00 d (1H, H5, furan, J 1.2)
6.82 d.d (1H, H4, furan, J 2.4, J 3.2), 7.31 d (1H, H3, furan, J 2.9), 7.35–7.49 m (3H,
HAr), 7.55–7.72 m (2H, HAr), 7.77 d (2H, HAr, J 7.1), 8.01 d (2H, HAr, J 7.1), 8.07 d
(1H, H5, furan, J 1.2)
IIIe 2219, 1722
6.81 d.d (1H, H4, furan, J 2.4, J 3.0), 7.21–7.47 m (3H, H6,7, coumarin; H3, furan),
7.62 d (1H, H8, coumarin, J 8.0), 7.86 d (1H, H5, coumarin, J 8.0), 8.01 d (1H, H5,
furan, J 1.2), 8.77 s (1H, H4, coumarin)
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864
DYACHENKO
Table 2. (Contd.)
δН, ppm (J, Hz)
Other signals
Comp.
ν(C≡N,
no. С=О), cm–1
СН= (1Н, s),
Н5thiazole (1Н, s)
IIIf
2202
2215
8.23, 8.12
8.06, 8.02
8.18, 7.93
8.11, 8.04
2.4 s (3H, CH3), 6.83 d.d (1H, H4, furan, J 2.4, J 3.1), 7.33 d (1H, H3, furan, J 2.8),
7.28 d (2Н, HAr, J 7.7), 7.91 d (2H, HAr, J 7.7), 8.01 d (1H, H5, furan, J 1.3)
7.24 d.d (1H, H4, furan, J 2.4, J 2.4), 7.55 s (1H, HAr), 7.69 d (1H, H3, furan, J 2.8),
7.72 d (1H, HAr, J 7.4), 7.76 d (1H, HAr, J 7.4), 7.91 d (1H, H5, furan, J 1.3)
6.70 d.d (1H, H4, furan, J 1.8, J 2.0), 6.83–6.96 m (3H, HAr), 7.15 t (1H, HAr, J 7.0),
7.32 d (1H, H3, furan, J 3.6), 8.07 d (1H, H5, furan, J 1.3), 10.37 br. s (1H, ОН)
0.88 t (3H, CH3, J 7.3), 1.14–1.72 m (4H, 2CH2), 2.41 s (3H, CH3), 2.58 t (2H, CH2,
J 7.1), 6.46 d (1H, H3, furan, J 2.9), 7.24 d (1H, H4, furan, J 2.9), 7.28 d (2Н, HAr, J
7.1), 7.89 d (2H, HAr, J 7.1)
IIIg
IIIh 3606 (OH),
2227
2216
IIIi
IIIj
IIIk
IIIl
2220
2219
2203
2214
8.22, 8.07
7.87, 7.36
8.25, 8.00
7.98, 7.79
8.44, 8.06
2.43 s (3H, CH3), 6.49 d (1H, H4, furan, J 2.9), 7.28 d (1H, H3, furan, J 2.9), 7.39 t
(1H, HAr, J 6.9), 7.47 t (2H, HAr, J 6.9), 8.02 d (2H, HAr, J 7.0)
0.81–1.07 m (4H, 2CH2), 1.99–2.27 m (1H, CH), 2.42 s (3H, CH3), 6.47 d (1H, H4,
furan, J 2.9), 7.24 d (1H, H3, furan, J 2.9)
2.44 s (3H, CH3), 6.51 d (1H, H4, furan, J 3.0), 7.31 d (1H, H3, furan, J 3.0), 7.41–
7.62 m (2H, HAr), 7.68–7.89 m (5H, HAr), 8.08 d (2H, HAr, J 7.6)
2.31 s (3H, CH3), 2.42 s (6H, 2CH3), 6.48 d (1H, H4, furan, J 3.0), 7.08 d (1H, HAr,
J 8.5), 7.12 s (1H, HAr), 7.26 d (1H, H3, furan, J 3.0), 7.54 d (1H, HAr, J 8.5)
2.44 s (3H, CH3), 6.52 d (1H, H4, furan, J 3.0), 7.26 d (1H, H3, furan, J 3.0), 7.38 t
(1H, H7, coumarin, J 8.0), 7.43 d (1H, H5, coumarin, J 8.0), 7.24 t (1H, H6,
coumarin, J 8.0), 7.91 d (1H, H8, coumarin, J 8.0), 8.81 s (1H, H4, coumarin)
2.34 s (3H, CH3), 2.42 s (3H, CH3), 6.48 d (1H, H4, furan, J 3.0), 7.19 d (1H, H3,
furan, J 3.0), 7.24 d (2H, HAr, J 7.7), 7.89 d (2H, HAr, J 7.7)
III
m
IIIn 2202, 1719
IIIo
IIIp
IIIq
IIIr
IIIs
IIIt
2211
2218
2209
2214
2228
2226
8.10, 8.03
8.24, 8.15
8.24, 8.01
8.26, 8.05
8.41, 7.38
6.49 d (1H, H4, furan, J 3.0), 2.45 s (3H, CH3), 7.32 d (1H, H3, furan, J 3.0), 7.67 d
(1H, HAr, J 8.4), 7.98 d (1H, HAr, J 8.4), 8.10 s (1H, HAr)
2.43 s (3H, CH3), 6.52 d (1H, H4, furan, J 3.1), 7.28 d (1H, H3, furan, J 3.1), 7.51 d
(2H, HAr, J 8.6), 7.98 d (2H, HAr, J 8.6)
2.43 s (3H, CH3), 6.51 d (1H, H4, furan, J 2.9), 7.29 d (1H, H3, furan, J 2.9), 7.65 d
