2,3-Benzodiazepine-1-thione in the synthesis of substituted and hetero-annelated 2,3-benzodiazepines

Article abstract of DOI:10.1007/s10593-009-0280-0

A series of S-substituted and 1,2-annelated derivatives of 2,3-benzodiazepine has been obtained on the basis of 2,3-benzodiazepine-1- thione.

Full text of DOI:10.1007/s10593-009-0280-0

Chemistry of Heterocyclic Compounds, Vol. 45, No. 4, 2009
2,3-BENZODIAZEPINE-1-THIONE IN THE
SYNTHESIS OF SUBSTITUTED AND HETERO-
ANNELATED 2,3-BENZODIAZEPINES
K. M. Khabarov1, O. I. Kharaneko1, and S. L. Bogza1*
A series of S-substituted and 1,2-annelated derivatives of 2,3-benzodiazepine has been obtained on the
basis of 2,3-benzodiazepine-1-thione.
Keywords: 2,3-benzodiazepin-1-one, 2,3-benzodiazepine-1-thione, 4-(4-methoxyphenyl)-5H-1,2,4-
triazolo-2,3-benzodiazepin-1-ylhydrazine, alkylation, acylation, cyclization.
In current medicinal chemistry the modification of the structure of 2,3-benzodiazepine is considered to
be one of the promising directions for the creation of new medicinal substances, stimulating the higher nervous
activity (brain integrative functions) – intellect, memory, ability to learn, increased stability of the organism in
extreme conditions [1, 2]. In contrast to 1,4- and 1,5-benzodiazepines, long known as neuroleptics and sedatives,
tranquilizers and anxiolytics based on 2,3-benzodiazepines do not as a rule possess sedative and
narcopotentiating properties, they show nootropic properties.
Most of the successes in the chemistry and pharmacology of derivatives of 2,3-benzodiazepines are
based on modification of 1-aryl-2,3-benzodiazepin-4-ones at the N(3)–C(4) fragment of the seven-membered
ring [3,4]. In contrast, compounds with the isomeric structure – 4-aryl-2,3-benzodiazepin-1-ones – remain
practically uninvestigated until now: only their synthesis and bromination are known [6]. In the present work the
possibility of functionalization and annelation in the 2,3-benzodiazepine series based on 4-aryl-2,3-benzo-
diazepine-1-thione has been studied.
4-(4-Methoxyphenyl)-2,5-dihydro-5H-2,3-benzodiazepin-1-one (2) was obtained by recyclization of
isocoumarin 1 with hydrazine hydrate. Attempts to replace the oxygen atom of the amide fragment with an atom
of sulfur in the benzodiazepinone 2 using phosphorus sulfide in pyridine did not lead to the expected thio-
derivative probably because of the constriction of the seven-membered ring which occurs readily in acid media
[7]. On the other hand, use of the Lawson's reagent in toluene gave 4-(4-methoxyphenyl)-2,5-dihydro-5H-2,3-
benzodiazepine-1-thione (3) in 95% yield. Substitution of the sulfur atom in the thione 3 with the hydrazine unit
occurs practically quantitatively on boiling with hydrazine hydrate to give the benzodiazepin-4-ylhydrazine 4.
_______
*To whom correspondence should be addressed, e-mail: serge-bogza@yandex.ru.
1M. L. Litvinenko Institute of Physico-Organic Chemistry and Coal Chemistry, National Academy of Sciences
of Ukraine, Donetsk 83114, Ukraine.
__________________________________________________________________________________________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, 594-601, April, 2009. Original article
submitted October 14, 2007.
468
0009-3122/09/4504-0468©2009 Springer Science+Business Media, Inc.

OMe
OMe
o
5
4
N2H4
6
9
m
LR
7
8
O
3
toluene
N
2 N
H
1
O
O
1
2
OMe
OMe
N2H4
N
N
N
N
H
S
N
HNH
2
3
4
LR = Lawson's reagent
The sulfur atom in thione 3 is readily alkylated with dimethyl sulfate, haloalkanes (methyl chloroacetate,
ω-chloroacetophenone), and acrylic acid. The product of alkylation with ethyl chloroacetate was isolated from
the reaction in the form of the acid 6.
