May 2016
Solvent-free Synthesis of Birhodanines
991
Scheme 2. Proposed mechanism for the reaction.
CO Me
2
S
S
O
CO Me
-
2
RNH
S
-
MeOH
R
RNH2
+
CS2
NH2
+
S
OMe
MeO
O
1
3
4
O
O
O
S
R
S
S
R
R
S
S
N
S
S
H
N
-
MeOH
3
OMe
Air
OMe
2
N
N
S
S
NHR
H
R
O
O
O
S
5
6
7
0
0
0
0
0
0
ꢀ
ꢁ
in to one-pot synthesis of 2,2 -dithioxo-[5,5 ]bithiazolidi-
3,3 -dipropyl-2,2 -dithioxo-[5,5 ]bithiazolidinylidene-4,4 -dione
0
(2c). Orange powder, yield 0.37 g (54%), mp 211–213 C; IR
potassium bromide): 1688, 1344, 1285, 1220, 1134 cm ; H
NMR (deuteriochloroform): d ppm 0.95 (t, 6H, J = 7.3, 2CH ),
nylidene-4,4 -dione derivatives of potential synthetic interest.
1 1
(
The key advantages of this procedure are the mild reaction
conditions, short reaction time, simple experimental, facile iso-
lation of the desired products, and avoidance of harsh reagents.
3
13
1
.68–1.77 (m, 4H, 2CH
2
), 4.08 (t, 4H, J = 7.3 Hz, 2NCH
), 20.5 (2CH
6.1 (2CH ), 124.7 (2C), 166.9 (2C = O), 194.6 (2C= S); ms: m/z
2
);
C
NMR (deuteriochloroform): d ppm 11.2 (2CH
3
2
),
4
3
2
+
46 (M , 100), 304 (13), 217 (67), 133 (23), 88 (38), 59 (54).
(346.49): C, 41.59; H, 4.07; N,
.08% found: C, 41.67; H, 4.11; N, 8.11%.
EXPERIMENTAL
14 2 2 4
Anal. Calcd. for C12H N O S
8
0 0 0 0
3,3 -dibutyl-2,2 -dithioxo-[5,5 ]bithiazolidinylidene-4,4 -dione
Melting points were measured with an Electrothermal 9100
apparatus (Electrotermal Engineering LTD, Rochford, UK).
Elemental analyses C, H, and N were performed using a Heraeus
CHN-O-Rapid analyzer (Hanau, Germany). IR spectra were
measured with a Shimadzu IR-460 spectrometer (Kyoto, Japan).
NMR spectra were recorded with a Bruker DRX-250 AVANCE
Rheinstetten, Germany) instrument (250.1 MHz for H and
2.5 MHz for C) with CDCl or DMSO-d as solvent. Mass
spectra were recorded with an Agilent-5975 C inert XL MSD mass
spectrometer (Ringoes, NJ) operating at an ionization potential of
ꢀ
(2d). Orange powder, yield 0.46 g (61%), mp 174–176 C; IR
(potassium bromide): 1680, 1432, 1268, 1205, 1139 cm
H NMR (deuteriochloroform): d ppm 0.95 (bs, 6H, 2CH ), 1.36–
1.39 (m, 4H, 2CH ), 1.64–1.67 (m, 4H, 2CH ), 4.12 (bs, 4H,
2NCH2); C NMR (deuteriochloroform): d ppm 13.6 (2CH3),
20.1 (2CH ), 29.1 (2CH ), 44.5 (2NCH ), 124.7 (2C), 166.9
ꢁ
1
;
1
3
2
2
13
1
(
2
2
2
+
13
6
(2C = O), 194.5 (2C= S); ms: m/z 374 (M , 50), 341 (100), 285
(22), 231 (22), 198 (35), 88 (19), 64 (16). Anal. Calcd. for
C H N O S (374.55): C, 44.89; H, 4.84; N, 7.48% found: C,
3
6
1
4 18 2 2 4
7
0 eV. Amines, dimethyl acetylene dicarboxylate, and carbon
44.95; H, 4.80; N, 7.57%.
