Thermolysis of symmetrical dithiobiurea and thioureidoethylthiourea derivatives

Article abstract of DOI:10.1002/hc.10188

Microwave and thermal heterocyclization of N,N′-disubstituted hydrazinecarbothioamide 1a,b and substituted thioureidoethylthioureas 2a-c as well as 1-phenyl-3[2-(3-phenylthio-ureido)phenyl]-thiourea 6 are reported.

Full text of DOI:10.1002/hc.10188

Heteroatom Chemistry
Volume 14, Number 6, 2003
Thermolysis of Symmetrical Dithiobiurea
and Thioureidoethylthiourea Derivatives
Alaa A. Hassan,1 Aboul-Fetouh E. Mourad,1 Kamal M. El-Shaieb,1
Ashraf H. Abou-Zied,1 and Dietrich Do¨pp2
1Chemistry Department, Faculty of Science, El-Minia University, El-Minia, A. R., Egypt
2Institut fu¨ r Chemie, Universita¨t Duisburg-Essen, D-47048 Duisburg, Germany
Received 19 February 2003; revised 14 April 2003
The ring-closure of 1-ethoxycarbonyl- and 1,6-
ABSTRACT: Microwave and thermal heterocycliza-
bis(ethoxycarbonyl)bithiourea proceed under the
influence of acids giving 5-amino (or mercapto)-
2-ethoxycarbonamide-1,3,4-thiadiazoles as well
tion of N,Nꢀ-disubstituted hydrazinecarbothioamide
1a,b and substituted thioureidoethylthioureas 2a–c
as well as 1-phenyl-3[2-(3-phenylthio-ureido)phenyl]-
as
2,5-bis(ethoxycarbonamido)-1,3,4-thiadiazole
ꢁ
C
thiourea 6 are reported.
2003 Wiley Periodicals, Inc.
[7]. The action of alkali or hydrazine on the same
ethoxycarbonylbithiourea produces 1,2,4-triazole
derivatives [7]. 3-Mercapto-4-phenyl-5-anilino-
1,2,4-triazole is formed during the reaction of
p-bromophenyl-6-phenyl-2,5-bithiourea with alkali
and alkali/CH3I [9]. Also, phase transfer catalyzed
cyclization of dithiobiureas and reaction with
ꢀ-bromoacetophenone affordes 1,3,4-thiadiazole
[5,8], 1,2,4-triazole [8], and 1,2,4-triazoline-2-thione
derivatives [13,14].
Recently it has been reported that the cyclization
of compounds having an extended urea-like chain of
more than five atoms is an excellent method for the
synthesis of heterocycles such as 1,3,4-thiadiazoles,
1,2,4-triazoles, and 1,3,5-triazines [11]. Furthermore
there is currently much interest in performing chem-
ical reactions under solvent-free conditions since
there are both financial and environmental benefits
[15,16].
In addition microwave (MW) heating has been
employed for the rapid synthesis of a wide variety
of organic molecules [17–22], wherein chemical re-
actions are accelerated because of selective absorp-
tion of MW energy by polar molecules. The applica-
tion of MW irradiation provides enhanced reaction
rates, higher yields, greater selectivity, and the ease of
manipulation.
Heteroatom Chem 14:535–541, 2003; Published online
in Wiley InterScience (www.interscience.wiley.com). DOI
10.1002/hc.10188
INTRODUCTION
Several authors have investigated the heterocy-
clization of 1,6-disubstituted dithiobiureas in
basic or acidic media and under various reaction
conditions [1–14]. N,Nꢀ-Diphenylhydrazine-1,2-di-
carbothioamide(1,6-diphenyl-2,5-dithiobiurea) (1a)
and substituted thioureidoethylthioureas 2b,d re-
acted with mercury bis(phenylacetylide) under ther-
mal decomposition affording heterocyclic systems
3, 4, and 8 (Schemes 1 and 2) [1]. Alkali catalyzed
thermal cyclization of 1-alkyl- and 1,6-dialkyl-2,5-
dithiobiureas results in the formation of compounds
5 and 9 (R = Me, Et, and n-Pr) [6]. Under same
conditions, 1-alkyl-6-aryl-2,5-dithiobiureas give
thiadiazolethiones 9 and triazolidine-3,5-dithiones
5, when the alkyl groups are methyl or ethyl [4,6].