Me2SO4
OMe
MeS
N
N
5
ClCH2CO2Me
OMe
3
N
O
N
S
CH2=CHCOOH
6
OH
PhCOCH2Cl
O
OMe
HO
S
N
OMe
N
7
N
N
O
S
Ph
8
The reactions of compound 4 with a variety of reagents were studied. On reaction with aliphatic acids it
formed 3-R-6-(4-methoxyphenyl)-7H-1,2,4-triazolo[3,4-a][2,3]benzodiazepines 9-11. Identification of the
products of the reaction of hydrazine 4 with aromatic acids under the same conditions was unsuccessful.
469

OMe
RCO2H
N
4
N
N
N
R
9–11
9 R = Me, 10 R = Et, 11 R = 3,4-(MeO)2C6H3CH2
Reaction of hydrazine 4 with triethyl orthoformate gave 6-(4-methoxyphenyl)-7H-1,2,4-triazolo-
[3,4 a][2,3]benzodiazepine (12). Nitrosation of the hydrazine 4 with acetic acid–sodium nitrite led to
intramolecular cyclization to 6-(4-methoxyphenyl)-7H-tetrazolo[5,4-a][2,3]benzodiazepine ( 13).
CH(OEt)3
OMe
N
N
N
N
12
4
HNO2
AcOH
OMe
N
N
N
N
N
13
Et
O
Me
NC
OMe
H2N
N
N
N
Me
N
14
Et
OMe
NC
OMe
H2N
Me
O
N
Me
N
N
N
4
MeO
15
MeCOCH2CO2Et
MeCOCH2COMe
9
OMe
Me
N
N
N
N
Me
16
470

Table 1. IR Spectra of Compounds 2-18
Com-
pound
ν, cm-1
2
3
4
5
3170 (C=O), 3050 (C–N), 2900, 1640 (C=N), 1600 (C=C), 1340, 1250
2920 (C=S), 1600 (C=C), 1350, 1250, 1190, 1025, 825, 780
2960 (C=N), 2840 (C=N), 1600 (C=C), 1350, 1250, 1140, 1020, 820
3050 (C=N), 3000 (C=N), 2910 (C–S), 2820 (C–S), 1600 (C=C), 1510, 1250,
1180, 1010, 770
6
2920 (C–S), 1735, 1600 (C=C), 1490, 1250, 1010, 760
7
2920 (C–S), 1710, 1600 (C=C), 1300, 1250, 1190, 1010, 760
3065 (C=N), 2945 (C–S), 1680, 1600 (C=C), 1320, 1250, 1190, 1040, 990, 775
3050 (C=N), 2900 (C=N), 2820 (C=N), 1600 (C=C), 1460, 1250, 1150
2960 (C=N), 2920 (C=N), 2810 (C=N), 1600 (C=C), 1450, 1250, 1150
2900 (C=N), 2820 (C=N), 1600 (C=C), 1500, 1450, 1250, 1010
3050 (C=N), 2920 (C=N), 2820 (C=N), 1600 (C=C), 1480, 1360, 1250, 1170, 1030
2900 (C=N); 2830 (C=N), 1600 (C=C), 1250, 1180, 1010
2950 (С=N), 2900 (C=N), 1600 (C=C), 1400, 1250, 1010
2920 (C=N), 2830 (C=N), 1600 (C=C), 1400, 1250, 1180, 1010
2900 (C=N), 1600 (C=C), 1390, 1250, 1010
8
9
10
11
12
13
14
15
16
17
18
3120 (C=N), 2900 (C=S), 1600 (C=C), 1250, 1010, 800, 760
1600 (C=C), 1520, 1410, 1250, 1370, 1010, 820, 700
Reaction of diazepin-1-ylhydrazine 4 with 2-methyl-3-oxopentane nitrile or 2-(4-methyoxyphenyl)-
3-oxobutyronitrile gave the aminotriazoles 14 and 15, and with acetylacetone gave the pyrazole 16. Reaction
with ethyl acetoacetate did not give the expected pyrazalone, but the triazolodiazepine 9 was isolated from the
reaction mixture in high yield.
