Triselenium dicyanide from malononitrile and selenium dioxide. One-pot synthesis of selenocyanates

Article abstract of DOI:10.1016/j.tetlet.2004.04.071

Triselenium dicyanide is formed by the interaction of malononitrile and selenium dioxide in dimethylsulfoxide or dimethylformamide. Addition of aromatic amines, indoles and some active methylene compounds to this reaction mixture gives the corresponding s

Full text of DOI:10.1016/j.tetlet.2004.04.071

Tetrahedron
Letters
Tetrahedron Letters 45 (2004) 4461–4463
Triselenium dicyanide from malononitrile and selenium
dioxide. One-pot synthesis of selenocyanates
Andrey V. Kachanov,* Oleg Yu. Slabko, Olga V. Baranova,
Evgenia V. Shilova and Vladimir A. Kaminskii
Department of Chemistry, Far Eastern National University, 690000, Vladivostok, Octyabrskaya St. 27, Russia
Received 24 February 2004; revised 8 April 2004; accepted 13 April 2004
Abstract—Triselenium dicyanide is formed by the interaction of malononitrile and selenium dioxide in dimethylsulfoxide or di-
methylformamide. Addition of aromatic amines, indoles and some active methylene compounds to this reaction mixture gives the
corresponding selenocyanates in one-pot.
Ó 2004 Elsevier Ltd. All rights reserved.
Triselenium dicyanide (TSD) is used as a selenocyanat-
ing reagent for the synthesis of aromatic1 and metallo-
organic2 selenocyanates. TSD has been well-known for a
long time.3 All the methods described for its synthesis
are based on inorganic selenocyano compounds as
starting materials. TSD has been obtained by oxidation
of potassium selenocyanate with chlorine or bromine,3
dinitrogen tetroxide,4 iodine pentafluoride,5 by oxida-
tion of silver selenocyanate with iodine,1 by interaction
of selenium dibromide and silver cyanide,6 by dispro-
portionation of selenocyanogen,3 by thermal decompo-
sition of sulphenyl selenocyanates7;8 and by
electrooxidation of the selenocyanate anion.9
probably because of the instability of TSD against
water. We discovered, however, that the reaction mix-
ture may be used for selenocyanation of the organic
substrates without isolation of the TSD. Aromatic
amines with a free para-position, indoles with a free 3-
position and some active methylene compounds may be
used as substrates. The corresponding selenocyanates 2–
6 were formed with good yields in most cases if these
substrates were added to the reaction mixture after the
exothermic reaction between malononitrile and selenium
dioxide12 (Scheme 1). Selenocyanates were isolated after
dilution of the reaction mixtures with water and were
purified by recrystallization.
We have discovered that TSD may be obtained very
easily by interaction of malononitrile (1 mol) with sele-
nium dioxide (1.5–2 mol) in dimethylsulfoxide or di-
methylformamide.10 The reaction is exothermic and
evolution of CO2 and N2 are observed as during the
oxidative coupling of malononitrile with SeO2 in the
presence of organic bases;11 more time is required to
start the exothermic reaction leading to TSD than for
the oxidative coupling.
Anthranilic and meta-aminobenzoic acid react normally
under these conditions, but o- and p-nitroanilines are
inactive. Reactions proceed regioselectively only para to
the amino-group in aromatic amines, in the 3-position
for indoles and at the methylene group for di-
benzoylmethane, acetylacetone and barbituric acid, as
well as for bindone; dimedone reacts nonselectively.
Addition of selenium dioxide to the mixture of malon-
onitrile and dimethylaniline in DMSO following the
procedure for the oxidative coupling of malononitrile11
led to another result: a mixture of four compounds was
formed: selenocyanate 2b, di(p-dimethylaminophen-
yl)selenide 7, di(p-dimethylaminophenyl)malononitrile
8 and a small amount of 4-(1,2,2-tricyanovinyl)di-
methylaniline 9; the pentacyanopropenide salt was
not detected13 (Scheme 2). A mixture of the same
TSD may be isolated from the reaction mixture after
dilution with water; the yield 36% is not very high
Keywords: Triselenium dicyanide; Selenocyanate; Malononitrile.