Correspondence to: A. A. Hassan; e-mail: alaahassan2001@
yahoo.com.
Contract grant sponsor: Alexander von Humboldt-Foundation.
2003 Wiley Periodicals, Inc.
c
ꢁ
535

536 Hassan et al.
R
S
C
H
N
R1
R1
N
S
C
S
C
R1
HN
NH NH
NH R1
(H2C)
2
H
N
N
C
S
2
1
R
a, R1 = Ph
b, R1 = allyl
a, R = H, R1 = Ph
b, R = H, R1 = allyl
c, R = H, R1 = PhCH2
d, R = CH3, R1 = Ph
N
N
Ph
HN
NH
N
H3C
N
N
CH3
S
S
N
H
R1
C
S
S
N
4
5, R1 = Me, Et
H
Ph
3
H
N
NHCSNHPh
NHCSNHPh
S
N
H
6
7
SCHEME 1
HN
S
N
HN
NH
N
NH
-RNH2
RHN
NHR
S
NHR
RHN
S
S
HS
1a, b
NH
R
S
9
a, R = Ph
b, R = allyl
-H2S
-H2S
HN
N
N
N
S
NHR
N
RHN
NHR
S
R
8
10, R = Ph
a, R = Ph
b, R = allyl
1a,b
2 R-N=C=S + H2N-NH2
R-NH2
R-NH-CS-NH-R
R-N=C=S
+
11
a, R = Ph
b, R = allyl
c, R = PhCH2
SCHEME 2

Thermolysis of Symmetrical Dithiobiurea and Thioureidoethylthiourea Derivatives 537
As a part of our program directed for the
when H2S is displaced the product formed would be
an N,Nꢀ-disubstituted[1,3,4]thiadiazole-2,5-diamine
8a,b. On the other hand, if the lone pair of elec-
trons on N-6 attacks the thiocarbonyl group at po-
sition 2 in 1a, followed by displacing H2S, the
product formed would be 4-phenyl-5-phenylamino-
4H[1,2,4]triazole-3-thiol (10).
Refluxing 1a with acetic acid afforded ac-
etanilide (0.041 g, 6%) in addition to compounds 8a,
9a, 10, and 11a. The formation of 1,3-disubstituted
thioureas 11a,b and acetanilide confirmed the elim-
ination of substituted amine during the heterocy-
clization of 1a,b.
development of new, simple and efficient, proce-
dures for the synthesis of heterocyclic systems from
thiosemicarbazide derivatives, we recently reported
different successful approaches for the synthesis
of thiazole, thiazine, thiadiazole, thiadiazine, thia-
diazepine, oxathiadiazole, and indazole as well as
pyridazine derivatives [23–27; A. A. Hassan, N. K.
Mohamed, A. M. Shawky, and D. Do¨pp, manuscript
in preparation]. The purpose of this work was to
investigate an alternative, convenient and versatile,
method for intramolecular heterocyclization of com-
pounds 1 in the absence of alkaline or acidic catalyst.
It has been reported that ethylenediamine when
reacting with allylisothiocyanate furnishes a linear
thiourea, which in turn is cyclized to a bis-thiazoline
[10]. The present work was also undertaken to dis-
cuss the intramolecular heterocyclization of 2a–c.
Upon heating or MW irradiation of 2a–c followed by
chromatographic separation, 11–13 were isolated as
products.
