TRANSFORMATIONS OF 2-ETHYL-2-METHYL-2,3-DIHYDRO-1H-INDOLE
79
acetate (6:1) as eluent. Yield 0.9 g (85%), light brown
crystals, mp 71–72°C. H NMR spectrum, δ, ppm:
6-H, J = 7.9, 1.4 Hz), 7.19 d (1H, 4-H, J = 1.4 Hz).
1
13
C NMR spectrum, δ , ppm: 9.02 (CH CH ), 26.50
C
3
2
3
2
0
2
7
1
.60 t (3H, CH CH , J = 7.3 Hz), 1.58 s (3H, 2-CH ),
(2-CH ), 34.64 (CH CH ), 41.70 (C ), 64.37 (C ),
3
2
3
3 2 3
7
5
3a
4
.11–2.15 m (2H, CH CH ), 2.22 s (3H, CH CO),
109.49 (C ), 119.18 (C ), 129.65 (C ), 130.27 (C ),
2
3
3
6
7a
.22 t (1H, 6-H, J = 7.6 Hz), 7.36 d.d (1H, 7-H, J = 7.6,
.4 Hz), 7.67 d.d (1H, 5-H, J = 7.6, 1.4 Hz), 7.79 d
132.73 (C ), 149.83 (C ). Mass spectrum: m/z 400.17
+
[M] . Found, %: C 66.09; H 7.02; N 7.13. C H N Se.
22
28
2
1
3
(1H, 4-H, J = 7.6 Hz). C NMR spectrum, δ , ppm:
Calculated, %: C 66.15; H 7.07; N 7.01.
-Ethyl-N-hydroxy-2-methyl-2,3-dihydro-1H-in-
dol-3-imine (6). Hydroxylamine hydrochloride, 0.2 g
C
7
.98 (CH CH ), 21.05 (CH CO), 23.06 (2-CH ), 30.10
3 2 3 3
2
2
6
4
(CH CH ), 72.36 (C ), 123.88 (C ), 124.21 (C ),
2 3
3a
7
5
7a
1
1
26.41 (C ), 137.14 (C ), 137.22 (C ), 153.45 (C ),
68.23 (CH C=O), 202.24 (C ). Mass spectrum:
(
(
2.8 mmol), was added to a solution of 0.1 g
0.6 mmol) of ketone 4 in 10 mL of methanol, and the
3
3
+
m/z 217.11 [M] . Found, %: C 71.79; H 6.88; N 6.51.
mixture was refluxed for 15 h (TLC). The solvent was
distilled off, 10 mL of water was added to the residue,
and the mixture was extracted with ethyl acetate (3×
10 mL). The combined extracts were dried over MgSO4
and evaporated, and the residue was purified by silica
gel chromatography (petroleum ether–EtOAc, 4 :1).
Yield 0.08 g (70%), yellow crystals, mp 120–121°C.
C H NO . Calculated, %: C 71.87; H 6.96; N 6.45.
13
15
2
2
-Ethyl-2-methyl-2,3-dihydro-1H-indol-3-one
4). Compound 3, 0.6 g (2.8 mmol), was dissolved in
0 mL of THF, a solution of 0.8 g (13.8 mmol) of
(
1
potassium hydroxide in 10 mL of methanol was added,
and the mixture was refluxed until the initial compound
disappeared (TLC). The mixture was then treated with
a saturated solution of ammonium chloride and
extracted with ethyl acetate (3×20 mL), the combined
1
H NMR spectrum, δ, ppm: 0.89 t (3H, CH CH , J =
3
2
7.4 Hz), 1.41 s (3H, 2-CH ), 1.68–1.72 m and 1.77–
3
1.81 m (1H each, CH CH ), 6.71 d (1H, 7-H, J =
2
3
extracts were dried over MgSO and evaporated, and
8.1 Hz), 6.76 t (1H, 5-H, J = 7.6 Hz), 7.26 d.d (1H,
6-H, J = 8.1, 7.6 Hz), 8.20 d (1H, 4-H, J = 7.6 Hz).
