Reaction of thiourea and substituted thioureas with 1,3-dibromopropyne

Article abstract of DOI:10.1134/S1070363208100228

4-Bromomethylidene-2-imino(phenylimino, acetylimino)-1,3-thiazolidine hydrobromides and 4-bromomethylidene-2-acetylimino-1,3-thiazolidine are synthesized by the reaction of thiourea, N-phenylthiourea, N,N′- diphenylthiourea and N-acetylthiourea with 1,3-d

Full text of DOI:10.1134/S1070363208100228

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 10, pp. 1949–1951. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © V.N. Elokhina, T.I. Yaroshenko, A.S. Nakhmanovich, S.V. Amosova, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78,
No. 10, pp. 1713–1715.
Reaction of Thiourea and Substituted Thioureas
with 1,3-Dibromopropyne
V. N. Elokhina, T. I. Yaroshenko, A. S. Nakhmanovich, and S. V. Amosova
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
fax: (3952)419346
e-mail: k301@irioch.irk.ru
Received October 18, 2007
Abstract―4-Bromomethylidene-2-imino(phenylimino, acetylimino)-1,3-thiazolidine hydrobromides and 4-
bromomethylidene-2-acetylimino-1,3-thiazolidine are synthesized by the reaction of thiourea, N-
phenylthiourea, N,N'-diphenylthiourea and N-acetylthiourea with 1,3-dibromopropyne in glacial acetic acid,
absolute methanol, acetonitrile at 20°С or upon heating (60°С).
DOI: 10.1134/S1070363208100228
Reaction of thiourea and substituted thioureas with
halogenoacetylenes is a convenient method for
synthesis of functionalized thiazines and thiazoles.
38% yield [3, 4]. The reaction of substituted thioureas
with 1-bromo-2-benzoylacetylene in MeCN, МеОН,
or benzene results in N-substituted 4-benzoyl-2-imino-
3-thiazolium bromides in good yield [5].
Reaction of thiourea with 1-acyl-2-bromo-
acetylenes in АсОН in the presence of Et2O.ВF3
We found that in the reaction of thiourea, N-
phenylthiourea, N,N'-diphenylthiourea and N-acetyl-
thiourea with 1,3-dibromopropyne (II) in absolute
methanol or glacial acetic acid upon heating are
formed 4-bromomethylidene-2-imino(phenylimino)-
1,3-thiazolidine hydrobromides IIIa–IIIc as the only
products. In the reaction of N-acetylthiourea (Id) with
1,3-dibromo-propyne (II) in acetonitrile upon heating
to 60°С 2-acetylimino-1,3-thiazolidine (IIId) is formed.
affords
2-amino-4-phenyl(2-thienyl)-1,3-thiazine-6-
thiones in high yield [1]. Substituted 3-bromo-1-
propynes react with thiourea in MeOH at 20°С or upon
heating with the formation of substituted 2-amino-
thiazoles [2]. Reaction of alkylthiochloroacetylenes
with thiourea in acetone at 20°С leads to S-
(alkylthioethynyl)isothiuronium chlorides in 23–30%
yield and N-[1-alkylthio)ethylidene]thioureas in 31–
S
RN
RHN
CH2
C
C
HBr
C
S + BrCH2
II
C
CBr
_HBr
R1HN
R1HN
CBr
Ia_Id
A
S
S
HN
RN
CH2
C
C
NEt3
_NEt3 HBr
CH2
C
C
HBr
R1N
CHBr
HN
CHBr
IIIa_IIIc
IVa
R = R1 = H (a), R = Ph, R1 = H (b), R = R1 = Ph (c), R = Me–CO, R1 = H (d).
1949

