Reaction of γ-bromodipnone with thiocarbamides [9]

Full text of DOI:10.1007/s10593-007-0082-1

Chemistry of Heterocyclic Compounds, Vol. 43, No. 4, 2007
REACTION OF γ-BROMODIPNONE WITH THIOCARBAMIDES
L. M. Potikha and V. A. Kovtunenko
Keywords: 2-(2-amino-4-phenyl-4,5-dihydrothiazol-4-yl)-1-phenyl-1-ethanone, γ-bromodipnone, 2,4-
diphenyl- thiophene.
One of the traditional methods for the synthesis of derivatives of thiazole is the reaction of α-halo-
carbonyl compounds with thiocarbamides [1]. A similar result is obtained if vinylogs of α-halocarbonyl
compounds are used in this reaction [2,3]. We have shown [4] that the reaction of 4-bromo-1,3-diphenyl-
2-buten-1-one (γ-bromodipnone) with α-aminoazines gives rise to products of nucleophilic substitution at
position 4 and Michael addition at position 3 of the dipnone system – condensed imidazoles. We have presently
established that the reaction of 1 with thiourea goes by such a scheme when the starting materials are heated in
ethanol and gave rise to 2-(2-amino-4-phenyl-4,5-dihydrothazol-4-yl)-1-phenyl-1-ethanone hydrobromide (2).
The reaction of the same γ-bromodipnone with thioacetamide under the same conditions gave
2,4-diphenylthiophene (3) in high yield. 2-(2-Amino-4-phenyl-4,5-dihydrothazol-4-yl)-1-phenyl-1-ethanone (4)
was obtained as the free base when the salt 2 reacted with morpholine.
S
S
NH2
Me
Ph
S
H2N
Ph
Ph
NH2
.
H2N
HBr
N
Ph
COPh
S
Br
COPh
2
1
3
S
Ph
HN
O
H2N
N
4
COPh
1
Characteristic of the H NMR spectra of thiazoles 2 and 4 is the presence of signals of two methylene
groups with a splitting characteristic of AB systems, a pattern previously observed [4] for the products of 3,4-
binucleophilic substitution of γ-bromodipnone. The structure of compound 4 was also confirmed by the presence
of strong field shifts of the protons in its 1H NMR spectrum, most evident for the aliphatic part (in comparison of
the spectrum of salt 2).
1H NMR spectra of DMSO-d6 solutions with TMS as internal standard were recorded on a Varian
Mercury 400 (400 MHz).
2-(2-Amino-4-phenyl-4,5-dihydrothiazol-4-yl)-1-phenyl-1-ethanone hydrobromide (2). A mixture of
γ-bromodipnone (1 g, 3.32 mmol) and thiourea (0.25 g, 3.32 mmol) in ethanol (50 ml) was boiled for 40 min.
The solvent was evaporated and the residue was recrystallized from AcOH . Yield 0.65 g (52%); mp 194-196°C
1
3
(from AcOH). NMR spectrum, δ, ppm (J, Hz): 7.95 (2H, br. s, NH2); 7.95 (2H, d, J = 8.0, H-2",6");
__________________________________________________________________________________________
Tara Shevchenko National University, Kiev 01033, Ukraine; e-mail potikha-l@mail.ru. Translated from
Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 625-626, April, 2007. Original article submitted December 1,
2006.
0009-3122/07/4304-0521©2007 Springer Science+Business Media, Inc.
521

3
3
3
7.61 (1H, t, J = 8.0, H-4"); 7.49 (4H, m, H-2′, 6′,3",5"); 7.35 (2H, t, J = 8.0, H-3′,5′); 7.26 (1H, t, J = 8.0,
H-4'); 4.10 (1H, d, 2J = 11.6, HA-5); 3.65 (1H, d, 2J = 11.6, HB-5); 4.60 (1H, d, 2J = 18.0, 4-CHAHB); 3.80 (1H, d,
2J = 18.0, 4-CHACHB). Found, %: Br 21.24; N 7.46; S 13.49. C17H17BrN2OS. Calculated, %: Br 21.18; N 7.42;
S 13.50.
2,4-Diphenylthiophene (3). Compound 3 was prepared by the method described above using
thioacetamide (0.25 g, 3,32 mmol) in place of thiourea. Yield 0.49 g (62%); mp 122-123°C ( from EtOH)
(mp 123-5-124°C [5]).
2-(2-Amino-4-phenyl-4,5-dihydrothiazol-4yl)-1-phenyl-1-ethanone (4). Morpholine (2 ml) was added
to a suspension of salt 2 (0.5 g, 1.33 mmol) in 2-propanol (5 ml) and the mixture was heated until the salt had
dissolved completely. The solvent and excess morpholine were evaporated and water (50 ml) was added to the
residue. The solid was filtered off and recrystallized from 2-propanol. Yield 0.27 g (68%); mp 152-154°C (from
1
3
3
2-propanol). NMR spectrum, δ, ppm (J, Hz): 7.77 (2H, d, J = 8.0, H-2",6"); 7.50 (1H, t, J = 8.0, H-4");
7.46 (2H, d, 3J = 8.0, H-2', 6'); 7.38 (2H, t, 3J = 8.0, H-3",5"); 7.23 (2H, t, 3J =8.0, H-3',5'); 7.13 (1H, t, 3J = 8.0,
2
2
H-4'); 6.42 (2H, br. s, NH2); 3.98 (1H, d, J = 11.6, HA-5); 3.61 (1H, d, J = 14.4, 4-CHAHB); 3.45 (1H, d,
2J = 10.8, HB-5); 3.41 (1H, d, J = 14.4, 4-CHACHB). Found, %: N 9.43; S 10.85. C17H16N2OS. Calculated, %:
2
N 9.45; S 10.82.
REFERENCES
1.
J. V. Metzger (editor), The Chemistry of Heterocyclic Compounds. 34, Part 1. John Wiley and Sons, Inc.,
New York, 1979.
2.
3.
4.
5.
J. Svetlik, F. Turecek, and I. Goljer, J. Org. Chem., 55, 4740 (1990).
M. M. Campbell, US Pat. 4582907; Chem. Abstr., 105, 78924 (1986).
V. Kovtunenko, L.Potikha, and A. Turov, Synth. Commun.,34, 3609 (2004).
H. Saikachi and T. Hisano, Yakugaku Zasshi, 81, 59 (1961); Chem. Abstr., 55, 76103 (1961).
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