6
06 JOURNAL OF CHEMICAL RESEARCH 2016
1
stirred at 60 °C for 7 h. When the reaction was judged to be complete
TLC monitoring), the mixture was poured into ice water (30 mL).
The pH of the mixture was adjusted by adding NaOH aqueous solution
20%) to yield a large amount of precipitate. The crude product was
812, 729. H NMR (400 MHz, CDCl ): δ 8.20 (s, 1H), 7.78 (dd, J = 7.2
3
(
and 2.4 Hz, 1H), 7.41–7.28 (m, 4H), 6.63 (dd, J = 8.8 and 2.4 Hz, 1H),
6.55 (d, J = 2.4 Hz, 1H), 3.82 (s, 3H), 3.46 (q, J = 7.2 Hz, 4H), 1.25 (t,
J = 7.2 Hz, 6H). C NMR (100 MHz, CDCl ): δ 160.2, 157.5, 151.8,
150.0, 147.2, 142.8, 136.6, 130.1, 122.8, 122.2, 119.5, 110.5, 109.6,
109.5, 108.4, 97.0, 45.0, 31.8, 12.4. HRMS for C H N O [M + H]
calcd 348.1707; found: 348.1716.
13
(
3
filtered, washed thoroughly with water, dried and recrystallised in
7
+
ethanol to give 5 as yellow solid in 80% yield, m.p. 165–166 °C (lit.
21
22
3
2
1
1
66–167 °C). H NMR (400 MHz, CDCl ): δ 10.07 (s, 1H), 8.19 (s,
3
1
H), 7.37 (d, J = 9.2 Hz, 1H), 6.61 (dd, J = 9.2 and 2.4 Hz, 1H), 6.44
7-(Diethylamino)-4-(1-methyl-1H-benzimidazol-2-yl)coumarin (2):
Compound 2 was prepared from 7-(diethylamino)-4-formylcoumarin
(0.29 g, 1.2 mmol) and N-methylphenylene-1,2-diamine (0.15 g,
1.2 mmol) by a method similar to that described for 1 in 76% yield as
13
(s, 1H), 3.45 (q, J = 7.2 Hz, 4H), 1.23 (t, J = 7.2 Hz, 6H). C NMR (100
MHz, CDCl ): δ 187.7, 161.7, 158.8, 153.4, 145.2, 132.4, 114.1, 110.1,
3
1
08.1, 97.0, 45.2, 12.3.
-(Diethylamino)-4-methylcoumarin (7): Ethyl acetoacetate
0.39 g, 3.0 mmol), m-diethylaminophenol (0.50 g, 3.0 mmol) and
–1
7
yellow solid, m.p. 225–227 °C. IR (KBr) cm : 3412, 2972, 1693, 1615,
1
(
1455, 1413, 1031, 742. H NMR (400 MHz, CDCl ): δ 8.04 (s, 1H), 7.78
3
ZnCl (0.40 g, 3.0 mmol) were added to a mortar successively. The
(d, J = 7.2 Hz, 1H), 7.60 (d, J = 8.8 Hz, 1H), 7.35–7.27 (m, 3H), 6.62
2
(
3
dd, J = 8.8 and 2.0 Hz, 1H), 6.56 (d, J = 2.0 Hz, 1H), 4.03 (s, 3H),
.41 (q, J = 7.2 Hz, 4H), 1.22 (t, J = 7.2 Hz, 6H). C NMR (100 MHz,
mixture was ground thoroughly with a pestle at room temperature.
Then, the mixture was heated at 50 °C and ground for 30 min. The
resulting solid was dissolved in 50 mL of ethyl acetate, extracted with
brine (3 × 50 mL). The organic phase was dried (Na SO ), filtered
13
CDCl ): δ 158.7, 155.4, 149.6, 148.9, 147.8, 142.8, 136.9, 124.6, 124.0,
1
for C H N O [M + H] calcd 348.1707; found: 348.1711.
3
23.6, 123.2, 120.0, 109.7, 108.8, 107.2, 98.3, 44.7, 31.9, 12.5. HRMS
2
4
+
and evaporated under vacuum. The resulting residue was purified by
column chromatography using petroleum ether/ethyl acetate (v/v = 5:1)
as eluent to afford 7 in 79% yield as colourless solid, m.p. 73–75 °C
21 22
3
2
Acknowledgements
This work was supported by the Natural Science Foundation of
Gansu Province (1508RJZA091).