RESULTS AND DISCUSSION
When compounds 1a,b, 2a–c, and 6 were heated
or irradiated in a MW reactor, a sticky residue
was obtained. Chromatographic separation of the
residue gave numerous zones, from which prod-
ucts 7–13 could be isolated (Schemes 1–3). Their
structures were assigned on the basis of elemen-
tal analyses and spectral data for unknown com-
pounds and known compounds were identified by
1H and 13C NMR spectra. Their formation may be
explained in terms of intramolecular nucleophilic
attack by either the 2-thiol or the NH group and
detachment of the RNH- or HS-moiety as depicted
in Schemes 2 and 3. When aniline or allylamine
is eliminated, the product would be a 5-substituted
amino-3H-[1,3,4]thiadiazole-2-thione 9a,b, whereas
The structures of 12 and 13 were confirmed on
1
the basis of elemental analysis, mass spectra, H,
1
and 13C NMR data. The H NMR spectrum of 12b
showed for the methylene groups at positions 5 and
4 resonances in the range δ = 3.54–3.87 and 4.62–
4.68 ppm respectively. The presence of methylene
groups is also evident from the 13C-DEPT-NMR spec-
trum exhibiting negative signals at δ = 40.28 and
52.31. In addition, for imidazolidine-NH, the 1H
NMR spectrum exhibited a broad singlet centered at
δ = 13.06 ppm, as well as another broad singlet res-
onated at 6.83 ppm due to NH attached to allyl and
S
S
C
C
S groups. The decoupled carbon spectra of 12b
H
N
showed signals at δ = 178.97 and 179.76 assigned to
acyclic and cyclic C S, respectively [28], pointing
out that the addition did not occur at the sulphur
atom. Compound 12 was also assigned on the basis
of intramolecular H bridge detected by IR (in dilute
CCl4) and 1H NMR (see the Experimental section).
The presence of two multiplets in the ranges
RNH
RNH
R
N
H
N
-RNH2
N
S
C
S
N
H
H
12
RN
H
N
H
N
C
RN
1
-RNH2
δ = 3.64–3.77 and 4.38–4.52 ppm in the H NMR of
SH
C
S
13a again are assigned to the C-4 and C-5 methylene
groups. The 13C-DEPT-NMR spectrum showed nega-
tive signals at δ = 41.64 and 49.94 ppm, confirming
the presence of two methylene groups, whereas the
proton-decoupled 13C-NMR spectrum showed two
signals at δ = 158.70 and 178.12 [28] for C N and
RNH
N
H
N
H
13
S
S
S
C
S
H
N
H
N
RNH
RNH
C
S groups, respectively.
-RNH2
R
N
The alternative structure 14 could be ruled out
according to 1H NMR spectra, as it would have
shown different resonances for the methylene groups
at positions 4 and 5 and the thiadiazepine-NHs. Also,
compounds 12 and 13 are alternatives of each other;
heating compound 13 afforded compound 12.
N
H
C
S
N
H
S
14
2b-c
SCHEME 3

538 Hassan et al.
1H (300.13 MHz) and 13C (75.47 MHz) NMR spectra.
Assignment of carbon resonances has been sup-
ported by DEPT experiments. Mass spectra were ob-
tained with a Varian MAT 311 doubly focussing in-
strument, using electron impact ionization (70 eV).
Elemental analyses were determined at the Micro-
analytical Center, Cairo University, Egypt. A Sam-
sung MX 145 MW oven was used at its full power
1400 W, 70% and 50% power level for the experi-
ments recorded for this study. Preparative layer chro-
matography (PLC): Glass plates 48 × 20 cm covered
with slurry applied and air dried layers of Merck
silica gel PF254. Detection of zones was carried out
by fluorescence quenching after 254 nm excitation;
zones were removed from the plates and extracted
with cold acetone.
Earlier it has been reported that when 1-
phenyl-3-[2-(3-phenylthioureido)phenyl]thiourea 6
is heated with HCl or KOH at reflux temperature,
2-phenylamino-4,5-phenylene-7-thioxo-1,3,6-thiahe-
ptadiazine is formed [29]. Recently, Sondhi et al.
[30] reported that condensation of 4-isothiocyanato-
butane-2-one with o-phenylenediamine in methanol
gives a pyrimidobenzimidazole derivative [30].
Moreover, 2,3-diaminopyridine on condensation
with 4-isothiocyanatobutan-2-one in refluxing acetic
acid gives pyrido[2,3-d]imidazo-2 (1H)thione [30].