The reaction of p-tolyl isothiocyanate and benzoyl isothiocyanate with diazepin-1-ylhydrazine 4 gave
the thiosemicarbazides 17 and 18, but attempts at further cyclization by standard methods did not give the
expected derivatives of triazolobenzodiazepine.
S
H
N
RNCS
N
4
HN
H
N
N
R
OMe
17, 18
17 R = 4-MeC6H4, 18 R = PhCO
The results obtained indicate the promise of using derivatives of 2,3-benzodiazepin-1-one(thione) in the
synthesis of new heterocyclic systems and new pharmacologically attractive compounds, suitable for
modification by the methods of combinatorial chemistry.
EXPERIMENTAL
1H NMR spectra were measured in DMSO-d6 with TMS as internal standard with a Varian Gemini (200
MHz) instrument and IR spectra in KBr tablets were measured with an IR-75 instrument. Melting points were
measured with a Boetius instrument and were not corrected. 3-(4-Methoxyphenyl)isocoumarin (1) was prepared
by a method described in [8].
471

Table 2. 1H NMR Spectra of Compounds 2-18
Com-
pound
Chemical shifts, δ, ppm (J, Hz)
2
3
4
5
3.8 (3H, s, OCH3); 4.0 (2H, s, H-5); 6.0 (2Н, d, J = 8.8, Н-o); 7.6-7.25 (3Н, m, Н-6,7,8);
7.8 (1Н, d, J = 7.3, Н-9); 7.83 (2H, d, J = 8.8, Н-m); 10.95 (1H, s, NH)
3.7 (2H, s, H-5); 3.8 (3H, s, OCH3); 7.0 (2H, d, J = 8.8, H-o); 7.6-7.2 (3H, m, Н-6,7,8);
7.95 (2H, d, J = 8.8, Н-m); 8.1 (1H, d, J = 7.3, Н-9); 13.2 (1H, s, NH)
3.8 (3H, s, OCH3); 4.0 (2H, s, H-5); 6.6 (3H, br. s, NH-NH2); 6.9 (2H, d, J = 8.8, Н-o);
7.45-7.15 (3H, m, Н-6,7,8); 7.65 (1H, d, J = 7.3, Н-9); 7.8 (2H, d, J = 8.8, Н-m)
2.6 (3Н, s, SCH3); 3.1 (1Н, d, J = 13.3, Н-5); 3.8 (3Н, s, OCH3);
4.2 (1Н, d, J = 13.3, Н-5); 6.9 (2Н, d, J = 8.8, Н-o); 7.55-7.3 (3Н, m, Н-6,7,8);
7.65 (1Н, d, J = 7.3, Н-9); 7.85 (2Н, d, J = 8.8, Н-m)
6
7
8
3.1 (1Н, d, J = 13.3, Н-5); 3.8 (3Н, s, OCH3); 4.2 (1Н, d, J = 13.3, Н-5);
6.9 (2Н, d, J = 8.8, Н-o); 7.55-7.3 (3Н, m, Н-6,7,8); 7.65 (1Н, d, J = 7.3, Н-9);
7.85 (2Н, d, J = 8.8, Н-m)
2.76 (2Н, t, J = 6.9, CH2); 3.1 (1Н, d, J = 12.9, Н-5); 3.36 (2Н, t, J = 6.9, CH2);
3.8 (3Н, s, OCH3); 4.2 (1Н, d, J = 12.9, Н-5); 6.9 (2Н, d, J = 8.8, Н-o);
7.55-7.3 (3Н, m, H-6,7,8); 7.67 (1Н, d, J = 5.6, H-9); 7.85 (2Н, d, J = 8.8, Н-m)
3.1 (1Н, d, J = 13.3, H-5); 3.8 (3Н, s, OCH3); 4.2 (1Н, d, J = 13.3, H-5);
