Synthesis and recylization of 2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f]- [1,3]thiazino[3,2-a]benzimidazolium salts

Article abstract of DOI:10.1007/s10593-014-1453-z

A series of [1,3]thiazino[3,2-a]benzimidazolium salts modified in the benzene ring by a condensed 1,4-dioxane ring has been prepared. Reaction with epichlorohydrin occurs with recyclization to form derivatives of 3-(2,3-epithiopropyl)benzimidazol-2-one.

Full text of DOI:10.1007/s10593-014-1453-z

Chemistry of Heterocyclic Compounds, Vol. 50, No. 1, April, 2014 (Russian Original Vol. 50, No. 1, January, 2014)
SYNTHESIS AND RECYLIZATION OF
2,3,9,10-TETRAHYDRO-8H-[1,4]DIOXINO[2,3-f]-
[1,3]THIAZINO[3,2-a]BENZIMIDAZOLIUM SALTS
M. A. Orlov1, I. V. Kapitanov1, N. I. Korotkikh1*, and O. P. Shvaika1
A series of [1,3]thiazino[3,2-a]benzimidazolium salts modified in the benzene ring by a condensed
1,4-dioxane ring has been prepared. Reaction with epichlorohydrin occurs with recyclization to form
derivatives of 3-(2,3-epithiopropyl)benzimidazol-2-one.
Keywords: 3-(2,3-epi-thiopropyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-2-ones, 2,3,9,10-
tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benzimidazolium salts, thiiranes, recyclization.
A proposed in the paper [1] method for the preparation of 3-(2,3-epithiopropyl)benzimidazol-2-ones 3
from the condensed thiazinium salts 2 via their recyclization in excess epichlorohydrin allowed to synthesize a
series of derivatives containing various substituents at position 1 of the imidazolone ring, and this method
proved convenient for working with small amounts of materials.
R
R
N
X–
S
N
N
N+
Cl
RX
O
O
S
N
N
S
OH
OH
1
2
3
R = PhCOCH2, 4-BrC6H4COCH2, (piperidin-1-yl)СОСН2, EtОСОСН2,
(morpholin-4-yl)СОСН2, MeОСОСН2
Since compounds 2 and 3, substituted in the benzene ring, were unknown it was of interest to prepare
such derivatives with the aim of searching for novel biologically active structures (particularly antitumor
medications with a thiirane ring [2]). It should be noted that there are only isolated examples in the literature of
structural analogs of compound 1 [3-7] (which is the precursor in the synthesis of compounds 2 and 3), despite
the continuing interest in compounds containing a thiirane ring [8-12].
_______
*To whom correspondence should be addressed, e-mail: nkorotkikh@ua.fm.
1L. M. Litvinenko Institute of Physical Organic and Coal Chemistry, 7 R. Luxemburg St., Donetsk 83114,
Ukraine.
_________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 123-128, January, 2014. Original
article submitted December 13, 2013.
0009-3122/14/5001-0111©2014 Springer Science+Business Media New York
111

We selected the alkoxy groups of a condensed [1,4]benzodioxane ring as the substituent in the benzene
ring and its introduction can lead to derivatives of the condensed heterocyclic system 2,3,9,10-tetrahydro-
8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benzimidazole 7. On its basis we proposed a synthesis of the salts
8a-g and the 3-(2,3-epithiopropyl)imidazol-2-ones 9a-g.
Synthesis of the condensed thiazine 7 was performed from the 2,3-dihydro-1,4-benzodioxine-
6,7-diamine dihydrochloride (4) according to the scheme below. The salt 4 was prepared from 1,4-benzo-
dioxane according to the reported method [13]. Compound 6 has been synthesized previously [14] by the
reaction of diamine 4 with alkyl xanthogenates and it has also been mentioned in the study [15] where its
melting point (around 300ºC) was given but the preparation method and spectroscopic parameters were not
reported.
NH2
NH2
O
O
O
O
N
S8
HCOOH
· 2HCl
50°C, 1 h
100°C, 3 h
N
H
4
5
O
O
H
N
Cl
N
N
O
O
O
RX, DMF
150°C
40 min
S
S
NaOH, H2O
room temp.