1950
ELOKHINA et al.
Apparently, the reaction proceeds via the formation
4-Bromomethylidene-2-imino-1,3-thiazolidine
(IVa). To a solution of 0.38 g of thiourea in 10 ml of
absolute methanol a solution of 0.98 g of 1,3-
dibromopropyne in 15 ml of absolute methanol and
0.51 g of triethylamine were added, the reaction
mixture was heated for 8 h at 60°С. The solution was
cooled to 0°С, the crystals formed were filtered off and
dried in a vacuum. Yield 0.18 g (19%), mp 191–192°С.
IR spectrum, cm–1: 3285 (=NH), 3090 (NH), 1585,
1630 (C=N, С=С), 1422 (СН2, def.), 1260 (С–N), 685
(C–S). Found, %: С 24.55; Н 2.65; Br 41.80; N 14.72;
S 16.65. С4Н5BrN2S. Calculated, % : С 24.87; Н 2.59;
Br 41.45; N 14.51; S 16.58.
of intermediate bromoethynylmethylsulfides (А),
which undergo intramolecular cyclization into 4-
bromomethylidene-2-imino(phenylimino, acetylimino)-
1,3-thiazolidine hydrobromides IIIa–IIIc.
In the IR spectra of compounds IIIa–IIId the
absorption bands of the C–S bond at 600–630 cm–1 ,
deformational vibrations of the СН2 group at 1400–
1440 cm–1, vibrations of С=С and С=N bonds at 1580–
1610 cm–1, of nonconjugated С=О group (for
compound IIId) at 1750 cm–1 are observed. The
stretching vibrations of the =NH group (for compound
IIIа) are observed at 3280 cm–1, the NH group
vibrations for compounds IIIb and IIId are located at
3110 and 3220 cm–1.
4-Bromomethylidene-2-phenylimino-1,3-thiazol-
idine hydrobromide (IIIb). To a solution of 0.76 g of
N-phenylthiourea (Ib) in 10 ml of absolute methanol
0.99 g of 1,3-dibromopropyne (II) in 15 ml of absolute
methanol was added, the mixture was heated to 60°С
and stirred at this temperature for 4 h. The reaction
mixture was cooled to 0°С, the precipitated colorless
crystals were filtered off, washed with cold ether, and
dried in a vacuum. Yield 0.45 g (26%), mp 251–253°С
(decomp.). In glacial АсОН at 20°С after 6 h the yield
was 18%. 1Н NMR spectrum, δ, ppm: 8.75 s (1Н, NH),
7.12–7.52 m (5Н, Ph), 5.44 s (1H, =CHBr), 4.83 s (2H,
CH2). 13С NMR spectrum, δC, ppm: 22.88 (СН2), 39.50
(=CHBr), 74.15 (C=CHBr), 127.44, 128.50, 132.18,
138.42 (Ph), 168.20 (NH=C–S). Found, %: С 33.88; Н
2.97; Br 45.22; N 8.42; S 9.14. C10H10Br2N2S.
Calculated, %: С 34.29; Н 2.85; Br 45.79; N 8.00; S
9.14.
When equimolar amounts of thiourea (Ia) and 1,3-
dibromopropyne (II) react in absolute methanol upon
heating to 60oC in the presence of equimolar amount
of triethylamine free base, 4-bromomethylidene-2-
imino-1,3-thiazolidine (IVa) is formed.
The composition and structure of the reaction
products are proved by the results of elemental
analysis and the data of IR, 1H and 13C NMR spectra.
EXPERIMENTAL
IR spectra were taken on a Specord 75-IR
1
instrument in KBr pellets. Н and 13С NMR spectra
were registered at 55°С on a Bruker-400 spectrometer
(working frequencies 400.13 and 100.62 MHz, respect-
tively) in DMSO-d6 with HMDS as an internal standard.
4-Bromomethylidene-2-imino-1,3-thiazolidine hyd-
robromide (IIIa). To a solution of 0.38 g of thiourea
in 15 ml of glacial АсОН a solution of 0.99 g of 1,3-
dibromopropyne in 20 ml of glacial АсОН was added,
the solution was stirred for 6 h at 20°С. The solution
became light-yellow. It was cooled to 0°С, the
precipitated colorless crystals were filtered off, washed
with cold ether and dried in a vacuum. Yield 0.75 g
(55%), mp 133–135°С. With the molar ratio of the
reagents I:II=1:2 the yield was 73%, for I:II=2:1 it
was 44%. In absolute methanol at 20°С the yield was
26%. 1Н NMR spectrum, δ, ppm: 9.21 s (1Н, HN=C–S),
7.92 s (1H, NH), 4.55 s (1H, =CHBr), 4.21 s (2H,
CH2). 13С NMR spectrum, δC, ppm: 20.55 (СН2), 46.71
(=CHBr), 74.01 (С=CHBr), 168.17 (HN=C–S). Found,
%: С 17.56; Н 2.30; Br 58.45; N 10.07; S 11.36.
C4H6Br2N2S. Calculated, %: С 17.52; Н 2.19; Br
58.39; N 10.22; S 11.68.
4-Bromomethylidene-3-phenyl-2-phenylimino-1,3-
thiazolidine hydrobromide (IIIc). To a solution of
1.14 g of N,N'-diphenylthiourea (Ic) in 10 ml of
absolute methanol a solution of 0.98 g of 1.3-
dibromopropyne (II) in 10 ml of absolute methanol
was added, heated to 60°С and stirred for 6 h. The
solution became light-yellow, then it was cooled to 0°С,
the precipitated crystals filtered, washed with cold
ether and dried in vacuum. Yield 0.82 g (39%), mp
228–230°С. When the reaction was carried out in
glacial АсОН at 110°С during 8 h, the yield was 28%.
1Н NMR spectrum, δ, ppm: 7.05–8.22 m (10Н, 2Ph),
4.91 s (1H, =CHBr), 4.48 s (2H, CH2). 13С NMR
spectrum, δC, ppm: 32.12 (СН2), 47.88 (=CHBr), 94.46
(C=CHBr), 125.96–142.52 (2Ph), 160.15 (N=C–S).
Found, %: С 45.47; Н 3.02; Br 38.00; N 6.18; S 7.45.
C16H14Br2N2S. Calculated, %: С 45.07; Н 3.29; Br
37.56; N 6.57; S 7.51.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 10 2008