4.8 (2Н, dd, J1 = 17.7, J2 = 6.6, CH2); 7.8 (2Н, d, J = 8.8, Н-o); 7.65-7.25 (6Н, m, Н arom);
7.68 (1Н, d, J = 7.3, H-9); 7.8 (2Н, d, J = 8.8, Н-m); 8.1 (2Н, d, J = 8.8, Н arom)
9
2.56 (3H, s, CH3); 3.85 (3H, s, OCH3); 4.05 (2H, s, H-5); 7.0 (2H, d, J = 8.8, Н-o);
7.65-7.35 (3H, m, H-6,7,8); 7.95 (1H, d, J = 7.3, H-9); 8.05 (2H, d, J = 8.8, Н-m)
10
1.44 (3H, t, J = 6.8, CH3); 2.95 (2H, q, J = 6.8, CH2); 3.85 (3H, s, OCH3);
4.05 (2H, s, H-5); 7.0 (2H, d, J = 7.3, Н-o); 7.65-7.35 (3H, m, H-6,7,8);
7.95 (1H, d, J = 7.3, H-9); 8.05 (2H, d, J = 8.2, Н-m)
11
3.68 (3Н, s, OCH3); 3.72 (3Н, s, OCH3); 3.85 (3Н, s, OCH3); 3.97 (2Н, s, CH2);
4.22 (2H, s, H-5); 6.9-6.7 (3H, m, Н arom); 7.0 (2H, d, J = 7.3, Н-o);
7.65-7.35 (3Н, m, Н arom); 7.95 (1H, d, J = 7.3, H-9); 8.05 (2H, d, J = 8.2, Н-m)
12
13
14
3.85 (3H, s, OCH3); 4.1 (2H, s, CH2); 7.05 (2H, d, J = 8.8, Н-o); 7.7-7.4 (3Н, m, H-6,7,8);
8.0 (1H, d, J = 7.3, H-9); 8.1 (2H, d, J = 8.8, Н-m); 8.9 (1H, s, Н arom)
3.85 (3H, s, OCH3); 4.15 (2Н, s, H-5); 7.05 (2Н, d, J = 8.8, Н-o); 7.8-7.5 (3Н, m, H-6,7,8);
8.1 (1Н, d, J = 7.3, H-9); 8.2 (2Н, d, J = 8.8, Н-m)
1.1 (3Н, t, J = 6.8, CH3); 1.89 (3Н, s, CH3); 2.38 (2Н, q, J = 6.8, CH2);
3.15 (1Н, d, J = 14, H-5); 3.8 (3Н, s, OCH3); 4.4 (1Н, d, J = 14, H-5); 5.91 (2Н, s, NH2);
6.95 (2Н, d, J = 8.8, Н-o); 7.6-7.33 (4Н, m, H-6,7,8); 7.95 (2Н, d, J = 8.8, Н-m)
15
16
17
18
2.08 (3Н, s, CH3); 3.15 (1Н, d, J = 13.3, H-5); 3.8 (3Н, s, OCH3);
4.4 (1Н, d, J = 13.3, H-5); 6.05 (2Н, s, NH2); 6.9 (2Н, d, J = 6.6, CН);
6.95 (2Н, d, J = 8.8, Н-o); 7.6-7.33 (4Н, m, H-6,7,8); 7.95 (2Н, d, J = 8.8, Н-m)
2.15 (3Н, s, CH3); 2.65 (3Н, s, CH3); 3.05 (1Н, d, J = 13.3, 5-CH); 3.8 (3Н, s, OCH3);
4.5 (1Н, d, J = 13.3, 5-CH); 6.05 (1Н, s, CH); 6.95 (2Н, d, J = 8.8, CН);
7.15 (1Н, d, J = 7.3, 6-CН); 7.4-7.35 (3Н, m, 7,8,9-CH); 7.95 (2Н, d, J = 8.8, CН)
3.8 (3Н, s, OCH3); 4.1 (2Н, s, H-5); 7.0 (2Н, d, J = 8.8, Н-o); 7.06 (2Н, d, J = 4, СН);
7.34 (2Н, d, J = 4, СН); 7.66-7.38 (3Н, m, H-6,7,8); 7.86 (1Н, d, J = 7.3, H-9);
8.35 (2Н, d, J = 8.8, Н-m); 9.4 (1Н, s, NH); 13.8 (1Н, s, NH)
3.8 (3Н, s, OCH3); 4.1 (2Н, s, H-5); 6.7 (2Н, d, J = 8.8, Н-o); 7.8-7.3 (7Н, m, СН);
7.86 (2Н, d, J = 8.8, Н-m); 8.04 (2Н, d, J = 7.4, СН); 10.4 (1Н, s, NH); 11.1 (1Н, s, NH);
12.84 (1Н, s, NH)
