Chemistry of Heterocyclic Compounds 2015, 51(6), 526–530
1
under vacuum. The H NMR spectrum of the synthesized
DAIL is consistent with the literature reported data.23
1H NMR spectrum (D2O), , ppm (J, Hz): 1.52–1.61 (2H,
m, CH2CH2SO3H); 1.69–2.13 (2H, m, CH2CH2N+); 2.56
(2H, t, J = 7.5, CH2SO3H); 3.83 (3H, s, CH3); 4.12 (2H, t,
J = 7.0, CH2N+); 8.15 (1H, d, J = 9.4, =CH); 8.19 (1H, d,
J = 9.4, =CH); 9.43 (1H, s, NCH=N+).
NMR spectrum, , ppm (J, Hz): 2.89 (1H, dd, J = 16.7,
J = 13.5) and 3.05 (1H, dd, J = 16.7, J = 2.5, CH2); 5.88
(1H, dd, J = 13.5, J = 2.5, CH); 6.68 (1H, t, J = 6.4, H Ar);
7.00 (1H, d, J = 6.4, H Ar); 7.19 (1H, t, J = 6.4, H Ar); 7.38
(1H, t, J = 6.2, H Ar); 7.47–7.56 (2H, m, H Ar); 7.71 (2H,
d, J = 6.9, H Ar). 13C NMR spectrum, , ppm: 45.4; 68.7;
118.7; 119.2; 119.3; 121.2; 127.5; 128.0; 129.2; 130.2;
132.7; 137.0; 141.7; 162.5; 205.4. Mass spectrum, m/z (Irel, %):
304 [M(81Br)] + (31), 302 [M(79Br)]+ (27), 223 [M–Br]+
(72), 121 [OCC6H4OH]+ (100). Found, %: C 59.41; H 3.60.
C15H11BrO2. Calculated,%: C 59.40; H 3.63.
Preparation of the nanosilica-supported dual acidic
ionic liquid catalyst. The NSSDAIL catalyst was prepared
by physical adsorption of the DAIL onto the surface of the
nanosilica support. The nanosilica support (Fumed silica
S5130 purchased from Sigma Chemical Company) was
preheated at 200°C for 5 h in an oven. DAIL (1 mmol) was
dissolved in EtOH (10 ml) at room temperature. Then
nanosilica (1 g) was added to the solution with vigorous
stirring. The mixture was stirred for 24 h at room
temperature. The solvent was removed in a rotary
evaporator to afford NSSDAIL which was washed with
acetone (2×10 ml) and dried in a vacuum oven.
Synthesis of 2'-hydroxychalcones 3a–m (General
method). 50% NaOH aqueous solution (1.0 ml) was added
to a well stirred solution of aldehyde 2a–m (10 mmol) and
2'-hydroxyacetophenone (1) (10 mmol) in EtOH (30 ml).
The reaction mixture was stirred at room temperature until
TLC monitoring indicated the completion of the reaction
(2–4 h). Then the reaction mixture was poured into ice
water. The precipitated chalcone was filtered, dried, and
recrystallized from methanol. Melting points of the
synthesized chalcones were compared with the reported
melting points. These are consistent with the literature
ones.2,4,7,24–27
Synthesis of flavanones 4a–m (General method). In a
25 ml round-bottom flask, a mixture of 2'-hydroxychalcone
3a–m (1 mmol) and NSSDAIL (0.20 g) was heated at 80°C
and stirred until TLC monitoring indicated no further
progress (35 to 70 min). Subsequently the reaction mixture
was cooled to room temperature and 5 ml acetonitrile was
added. The catalyst was separated by filtration and the
solvent was removed under reduced pressure. The product
was purified by column chromatography (n-hexane/ethyl
acetate).The catalyst was washed twice with acetonitrile
(5 ml), dried in an oven at 100°C, and reused.
N-[4-(4-Oxo-3,4-dihydro-2H-chromen-2-yl)phenyl]acet-
amide (4d). Pale-yellow solid. Mp 175–176C. IR spectrum,
ν, cm–1: 3291 (NH), 1603 (C=O), 1528 (C=C), 1465
1
(C=C), 1114 (C–O–C). H NMR spectrum, , ppm (J, Hz):
2.20 (3H, s, CH3); 2.86 (1H, dd, J = 16.9, J = 2.7) and 3.07
(1H, dd, J =16.9, J = 13.2, CH2); 5.45 (1H, dd, J = 13.2,
J = 2.7, CH); 7.02–7.08 (2H, m, H Ar); 7.43 (2H, d,
J = 8.2, H Ar); 7.51 (1H, t, J = 7.8, H Ar); 7.59 (2H, d,
J = 8.2, H Ar); 7.63 (1H, s, NH); 7.92 (1H, d, J = 7.6,
H Ar). 13C NMR spectrum, , ppm: 24.6; 44.5; 79.2; 118.1;
120.1; 120.9; 121.7; 127.0; 134.4; 136.3; 138.4; 161.5;
168.6; 192.1. Mass spectrum, m/z (Irel, %): 281 [M]+ (98),
223 [M–NHCOCH3]+ (12), 119 (100). Found, %: C 72.69;
H 5.37; N 4.90. C17H15O3N. Calculated, %: C 72.59;
H 5.34; N 4.98.