REACTION OF THIOUREA AND SUBSTITUTED THIOUREAS
1951
REFERENCES
4-Bromomethylidene-2-acetylimino-1,3-thiazol-
idine (IIId). To a solution of 0.59 g of acetylthiourea
(Id) in 10 ml of acetonitrile a solution of 0.99 g of 1,3-
dibromopropyne (II) in 10 ml of acetonitrile was
added, heated to 60°С and stirred for 6 h. The reaction
mixture was cooled to 0°С, the crystalline precipitate
formed filtered, washed with cold ether and dried in
vacuum. Yield 0.68 g (58%), mp 210–212°С. 1Н NMR
spectrum, δ, ppm: 2.45 s (3Н, СН3), 5.15 s (2Н, СН2),
5.42 s (1Н, CH), 9.78 s (1H, NH). 13С NMR spectrum,
δC, ppm: 26.78 (СН3), 30.48 (СН2), 95.03 (=СНBr),
134.83 (C=CHBr), 158.75 (N=CS), 177.95 (C=O).
Found, %: С 30.44; Н 3.05; Br 33.80; N 11.75; S
13.42. C6H7BrN2OS. Calculated, %: С 30.64; Н 2.98;
Br 34.04; N 11.91; S 13.62.
1. Glotova, T.E., Komarova, T.N., Nakhmanovich, A.S.,
and Lopyrev, V.A., Russ. Chem. Bull., Int. Ed.,
2000, vol. 49, no. 11, p. 1917.
2. Yura, Y., Chem. Pharm. Bull. Japan, 1962, no.10, pp. 372,
376.
3. D’yachkova, S.G., Gusarova, N.K., Nikitina, E.A.,
Larina, L.I., Sinegovskaya, L.M., Abramov, A.V., and
Trofimov, B.A., Russ. J. Gen. Chem., 2001, vol. 71,
no.11, p. 1717.
4. D’yachkova, S.G., Beskrylaya, E.A., Gusarova, N.K.,
Larina, L.I., and Trofimov, B.A. Russ. Chem. Bull., Int.
Ed., 2000. vol. 49. no.7, p. 1319.
5. Komarova, T.N., Nakhmanovich, A.S., Glotova, T.E.,
Elokhina, V.N., Albanov, A.I., and Lopyrev, V.A.,
Russ. Chem. Bull., Int. Ed., 1997, vol. 46, no. 1, p. 195.
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