In the present investigation, 2-mercaptobenzimi-
dazole (7) and diphenylthiourea 11a were the only
products found to be originating from intramole-
cular thermal cyclization of 1-phenyl-3-[2-(3-phenyl-
thioureido)phenyl]thiourea 6. Product 7 may also
be obtained from the reaction of 5-phenyl-3H-1,3,4-
oxadiazole-2-thione with o-phenylenediamine [31].
As shown in Table 1 the application of MW ir-
radiation provided higher yields in comparison with
yields obtained by application of thermal process.
General Procedure for Starting Materials
To a stirred solution of hydrazine hydrate or the
respective diamine (10 mmol) in 20 ml dimethyl-
formamide, phenyl-, allyl-, or benzylisothiocyanate
(20 mmol) was added dropwise at room temperature.
Stirring at room temperature was continued for 3 h,
the mixture was set aside overnight, and then added
to ice water. A white precipitate was formed which
was recrystallized from a suitable solvent: N,Nꢀ-
Diphenylhydrazinecarbothioamide (1a) [32,33],
N,Nꢀ-diallylhydrazinecarbothioamide (1b) [34], 1-
phenyl-3-[2-(3-phenylthioureido)ethyl]thiourea (2a)
EXPERIMENTAL
All the melting points were determined in open glass
capillaries on Gallenkamp melting point apparatus
and are uncorrected. The IR spectra were recorded
with a Shimadzu 408 or a Bruker Vector 22 FT-
IR instrument, using potassium bromide pellets. A
Bruker WM 300 instrument was used to determine
[35],
1-allyl-3-[2(3-allylthioureido)ethyl]thiourea
(2b) [10], and 1-phenyl-3-[2-(3-phenylthioureido)-
phenyl]thiourea (6) [29].
TABLE 1 Thermolysis of 1.5 g Each of Starting Materials
1a,b, 2a–c, and 6 by Conventional Heating (A) and MW Irra-
diation (B)
1-Benzyl-3-[2-(3-benzylthioureido)ethyl]thiourea
(2c). Colorless crystals from ethanol. Yield 71%,
m.p. 143–145◦C. IR: ν (KBr) cm−1 3270, 3110
(NH), 2940 (Ali-CH), 1640, 1590 (C N, C C) and
Yield in g (%)
Starting Materials
(Conditions)
Products
A
B
1
1360 cm−1 (C S). H NMR (300 MHz, DMSO-d6)
1a
8a
9a
(22) 0.295 (26) 0.340
(18) 0.217 (21) 0.217
(12) 0.157 (16) 0.213
(5) 0.055 (9) 0.097
(33) 0.422 (38) 0.492
(24) 0.275 (30) 0.338
(4) 0.044 (7) 0.073
(7) 0.069 (11) 0.111
(11) 0.116 (15) 0.161
(47) 0.505 (55) 0.596
(7) 0.059 (9) 0.078
(5) 0.060 (8) 0.098
(58) 0.680 (63) 0.739
(7) 0.073 (10) 0.108
(10) 0.107 (14) 0.146
(41) 0.427 (52) 0.544
(6) 0.052 (10) 0.094
(46) 0.272 (60) 0.335
δ 3.69 (s, 4H, 2CH2), 4.66 (s, 4H, 2 benzyl-CH2),
7.11–7.39 (m, 10H, Ar-H), 7.85 (s, br, 2H, 2 NH), 9.61
(s, br, 2H, 2NH). MS (70 eV) m/z (%) 358 (M+, 19),
296 (53), 265 (43), 223 (8), 206 (13), 181 (39), 149
(87), 91 (100); C18H22N4S2 (358.53); calcd C, 60.30;
H, 6.19; N, 15.63; S, 17.89; found C, 60.46; H, 6.03;
N, 15.49; S, 18.06%.
A: 188–190◦C.
B: 7 min, power 100%
10
11a
8b
9b
1b
A: 188–190◦C.
B: 6 min, power 100%
2a
11b
11a
12a
13a
11b
12b
13b
11c
12c
13c
11a
7
A: 203–205◦C.