N
H
6
OH
7
R
R
N
N+
X–
S
O
O
O
O
Cl
O
O
S
N
N
, 15 min
8a–g
9a–g
OH
8, 9 a R = 4-ClC6H4COCH2, b R = 4-BrC6H4COCH2, c R = 4-MeC6H4COCH2,
d R = 4-MeOC6H4COCH2, e R = 4-MeC6H4CH2, f R = 4-FC6H4CH2, g R = PhCH2;
8 a,b,e–g X = Cl, c,d X = Br
The alkylation of compound 7 using phenacyl and benzyl halides in DMF gives 41-77% yields of the
salts 8a-g. Heating the latter in excess epichlorohydrin as in the case of salt 2 [1] led to recyclization and the
formation of the 3-(2,3-epithiopropyl)benzimidazol-2-ones 9a-g in 75-88% yields.
1
The H NMR spectra of the intermediate compounds 5, 6 show characteristic signals for the dioxane
fragment methylene groups at 4.21-4.23 ppm, the meso-proton of imidazole 5 at 8.03 ppm, and the NH protons
1
of the imidazolethione 6 at 12.20 ppm. In the H NMR spectra of the salts 8a-g, the 1,4-benzodioxane
OCH2CH2O fragment gives a singlet at 4.32-4.33 ppm. For the thiiranes 9a-g it is shifted upfield (4.17-4.19
ppm) as a result of the change in molecular charge. Characteristic for the salts 8a-g [1, 16] are the signals of the
OH group protons at 6.05-6.26 ppm, those for the thiazine ring (3.48-3.66 ppm for the CH2S group, 4.25-4.46
ppm for the NCH2 group, and 4.64-4.74 ppm for the CHOH proton), and also for the substituent methylene
group at 5.50-5.57 ppm in the benzyl or 6.10-6.19 ppm in the phenacyl derivatives. There are a characteristic
thiirane multiplet (2.46-2.54 ppm) and doublet (2.57-2.59 ppm) for the 2,3-epithiopropyl fragment in
compounds 9a-g due to geminal and vicinal proton splittings as well as two double doublets for the NCH2
fragment at 3.93-4.11 ppm and a CHS proton multiplet at 3.19-3.29 ppm.
Hence, we have developed a method for the preparation of 6-substituted [1,3]thiazino[3,2-a]benz-
imidazolium salts and 3-(2,3-epithiopropyl)benzimidazol-2-ones modified in the benzene ring by a condensed
1,4-dioxane fragment.
112

EXPERIMENTAL
1H NMR spectra were recorded on a Bruker Avance II 400 spectrometer (400 MHz) using DMSO-d6
with TMS as internal standard. Elemental analysis for C, H, and halogen was carried out by combustion in an
oxygen stream and analysis for nitrogen by the Dumas method. Melting points were determined on a Boetius PHMK
05 block and are not corrected. TLC was performed on Merck Silica Gel 60 F254 plates with CHCl3–MeOH (10: 1)
as eluent and developed using UV light.
6,7-Dihydro-1H-[1,4]dioxino[2,3-f]benzimidazole (5). HCOOH (96%, 20 ml) was added to the
2,3-dihydro-1,4-benzodioxine-6,7-diamine dihydrochloride (4) (20 g, 84 mmol). The mixture obtained was
heated on a boiling water bath for 3 h. After cooling, 30% ammonia solution was added to an alkaline reaction.
The precipitate formed was filtered off, washed with water, dried, and recrystallized from CHCl3. Yield 10.3 g
1
(70%). Colorless crystals. Mp 193-194ºC. Rf 0.33. Н NMR spectrum, δ, ppm: 4.23 (4Н, s, OCH2CH2O); 7.01
(2H, s, Н Ar); 8.03 (1H, s, Н Ar). Found, %: C 61.33; H 4.60; N 15.92. C9H8N2O2. Calculated, %: C 61.36;
H 4.58; N 15.90.
1,3,6,7-Tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazole-2-thione (6). A mixture of compound 5 (10.3
g, 58.5 mmol) and sulfur (1.9 g, 58.5 mmol) was heated at 250ºC for 1 h. After cooling, a solution of NaOH (4.0 g,
100 mmol) in water (100 ml) was added, stirred to dissolution, and activated carbon (0.5 g) was added. The
mixture obtained was refluxed for 15 min, filtered, and acidified using excess AcOH. The precipitate was filtered
off, washed with water and then acetone, and dried. Yield 10.1 g (83%). Colorless powder. Mp > 350ºC. Rf 0.69.
1Н NMR spectrum, δ, ppm: 4.21 (4Н, s, OCH2CH2O); 6.61 (2H, s, H Ar); 12.20 (2H, s, NН). Found, %: C 51.95;
H 3.90; N 13.41; S 15.37. C9H8N2O2S. Calculated, %: C 51.91; H 3.87; N 13.45; S 15.40.