2-(5-Bromo-2-hydroxyphenyl)-2,3-dihydrochromen-
4-one (4m). Pale-yellow solid. Mp 104–105C. IR spectrum,
ν, cm–1: 3429 (OH), 1672 (C=O), 1555 (C=C), 1466
(C=C), 1163 (C–O–C). 1H NMR spectrum, , ppm (J, Hz):
2.93 (1H, dd, J = 17.0, J = 13.3) and 3.16 (1H, dd, J = 17.0,
J = 2.7, CH2); 5.74 (1H, dd, J = 13.3, J = 2.7, CH); 6.84
(1H, d, J = 8.5, H Ar); 7.09–7.14 (3H, m, H Ar, OH); 7.34
(1H, dd, J = 8.5, J = 2.3, H Ar); 7.55 (1H, dd, J = 7.9,
J = 1.0, H Ar); 7.61 (1H, d, J = 2.3, H Ar); 7.97 (1H, dd,
J = 7.5, J = 1.5, H Ar). 13C NMR spectrum, , ppm: 42.9;
77.4; 112.9; 118.1; 120.9; 122.3; 123.4; 126.9; 127.3;
129.5; 132.3; 136.5; 152.3; 176.3; 192.9. Mass spectrum,
m/z (Irel, %): 320 [M(81Br)]+ (24), 318 [M(81Br)]+ (21), 302
(96), 300 (72), 121 [OCC6H4OH]+ (100). Found, %: C 56.48;
H 3.58. C15H11BrO3. Calculated, %: C 56.42; H 3.45.
1
2-(3-Hydroxyphenyl)-2,3-dihydrochromen-4-one (4b).
Pale-yellow solid. Mp 141–142C. IR spectrum, ν, cm–1:
3397 (OH), 1674 (C=O), 1599 (C=C), 1463 (C=C), 1110
(C–O–C). 1H NMR spectrum, , ppm (J, Hz): 2.86 (1H, dd,
J = 17.1, J = 3.3) and 3.06 (1H, dd, J = 17.1, J = 12.9,
CH2); 5.42 (1H, dd, J = 12.9, J = 3.3, CH); 6.61 (1H, s,
OH); 6.89 (1H, dd, J = 8.1, J = 2.4, H Ar); 6.98–7.07 (4H,
m, H Ar); 7.28 (1H, t, J = 8.1, H Ar); 7.51 (1H, td, J = 7.9,
J = 1.6, H Ar); 7.93 (1H, dd, J = 8.2, J = 1.7, H Ar).
13C NMR spectrum, , ppm: 44.5; 79.2; 113.1; 115.9;
118.2; 120.7; 121.7; 127.1; 130.2; 136.6; 140.3; 156.3;
161.6; 193.0. Mass spectrum, m/z (Irel, %): 240 [M]+ (100),
223 [M–OH]+ (18), 121 [OCC6H4OH]+ (82). Found, %:
C 75.18; H 5.11. C15H12O3. Calculated, %: C 75.00; H 5.00.
2-(2-Bromophenyl)-2,3-dihydrochromen-4-one (4c).
Pale-yellow solid. Mp 85–86C. IR spectrum, ν, cm–1:
Supporting material to this article containing H and 13
C
NMR spectra and mass spectra of flavanones 4b–d,f,l,m is
available for the authorized users.
We are grateful to Research Council of K. N. Toosi
University of Technology for partial financial support of
this work.
References
1. Kavala, V.; Lin, Ch.; Kuo, Ch.-W.; Fang, H.; Yao, Ch.-F.
Tetrahedron 2012, 68, 1321.
2. Cabera, M.; Simones, M.; Falchi G.; Lavaggi, M. L.; Piro, O. E.;
Castellano, E. E.; Vidal, A.; Azqueta, A.; Monge, A.; López de
Ceráin, A.; Sagrera, G.; Seoane, G.; Cerecetto, H.; González, M.
Bioorg. Med. Chem. 2007, 15, 3356.
3. Chen, P. Y.; Wang, T. P.; Chiang, M. Y.; Huang, K. S.;
Tzeng, Ch. Ch.; Chen, Y. L.; Wang, E. Ch. Tetrahedron 2011,
67, 4155.
1
1644 (C=O), 1584 (C=C), 1466 (C=C), 1155 (C–O–C). H
529