B: 6 min, power 100%
2b
A: 103–105◦C.
B: 4 min, power 50%
2c
Heterocyclization by Conventional Heating
of Neat 1a,b, 2a–c, and 6
A: 143–145◦C.
B: 6 min, power 70%
6
1a,b, 2a–c or 6 (1.5 g) was heated in an oil bath to its
melting point. After cooling, a 30 ml of ethanol were
added, any insoluble material was filtered off and
washed with ethanol to give compounds 8a,b. The fil-
trate was concentrated and the residue was subjected
A: 153–155◦C.
B: 7 min, power 100%

Thermolysis of Symmetrical Dithiobiurea and Thioureidoethylthiourea Derivatives 539
to PLC using cyclohexane/ethyl acetate (2:1) as de-
5-Allylamino-3H-[1,3,4]thiadiazole-2-thione (9b).
Colorless crystals from cyclohexane. m.p. 56–58◦C
veloping solvent to give three zones from heating of
1a,b. The fastest migrating zone contained 11a,b,
the second zone contained 9a,b and the slowest zone
contained 10.
1
(lit. [25] 58◦C). H NMR (CDCl3) δ = 4.31–4.35 (m,
2H, allyl-CH2N ), 5.16–5.28 (m, 2H, CH2 ), 5.90–
5.99 (m, 1H, CH ), 7.53 (br, s, 1H, allyl-NH), 12.35
(s, br, 1H-thiadiazole-NH). 13C NMR (CDCl3) 45.93
(allyl-CH2N), 116.89 (CH2 ), 133.71 (CH ), 149.14
(thiadiazole-C-5), 178.46 (C S). MS (70 eV) m/z (%)
173 (M+, 51), 115 (100), 100 (12), 56 (58), 41 (40).
C5H7N3S2 (173.26); calcd C, 34.66; H, 4.07; N, 24.25;
S, 37.01; found C, 34.81; H, 4.24; N, 24.36; S, 36.83%.
On the other hand, chromatographic separation
of the residue from heating 2a–c using cyclohex-
ane/ethyl acetate (3:1) as eluent afforded three zones.
The fastest moving one contained 11a–c. The second
zone contained 12a–c while the last zone contained
13a–c. Chromatographic separation of the residue
from heating compound 6 using cyclohexane/ethyl
acetate (2:1) as eluent afforded two zones, the fastest
migrating one contained 11a, and the second zone
contained 7. The zones were extracted with acetone,
crystallized and identified.
4-Phenyl-5-phenylamino-4H-[1,2,4]triazole-3-thi-
ol (10). Colorless crystals from ethanol. m.p.
206–208◦C (lit. [37,38] 206–209◦C).
1,3-Diphenylthiourea (11a). Colorless powder
from ethanol. m.p. 151–153◦C (lit. [39,40] 153–
154◦C).
Heterocyclization by Microwave Irradiation
of 1a,b, 2a–c, and 6
1,3-Diallylthiourea (11b). Colorless crystals
from ether/hexane. m.p. 48–50◦C (lit. [40] 47–49◦C).
1.5 g of 1a,b, 2a–c, or 6 was irradiated in an open
glass tube (the time of irradiation is listed in Table 1).
After completion of the reaction as monitored by
TLC, the residue was separated as reported above.
Comparison of the yields from compounds 1, 2, and
6 is given in Table 1.
1,3-Dibenzylthiourea (11c). White crystals from
ethanol. m.p. 146–148◦C (lit. [40] 146–147◦C).
2-Thioxoimidazolidine-1-carbothioic Phenylami-
de (12a). Colorless crystals. m.p. 174–176◦C (lit.
[41] 176–177◦C).
N,N-Diphenyl-[1,3,4]thiadiazole-2,5-diamine(8a).
Colorless crystals from DMF, m.p. 239–241◦C (lit.
[1,5] 240–243◦C).
2-Thioxoimidazolidine-1-carbothioic Allylamide
(12b). Colorless crystals from acetonitrile. m.p.
126–128◦C. IR: ν (KBr) 3191 (NH), 2928 (Ali-
CH), 1531 (C C) and 1354 cm−1 (C S), ν (CCl4,
10−3 M, d = 3 cm): 3170 (broad NH assoc.) and
1331 cm−1 (C S, intramolecular H-bridge). 1H NMR
(CDCl3) δ = 3.54–3.78 (t, 2H, imidazolidine-5-CH2,
J = 9.04 Hz), 4.28–4.32 (br, s, 2H, allyl-CH2N),
4.62–4.68 (t, 2H, imidazolidine-4-CH2, J = 9.02 Hz),
5.21–5.38 (m, 2H, allyl CH2 ), 5.89–6.02 (m, 1H,
allyl-CH ), 6.83 (s, br, 1H, allyl-NH), 13.06 (s,
br, 1H, imidazolidine-NH) the latter two signals
fade upon treatment of the CDCl3-solution with
D2O. 13C NMR (CDCl3) δ = 40.28 (imidazolidine-
CH2-5), 48.64 (allyl-CH2N), 52.31 (imidazolidine-
4-CH2), 117.37 (allyl-CH2 ), 132.14 (allyl-CH ),
178.97 (acyclic-C S), 179.76 (cyclic C S). MS (70
eV) m/z (%) 201 (M+, 100), 186 (96), 168 (8), 102 (55),
99 (12), 44 (99), 41 (42). C7H11N3S2 (201.31); calcd C,
41.76; H, 5.51; N, 20.87; S, 31.81; found C, 41.61; H,
5.64; N, 20.76; S, 31.90%.
N,N-Diallyl-[1,3,4]thiadiazole-2,5-diamine (8b).
Colorless crystals from ethanol. m.p. 133–135◦C (lit.
[36] 135◦C). 1H NMR (DMSO-d6) δ = 3.75 (br, s, 4H,
2CH2N), 5.05–5.09 (m, 4H, 2CH2 ), 5.82–5.88 (m,
2H, 2CH ), 6.94 (br, s, 2H, 2NH). 13C NMR (DMSO-
d6) 46.56 (CH2 N), 115.82 (CH2 ), 135 (CH ),
159.81 (thiadiazole-C-2). MS (70 eV) m/z (%) 196
(M+, 46), 181 (10), 155 (13), 114 (42), 100 (11), 81
(17), 56 (23), 41 (100). C8H12N4S (196.28); calcd C,
48.96; H, 6.16; N, 28.54; S, 16.34; found C, 48.81; H,
6.04; N, 28.66; S, 16.23%.
5-Phenylamino-3H-[1,3,4]thiadiazole-2-thione
(9a). Pale yellow crystals from ethanol. m.p. 226–
228◦C (lit. [6] 228◦C). 1H NMR (DMSO-d6) δ = 6.96–
6.99 (m, 1H, Ar-H), 7.28–7.41 (m, 4H, Ar-H), 10.14
(s, br, 1H, NH), 13.50 (s, br, 1H, thiadiazole-NH).
13C NMR (DMSO-d6) 117.6, 121.39, 129.14, 129.32,
129.59, 139.98 (Ar-CH), 157.08 (thiadiazole-C-5),
180.55 (C S). MS (70 eV) m/z (%) 209 (M+, 100),
135 (11), 93 (6), 77 (39). C8H7N3S2 (209.29); calcd C,
45.91; H, 3.32; N, 20.08; S, 30.64; found C, 46.11; H,
3.14; N, 19.96; S, 30.53%.
2-Thioxoimidazolidine-1-carbothioic Benzylyla-
mide (12c). Colorless crystals. m.p. 135–137◦C (lit
[42]. 135–136◦C).

540 Hassan et al.
7-Phenylimino-[1,3,6]thiadiazepane-2-thione
ACKNOWLEDGMENT
(13a). Colorless crystals from methanol. m.p.
235–237◦C. IR: ν (KBr) 3410 (NH), 3020 (Ar-
CH), 2920 (Ali-CH2) and 1625, 1585 cm−1 (C N,
A. A. Hassan is thankful to the Alexander von
Humboldt-Foundation for the donation of the Shi-
madzu 408 IR spectrophotometer.
