H. Abul-Khair, S. Elmeligie, A. Bayoumi, A. Ghiaty, A. El-Morsy, and M. H. Hassan
Vol 000
(
molecular ion) (21.30%), 363 (M+2) (7.08%), 215 (M+
from ethanol 70% afforded the corresponding Alkyl 2-(5-
ethyl-4,5-dihydro-4-oxo-[1,2,4]triazolo [4,3-a]quinoxalin-1-
ylthio)acetate derivatives (13a-f).
ÀCl C H ) (15.12%), 189 (M+ ÀCl C H CHN) (100%). Anal.
2
6
3
2 6 3
Calcd. for C17
C, 56.52; H, 3.98; N, 15.46.
-(2-((Thiophen-2-yl)methylene)hydrazinyl)-1-ethylquinoxalin-
(1H)-one (9 ). This compound was obtained as a yellow crystals,
.86 g, (60%), mp 218-220°C; ir: NH 3263, CO 1647 cm
2 4
H14Cl N O: C, 56.52; H, 3.91; N, 15.51. Found:
Methyl 2-(5-ethyl-4,5-dihydro-4-oxo-[1,2,4]triazolo [4,3-a]
3
quinoxalin-1-ylthio)acetate (13
C; ir: CO 1679, 1743 cm (amide and ester respectively); H
a
). 2.38 g, (75%), mp 157-159°
À1
1
2
g
À1
1
;
NMR: δ 1.29 [t, 3H, NCH
OCH ], 4.32 [q, 2H, NCH
SCH and 7.50-7.75 [m, 4H, aromatic]; ms: m/z 318
(molecular ion) (32.10%), 259 (M+ ÀCO OCH ) (100%), 231
CO) (60.06%); Anal. Calcd. for C14 S:
2
-CH
3
, J = 1.50 Hz], 3.70 [s, 3H,
1
H NMR: δ 1.23 [t, 3H, CH -CH , J = 7.20 Hz], 4.28 [q, 2H, CH -
3
2
-CH
3
, J = 1.50 Hz], 4.46 [s, 2H,
3
2
2
CH , J = 6.90 Hz], 7.11-7.65[m, 7H, aromatic], 8.79 [s, 1H, NCH]
and11.21 [s, 1H, NH]; ms: m/z 298 (molecular ion) (14.95%), 269
]
2
3
3
(
M+ ÀCH
Calcd. for C15
0.08; H, 4.56; N, 18.50.
-(2-(2-Indolon-3-yl)hydrazonyl)-1-ethylquinoxalin-2(1H)-
2
CH
H
3
) (12.96%), 189 (M+ ÀC
4
H
3SCN) (100%). Anal.
(M+ ÀCOOCH
3
H N O
14 4 3
N
4
OS: C, 60.38; H, 4.73; N, 18.78. Found: C,
C, 52.82; H, 4.43; N, 17.60. Found: C, 52.53; H, 4.77; N, 17.44.
14
6
Ethyl 2-(5-ethyl-4,5-dihydro-4-oxo-[1,2,4]triazolo [4,3-a]
3
quinoxalin-1-ylthio)acetate (13
C; ir: CO 1677, 1737 cm (amide and ester respectively); H
b
). 3.51 g, (95%), mp 165-167°
À1
1
one (10). A mixture of 2.04 g (0.01 mol) of 1-ethyl-2-
oxoquinoxalin-3-yl hydrazine (8) and 1.47 g (0.01 mol) isatine,
was refluxed in 15 mL glacial acetic acid for 6 h. The reaction
mixture was cooled to the room temperature. The orange
precipitated product was filtered, washed with distilled water,
dried, and crystallized from ethanol 80% to afford a faint
yellow crystalline product, 3.09 g, (93%), mp 275-277°C; ir:
NH 3332, CO 1653, 1708 cm (quinoxalinone and indolone
respectively); H NMR: δ 1.27 [t, 3H, CH
4
7
NMR: δ 1.14 [t, 3H, NCH
OCH CH , J = 1.20 Hz], 4.08 [q, 2H, NCH
2
Hz], 4.26 [q, 2H, OCH CH , J = 1.20 Hz], 4.40 [s, 2H, SCH ]
2
-CH
3
, J = 1.50 Hz], 1.20 [t, 3H,
-CH , J = 1.50
2
3
2
3
2
3
and 7.43-7.73 [m, 4H, aromatic]; ms: m/z 332 (molecular ion)
(27.83%), 259 (M+ ÀCOOC H ) (100%), 231 (M+
2
5
ÀCOOC H CO) (22.40%); Anal. Calcd. for C H N O S: C,
2
5
15 16 4 3
À1
54.20; H, 4.85; N, 16.86. Found: C, 52.53; H, 4.60; N, 16.94.