0
0
0
disulfide were obtained from Merck and were used without further
purification.
3,3 -bis-(2-hydroxyethyl)-2,2 -dithioxo-[5,5 ]bithiazolidinylidene-
0
ꢀ
4,4 -dione (2e). Orange powder, yield 0.39 g (56%), mp 236–238 C;
0
ꢁ1
Typical experimental procedure for the preparation of 3 -
IR (potassium bromide): 3510, 1687, 1438, 1272, 1203, 1116 cm
;
0
0
0
1
dimethyl-2,2 -dithioxo-[5,5 ]bithiazolidinylidene-4,4 -dione
2a). To a stirred solution of carbon disulfide (0.36 g, 4.8 mmol)
H NMR (DMSO-d ): d ppm 3.62 (bs, 4H, 2CH ), 4.09 (bs, 4H,
6 2
13
(
2CH ), 4.91 (s, 2H, 2OH); C NMR (DMSO-d ) d ppm 47.2
2 6
and dimethyl acetylene dicarboxylate (0.28 g, 2 mmol) was added
dropwise methyl amine (0.12g, 4 mmol) in 5 min. The reaction
mixture was allowed to stir for 2 min. After completion, the
product was purified by addition of EtOH. Product 2a was
(2NCH ), 57.1 (2OCH ), 124.5 (2C), 167.2 (2C = O), 196.1
2 2
+
(2C = S); ms: m/z 350 (M , 70), 307 (100), 263 (33), 176 (89), 116
(18), 88 (35). Anal. Calcd. for C H N O S (350.44): C, 29.80;
10 10 2 4 4
H, 1.88; N, 8.69% found: C 29.88; H 1.85; N 8.74%.
ꢀ
0 0 0
3,3 -bis-(2-methoxyethyl)-2,2 -dithioxo-[5,5 ]bithiazolidinylidene-
obtained as red powder, yield 0.29g (50%), mp 316–317 C; ms:
+
0
ꢀ
m/z 290 (M , 100) [11].
4,4 -dione (2f). Orange powder, yield 0.42 g (55%), mp 203–205 C;
0
0
0
0
ꢁ1
3
,3 -diethyl-2,2 -dithioxo-[5,5 ]bithiazolidinylidene-4,4 -
IR (potassium bromide): 1688, 1430, 1272, 1116, 747 cm
H NMR (deuteriochloroform): d ppm 3.33 (s, 6H, 2OCH ), 3.69
(t, 4H, J = 5.5 Hz, 2NCH ), 4.35 (t, 4H, J = 5.5 Hz, 2OCH );
;
ꢀ
1
dione (2b). Orange powder, yield 0.33 g (52%), mp 252–253 C;
3
ꢁ
1
1
13
IR (potassium bromide): 1693, 1450, 1242, 1138, 745 cm ; H
NMR (deuteriochloroform): d ppm 1.28 (t, 6H, J = 7.0 Hz, 2CH ),
.19 (q, 4H, J = 7.0 Hz, 2CH2); C NMR (deuteriochloroform):
d ppm 12.3 (2CH ), 39.9 (2CH ), 124.7 (2C), 166.7 (2C = O), 194.2
C
2
2
3
NMR (deuteriochloroform): d ppm 43.6 (2NCH ), 58.9 (2OCH ),
2 3
1
3
4
68.1 (2OCH ), 124.7 (2C), 166.9 (2C = O), 194.8 (2C = S); ms: m/z
2
+
3
2
378 (M , 78%), 345 (25), 320 (85), 287 (52), 262 (70), 175 (60),
+
(
(
2C = S); ms: m/z 318 (M , 100), 231 (9), 203 (75), 119 (38), 88
52). Anal. Calcd. for C10 (318.44): C, 37.72; H, 3.17;
N, 8.80% found: C, 37.65; H, 3.21; N, 8.86%.
2 14 2 4 4
116 (45), 88 (43), 58 (100). Anal. Calcd. for C H N O S
1
H
10
N
2
O
2
S
4
(378.49): C, 34.27; H, 2.88; N, 7.99% found: C, 34.32; H, 2.91; N,
8.06%.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet