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TEIMURI‐MOFRAD ET AL.
acetone (2 × 30 ml) and dried under vacuum at 50 °C for
48 h to afford [Fe3O4@SiO2@Im‐Fc][OAc].
(100 MHz, DMSO‐d6, δ, ppm): 37.39, 57.31, 115.07,
116.79, 119.66, 120.30, 123.53, 125.00, 127.18, 128.51,
129.21, 129.70, 130.02, 130.82, 131.60, 145.08, 146.78,
159.68. Anal. Calcd for C20H13BrN2O (%): C, 63.68; H,
3.47; N, 7.43. Found (%): C, 63.67; H, 3.48; N, 7.44.
3.4 | General procedure for synthesis of 2‐
amino‐3‐cyano‐4H‐pyran derivatives
To a mixture of 2‐naphthol (1 mmol), aldehyde (1 mmol)
3‐Amino‐8‐bromo‐1‐(pyridin‐4‐yl)‐1H–benzo[f]
chromene‐2‐carbonitrile (4n)
and
malononitrile
(1.2
mmol)
was
added
[Fe3O4@SiO2@Im‐Fc][OAc}(10 mg). The mixture was
stirred at 90 °C under solvent‐free conditions in an oil
bath and the completion of the reaction was monitored
by TLC (EtOAc–n‐hexane, 1:4). After completion of the
reaction, the mixture was cooled to room temperature,
and ethanol (2 ml) was added, and the mixture was stirred
for 10 min. The catalyst was separated out using an exter-
nal magnet and the obtained solid was collected by filtra-
tion and purified by recrystallization from EtOH–acetone
(4:1) or was subjected to preparative silica gel layer chro-
matography (EtOAc–n‐hexane, 1:5) to give pyran as a
pure solid. Characterized data for the known compounds
were in good agreement with those in the literature. The
recovered catalyst was washed with EtOH, dried and
reused for the next run. The catalyst was recovered and
reused five times without any significant changes in the
yield and the reaction time. All new compounds were
Brown solid; m.p. 268–270 °C. FT‐IR (KBr, ν, cm−1): 3359,
1
3299, 3043, 2873, 2191, 1591, 1588, 1407, 1244. H NMR
(400 MHz, DMSO‐d6, δ, ppm): 5.42 (1H, s, CH), 7.17–
7.19 (3H, m, NH2, Ar‐H), 7.41 (1H, d, J = 9 Hz, Ar‐H),
7.56–7.59 (1H, m, Ar‐H), 7.73 (1H, d, J = 9.09 Hz, Ar‐
H), 7.97 (1H, d, J = 9.03 Hz, Ar‐H), 8.24 (1H, d,
J = 1.68 Hz, Ar‐H), 8.46 (2H, d, J = 5.28 Hz, Ar‐H). 13C
NMR (100 MHz, DMSO‐d6, δ, ppm): 37.06, 56.16, 114.58,
118.23, 118.40, 120.11, 122.19, 125.75, 128.74, 129.30,
130.18, 130.44, 132.16, 147.35, 150.19, 153.52, 159.89,
159.93. Anal. Calcd for C19H12BrN3O (%): C, 60.34; H,
3.20; N, 11.11. Found (%): C, 60.32; H, 3.27; N, 11.26.
3‐Amino‐8‐bromo‐1‐(thiophen‐2‐yl)‐1H–benzo[f]
chromene‐2‐carbonitrile (4o)
White solid; m.p. 203–205 °C. FT‐IR (KBr, ν, cm−1):
3459, 3289, 3171, 2858, 2201, 1657, 1583, 1407, 1238.
1H NMR (400 MHz, DMSO‐d6, δ, ppm): 5.71 (1H, s,
CH), 6.86–6.88 (1H, m, Ar‐H), 6.99 (1H, d,
J = 2.98 Hz, Ar‐H), 7.13 (2H, s, NH2), 7.27 (1H, d,
J = 4.96 Hz, Ar‐H), 7.35 (1H, d, J = 8.99 Hz, Ar‐H),
7.60–7.63 (1H, m, Ar‐H), 7.92 (1H, d, J = 9.01 Hz, Ar‐
H), 7.98 (1H, d, J = 9.11 Hz, Ar‐H), 8.21 (1H, s, Ar‐
H). 13C NMR (100 MHz, DMSO‐d6, δ, ppm): 32.99,
57.62, 116.41, 118.18, 118.32, 120.24, 124.19, 125.04,
125.91, 126.75, 128.82, 128.93, 130.03, 130.30, 132.10,
146.63, 150.01, 160.12. Anal. Calcd for C18H11BrN2OS
(%): C, 56.41; H, 2.89; N, 7.31; S, 8.37. Found (%):
56.43; H, 2.93; N, 7.18; S, 8.51.
