New synthesis of the [1, 3]thiazolo- [3', 2':2, 3][1, 2, 4]triazino[5, 6-b]indole system

Full text of DOI:10.1007/s10593-010-0421-5

Chemistry of Heterocyclic Compounds, Vol. 45, No. 10, 2009
NEW SYNTHESIS OF THE [1,3]THIAZOLO-
[3',2':2,3][1,2,4]TRIAZINO[5,6-b]INDOLE SYSTEM
D. G. Kim1* and A. V. Zhuravlyova1
Keywords: 3-propargylthio-5H-[1,2,4]triazino[5,6-b]indole, 3-methyl[1,3]thiazolo[3',2':2,3][1,2,4]triazino-
[5,6-b]indole, one-pot synthesis.
Tomchin [1] was the first to report the preparation of the new 2,3-diphenyl[1,3]thiazolo[3',2':2,3]-
[1,2,4]triazino[5,6-b]indole system by the reaction of 3-benzoylphenylmethylthio[1,2,4]triazino[5,6-b]indole
with PPA but no spectral evidence was given for the formation of this product.
In an attempt to obtain 3-propargylthio-5H-[1,2,4]triazino[5,6-b]indole (1) by a one-pot synthesis from
isatin-β-thiosemicarbazone (2) by the action of aqueous alkali and propargyl bromide under phase-transfer
H
N
N
N
N
S
SNa
NaOH
N
NH2
O
N
N
H
HCl
H
N
N
2
SH
,
Br
[Et3NCH2Ph]Cl
N
N
Me
H
CH2
4
3
2
,
N N
N
Br
NaOH–H2O–DMSO
N
S
1
S
N
N
N
3
N
3a
H
NaOH
N
N
N
N
S
S
N
N
N
N
H
1
_______
* To whom correspondence should be addressed, e-mail: kim_dg48@mail.ru, dgkim@susu.ac.ru.
1South Urals State University, Chelyabinsk 454080, Russia.
__________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1590-1592, October, 2009.
Original article submitted September 1, 2009.
0009-3122/09/4510-1281©2009 Springer Science+Business Media, Inc.
1281

catalysis conditions, we unexpectedly obtained another representative of this heterocyclic system, namely,
3-methyl[1,3]thiazolo[3',2':2,3][1,2,4]triazino[5,6-b]indole (3). Triazinoindole 1 is formed by the reaction of
5H-[1,2,4]triazino[5,6-b]indole-3-thiol (4) with propargyl bromide in the NaOH-H2O-DMSO superbase medium
[2]. Triazinoindole 3 is probably formed by intramolecular cyclization of triazinoindole 1 through intermediate 3a.
Thus, heating triazinoindole 1 in aqueous NaOH at reflux leads to triazinoindole 3.
The 1H NMR spectrum of triazinoindole 3 shows singlets for the methyl group protons at 2.64 ppm and
for H-2 at 7.47 ppm. The mass spectrum has a molecular ion peak (M+ 240).
1
The H NMR spectrum was taken on a Bruker spectrometer at 400 MHz in DMSO-d6 with TMS as the
internal standard. The electron impact mass spectra were taken on a Hewlett-Packard GC/MS computer with an
HP-5890 gas chromatograph at 70 eV.
3-Propargylthio-5H-[1,2,4]triazino[5,6-b]indole (1). Propargyl bromide (0.152 g, 1 mmol) was added
to a mixture of indolethiol 4 (0.202 g, 1 mmol) and NaOH (0.04 g, 1 mmol) in DMSO (10 ml). The reaction
mixture was stirred for 1.5 h at room temperature. Then, water (50 ml) was added. The colorless light brown
precipitate was filtered off, washed with water, and dried to give 0.202 g (84%) triazinoindole 1; mp ~173°C.
1H NMR spectrum, δ, ppm: 3.17 (1H, s, CH≡); 4.13 (2H, s, S–CH2); 7.45, 7.60, 7.71, 8.31 (4H, benzene ring).
3-Methyl[1,3]triazolo[3',2':2,3][1,2,4]triazino[5,6-b]indole (3). A. A solution of thiosemicarbazone 2
(0.5 g, 2 mmol) [3] in 1 N NaOH (40 ml) was heated at reflux for 3 h. Then, propargyl bromide (0.24 g, 2 mmol)
and triethylbenzylammonium chloride (50 ml) as the phase-transfer catalyst were added and the mixture was
stirred for 1.5 h at room temperature. The red precipitate was filtered off, washed with water, and dried to give
1
triazinoindole 3 in 43% yield; mp 140°C (ethanol, dec.). H NMR spectrum, δ, ppm: 2.64 (3H, s, CH3); 7.47
(1H, s, H-2); 7.33, 7.69, 8.23 (4H, benzene ring). Found, %: C 59.74; H 3.31; N 23.42. C12H8N4S. Calculated,
%: C 59.98; H 3.36; N 23.32.
B. A solution of triazinoindole 1 (0.1 g, 0.4 mmol) in 1 N NaOH (5 ml) was heated at reflux for 1.5 h.
The red precipitate was filtered off, washed with water, and dried to give triazinoindole 3 in 60% yield. This
product was identical to the product obtained by method A and the melting point of a mixed sample was not
depressed.
REFERENCES
1.
2.
A. B. Tomchin, Zh. Org. Khim., 18, 1272 (1982).
A. V. Zhuravleva, A. A. Koryukova, and D. G. Kim, in: XI Youth Conference on Organic Chemistry [in
Russian], Yekaterinburg (2008), p. 332.
3.
G. I. Zhungietu and M. A. Rekhter, Isatin and Its Derivatives [in Russian], Shtinitsa, Kishinev (1977),
p. 109.
1282