8
64
SABETPOOR & HATAMJAFARI, Orient. J. Chem., Vol. 30(2), 863-865 (2014)
Scheme 1:
All chemicals were obtained from Merck 5,7-dihydroxy-4-methyl-2H-chromen-2-one (S3)
0
or Flukawithout further purification. Silica gel SILG/
White powder, yield (87%), mp:281-282 C
-
1
UV 254 plates were used for TLC. IR spectra were IR (max/cm )(KBr): 3498, 3440(2OH), 1674(C=O),
measured on Shimadzu IR-470 1602(C=C)
a
1
Spectrophotometer. H NMR spectra were
determined on Bruker400 DRX AVANCE instrument
at 400 MHz, respectively.
1
H NMR(DMSO) = 2.47(3H ,s, CH ),
3
5.82(1H, s, CH), 6.16(1H, d, J=2.4 Hz, H ), 6.26(1H,
a
d, J=2.4 Hz, H ), 10.37(2H, brs, 2OH).
b
Typical procedure adopted for the synthesis of 7-
hydroxy-4-methyl-2H-chromen-2-one (S1)
A mixture of resorsinol (1 mmol), ethyl
7-hydroxy-4,8-dimethyl-2H-chromen-2-one (S4)
0
White powder, yield (89%), mp: 261-263 C
-
1
acetoacetate (1 mmol), and glutamic acid (20 mol%) IR (max/cm )(KBr): 3494(OH), 1670(C=O), 1606
was stirred at 110°C for a 15 min. The progress of (C=C)
the reaction was monitored by using TLC. After
completion of the reaction, the solid catalyst
1
HNMR(DMSO): ä =2.27, 2.54(6H, s,
(
glutamic acid) was washed with water, and finally 2CH ), 6.03(1H, s, CH), 6.56(1H, d, J=0.8 Hz, H ),
3
a
purified by recrystallization in ethanol/water.
Data of compounds (S1-S5)
6.60(1H, d, J=0.8 Hz, H ).
b
4
-methyl-2H-chromen-2-one (S5)
0
7
-hydroxy-4-methyl-2H-chromen-2-one (S1)
White powder, Yield: (83%), mp: 80-82 C
0
-1
-1
White powder,Yield:(93%), mp:187-189 C IR (max/cm )(KBr): 1683(C=O), 1604(C=C)cm
-
1
IR (max/cm )(KBr): 3440(OH), 1683(C=O),
1
-
1
1
604(C=C)cm
H NMR (400MHz; DMSO-d ) = 2.34 (3H,
6
s, CH ), 6.10 (1H, s, CH), 6.68(1H, d, J=2.0 Hz, H ),
3
c
1
H NMR (400MHz; DMSO-d ) = 2.34 (3H, 6.79(1H, d, J=2.0 Hz, H ), 7.76(1H, d, J=8.8 Hz, H ).
6
b
a
s, CH ), 6.10 (1H, s, CH), 6.68(1H, d, J=2.0 Hz, H ),
3
c
6
.79(1H, d, J=2.0 Hz, H ), 7.76(1H, d, J=8.8 Hz,
RESULTSAND DISCUSSION
b
H ),8.85(1H, brs, OH).
a
Herein, we report glutamic acid ascatalyst
which could provide high yield, an efficient,
environmentally friendly, easy separationand simple
dihydroxy-4-methyl-2H-chromen-2-one (S2)7,8
0
White powder, Yield: (90%), mp: 241-243 C route for thesynthesis of coumarins.
-
1
IR (max/cm )(KBr): 3444(OH), 1677(C=O),
-
1
1
600(C=C)cm
ACKNOWLEDGEMENTS
1
H NMR(DMSO) = 2.34(3H, s, CH ),
We gratefully acknowledge the
3
6.11(1H, s, CH), 6.83-7.09(1H, m, Harom), 6.82(1H, financialsupport from the Research Council of
d, J=8.0 Hz, H ), 7.09(1H, d, J=8.0 Hz, H ), 9.30(1H, TonekabonBranch Islamic Azad University.
a
b
brs, OH), 10.0(1H, brs, OH).