* Corresponding author. Tel./fax: +7-4232-429510; e-mail: kachanov@
chem.dvgu.ru
0040-4039/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2004.04.071

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A. V. Kachanov et al. / Tetrahedron Letters 45 (2004) 4461–4463
Scheme 1.
Scheme 2.
compounds (in other proportions) was formed when
i-PrOH was used instead of DMSO.
reaction as the last method, however, it is very simple
and convenient.
Selenocyanates are important in selenoorganic chemis-
try; they may be transformed to various selenoorganic
derivatives.14 Several methods are known for the syn-
thesis of aromatic selenocyanates: reactions of diazo-
nium salts with potassium selenocyanate;15 reactions of
iodarenes with potassium selenocyanate catalyzed by
copper(I) iodide;16 photo-induced substitution of halo-
gen is in halogenarenes by selenocyanate anion;17 reac-
tion of diselenium dicyanide (selenocyanogene) with
indole18a;b and the reaction of activated aromatic sub-
strates with triselenium dicyanide as mentioned above.1
This proposed one-pot synthesis is based on the same
References and notes
1. Challenger, F.; Peters, A. T.; Halevy, J. J. Chem. Soc.
1926, 1648–1655.
2. Aynsley, E. E.; Greenwood, N. N.; Sprague, M. J.
J. Chem. Soc. 1965, 4, 2395–2402.
3. Verneuil, A. Ann. Chim. Phys. 1886, 9, 326–329.
€
4. Muthmann, W.; Schroder, E. Ber. 1900, 33, 1765–1766.
5. Aynsley, E. E.; Greenwood, N. N.; Sprague, M. J.
J. Chem. Soc. 1964, 4, 704–708.
€
6. Kaufmann, H. P.; Kogler, F. Ber. 1926, 59, 178–182.

A. V. Kachanov et al. / Tetrahedron Letters 45 (2004) 4461–4463
4463
7. Rheinboldt, H.; Giesbrecht, E. J. Am. Chem. Soc. 1949,
71, 1740–1741.
7.34 (d, J ¼ 2:7, 1H, H-3), 7.47 (d, J ¼ 8:6, 1H, H-6), 8.34
(d, 1H, –COOH); [M)H]ꢀ m/z 241.
8. Emeleus, H. J.; Haas, A. J. Chem. Soc. 1963, 2, 1272–
1275.
9. Georges, C.; Gerard, D. C. R. Acad. Sci., C 1969, 269,
740–743.
Compound 2i––78; 91–92 (C6H6); d 1.17 (s, 1H, H–OH),
4.50 (s, 2H, –NH2), 4.65 (s, 2H, –CH2–), 6.67 (d, J ¼ 8:0,
1H, H-5); 7.43 (m, 2H, H-2, 6); [M+H]þ m/z 229.
Compound 3––94; 145–146 (C6H6); d 6.12 (s, 1H, –NH–);
7.10 (d, J ¼ 8:8, 4H, H-2, 20, 6, 60); 7.59 (d, J ¼ 8:8, 4H,
H-3, 30, 5, 50); [M+H]þ m/z 378.
10. Triselenium dicyanide from malononitrile and selenium
dioxide. Selenium dioxide (0.67 g, 6 mmol) was added with
stirring to solution of malononitrile (0.2 g, 3 mmol) in
DMSO (2 mL). The mixture became reddish after 5 min,
an exothermic reaction with vigorous gas evolution began
during the next 10 min. The volume of gas was 52 mL, half
of the volume was absorbed by a water solution of NaOH.
The mixture was diluted with water (6 mL) and after
cooling, a yellow precipitate was formed within 5 min. The
precipitate was filtered, dried and crystallized from benz-
ene, 0.21 g (1.1 mmol) of TSD was obtained; mp 133–
134 °C, lit. mp 133–134 °C;5 IR (KBr, cmꢀ1) 2141, 511, lit.