2,3,9,10-Tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benzimidazol-9-ol (7). Compound 6
(10.4 g, 50 mmol) was added to a solution of NaOH (2.0 g, 50 mmol) in H2O (100 ml) and stirred at room
temperature to dissolution. Stirring was continued and epichlorohydrin (3.91 ml, 50 mmol) was added. The
precipitate was filtered off, washed with water, dried, and recrystallized from DMF (50 ml). Yield 7.1 g (54%).
Colorless powder. Mp 284-285ºC (decomp.). Rf 0.38. 1Н NMR spectrum, δ, ppm (J, Hz): 3.19 (1Н, dd, 3J = 4.6,
2
2
2
2J = 12.2) and 3.35 (1Н, d, J = 12.2, CH2S); 3.94 (1Н, d, J = 13.0) and 4.12 (1H, d, J = 13.0, NCH2); 4.27
(4Н, s, OCH2CH2O); 4.40-4.46 (1H, m, CHOН); 5.79 (1H, s, OH); 6.94 (2H, s, H Ar). Found, %: C 54.57;
H 4.54; N 10.63; S 12.10. C12H12N2O3S. Calculated, %: C 54.53; H 4.58; N 10.60; S 12.13.
Synthesis of 9-Hydroxy-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benzimid-
azolium Salts 8a-g (General Method). Compound 7 (264 mg, 1.0 mmol), the alkylating agent (1.2 mmol), and
DMF (0.2 ml) were mixed. The mixture was heated at 150ºC for 40 min. Once cooled the precipitate formed
was filtered off, washed with DMF (0.3 ml) and Et2O (1 ml), and dried. Recrystallization from DMF gave the
salts 8a-g as colorless powders. Yields 41-77%.
6-(4-Chlorophenacyl)-9-hydroxy-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benzimid-
azolium Chloride (8a). Yield 52%. Mp 244-245ºC (decomp.). Rf 0.06. 1Н NMR spectrum, δ, ppm (J, Hz): 3.51
(1Н, dd, 3J = 5.0, 2J = 12.4) and 3.66 (1Н, d, 2J = 12.4, CH2S); 4.32 (4Н, s, OCH2CH2O); 4.33-4.36 (1Н, m) and 4.46
(1H, dd, 3J = 2.8, 2J = 13.6, NCH2); 4.67-4.73 (1H, m, CHOН); 6.19 (2H, s, N+CH2CO); 6.21 (1H, d, J = 3.4, OH); 7.54
(1H, s, H Ar); 7.55 (1H, s, H Ar); 7.90 (2Н, d, J = 8.4, H Ar); 8.10 (2Н, d, J = 8.4, H Ar). Found, %: C 53.03; H 3.97;
Cl 15.59; N 6.21; S 7.11. C20H18Cl2N2O4S. Calculated, %: C 52.99; H 4.00; Cl 15.64; N 6.18; S 7.07.
6-(4-Bromophenacyl)-9-hydroxy-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benz-
imidazolium Chloride (8b). Yield 60%. Mp 250-251ºC (decomp.). Rf 0.07. 1Н NMR spectrum, δ, ppm (J, Hz):
3
2
2
3.50 (1Н, dd, J = 5.0, J = 12.4) and 3.65 (1Н, d, J = 12.4, CH2S); 4.32 (4Н, s, OCH2CH2O); 4.34-4.37 (1Н,
m) and 4.46 (1H, dd, 3J = 2.6, 2J = 13.6, NCH2); 4.68-4.74 (1H, m, CHOН); 6.18 (2H, s, N+CH2CO); 6.20 (1H,
d, J = 3.4, OH); 7.54 (1H, s, H Ar); 7.55 (1H, s, H Ar); 7.89 (2Н, d, J = 8.4, H Ar); 8.08 (2Н, d, J = 8.4, H Ar).
Found, %: C 48.30; H 3.62; Br 16.10; Cl 7.08; N 5.68; S 6.41. C20H18BrClN2O4S. Calculated, %: C 48.26;
H 3.64; Br 16.05; Cl 7.12; N 5.63; S 6.44.