4
the residue was purified by silica gel column chroma-
tography using petroleum ether–ethyl acetate (8:1) as
1
3
C NMR spectrum, δ , ppm: 8.16 (CH CH ), 27.04
C
3
2
1
2
7
eluent. Yield 0.4 g (75%), light green oil. H NMR
(2-CH ), 34.37 (CH CH ), 64.48 (C ), 110.36 (C ),
3 2 3
5
3a
4
6
spectrum, δ, ppm: 0.82 t (3H, CH CH , J = 7.4 Hz),
118.42 (C ), 118.59 (C ), 130.00 (C ), 133.02 (C ),
3
2
7
a
3
1
.30 s (3H, 2-CH ), 1.63–1.70 m and 1.76–1.82 m (1H
153.59 (C ), 162.02 (C ). Mass spectrum: m/z 190.11
3
+
each, CH CH ), 6.81 t (1H, 5-H, J = 7.5 Hz), 8.88 d
[M] . Found, %: C 69.37; H 7.38; N 14.84. C H N O.
2
3
11 14
2
(
7
1H, 7-H, J = 8.0 Hz), 7.44 d.d (1H, 6-H, J = 8.0,
.5 Hz), 7.59 d (1H, 4-H, J = 7.5 Hz). C NMR spec-
Calculated, %: C 69.45; H 7.42; N 14.73.
1
3
(
3RS)-2-Ethyl-2-methyl-2,3-dihydro-1H-indol-3-
trum, δ , ppm: 8.07 (CH CH ), 22.91 (2-CH ), 30.88
(
1
2
%
C
3
2
3
ol (7). Sodium tetrahydridoborate, 0.04 g (1.1 mmol),
was added in portions with vigorous stirring to a solu-
tion of 0.1 g (0.6 mmol) of ketone 4 in 10 mL of
ethanol, and the mixture was stirred until the initial
ketone disappeared (TLC). The mixture was evaporat-
ed, the residue was treated with 5 mL of water and
extracted with ethyl acetate (3×10 mL), the combined
2
7
5
CH CH ), 67.44 (C ), 112.56 (C ), 118.86 (C ),
2 3
3
a
4
6
7a
20.75 (C ), 124.74 (C ), 137.14 (C ), 159.92 (C ),
05.15 (C ). Mass spectrum: m/z 175.23 [M] . Found,
3
+
: C 75.32; H 7.38; N 8.05. C H NO. Calculated, %:
11 13
C 75.40; H 7.48; N 7.99.
5
,5′-(Selanediyl)bis(2-ethyl-2-methyl-2,3-dihy-
dro-1H-indole) (5). Compound 1, 0.1 g (0.6 mmol),
extracts were dried over MgSO and evaporated, and
4
was dissolved in 5 mL of ethanol, 0.07 g (0.6 mmol) of
the residue was purified by silica gel chromatography
(petroleum ether–EtOAc, 5 : 1). Yield 0.09 g (89%),
white crystals, mp 86–87°C. H NMR spectrum, δ,
SeO in 5 mL of ethanol was added, and the mixture
2
1
was refluxed until the initial compound disappeared
(TLC). The mixture was diluted with 10 mL of water,
ppm: 1.03 [0.94] t (3H, CH CH , J = 7.4 Hz), 1.15
3
2
the organic phase was separated and dried over MgSO4,
the solvent was distilled off, and the residue was
subjected to silica gel column chromatography (petro-
leum ether–EtOAc, 8 : 1). Yield 0.1 g (45%), light
[1.24] s (3H, 2-CH ), 1.65–1.80 [1.54–1.59] m (2H,
3
CH CH ), 4.61 [4.73] s (1H, 3-H), 6.64 [6.60] d (1H,
2
3
7-H, J = 7.8 Hz), 6.77 [6.75] t (1H, 5-H, J = 7.3 Hz),
7.14 [7.12] d.d (1H, 6-H, J = 7.8, 7.3 Hz), 7.32 [7.28] d
1
13
brown oil. H NMR spectrum, δ, ppm: 0.92 t (3H,
(1H, 4-H, J = 7.3 Hz). C NMR spectrum, δ , ppm:
C
CH CH , J = 7.3 Hz), 1.23 s (3H, 2-CH ), 1.58–1.62 m
8.36 [8.58] (CH CH ), 23.76 [18.93] (2-CH ), 27.39
3
2
3
3
2
3
2
(
2H, CH CH ), 2.72 d and 2.85 d (1H each, 3-H, J =
[33.01] (CH CH ), 66.43 [67.16] (C ), 79.31 [78.84]
2
3
2 3
3
7
5
1
5.7 Hz), 6.46 d (1H, 7-H, J = 7.9 Hz), 7.16 d.d (1H,
(C ), 110.56 [110.05] (C ), 119.03 [118.73] (C ),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 56 No. 1 2020