C
C). 1H NMR (DMSO-d6) δ = 3.67–3.77 (t, 2H,
thiadiazepane-5-CH2, J = 8.99 Hz), 4.42–4.48 (t,
2H, thidiazepane-4-CH2, J = 9.01 Hz), 7.23–7.29,
7.36–7.41, 7.71–7.97 (m, 5H, Ar-H), 9.67 (s, br, 1H,
thiadiazepane-NH), 9.81 (s, br, 1H, thiadiazepane-
NH). 13C NMR (DMSO-d6) 41.64 (C-5), 49.95 (C-4),
120.44, 121.52, 123.58, 126.05, 132.31, 148.26 (Ar-C),
158.72 (C-7), 178.12 (C S). MS (70 eV) m/z (%) 237
(M+,10), 235 (100), 163 (98), 150 (56), 136 (28), 135
(6), 43 (4). C10H11N3S2 (237.35); calcd C, 50.61; H,
4.68; N, 17.70; S, 27.02; found C, 50.49; H, 4.55; N,
17.61; S, 27.19%.
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27, 707.
7-Allylimino-[1,3,6]thiadiazepane-2-thione(13b).
Colorless crystals from ethanol. m.p. 98–100◦C. IR: ν
(KBr) 3219 (NH), 2921 (Ali-CH) and 1620, 1571 cm−1
(C N, C C). 1H NMR (DMSO-d6) δ = 3.39 (br, t, 2H,
thiadiazepane-5-CH2), 3.49 (br, t, 2H, thiadiazepane-
4-CH2), 4.01 (br, s, 2H, allyl-CH2N), 5.04–5.16 (m,
2H, allyl-CH2 ), 5.76–5.88 (m, 1H, allyl-CH ),
7.52 (br, s, 1H, thiadiazepane-NH), 7.63 (br, s, 1H,
thiadiazepane-NH). 13C NMR (DMSO-d6) 36.81
(C-5), 43.01 (allyl-CH2N), 46.09 (C-4), 115.66 (allyl-
CH2 ), 135.13 (allyl-CH ), 158.12 (C-7), 182.38
(C S). MS (70 eV) m/z (%) 201 (M+, 78), 186 (82),
168 (7), 102 (64), 56 (100), 41 (76). C7H11N3S2
(201.31), calcd C, 41.76; H, 5.51; N, 20.87; S, 31.85;
found C, 41.87; H, 5.44; N, 21.04; S, 31.97%.
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7-Benzylimino-[1,3,6]thiadiazepane-2-thione
(13c). Colorless crystals, m.p. 128–130◦C (ethanol).
IR: ν (KBr) 3310 (NH), 3025 (Ar-CH) 2945 (Ali-
1
CH) and 1628, 1568 cm−1 (C N, C C). H NMR
(DMSO-d6) δ = 3.61–3.74 (t, 2H, thiadiazepane-5-
CH2, J = 8.86 Hz), 4.39–4.44 (t, 2H, thiadiazepane-
4-CH2, J = 8.87 Hz), 4.76 (s, 2H, CH2), 7.21–7.28,
7.33–7.39, 7.68–7.94 (m, 5H, Ar-H), 9.65 (br, s, 1H,
thiadiazepane-NH), 9.77 (br, s, 1H, thidiazepane-
NH). 13C NMR (DMSO-d6) 40.14 (C-5), 48.53 (C-4),
49,22 (CH2-Ph), 120.11, 120.86, 122.44, 125.31,
130.12, 140.41 (Ar-C), 158.62 (C-7), 181.16 (C S).
MS (70 eV) m/z (%) 251 (M+, 16), 249 (100), 177
(84), 164 (49), 149 (11), 43 (6). C11H13N3S2 (251.37),
calcd C, 52.56; H, 5.21; N, 16.72; S, 25.51; found C,
52.39; H, 5.34; N, 16.61; S, 25.68%.
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1,3-Dihydrobenzimidazole-2-thione (7). White
powder from acetonitrile. m.p. 301–303◦C (lit.
[31,43] 303–307◦C).

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