113

9-Hydroxy-6-(4-methylphenacyl)-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benz-
imidazolium Bromide (8c). Yield 52%. Mp 242-243ºC (decomp.). Rf 0.09. 1Н NMR spectrum, δ, ppm (J, Hz):
3
2
2
2.45 (3H, s, CH3); 3.48 (1Н, dd, J = 5.1, J = 12.5) and 3.64 (1Н, d, J = 12.5, CH2S); 4.33 (4Н, s,
OCH2CH2O); 4.34-4.37 (1Н, m) and 4.44 (1H, dd, 3J = 2.7, 2J = 13.7, NCH2); 4.67-4.73 (1H, m, CHOН); 6.05
(1H, d, J = 3.4, OH); 6.14 (2H, s, N+CH2CO); 7.47 (2Н, d, J = 8.4, H Ar); 7.53 (1H, s, H Ar); 7.55 (1H, s,
H Ar); 8.04 (2Н, d, J = 8.4, H Ar). Found, %: C 52.80; H 4.45; Br 16.70; N 5.90; S 6.70. C21H21BrN2O4S.
Calculated, %: C 52.84; H 4.43; Br 16.74; N 5.87; S 6.72.
9-Hydroxy-6-(4-methoxyphenacyl)-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benz-
imidazolium Bromide (8d). Yield 41%. Mp 235-236ºC (decomp.). Rf 0.09. 1Н NMR spectrum, δ, ppm (J, Hz):
3
2
2
3.48 (1Н, dd, J = 4.8, J = 12.4) and 3.65 (1Н, d, J = 12.4, CH2S); 3.89 (3H, s, ОCH3); 4.32 (4Н, s,
OCH2CH2O); 4.33-4.36 (1Н, m) and 4.42 (1H, dd, 3J = 2.6, 2J = 13.6, NCH2); 4.66-4.71 (1H, m, CHOН); 6.05
(1H, d, J = 3.6, OH); 6.10 (2H, s, N+CH2CO); 7.17 (2Н, d, J = 8.8, H Ar); 7.51 (1H, s, H Ar); 7.53 (1H, s,
H Ar); 8.11 (2Н, d, J = 8.8, H Ar). Found, %: C 51.16; H 4.32; Br 16.24; N 5.70; S 6.47. C21H21BrN2O5S.
Calculated, %: C 51.12; H 4.29; Br 16.20; N 5.68; S 6.50.
9-Hydroxy-6-(4-methylbenzyl)-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benz-
imidazolium Chloride (8e). Yield 75%. Mp 230-231ºC. Rf 0.08. 1Н NMR spectrum, δ, ppm (J, Hz): 2.28 (3H,
3
2
2
2
s, CH3); 3.50 (1Н, dd, J = 4.8, J = 12.4) and 3.63 (1Н, d, J = 12.4, CH2S); 4.25 (1Н, d, J = 13.2) and 4.38
3
2
(1H, dd, J = 2.8, J = 13.2, NCH2); 4.32 (4Н, s, OCH2CH2O); 4.65-4.69 (1H, m, CHOН); 5.50 (2H, s,
N+CH2Ar); 6.15 (1H, d, J = 2.8, OH); 7.20 (2Н, d, J = 7.8, H Ar); 7.25 (2Н, d, J = 7.8, H Ar); 7.51 (2H, s,
H Ar). Found, %: C 59.38; H 5.20; Cl 8.81; N 6.89; S 7.96. C20H21ClN2O3S. Calculated, %: C 59.33; H 5.23;
Cl 8.76; N 6.92; S 7.92.
6-(4-Fluorobenzyl)-9-hydroxy-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benz-
imidazolium Chloride (8f). Yield 73%. Mp 232-233ºC. Rf 0.07. 1Н NMR spectrum, δ, ppm (J, Hz): 3.51 (1Н,
3
2
2
3
2
dd, J = 5.2, J = 12.0) and 3.63 (1Н, d, J = 12.0, CH2S); 4.26 (1H, dd, J = 1.2, J = 13.2) and 4.39 (1H, dd,
3J = 3.2, J = 13.2, NCH2); 4.33 (4Н, s, OCH2CH2O); 4.65-4.69 (1H, m, CHOН); 5.56 (2H, s, N+CH2Ar); 6.19
2
(1H, d, J = 3.6, OH); 7.21-7.29 (2Н, m, H Ar); 7.40-7.48 (2Н, m, H Ar); 7.52 (1H, s, H Ar); 7.54 (1H, s, H Ar).
Found, %: C 55.85; H 4.40; N 6.89. C19H18ClFN2O3S. Calculated, %: C 55.81; H 4.44; N 6.85.