4-(4-Methoxyphenyl)-2,5-dihydro-5H-2,3-benzodiazepin-1-one (2). A mixture of isocoumarin 1
(25.2 g, 100 mmol), 2-propanol (100 ml), and hydrazine hydrate (6 ml, 120 mmol) was boiled for 2 h. After
cooling, the precipitate was filtered off, washed with 2-propanol, and dried to give diazepinone 2 (25.2 g, 94%);
mp 190-191°C. Found, %: C 72.10; H 5.3; N 10.40. C16H14N2O2. Calculated, %: C 72.17; H 5.30; N 10.52.
4-(4-Methoxyphenyl)-2,5-dihydro-5H-2,3-benzodiazepine-1-thione (3). A mixture of compound 2 (30 g,
112 mmol) in toluene (200 ml) was heated to boiling and Lawson's reagent (22 g) was added. The undissolved
compound 2 relatively rapidly dissolved and thione 3 began to precipitate. The mixture was boiled for 30 min,
cooled, compound 3 was filtered off and washed on the filter with toluene. Yield 30 g (95%); mp 205-206°C. Found,
%: C 67.80; H 4.90; N 9.90; S 11.30. C16H14N2OS. Calculated, %: C 68.06; H 5.00; N 9.92; S 11.36.
472

4-(4-Methoxyphenyl)-2,5-dihydro-5H-2,3-benzodiazepin-1-ylhydrazine (4). A mixture of thione 3 (1
g, 3.5 mmol) and hydrazine hydrate (5 ml) were boiled for 30 min, cooled, the precipitate was filtered off,
washed with water and a small amount of methanol, to give the hydrazine 4 (0.9 g, 91%); mp 153-154°C.
Found, %: C 68.40; H 5.80; N 20.10; C16H16N4O. Calculated, %: C 68.55; H 5.75; N 19.99.
3-R-6-(4-Methoxyphenyl)-7H-1,2,4-triazolo[3,4-a][2,3]benzodiazepines 9-11 (General Method). A
mixture of hydrazine 4 (0.6 g, 2.15 mmol), 1 drop conc. HCl, 2-propanol (2 ml) and the corresponding acid
(2.6 mmol) was boiled for 6 h and poured into water (50 ml), and made basic with NaOH to pH 9-10. The oil
which precipitated crystallized rapidly. The crystalline precipitate was filtered off, dried, and recrystallized from
1:1 benzene–hexane.
6-(4-Methoxyphenyl)-3-methyl-7H-1,2,4-triazolo[3,4-a]benzodiazepine (9). Yield 0.325 g (49%); mp
184-185°C. Found, %: C 70.95; H 5.2; N 18.3. C18H16N4O. Calculated, %: C 71.04; H 5.30; N 18.41.
3-Ethyl-6-(methoxyphenyl)-7H-1,2,4-triazolo[3,4-a][2,3]benzodiazepine (10). Yield 0.323 g (48%);
mp 130-131°C. Found, %: C 71.65; H 5.75; N 17.50. C19H18N4O. Calculated, %: C 71.68; H 5.70; N 17.60.
3-(3,4-Dimethoxybenzyl)-6-(4-methoxyphenyl)-7H-1,2,4-triazolo[3,4-a][2,3]benzodiazepine
(11).