1
characterized using melting point, FT‐IR, H NMR, 13C
NMR and elemental (C, H and N) analyses.
3‐Amino‐1‐(4‐isopropylphenyl)‐1H–benzo[f]chromene‐
2‐carbonitrile (4c)
White solid; m.p. 218–220 °C. FT‐IR (KBr, ν, cm−1): 3424,
1
333, 3053, 2957, 2190, 1648, 1588, 1412, 1233. H NMR
(400 MHz, DMSO‐d6, δ, ppm): 1.10–1.11 (3H, d,
J = 2.85 Hz, CH3), 1.12–1.13 (3H, d, J = 2.85 Hz, CH3),
2.72–2.82 (1H, m, CH), 5.24 (1H, s, CH), 6.96 (2H, s,
NH2), 7.07–7.13 (4H, m, Ar‐H), 7.34 (1H, d, J = 8.94 Hz,
Ar‐H), 7.39–7.47 (2H, m, Ar‐H), 7.86 (1H, d,
J = 8.09 Hz, Ar‐H), 7.90–7.93 (2H, m, Ar‐H). 13C NMR
(100 MHz, DMSO‐d6, δ, ppm): 23.76, 23.80, 32.96, 37.61,
58.01, 115.98, 116.80, 120.59, 123.62, 124.92, 126.62,
126.85, 127.11, 128.46, 129.37, 130.15, 130.81, 143.15,
146.56, 146.76 and 159.72. Anal. Calcd for C20H20N2O
(%): C, 81.15; H, 5.92; N, 8.23. Found (%): C, 81.23; H,
5.99; N, 8.11.
3‐Amino‐8‐bromo‐1‐(3‐nitrophenyl)‐1H–benzo[f]
chromene‐2‐carbonitrile (4p)
Light brown solid; m.p. 215–218 °C. FT‐IR (KBr, ν, cm
−1): 3445, 3357, 3065, 2967, 2187, 1655, 1589, 1406,
1231. 1H NMR (400 MHz, DMSO‐d6, δ, ppm): 5.61
(1H, s, CH), 7.20 (2H, s, NH2), 7.42 (2H, d,
J = 9.01 Hz, Ar‐H), 7.51–7.57(2H, m, Ar‐H), 7.63 (1H,
d, J = 7.74 Hz, Ar‐H), 7.78 (1H, d, J = 9.11 Hz, Ar‐
H), 7.93 (1H, d, J = 9.06 Hz, Ar‐H), 8.01 (1H, d,
J = 8.01 Hz, Ar‐H), 8.06 (1H, s, Ar‐H), 8.15 (1H, d,
J = 1.75 Hz, Ar‐H). 13C NMR (100 MHz, DMSO‐d6, δ,
ppm): 38.26, 56.92, 114.92, 118.24, 118.43, 120.09,
121.36, 121.94, 125.79, 128.66, 129.37, 130.21, 130.41,
130.51, 132.19, 133.69, 147.58, 148.03, 159.86, 159.90.
3‐Amino‐1‐(4‐bromophenyl)‐1H–benzo[f]chromene‐2‐
carbonitrile (4i)
Brownwish powder; m.p. 212–215 °C. FT‐IR (KBr, ν, cm
−1): 3459, 3289, 3171, 2858, 2190, 1648, 1588, 1412, 1233.
1H NMR (400 MHz, DMSO‐d6, δ, ppm): 5.33 (1H, s, CH),
7.06 (2H, s, NH2), 7.15 (2H, d, J = 8.35 Hz, Ar‐H), 7.34
(1H, d, J = 8.9, Ar‐H), 7.38–7.44 (4H, m, Ar‐H), 7.79 (1H,
d, J = 7.93 Hz, Ar‐H), 7.89–7.94 (2H, m, Ar‐H). 13C NMR