2131, 513;5 2141.19 The substance 1 was identical with a
sample of triselenium dicyanide obtained by the published
method.19 The same yield of TSD was obtained using
DMF instead DMSO.
11. Kaminskii, V. A.; Slabko, O. Yu.; Kachanov, A. V.;
Buchvetskii, B. V. Tetrahedron Lett. 2003, 44, 139–140.
12. Synthesis of selenocyanates in one-pot. (a) From aromatic
amines and indoles: selenium dioxide (0.34 g, 3 mmol) was
reacted with malononitrile (0.1 g, 1.5 mmol) in DMSO as
described above. The aromatic substrate (2.25 mmol) was
added with stirring to the reaction mixture after termina-
tion of the exothermic reaction. The homogeneous solu-
tion was diluted with water (5–10 mL) after 15–40 min and
the precipitate was filtered, dried and crystallized. (b)
From active methylene compounds: the reaction was
carried out in the same manner but the mole ratio
malononitrile:SeO2 1:1.5 and DMF was used instead of
DMSO.
1
Compound 4a––94; 99–100 (50% MeOH) (98.5–100); H
NMR spectra are in close agreement with the literature;18a
[M+H]þ m/z 221.
Compound 4b––56; 125–126 (50% MeOH) (126–127); H
1
NMR spectra are in close agreement with the literature;18b
[M+H]þ m/z 236.
Compound 4c––60; 123–124 (50% EtOH); d 1.48 (t,
J ¼ 7:2, 3H, –CH3); 4.49 (q, J ¼ 7:2, 2H, –CH2–); 7.32
(m, 1H, H-7); 7.46 (m, 2H, H-5, 6); 8.05 (d, J ¼ 9:28, 1H,
H-4); 9.25 (s, 1H, –NH–); [M+H]þ m/z 294.
Compound 4d––76; 118.5–120 (EtOH); d 2.46 (q, J ¼ 6:1,
2H, –CH2–); 2.79 (t, J ¼ 6:1, 2H, –CH2–CO–); 4.28 (t,
J ¼ 6:1, 2H, –CH2–N); 7.31 (t, J ¼ 7:81, 1H, H-5); 7.42
(d, J ¼ 8:06, 1H, H-7); 7.50 (t, J ¼ 7:94, 1H, H-6); 8.32 (d,
J ¼ 8:3, 1H, H-4); [M+H]þ m/z 291.
Compound 5a––46; 76–78 (hexane–C6H6) (78–80); d 2.56
(s, 6H, –CH3), 11.07 (s, 1H, –CH); [M)H]ꢀ m/z 204.
Compound 5b––84; 102–104 (hexane–C6H6); d 6.79 (s, 1H,
–CH–), 7.49 (t, J ¼ 7:6; 4H, Ar-H), 7.65 (m, 2H, Ar-H),
7.97 (d, J ¼ 7:3, 4H, Ar-H); [M)H]ꢀ m/z 328.
Compound 5c––42; 190–200 °C dec (re-precipitation with
water from DMF); d 8.31 (s, 1H, –CH–), 10.45 (s, 2H,
–NH–); [M)H]ꢀ m/z 232.
Compound 6––59; 186–190 °C dec (C6H6); d 5.61 (s, 1H,
–CH–), 7.98 (m, 7H, Ar-H), 9.67 (d, J ¼ 8:0; 1H, Ar-H);
[M)H]ꢀ m/z 378.
In all the IR-spectra the absorption of the SeCN-group
was observed at 2144–2155 cmꢀ1. Selenium isotope mul-
tiplicity of quasi-molecular ion signals were observed in all
the mass-spectra. We cite the significances for quasi-
molecular ions containing isotope 80Se.