1
3
-CH
, J = 7.20 Hz], 11.20 [s, 1H, NH], 6.94-
.73 [m, 8H, aromatic] and 13.67 [s, 1H, NH exchangeable]; ms:
2
, J = 6.60 Hz],
n-Propyl 2-(5-ethyl-4,5-dihydro-4-oxo-[1,2,4]triazolo [4,3-
2 3
.25 [q, 2H, CH -CH
a]quinoxalin-1-ylthio)acetate (13
c
). 2.24 g, (65%), mp 190-
À1
1
92°C; ir: CO 1675, 1740 cm (amide and ester respectively);
m/z 333 (molecular ion) (18.97%), 304 (M+ ÀC H ) (100%), 276
2
5
ms: m/z 346 (molecular ion) (13.88%), 259 (M+ ÀCOOC H )
3
7
(
M+ ÀCOC
4.86; H, 4.54; N, 21.01. Found: C, 64.92; H, 4.54; N, 20.90.
Potassium salt of 5-ethyl-1-mercapto-[1,2,4]triazolo[4,3-a]
quinoxalin-4(5H)-one (11). A mixture of 2.04 g (0.01 mol)
of 1-ethyl-2-oxoquinoxalin-3-yl hydrazine (8), 0.76 g (0.71 mL,
.01 mol) carbon disulphide and 0.56 g (0.01 mol) potassium
2 5 15 5 2
H ) (8.83%). Anal. Calcd. for C18H N O : C,
(
100%), 231 (M+ ÀCOOC H CO) (38.27%); Anal. Calcd. for
2
5
6
C H N O S: C, 55.48; H, 5.24; N, 16.17. Found: C, 55.61; H,
1
6 18 4 3
5.16; N, 16.35.
Isopropyl 2-(5-ethyl-4,5-dihydro-4-oxo-[1,2,4]triazolo [4,3-
a]quinoxalin-1-ylthio)acetate (13 ). 2.76 g, (80%), mp 147-
d
À1
0
149°C; ir: CO 1674, 1734 cm (amide and ester respectively);
hydroxide were refluxed in 20 mL ethanol for 2 h. The mixture
was then allowed to reach the room temperature to afford a faint
ms: m/z 346 (molecular ion) (15.13%), 259 (M+ ÀCOOCH
(CH
3
)
2
) (100%), 231 (M+ ÀCOOCH(CH
3 2
) CO) (22.16%);
yellow precipitated product, 2.80 g, (98%), mp > 300°C; ir: CO
18 4 3
Anal. Calcd. for C16H N O S: C, 55.48; H, 5.24; N, 16.17.
Found: C, 55.61; H, 5.43; N, 16.29.