6-Benzyl-9-hydroxy-2,3,9,10-tetrahydro-8H-[1,4]dioxino[2,3-f][1,3]thiazino[3,2-a]benzimidazolium
Chloride (8g). Yield 77%. Mp 231-232ºC. Rf 0.08. 1Н NMR spectrum, δ, ppm. (J, Hz): 3.53 (1Н, dd, 3J = 5.2,
2J = 12.0) and 3.65 (1Н, d, 2J = 12.0, CH2S); 4.28 (1H, d, 2J = 13.2) and 4.42 (1H, dd, 3J = 2.8, 2J = 13.2, NCH2);
4.32 (4Н, s, OCH2CH2O); 4.64-4.68 (1H, m, CHOН); 5.57 (2H, s, N+CH2Ph); 6.26 (1H, d, J = 3.6, OH);
7.36-7.39 (5Н, m, H Ph); 7.52 (2H, s, H Ar). Found, %: C 58.33; H 4.94; Cl 9.11; N 7.13; S 8.22.
C19H19ClN2O3S. Calculated, %: C 58.38; H 4.90; Cl 9.07; N 7.17; S 8.20.
Synthesis of 1-Substituted 3-(2,3-Epithiopropyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benz-
imidazol-2-ones 9a-g (General Method). The salt 8a-g was refluxed with a 20-fold molar excess of
epichlorohydrin for 15 min. The mixture was cooled and the product was filtered off and recrystallized from
epichlorohydrin. If the product was soluble (compounds 9e-g) the epichlorohydrin was evaporated and the
residue was dissolved in CHCl3 and filtered through a silica gel layer. The chloroform was evaporated in vacuo
and the material was recrystallized from ether. The thiirane products obtained are colorless powders. Yields
75-88%.
1-(4-Chlorophenacyl)-3-(2,3-epithiopropyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-
2-one (9a). Yield 80%. Mp 205-206ºC. Rf 0.79. 1Н NMR spectrum, δ, ppm (J, Hz): 2.46-2.48 (1Н, m) and 2.57
3
3
2
(1Н, d, J = 6.0, CH2S); 3.21-3.28 (1H, m, NCH2CHS); 3.93 (1H, dd, J = 6.4, J = 14.8) and 4.11 (1H, dd,
3J = 5.6, 2J = 14.8, NCH2CHS); 4.18 (4Н, s, OCH2CH2O); 5.41 (2H, s, NCH2CO); 6.78 (1H, s, H Ar); 6.93 (1H,
s, H Ar); 7.81 (2Н, d, J = 8.4, H Ar); 8.02 (2Н, d, J = 8.4, H Ar). Found, %: C 57.60; H 4.07; Cl 8.55; N 6.70;
S 7.72. C20H17ClN2O4S. Calculated, %: C 57.62; H 4.11; Cl 8.50; N 6.72; S 7.69.
114

1-(4-Bromophenacyl)-3-(2,3-epithiopropyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-2-one
1
(9b). Yield 83%. Mp 208-209ºC. Rf 0.78. Н NMR spectrum, δ, ppm. (J, Hz): 2.46-2.49 (1Н, m) and 2.58 (1Н,
d, 3J = 6.0, CH2S); 3.21-3.29 (1H, m, NCH2CHS); 3.95 (1H, dd, 3J = 6.4, 2J = 14.8) and 4.10 (1H, dd, 3J = 5.6,
2J = 14.8, NCH2CHS); 4.19 (4Н, s, OCH2CH2O); 5.42 (2H, s, NCH2CO); 6.77 (1H, s, H Ar); 6.94 (1H, s, H Ar);
7.82 (2Н, d, J = 8.4, H Ar); 8.01 (2Н, d, J = 8.4, H Ar). Found, %: C 52.10; H 3.68; Br 17.36; N 6.10; S 6.91.
C20H17BrN2O4S. Calculated, %: C 52.07; H 3.71; Br 17.32; N 6.07; S 6.95.
3-(2,3-Epithiopropyl)-1-(4-methylphenacyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-
2-one (9c). Yield 83%. Mp 198-199ºC. Rf 0.85. 1Н NMR spectrum, δ, ppm (J, Hz): 2.42 (3H, s, CH3); 2.52-2.54
(1Н, m) and 2.59 (1Н, d, 3J = 6.4, CH2S); 3.20-3.28 (1H, m, NCH2CHS); 3.95 (1H, dd, 3J = 6.6, 2J = 14.8) and
3
2
4.11 (1H, dd, J = 5.6, J = 14.8, NCH2CHS); 4.19 (4Н, s, OCH2CH2O); 5.39 (2H, s, NCH2CO); 6.74 (1H, s,
H Ar); 6.93 (1H, s, H Ar); 7.40 (2Н, d, J = 8.0, H Ar); 7.98 (2Н, d, J = 8.0, H Ar). Found, %: C 63.60; H 5.06;
N 7.11; S 8.05. C21H20N2O4S. Calculated, %: C 63.62; H 5.08; N 7.07; S 8.09.