Yield 0.325 g (30%); mp 130-131°C. Found, %: C 70.90; H 5.52; N 12.68. C26H24N4O3. Calculated, %: C 70.89;
H 5.49; N 12.72.
6-(4-Methoxyphenyl)-7H-1,2,4-triazolo[3,4-a][2,3]benzodiazepine (12). A mixture of compound 4
(0.5 g, 1.8 mmol) and trimethyl orthoformate (5 ml, 33.8 mmol) was boiled for 4 h. A fine crystalline precipitate
separated during this time. After cooling the precipitate was filtered off and washed with a small amount of
methanol to give compound 12 (0.4 g, 77%); mp 218-219°C. Found, %: C 70.40; H 4.83; N 19.40. C17H14N4O.
Calculated, %: C 70.33; H 4.86; N 19.30.
6-(4-Methoxyphenyl)-7H-tetrazolo[5,4-a][2,3]benzodiazepine (13). To a solution of hydrazine 4
(0.25 g, 0.9 mmol) in acetic acid (3 ml) NaNO2 (0.07 g, 1 mmol) was added with vigorous stirring, the flask was
closed tightly, and stirring was continued. After 30 min the precipitate formed was filtered off, washed with
water and a small amount of methanol to give compound 13 (0.12 g, 46%); mp 139-141°C. Found, %: C 65.94;
H 4.52; N 24.00. C16H13N5O. Calculated, %: C 65.97; H 4.50; N 24.04.
1-(3,5-Dimethyl-1H-pyrazol-1-yl)-4-(4-methoxyphenyl)-5H-2,3-benzodiazepine (16). A mixture of
compound 4 (1 g, 3.6 mmol), dioxane (5 ml), and acetylacetone (0.5 ml, 5 mmol) was boiled for 30 min and
then poured into water (40 ml). The precipitate formed was filtered off, dried, and crystallized from 2-propanol
to give compound 16 (0.9 g, 76%); mp 208-209°C. Found, %: C 73.21; H 5.83; N 16.25. C21H20N4O.
Calculated, %: C 73.23; H 5.85; N 16.27.
1-(5-Amino-3-ethyl-4-methylpyrazol-1-yl)-4-(4-methoxyphenyl)-5H-2,3-benzodiazepine (14) and
1-(5-Amino-4-(4-methoxyphenyl)-3-methylpyrazol-1-yl)-4-(4-methoxyphenyl)-5H-2,3-benzodiazepine (15)
(General Method). A mixture of compound 4 (1 g, 3.6 mmol), 1 drop conc. HCl, 2-propanol (5 ml), and
2-methyl-3-oxopentonitrile (3.8 mmol) or 2-(4-methoxyphenyl)-3-oxobutyronitrile (3.8 mmol) was boiled for
3 h and then poured into water (30 ml). The crystalline precipitate was filtered off, dried, and crystallized from
benzene.
1-(5-Amino-3-ethyl-4-methylpyrazol-1-yl)-4-(4-methoxyphenyl)-5H-2,3-benzodiazepine (14). Yield 0.9 g,
67%); mp 195-196°C. Found, %: C 70.74; H 6.20; N 18.73. C22H23N5O. Calculated, %: C 70.76; H 6.21; N 18.75.
1-(5-Amino-4-(4-methoxyphenyl)-3-methylpyrazol-1-yl)-4-(4-methoxyphenyl)-5H-2,3-benzodiaze-
pine (15). Yield 1 g (62%); mp 177-179°C. Found, %: C 71.81; H 5.55; N 15.53. C27H25N5O2. Calculated, %:
C 71.82; H 5.58; N 15.51.
4-(4-Methoxyphenyl)-1-(methylthio)-5H-2,3-benzodiazepine (5). Dimethyl sulfate (0.4 ml) was
added with vigorous stirring to a mixture of compound 3 (1 g, 3.6 mmol) and ground KOH (0.5 g) in acetone
(10 ml), stirring was continued for 1 h, and then poured into water (50 ml). The precipitate formed was filtered
off, washed with water and a small amount of methanol to give compound 5 (0.95 g, 90%); mp 170-171°C.