(2H, HAr, J 7.5), 7.95 d (2H, HAr, J 7.5)
0.85–1.07 m (4H, 2CH2), 1.99–2.34 m (1H, CH), 7.29 d.d (1H, H4, thiophene, J 6.1,
J 4.5), 7.93 d (1H, H3, thiophene, J 4.6), 8.03 d (1H, H5, thiophene, J 3.7)
6.92 d (2H, HAr, J 8.4), 7.28–7.54 m (4H, HAr), 7.69–8.21 m (6H, HAr)
7.22–7.48 m (2H, HAr), 7.59–7.66 m (1H, HAr), 7.78 m (3H, HAr), 8.04 d (1H, H5,
thiophene, J 3.8), 8.74 s (1H, H4, coumarin)
8.64, 8.33
8.51, 8.47
IIIu 2221, 1712
IIIv
2217
8.44, 8.15
3.84 s (3H, CH3), 7.17 d (2H, HAr, J 8.0), 7.32 d.d (1H, H4, thiophene, J 5.8, J 3.4),
7.91 d (1H, H3, thiophene, J 4.5), 8.04 d (2H, HAr, J 8.0), 8.22 d (1H, H5, thiophene,
J 3.7)
progress and the purity of the obtained compounds
were monitored by TLC on Silufol UV-254 plates,
eluting with acetone–hexane (3:5) and detecting with
iodine vapor or UV irradiation.
amides VIIa–VIIc were prepared by the proce-dures
reported in [28] and [29], respectively.
2-[4-Aryl(hetaryl,
cyclopropyl)thiazol-2-yl]-3-
hetarylacrylonitriles (IIIa–IIIv). a. A mixture of
10 mmol of thiopyran I, 10 mmol of α-bromoketone
II, and 1.4 mL (10 mmol) of triethylamine in 25 mL of
2,6-Diamino-4-hetaryl-4H-thiopyran-3,5-dicarbo-
nitriles Ia–Ic and 3-hetarylmethylidenecyanothioacet-
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SYNTHESIS OF 2-[4-ARYL(HETARYL, CYCLOPROPYL)THIAZOL-2-YL]-...
865
13. Dyachenko, V.D. and Rylskaya, T.A., Russ. J. Gen.
Chem., 2011, vol. 81, no. 1, p. 160. DOI:10.1134/
S1070363211010312.
2-propanol was refluxed for 8 h and filtered. After 48 h
the precipitate was separated, washed with 2-propanol
and hexane, and recrystallized from butanol.
14. Dyachenko, V.D. and Rylskaya, T.A., Chem. Hetero-
cycl. Compd., 2013, vol. 49, no. 6, p. 897. DOI:
10.1007/s10593-013-1323-0.
b. A mixture of 10 mmol of acrylic acid thioamide
VII and 10 mmol of α-bromoketone II in 25 mL of
DMF was stirred at 20°C for 30 min and then left
standing for 24 h. The reaction mixture was diluted
with an equal volume of water, and the resulting
precipitate was filtered off. The melting points and Rf
values of compounds IIIa–IIIv obtained were identical
to those of the samples synthesized by the method a.
15. Dyachenko, V.D., Chernega, A.N., and Garasevich, S.G.,
Russ. J. Gen. Chem., 2005, vol. 75, no. 10, p. 1610.
DOI: 10.1007/s11176-005-0475-8.
16. Dyachenko, V.D., Ukr. Khim. Zh., 2008, vol. 74, no. 10,
p. 100.
17. Dyachenko, V.D., Krivokolysko, S.G., and Litvinov, V.P.,
Mendeleev Commun., 1998, no. 1, p. 23. DOI: 10.1070/
MC1998v008n01ABEH000816.
Mass spectrum of compound IIIh, m/z (Irel, %): 296
[M + 2]+ (4), 295 [M + 1]+ (16), 293 [M – 1]+ (15), 266
(14), 253 (95), 240 (31), 121 (75), 89 (27), 77 (22), 63
(20), 51 (14), 39 (13).
18. Zaikin, V.G., Varlamov, A.V., Mikaya, A.I., and
Protasov, N.S., Osnovy mass-spectrometrii organiches-
kikh soedinenii (Fundamentals of Mass Spectrometry of
Organic Compounds), Moscow: MAIK Nauka Inter-
periodika, 2001.
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