Aminolysis of 2-amino-5-benzylidene-1,3-thiazol-4(5H)-one in cyclic amines: Recyclization to 2-amino-5-benzylidene-1,5-dihydro-4H-imidazol-4-one derivatives

Full text of DOI:10.1134/S1070363207050313

ISSN 1070-3632, Russian Journal of General Chemistry, 2007, Vol. 77, No. 5, pp. 971 972.
Pleiades Publishing, Ltd., 2007.
Original Russian Text
S.M. Ramsh, N.L. Medvedskii, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 5, pp. 877 878.
LETTERS
TO THE EDITOR
Aminolysis of 2-Amino-5-benzylidene-1,3-thiazol-4(5H)-one
in Cyclic Amines: Recyclization to 2-Amino-5-benzylidene-
1,5-dihydro-4H-imidazol-4-one Derivatives
S. M. Ramsh and N. L. Medvedskii
St. Petersburg State Institute of Technology,
Moskovskii pr. 26, St. Petersburg, 190013 Russia
Received November 17, 2006
DOI: 10.1134/S1070363207050313
It is known [1] that the amino group in 2-amino-5-
benzylidene-1,3-thiazol-4(5H)-one (5-benzylidene-
pseudothiohydantoin, I) is replaced by phenylamino
group by the action of aniline. We have found that
aminolysis of compound I in piperidine or morpholine
involves not only expected transamination to give
2-piperidino (IIa) or 2-morpholino derivative (IIb) of
5-benzylidene-1,3-thiazol-4(5H)-one but also repla-
cement of the endocyclic sulfur atom by nitrogen with
formation of 2-piperidino- or 2-morpholino-5-benzyl-
idene-1,5-dihydro-4H-imidazol-4-one IIc or IId,
respectively.
O
O
A
NH
O
N
N
...
CHC6H5
...
A
NH
CHC6H5
N
Q
CHC6H5
H2N
S
SH
H2N
A
I
IIa IId
Q = S (a, b), NH (c, d); A = CH2 (a, c), O (b, d).
The formation of compounds IIa and IIb is likely
to occur without opening of the thiazole ring [2],
while dihydroimidazole derivatives IIc and IId can be
formed only as a result of recyclization of open-chain
intermediate arising from opening of the thiazole ring
at the C2 S or C5 S bond in a way similar to the re-
action of I with hydroxide ion [3] or reactions of
amines with 4,5-dihydrothiazol-2-amine [4, 5]. The
structure of the alkaline hydrolysis [6], alcoholysis
[2], and aminolysis products [7] of 2-amino-1,3-thia-
zol-4(5H)-one derivatives suggests that these reactions
under reflux until it became homogeneous (about
10 min) and was then left to stand for 24 h at room
temperature. The precipitate was filtered off, washed
with petroleum ether ethanol (10:1), and recrystallized
from toluene to isolate 0.250 g (20%) of 5-benzyl-
idene-2-piperidino-1,5-dihydro-4H-imidazol-4-one
(IIc) with mp 208 210 C (published data [9]: mp
198 C for the Z isomer). The filtrate was combined
with the washings, and a solid separated from the
solution in several days. The precipitate was filtered
off and recrystallized first from toluene and then from
ethanol. We thus isolated 0.253 g (19%) of 5-benzyl-
idene-2-piperidino-1,3-thiazol-4(5H)-one (IIa) with
mp 202 204 C; published data: mp 202 204 C [10],
209 211 C [11].
involve cleavage of the C2 S bond.
2-Amino-5-benzylidene-1,3-thiazol-4(5H)-one
(I) was synthesized by the procedure described in [8].
Aminolysis of 2-amino-5-benzylidene-1,3-thiazol-
4(5H)-one (I) in piperidine. A mixture of 1.00 g of
compound I and 9.57 g of piperidine was heated
Aminolysis of 2-amino-5-benzylidene-1,3-thia-
zol-4(5H)-one (I) in morpholine. A mixture of
971

972
RAMSH, MEDVEDSKII
2.00 g of compound I and 9.20 g of morpholine was
heated under reflux until it became homogeneous
(about 5 min) and was left to stand overnight at room
temperature. The precipitate was filtered off, washed
with petroleum etherethanol (1:1), and treated in
succession with boiling acetone and propan-2-ol.
After 2 days, a solid separated from the solution in
propan-2-ol; it was filtered off and recrystallized from
propan-2-ol. Yield of 5-benzilydene-2-morpholino-
3. Fedoseev, V.M., Mandrugin, A.A., and Semenen-
ko, M.N., Khim. Geterotsikl. Soedin., 1984, no. 1,
p. 44.
4. Rodyunin, A.A., Mandrugin, A.A., and Fedose-
ev, V.M., Abstracts of Papers, I Vsesoyuznaya kon-
ferentsiya po teoreticheskoi organicheskoi khimii
(I All-Union Conf. on Theoretical Organic Chem-
istry), Volgograd, 1991, p. 159.
5. Mandrugin, A.A., Fedoseev, V.M., Khomutov, S.M.,
and Roshchina, T.M., Abstracts of Papers, I Vseso-
yuznaya konferentsiya po teoreticheskoi organicheskoi
khimii (I All-Union Conf. on Theoretical Organic
Chemistry), Volgograd, 1991, p. 158.
6. Ramsh, S.M., Ivanenko, A.G., Shpilevyi, V.A., Med-
vedskii, N.L., and Kushakova, P.M., Khim. Getero-
tsikl. Soedin., 2005, no. 7, p. 1089.
1,5-dihydro-4H-imidazol-4-one (IId) 0.501
g
(19.9%), mp 220 221 C; published data [9]: mp
232 C, Z isomer). The filtrate was combined with the
washings; after 30 min, the precipitate was filtered off
and recrystallized twice from toluene. Yield of
5-benzylidene-2-morpholino-1,3-thiazol-4(5H)-one
(IIb) 0.284 g (10.6%), mp 202 204 C; published data:
mp 202 204 C [10], 203-204 C [11].
7. El’tsov, O.S., Mokrushin, V.S., Bel’skaya, N.P., and
Kozlova, N.M., Izv. Ross. Akad. Nauk, Ser. Khim.,
2003, no. 2, p. 440.
8. Liberman, D., Himbert, J., and Hengl, L., Bull. Soc.
Chim. Fr., 1948, p. 1120; Chem. Abstr., 1949, vol. 43,
p. 3819.
The purity of compounds IIa IId was checked by
TLC and elemental analysis, and their structure was
1
confirmed by the IR and H NMR spectra. The m/z
values for the molecular ions in the mass spectra of
IIc and IId coincided with the calculated values.
9. Khodair, A.I., El-Subbagh, H.I., and Al-Obaid, A.M.,
Phosph., Sulfur Silicon, 1998, vol. 140, p. 159.
10. Raouf, A.R.A., Omar, M.T., Omran, S.M.A., and El-
Bayoumy, K.E., Acta Chim. (Budapest), 1974, vol. 83,
nos. 3 4, p. 359.
REFERENCES
1. Culvenor, C.C.J., Davies, W., Maclaren, J.A., Nel-
son, P.F., and Savige, W.E., J. Chem. Soc., 1949,
p. 2573.
11. Kutschy, P., Dzurilla, M., Kristian, P., and Kutschyo-
va, K., Coll. Czech. Chem. Commun., 1981, vol. 46,
no. 2, p. 436.
2. Omar, M.T. and Kasem, M.A., J. Heterocyclic Chem.,
1981, vol. 18, no. 7, p. 1413.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 77 No. 5 2007