IMINOFURAN CHEMISTRY: VII.
263
2-tert-Butyl-3-(4-ethoxycarbonylphenyl)-5-oxo-2,5-
dihydrofuran-2-yl acetate (IVf) Yield 3.18 g (88%),
light yellowish crystals, t.decomp. 97–99°C (toluene). IR
spectrum, ν, cm–1: 3358 (NH), 3105 (CH), 1770 (C=Olact),
1736br. (COO), 1668 (C=C). 1H NMR spectrum (CDCl3),
δ, ppm: 1.08 s (9H, CMe3), 1.29 t (3H, CH3CH2), 2.07 s
(3H, MeCO), 4.30 q (2H, CH3CH2), 6.09 s (1H, CH),
6.89 s (1H, NH), 7.45 m (4H, C6H4). Found, %: C 63.10;
H 6.38; N 3.84. C19H23NO6. Calculated, %: C 63.15;
H 6.41; N 3.88.
cooled to 0°C. The separated precipitate was filtered
off, washed on the filter with anhydrous ethyl ether, and
recrystallized from toluene.
4-(2-Bromophenylamino)-2-tert-butyl-2,5-dihydro-
5-oxofuran-2-yl acetate (IVa). Yield 2.47 g (67%), col-
orless crystals, t.decomp. 99–100°C (toluene). 1H NMR
spectrum (CDCl3), δ, ppm: 1.06 s (9H, CMe3), 2.02 s
(3H, MeCO), 6.07 s (1H, CH), 6.87 s (1H, NH), 7.20 m
(4H, C6H4). Found, %: C 52.28; H 4.81; Br 21.65; N 3.78.
C16H18BrNO4. Calculated, %: C 52.19; H 4.93; Br 21.70;
N 3.80.
5-Aryl-3-methylenehydrazono-3H-furan-2-ones
VIa–VIg. In 10 ml of acetic anhydride 0.01 mol of acid
Va–Vg was stirred at boiling over 5–10 min. The strongly
colored dark-red solution was cooled to 0°C. The sepa-
rated precipitate was filtered off, washed on the filter with
anhydrous ethyl ether, and recrystallized from toluene.
2-Tert-butyl-4-(2-iodophenylamino)-2,5-dihydro-5-
oxofuran-2-yl acetate (IVb). Yield 3.09 g (83%), color-
less crystals, t.decomp. 98–99°C (toluene). IR spectrum,
ν, cm–1: 3364 (NH), 3096 (CH), 1776 (C=Olact), 1742
(COO), 1672 (C=C). 1H NMR spectrum (CDCl3), δ, ppm:
1.07 s (9H, CMe3), 2.02 s (3H, MeCO), 6.05 s (1H, CH),
6.84 s (1H, NH), 7.20 m (4H, C6H4). Found, %: C 46.22;
H 4.33; I 30.50; N 3.31. C16H18INO4. Calculated, %:
C 46.28; H 4.37; I 30.56; N 3.37.
3-{2-[(4-Methoxyphenyl)phenylmethylene]-
hydrazono}-5-phenyl-3H-furan-2-one (VIa). Yield
2.45 g (64%), orange crystals, mp 170–171°C (toluene).
IR spectrum, ν, cm–1: 1795 (C=Olact), 1605 (C=C, C=N).
1H NMR spectrum (DMSO-d6), δ, ppm: 3.83 s (3H,
OMe), 7.50 m (13H, CH + C6H4 + 2C6H5). Found, %:
C 75.41; H 4.72; N 7.33. C24H18N2O3. Calculated, %:
C 75.38; H 4.74; N 7.33.
4-(4-Bromophenylamino)-2-tert-butyl-2,5-dihydro-
5-oxofuran-2-yl acetate (IVc). Yield 2.80 g (76%),
yellowish crystals, t.decomp. 170–171°C (toluene). IR
spectrum, ν, cm–1: 3350 (NH), 3115 (CH), 1773 (C=Olact),
1741 (COO), 1665 (C=C). 1H NMR spectrum (CDCl3),
δ, ppm: 1.07 s (9H, CMe3), 2.07 s (3H, MeCO), 6.09 s
(1H, CH), 6.89 s (1H, NH), 7.20 m (4H, C6H4). Found,
%: C 52.15; H 4.90; Br 21.68; N 3.74. C16H18BrNO4.
Calculated, %: C 52.19; H 4.93; Br 21.70; N 3.80.
5-(4-Methylphenyl)-3-{2-[(4-methoxyphenyl)-
phenylmethylene]hydrazono}-3H-furan-2-one (VIb).
Yield 2.93 g (73%), orange crystals, mp 164–165°C
(toluene). IR spectrum, ν, cm–1: 1797 (C=Olact), 1607
1
(C=C, C=N). H NMR spectrum (DMSO-d6), δ, ppm:
4-(2,4-Dibromophenylamino)-2-tert-butyl-2,5-
dihydro-5-oxofuran-2-yl acetate (IVd). Yield 3.58
g (80%), yellowish crystals, t.decomp. 105–107°C
(toluene). IR spectrum, ν, cm–1: 3352 (NH), 3120 (CH),
2.44 s (3H, Me), 3.81 s (3H, OMe), 7.50 m (12H, CH
+ 2C6H4 + C6H5). Found, %: C 75.71; H 5.02; N 7.06.
C24H18N2O3. Calculated, %: C 75.74; H 5.08; N 7.07.
3-[2-(9H-Fluoren-9-ylidene)hydrazono]-5-phenyl-
3H-furan-2-one (VIc). Yield 3.22 g (92%), dark red crys-
tals, mp 191–192°C (toluene). IR spectrum, ν, cm-1: 1796
1
1782 (C=Olact), 1738 (COO), 1672 (C=C). H NMR
spectrum (CDCl3), δ, ppm: 1.07 s (9H, CMe3), 2.05 s
(3H, MeCO), 6.13 s (1H, CH), 6.93 s (1H, NH), 7.40
m (3H, C6H3). Found, %: C 42.95; H 3.80; Br 35.70;
N 3.10. C16H17Br2NO4. Calculated, %: C 42.98; H 3.83;
Br 35.74; N 3.13.
1
(C=Olact), 1591 (C=C, C=N). H (DMSO-d6), δ, ppm:
6.83 s (1H, CH), 7.50 m (13H, C6H5 + C13H8). Found,
%: C 78.81; H 4.02; N 8.02. C23H14N2O2. Calculated, %:
C 78.84; H 4.03; N 8.00.
2-tert-Butyl-4-(2,4-dichlorophenylamino)-5-oxo-
2,5-dihydrofuran-2-yl acetate (IVe). Yield 3.26 g (91%),
yellowish crystals, t.decomp. 100–101°C (toluene). IR
spectrum, ν, cm–1: 3368 (NH), 3112 (CH), 1782 (C=Olact),
1735 (COO), 1671 (C=C). 1H NMR spectrum (CDCl3),
δ, ppm: 1.07 s (9H, CMe3), 2.07 s (3H, MeCO), 6.09 s
(1H, CH), 6.89 s (1H, NH), 7.20 m (4H, C6H4). Found,
%: C 53.63; H 4.76; Cl 19.72 N 3.88. C16H17Cl2NO4.
Calculated, %: C 53.65; H 4.78; Cl 19.79 N 3.91.
5-(4-Methylphenyl)-3-[2-(9H-fluoren-9-ylidene)-
hydrazono]-3H-furan-2-one (VId). Yield 3.46 г (95%),
dark red crystals, mp 178–179°C (toluene). IR spectrum,
1
ν, cm–1: 1795 (C=Olact), 1598 (C=C, C=N). H NMR
spectrum (CDCl3), δ, ppm: 2.42 s (3H, Me), 6.81 s (1H,
CH), 7.50 m (12H, C6H4+C13H8). Found, %: C 79.11;
H 4.42; N 7.66. C24H16N2O2. Calculated, %: C 79.11;
H 4.43; N 7.69.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 2 2011