13
1
(
lit. 72–75 °C). H NMR (400 MHz, CDCl ): δ 7.38 (d, J = 8.8 Hz,
3
1
H), 6.59 (d, J = 8.8 Hz, 1H), 6.49 (s, 1H), 5.93 (s, 1H), 3.41 (q, J = 7.2
13
Hz, 4H), 2.34 (s, 3H), 1.21 (t, J = 7.2 Hz, 6H). C NMR (100 MHz,
CDCl ): δ 162.2, 156.0, 152.9, 150.5, 125.5, 109.1, 108.7, 108.4, 97.7,
Paper 1604241 doi: 10.3184/174751916X14738553653270
Published online: 22 September 2016
3
4
4.8, 18.4, 12.4.
7-(Diethylamino)-4-formylcoumarin (8): 7-(Diethylamino)-4-
methylcoumarin (0.41 g, 1.8 mmol) and SeO2 (0.31 g, 2.7 mmol)
were dissolved in 10 mL of xylene. The resulting solution was stirred
under reflux conditions for 12 h. The mixture was filtered whilst
hot to remove selenium and the solvent was evaporated by rotary
evaporation under vacuum. The resulting residue was purified by
column chromatography using petroleum ether/ethyl acetate (v/v = 7:1)
References
1
F.G. Medina, J.G. Marrero, M. Macías-Alonso, M.C. González, L.
Córdova-Guerrero, A.G.T. García and S. Osegueda-Robles, Nat. Prod.
Rep., 2015, 32, 1472.
2
3
K. Paul, S. Bindal and V. Luxami, Bioorg. Med. Chem. Lett., 2013, 23,
3
667.
14
as eluent to afford 8 in 61% yield as red solid, m.p. 83–84 °C (lit.
S.C. Tsay, J.R. Hwu, R. Singha, W.C. Huang, Y.H. Chang, M.H. Hsu, F.
1
8
4–85 °C). H NMR (400 MHz, CDCl ): δ 10.05 (s, 1H), 8.46 (d,
3
J = 8.8 Hz, 1H), 7.05–6.97 (m, 2H), 6.63 (s, 1H), 3.47 (q, J = 7.2 Hz,
13
4
H), 1.23 (t, J = 7.2 Hz, 6H). C NMR (100 MHz, CDCl ): δ 192.2,
4
5
Biol. Drug Des., 2015, 86, 637.
3
1
61.3, 157.0, 149.3, 143.6, 127.3, 119.0, 111.2, 105.7, 100.0, 46.3, 12.1.
-(Diethylamino)-3-(1-methyl-1H-benzimidazol-2-yl)coumarin
1): N-Methylphenylene-1,2-diamine (0.15 g, 1.2 mmol) was dissolved
in 10 mL of methanol and sodium bisulfite (0.12 g, 1.2 mmol) was
added. Then, solution of 7-(diethylamino)-3-formylcoumarin
0.29 g, 1.2 mmol) in methanol (10 mL) was added dropwise with
7
(
6
7
X.L. Wang, Z.Y. Xue, Y.Y. Ma and F. Yang, J. Chem. Res., 2014, 38, 493.
X.L. Wang, F. Yang, Z.Y. Xue, X.Q. Wang and C. Chen, J. Chem. Res.,
2015, 39, 213.
a
8
N. Barooah, J. Mohanty and A.C. Bhasikuttan, Chem. Commun., 2015, 51,
(
13225.
stirring. The mixture was stirred under reflux conditions for 6 h.
The solvent was evaporated under reduced pressure and the resulting
mixture was dissolved in dichloromethane (50 mL). The organic
phase was washed successively with diluted aqueous hydrochloric
acid (2 × 50 mL), saturated aqueous sodium bicarbonate (2 × 50 mL)
and brine (3 × 50 mL). After dried over Na SO , the solvent was
9
10
S. Senthllkumar, S. Nath and H. Pal, Photochem. Photobiol., 2004, 80,
104.
11 J.Q. Xue, Y.X. Zhao, F.P. Wu and D.C. Fang, J. Phys. Chem. A, 2010, 114,
5171.
1
2
3
J.Q. Xue, Y.X. Zhao, J. Wu and F.P. Wu, J. Photochem. Photobiol. A:
Chem., 2008, 195, 261.
chemistry/aldrich-handbook.html [accessed 6 September 2016].
2
4
evaporated under vacuum. The resulting residue was purified by
column chromatography using petroleum ether/ethyl acetate (v/v =
1
3
:1) as eluent to afford 1 in 81% yield as yellow solid, m.p. 224–226 °C
13
–1
(
lit. 225–229 °C). IR (KBr) cm : 2968, 1698, 1607, 1528, 1260, 1135,
14 K. Ito and J. Maruyama, Chem. Pharm. Bull., 1983, 31, 3014.