Found, %: C 68.87; H 5.42; N 9.50; S 10.79. C17H16N2OS. Calculated, %: C 68.89; H 5.44; N 9.45; S 10.82.
473

[4-(4-methoxyphenyl)-5H-2,3-benzodiazepin-1-yl]thioacetic Acid (6). Methyl monochloroacetate
(0.6 ml, 5.5 mmol) was added with vigorous stirring to a mixture of compound 3 (1 g, 3.6 mmol) and ground
NaOH (0.44 g) in acetone (10 ml), stirring was continued for 1 h, then the mixture was added to water (50 ml).
The solution was acidified with acetic acid (2 ml), the precipitate which formed was filtered off and washed with
water to give compound 6 (1.1 g, 92%); mp 127-128°C. Found, %: C 63.50; H 4.72; N 8.25; S 9.41.
C18H16N2O3S. Calculated, %: C 63.51; H 4.74; N 8.23; S 9.42.
3-[4-(4-Methoxyphenyl)-5H-2,3-benzodiazepin-1-yl]thiopropionic acid (7). A mixture of compound
3 (1g, 3.6 mmol) and acrylic acid (0.5 ml, 7 mmol) was boiled in toluene (5 ml), the solvent was evaporated,
methanol (3 ml) was added to the residue, the mixture was heated to boiling then cooled to room temperature.
The fine white precipitate was filtered off and washed with a small amount of methanol to give compound 7 (1.1
g, 87%); mp 158-159°C. Found, %: C 64.41; H 5.14; N 7.88; S 9.06. C19H18N2O3S. Calculated, %: C 64.39;
H 5.12; N 7.90; S 9.05.
2-[4-(4-Methoxyphenyl)-5H-2,3-benzodiazepin-1-yl]thio-1-phenylethanone (8). γ-Chloroacetophenone
(0.6 g, 3.9 mmol) was added with vigorous stirring to a mixture of compound 3 (1 g, 3.6 mmol) and ground
KOH (0.4 g) in acetone (10 ml), stirring was continued for 1 h and the mixture added to water (50 ml). The
precipitate formed was filtered off, washed with water and a small amount of methanol to give compound 8
(1.2 g, 84%); mp 135-136°C. Found, %: C 72.00; H 5.05; N 7.01; S 9.06. C24H20N2O2S. Calculated, %: C 71.98;
H 5.03; N 6.99; S 7.94.
2-[4-(4-Methoxyphenyl)-5H-2,3-benzodiazepin-1-yl]-N-(4-methylphenyl)hydrazincarbothioamide
(17). A mixture of compound 4 (1 g, 3.6 mmol), 4-methylphenylisothocyanate (0.6 g, 4 mmol), and 1 drop of
triethylamine was boiled for 8 h. After cooling the crystals which formed were filtered off and washed with a
small amount of 2-propanol to give compound 17 (1 g, 67%); mp 170-171°C. Found, %: C 67.12; H 5.38;
N 16.33; S 7.47. C24H23N5OS. Calculated, %: C 67.11; H 5.40; N 16.30; S 7.46.
1-({2-[4-(4-Methoxyphenyl)-5H-2,3-benzodiazepin-1-yl]hydrazino}carbothioyl)benzamide
(18).
Benzoyl chloride (0.7 ml) was added to a mixture of KCNS (0.52 g) and anhydrous acetonitrile (10 ml) and
stirred for 30 min. Then compound 4 (1.5 g, 5.4 mmol) was added to the mixture and stirring was continued for
a further 2 h. The mixture was poured into water (50 ml) and the yellow residue was filtered off, It was washed
with water and a small amount of methanol, and dried to give compound 18 (2.1 g, 88%); mp 142-144°C.
Found, %: C 65.01; H 4.75; N 15.80; S 7.20. C24H21N5O2S. Calculated, %: C 64.99; H 4.77; N 15.79; S 7.22.
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