The selected data for compounds are listed as follows––
yield, %; melting point, °C (solvent for recrystallization)
(literature melting point, °C); 1H NMR (250 MHz, DMSO
for 2g, 2h, 5c, CDCl3 for others), APCI/MS for 2–4 or
API-ES/MS for 5–6:
13. Simultaneous reaction of malononitrile, dimethylaniline and
selenium dioxide: selenium dioxide 0.44 g (4 mmol) was
added with stirring to solution of malononitrile 0.13 g
(2 mmol) and dimethylaniline 0.48 g (4 mmol) in DMSO
(4 mL). The reaction mixture rapidly became dark-red in
colour and after 10 min it was diluted with water, the
resulting crude precipitate was filtered, dried and sepa-
rated by preparative thin-layer chromatography on alu-
mina (hexane–ethyl acetate 3:1). Compounds 2b and 7
were isolated as individual substances in 0.07 g (6%) and
0.36 g (56%) amounts; attempts to separate compounds 8
and 9 were unsuccessful, their structures were established
by mass-spectral data.
Compound 2a––75; 88–89 (50% MeOH) (90–92); 1H
NMR spectra are in close agreement with the literature;18
[M+H]þ m/z 199.
1
Compound 2b––65; 100–102 (50% i-PrOH) (104–105); H
NMR spectra are in close agreement with the of litera-
ture;18 [M+H]þ m/z 228.
Compound 2c––85; 120–122 (i-PrOH); d 3.21 (t, J ¼ 4:89,
4H, –CH2–); 3.85 (t, J ¼ 4:89, 4H, –CH2–); 6.87 (dt,
J1 ¼ 9:0, J2 ¼ 2:2, 2H, H-3, 5); 7.56 (dt, J1 ¼ 9:2 J2 ¼ 2:2,
2H, H-2, 6); [M+H]þ m/z 269.
Compound 2d––93; 92–94 (50% MeOH) (92–93); 1H
NMR spectra are in close agreement with the literature;18
[M+H]þ m/z 213.
Compound 2e––99; 150–152 (C6H6) (160–170 dec); 1H
NMR spectra are in close agreement with the literature;18
[M+H]þ m/z 249.
Compound 7 yield 56%; 118–120 °C mp (from i-PrOH);
IR (KBr, cmꢀ1) 3019, 3007, 1593, 1500; 1H NMR
(250 MHz,CDCl3) d 2.92 (s, 12H, –CH3); 6.61 (d,
J ¼ 8:8, 4H, Ar-H); 7.35 (d, J ¼ 8:8, 4H, Ar-H); APCI
MS (m/z) [M+H]þ 321.
Compound 2f––96; 60–62 (MeOH); d 2.93 (s, 6H, H–Me);
6.97 (d, J ¼ 8:0, 1H, H-3); 7.57 (t, J ¼ 8:3, 1H, H-6); 7.65
(t, J ¼ 8:3, 1H, H-7); 7.91 (d, J ¼ 8:0, 1H, H-2); 8.23 (m,
1H, H-5); 8.27 (m, 1H, H-8); [M+H]þ m/z 277.
Compound 2g––85; 170–172 dec (80% EtOH); d 6.09 (ws,
1H, H–COOH), 6.70 (d, J ¼ 8:8, 1H, H-5); 7.60 (dd,
J1 ¼ 8:6, J2 ¼ 2:2, 1H, H-6); 8.25 (d, J ¼ 2:2, 1H, H-2);
[M)H]ꢀ m/z 241.
14. Krief, A.; Delmotte, C.; Dumont, W. Tetrahedron 1997,
53, 12147–12158.
15. Bauer, H. Ber. 1913, 46, 93–98.
16. Suzuki, H.; Shinoda, M. Synthesis 1977, 9, 640–641.
17. Frolov, A. N.; Smirnov, E. V.; Kulbitskaya, O. V.; Eltsov,
A. V. Zh. Org. Khim. (Russ.) 1980, 16, 2302–2309.
€
18. (a) Agenas, L.-B. Acta Chem. Scand. 1963, 17, 268–270;
€
(b) Agenas, L.-B. Acta Chem. Scand. 1968, 22, 1773–
1781.
19. Hauge, S. Acta Chem. Scand. 1971, 25, 3081–3093.
Compound 2h––76; 176–180 dec (50% DMFA); d 3.35
(ws, 2H, –NH2), 6.95 (dd, J1 ¼ 2:7, J2 ¼ 8:6, 1H, H-5),