2
302
SCHUL’TSEV
precipitate was isolated 8.9 g of 2-(4-nitrophenyl)ethyl
nitrate. The total yield of crude product was 55.34 g
of which crystallized on the condenser walls. Heating
was stopped, the reaction mixture was allowed to cool,
then the pressure in the system was equalized with
atmospheric one, 2.15 g (0.0383 mol) of KOH was
added, the mixture heating was continued and pressure
was reduced to 10 mm Hg. The liquid became black,
and 4-aminostyrene distilled off in the temperature
range 250–260ºC. The collected distillate was decanted
from a small amount of the yellow crystals of 2-(4-
aminophenyl)ethanol, receiver was washed with a
small amount of cooled diethyl ether, the extract was
combined with the distillate. The condenser and
allonge working surfaces were washed with diethyl
ether to recover residual 4-aminostyrene, while the
crystalline 2-(4-aminophenyl)ethanol remained on the
glass surface. The etheral solutions were combined
together, washed with a little water and dried over two
portions of KOH. Then the solvent was removed under
vacuum on a rotary evaporator, finally at 2 mm Hg, at
(
52.2%). The yield of pure 2-(4-nitrophenyl)ethyl
nitrate 37.73 g (35.6%), mp 54–55ºC, a needle with a
slight greenish-yellow tinge.
Synthesis of 2-(4-aminophenyl)ethanol. To a
solution of 1.28 g (0.2048 mol) of 2-(4-nitrophenyl)-
ethyl nitrate in 260 ml of methanol was added NiRe
prepared from 1.0 g of Ni–Al alloy, then 25 ml of
N H ·H O was added and the mixture was stirred till
2
4
2
exothermic reaction began. When the reaction intensity
decreased, to the reaction mixture was added another
2
5 ml portion of N H ·H O, the mixture was heated in
2 4 2
a water bath to initiation of a violent reaction. After
decomposition of most of the hydrazine, to the mixture
was added 17 ml of N H ·H O, and the reaction
2
4
2
mixture was heated at 80ºC until the reaction
completion, and then kept at 40–45ºC to complete
cessation of gas evolution. Then catalyst was removed
from warm solution by filtration, volatiles were
distilled off by heating under vacuum in a rotary
evaporator. To the liquid residue was added 50 ml of
absolute ethanol, the solvent was distilled off and the
residual suspension was left for crystallization. The
crystals were filtered off from the mother liquor,
washed with absolute ethanol and after drying in
vacuum over P O was obtained 9.83 g of 2-(4-
3
0–40ºC. 3.18 g (69.7%) of 4-aminostyrene was
isolated, yellow liquid crystallized upon cooling.
For purification, the 4-aminostyrene was distilled in
the presence of small amount of KOH at 6–7 mm Hg
on a bath with temperature 130–150ºC. Yield 2.46 g
(
54%), mp 23–24ºC (plates).
Use of BaO instead of BaCO has no effect on the
3
4
10
course of the process.
aminophenyl)ethanol as white crystals, mp 107–108ºC.
The filtrate was evaporated in a vacuum, the residue
was poured onto a petri dish and after the evaporation
of volatile components, the substance was rubbed on
the filter with a small amount of absolute ethanol.
After filtration, the precipitate was washed with
absolute ethanol and dried in air. As a result, 5.26 g of
b. A mixture of 5.49 g (0.0400 mol) of 2-(4-
aminophenyl)ethanol and 4.0 g (0.0713 mol) of
powdered KOH was heated to 200ºC, left for 1 min,
then pressure was reduced stepwise for 1 min to
1
2 mm Hg, and after 30 s to 10 mm Hg, while the bath
temperature was raised to 210ºC. On the walls of the
condenser and nozzle crystallized original 2-(4-
aminophenyl)ethanol, which then was washed back to
the distillation flask by the distilling liquid.The
reaction mixture was heated further at 250–260ºC at
a white finely crystalline substance was obtained, mp
1
1
05ºC. Total yield 15.09 g (83%). H NMR spectrum,
δ, ppm: 2.613, 2.632, 2.650 m (2H, CH ), 3.598, 3.617,
2
3
6
6
,635 m (2H , CH O), 6.593, 6.599, 6.604, 6.615,
.620, 6.627 (2H, 2,6-Ar), 6.899, 6.906, 6.910, 6.922,
.926, 6.933 (2H, 3,5-Ar).
2
1
1–14 mm Hg, while distillate soaked in a crystalline
mass on the condenser walls. After about 1 h the
heating was stopped, aminostyrene and original 4-
amino alcohol were washed off with diethyl ether from
the walls, the ether was removed under vacuum, from
the residue was extracted with water a part of 2-(4-
aminophenyl)ethanol. The mixture without separation
was frozen and then water phase was allowed to
melting, the solution was decanted, the crystalline
Synthesis of 4-aminostyrene. a. A mixture of 5.25 g
(
(
0.0383 mol) of 2-(4-aminophenyl)ethanol, 2.12 g
0.0153 mol) of K CO and 0.5 0 g (0.0025 mol) of
2
3
BaCO was heated in an oil bath in the setup for
3
distillation up to 200ºC, the system pressure was
reduced to 30 mm Hg. The formed light-brown liquid
gently boiled. Heating continued for a short time, then
the pressure was reduced to 10 mm Hg and the
temperature was increased stepwise to 245ºC. Initially
distilled off the source 2-(4-aminophenyl)ethanol, part
solid phase was mixed with 50 ml of H O, then 4-
2
aminostyrene was extracted with diethyl ether, dried
over KOH and the solvent was removed from the
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 81 No. 11 2011