3-(2,3-Epithiopropyl)-1-(4-methoxyphenacyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-
2-one (9d). Yield 88%. Mp 214-215ºC. Rf 0.78. 1Н NMR spectrum, δ, ppm (J, Hz): 2.51-2.53 (1Н, m) and 2.59
3
3
2
(1Н, d, J = 6.4, CH2S); 3.19-3.27 (1H, m, NCH2CHS); 3.87 (3H, s, ОCH3); 3.94 (1H, dd, J = 6.8, J = 14.8)
and 4.10 (1H, dd, 3J = 5.6, 2J = 14.8, NCH2CHS); 4.19 (4Н, s, OCH2CH2O); 5.36 (2H, s, NCH2CO); 6.72 (1H,
s, H Ar); 6.93 (1H, s, H Ar); 7.11 (2Н, d, J = 8.8, H Ar); 8.05 (2Н, d, J = 8.8, H Ar). Found, %: C 61.13;
H 4.84; N 6.80; S 7.72. C21H20N2O5S. Calculated, %: C 61.15; H 4.89; N 6.79; S 7.77.
3-(2,3-Epithiopropyl)-1-(4-methylbenzyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-
2-one (9e). Yield 78%. Mp 107-108ºC. Rf 0.84. 1Н NMR spectrum, δ, ppm (J, Hz): 2.25 (3H, s, CH3); 2.49-2.53
(1Н, m) and 2.57 (1Н, d, 3J = 6.0, CH2S); 3.20-3.26 (1H, m, NCH2CHS); 3.95 (1H, dd, 3J = 6.4, 2J = 14.8) and
3
2
4.10 (1H, dd, J = 5.6, J = 14.8, NCH2CHS); 4.17 (4Н, s, OCH2CH2O); 4.92 (2H, s, NCH2Ar); 6.62 (1H, s,
H Ar); 6.90 (1H, s, H Ar); 7.12 (2Н, d, J = 7.6, H Ar); 7.19 (2Н, d, J = 7.6, H Ar). Found, %: C 65.16; H 5.51;
N 7.62; S 8.67. C20H20N2O3S. Calculated, %: C 65.20; H 5.47; N 7.60; S 8.70.
3-(2,3-Epithiopropyl)-1-(4-fluorobenzyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-
2-one (9f). Yield 75%. Mp 143-144ºC. Rf 0.82. 1Н NMR spectrum, δ, ppm (J, Hz): 2.49-2.52 (1Н, m) and 2.58
3
3
2
(1Н, d, J = 6.4, CH2S); 3.22-3.28 (1H, m, NCH2CHS); 3.95 (1H, dd, J = 6.8, J = 15.0) and 4.10 (1H, dd,
3J = 5.4, 2J = 15.0, NCH2CHS); 4.17 (4Н, s, OCH2CH2O); 4.98 (2H, s, NCH2Ph); 6.65 (1H, s, H Ar); 6.91 (1H,
s, H Ar); 7.25-7.35 (5Н, m, H Ph). Found, %: C 64.36; H 5.08; N 7.94; S 9.08. C19H18N2O3S. Calculated, %:
C 64.39; H 5.12; N 7.90; S 9.05.
1-Benzyl-3-(2,3-epithiopropyl)-1,3,6,7-tetrahydro-2H-[1,4]dioxino[2,3-f]benzimidazol-2-one (9g).
1
Yield 75%. Mp 127-128ºC. Rf 0.84. Н NMR spectrum, δ, ppm (J, Hz): 2.49-2.52 (1Н, m) and 2.58 (1Н, d,
3J = 6.4, CH2S); 3.22-3.28 (1H, m, NCH2CHS); 3.95 (1H, dd, J = 6.8, J = 15.0) and 4.10 (1H, dd, J = 5.4,
2J = 15.0, NCH2CHS); 4.17 (4Н, s, OCH2CH2O); 4.98 (2H, s, NCH2Ph); 6.65 (1H, s, H Ar); 6.91 (1H, s, H Ar);
7.25-7.35 (5Н, m, H Ph). Found, %: C 64.36; H 5.08; N 7.94; S 9.08. C19H18N2O3S. Calculated, %: C 64.39;
H 5.12; N 7.90; S 9.05.
3
2
3
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