À1
1
656 cm ; Anal. Calcd. for C11
H
9
KN
4
OS: C, 46.46; H, 3.19;
N, 19.70. Found: C, 46.58; H, 3.25; N, 19.84.
n-Butyl 2-(5-ethyl-4,5-dihydro-4-oxo-[1,2,4]triazolo [4,3-a]
5
-Ethyl-1-mercapto-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-
quinoxalin-1-ylthio)acetate (13
C; ir: CO 1670, 1741 cm (amide and ester respectively); ms:
e
). 2.95 g, (82%), mp 182-184°
À1
one (12). A mixture of 2.04 g (0.01 mol) of 1-ethyl-2-
oxoquinoxalin-3-yl hydrazine (8), 0.76 g (0.71 mL, 0.01 mol)
carbon disulphide and 0.56 g (0.01 mol) potassium hydroxide
were refluxed in 20 mL ethanol for 2 h. The mixture was then
allowed to reach the room temperature and poured onto 20 mL
m/z 360 (molecular ion) (33.77%), 287 (M+ ÀOC
) (100%); Anal. Calcd. for C17H N O
20 4 3
H ) (11.94%),
4 7
259 (M+ ÀCOOC
H
S:
4
7
C, 56.65; H, 5.59; N, 15.54. Found: C, 56.81; H, 5.60; N, 15.51.
tert-Butyl 2-(5-ethyl-4,5-dihydro-4-oxo-[1,2,4]triazolo [4,3-
1
N HCl. The yellow precipitated product was filtered, washed
with distilled water crystallized from ethanol 80% to afford
.23g (90%) of compound 12 as a faint yellow crystalline needles,
a]quinoxalin-1-ylthio)acetate (13
172°C; ir: CO 1680, 1733 cm (amide and ester respectively);
f
). 2.66 g, (74%), mp 170-
À1
2
ms: m/z 360 (molecular ion) (6.75%), 259 (M+ ÀCOOC
(100%), 231 (M+ ÀCOOC(CH CO) (25.68%); Anal. Calcd.
for C17 S: C, 56.65; H, 5.59; N, 15.54. Found: C,
4 7
H )
À1
1
mp 285-287°C; ir: SH 2630, CO 1683 cm ; H NMR: δ 1.25 [t,
3 3
)
3H, CH
3
-CH
2
, J = 7.20 Hz], 4.24 [q, 2H, CH
2
-CH
3
, J = 7.20 Hz],
H N O
20 4 3
7.32-7.63 [m, 4H, aromatic] and 14.77 [s, 1H, SH exchangeable];
56.71; H, 5.42; N, 15.32.
ms: m/z 246 (molecular ion) (100%), 218 (M+ ÀCO) (74.81%),
04 (M+ ÀC H ) (5.75%). Anal. Calcd. for C H N O : C, 53.64;
1-(2-Oxopropylthio)-5-ethyl-[1,2,4]triazolo[4,3-a]quinoxalin-4
(5H)-one (14). A mixture of 2.84 g (0.01 mol) of the potassium salt
(11) and 1.00 mL (0.012 mol) chloroacetone in 20 mL DMF was
heated on a water bath for 2h. After cooling to the room
temperature, the reaction mixture was added to 200 mL cold water
with continuous stirring. The white precipitated product was
filtered, washed with water and crystallized from ethanol producing
2
2
5
18 15 5 2
H, 4.09; N, 22.75. Found: C, 53.29; H, 3.96; N, 22.52.
General procedure for preparation of Alkyl 2-(5-ethyl-4,
-dihydro-4-oxo-[1,2,4]triazolo [4,3-a]quinoxalin-1-ylthio)ace-
5
tates (13). A mixture of 2.46 g (0.01 mol) of 5-ethyl-1-mercapto-
1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-one (12), (0.012 mol)
[
À1
of the appropriate alkyl chloroacetate and 1 g anhydrous
potassium carbonate were stirred in (20 mL) DMF for 1 h on
a water bath. The mixture was then poured onto 100 mL ice
cold water with continuous stirring. The white crystalline
product was filtered, washed with distilled. Recrystallization
1.87 g (62%), mp 206-208°C; ir: CO 1671, 1712 cm (amide and
ketone respectively); ms: m/z 302 (molecular ion) (10.19%), 259
(M+ ÀCO CH ) (57.32%), 43 (CH CO) (100%); Anal. Calcd. for
3
3
1
4 14 4 2
C H N O S: C, 55.61; H, 4.67; N, 18.53. Found: C, 55.84; H,
4.74; N, 18.87.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet