ACID AND ALKALINE HYDROLYSIS OF SUBSTITUTED 5-ARYL-1,2-OXAZOLIDINE-...
1909
Scheme 2.
CN
CN
O
KOH, EtOH
NO2
+
I
Ph
N
Ph
O
A
B
EtOH
CN
OEt
OEt Ph
OH
CN
K+
+
NO2
NO2
CN
O
Ph
Ph
Ph
CN
N
Ph
NO2
O
XI
C
XII
XIII
of concentrated hydrochloric acid, and 10 ml of water
was heated for 2 h under reflux. The mixture was
cooled, and the precipitate was filtered off. Yield of
cinnamic acid (III) 0.414 g (56%), mp 132°C [1];
yield of compound VII 0.470 g (58%), mp 198°C [2].
The filtrate was evaporated to isolate 0.122 g (20%) of
benzoic acid (IV), mp 122°C [3], or 0.150 g (22%) of
p-toluic acid (VIII), mp 178°C [4].
Hydrolysis of 5-aryl-1,2-oxazolidine-3,3-dicarbo-
nitriles I and II in acetic acid (general procedure).
A mixture of 5 mmol of compound I or II, 40 ml of
acetic acid, and 10 ml of water was heated under reflux
until nitrogen dioxide no longer evolved (~1 h). The
mixture was evaporated, and the residue was subjected
to chromatography using benzene (compounds V and
IX) or hexane (VI, X) as eluent.
5-Phenyl-4,5-dihydro-1,2-oxazole-3-carbonitrile
2-oxide (V). Yield 0.658 g (70%), mp 90°C (from
ethanol) [5].
2-Nitroethenylbenzene (VI). Yield 0.387 g (52%),
mp 58°C (from ethanol) [6].
5-(4-Methylphenyl)-4,5-dihydro-1,2-oxazole-
3-carbonitrile 2-oxide (IX). Yield 0.737 g (73%),
mp 76°C (from ethanol) [5].
Alkaline hydrolysis of isoxazole I under severe condi-
tions resulted in the formation of a tarry product which
was not identified.
Compounds III–X, XII, and XIII showed no de-
pression of the melting point on mixing with authentic
samples.
5-Aryl-1,2-oxazolidine-3,3-dicarbonitriles I and
II (general procedure). A solution of 5 mmol of
2,2-dinitromalononitrile in 10 ml of anhydrous diethyl
ether was cooled to 0±5°C, a solution of 10 mmol of
ethenylbenzene or 4-ethenyltoluene in diethyl ether
was added, and the mixture was kept for 10 days at
25°C. The mixture was evaporated, and the residue
was subjected to chromatography in a 10×500-mm
column charged with activated silica gel (100–400 μm)
using CHCl3 (compound I) or benzene (II) as eluent.
2-(2-Nitro-1-phenylethoxy)-5-phenyl-1,2-oxazoli-
dine-3,3-dicarbonitrile (I). Yield 0.464 g (25%),
mp 115°C. IR spectrum, ν, cm–1: 2245 (C≡N); 1550,
1380 (NO2); 1070–1030 (ONO). 1H NMR spectrum, δ,
ppm: 3.14 d (2H, CH2), 4.28 d (2H, CH2), 5.46 t (1H,
CH), 5.82 t (1H, CH), 7.53–7.62 m (10H, C6H5).
Found, %: C 62.46; H 4.22; N 15.18. C19H16N4O4. Cal-
culated, %: C 62.64; H 4.40; N 15.38.
1-Methyl-4-(2-nitroethenyl)benzene (X). Yield
0.489 g (60%), mp 97°C (from ethanol) [7].
5-(4-Methylphenyl)-2-[1-(4-methylphenyl)-2-
nitroethoxy]-1,2-oxazolidine-3,3-dicarbonitrile (II).
Yield 0.529 g (27%), mp 144°C. IR spectrum, ν, cm–1:
2245 (C≡N); 1550, 1380 (NO2); 1070–1030 (ONO).
1H NMR spectrum, δ, ppm: 2.31 s (3H, CH3), 3.10 d
(2H, CH2), 4.30 d (2H, CH2), 5.42 t (1H, CH), 5.80 t
(1H, CH), 7.15–7.53 m (8H, C6H4). Found, %:
C 64.11; H 4.91; N 14.08. C21H20N4O4. Calculated, %:
C 64.29; H 5.10; N 14.29.
Hydrolysis of 5-aryl-4,5-dihydro-1,2-oxazole-3-
carbonitrile 2-oxides V and IX in hydrochloric acid
(general procedure). A mixture of 3 mmol of com-
pound V or IX, 10 ml of concentrated hydrochloric
acid, and 5 ml of water was heated for 1.5 h under
reflux. The mixture was cooled, and the precipitate
was filtered off. Yield of III 0.198 g (45%), mp 132°C
[1]; yield of VII 0.230 g (48%), mp 198°C [2].
Hydrolysis of 5-aryl-1,2-oxazolidine-3,3-dicarbo-
nitriles I and II in hydrochloric acid (general proce-
dure). A mixture of 5 mmol of compound I or II, 30 ml
Hydrolysis of (2-nitroethenyl)benzenes VI and X
in hydrochloric acid (general procedure). A mixture
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 12 2011