1452
P. Shah et al. / Tetrahedron 69 (2013) 1446e1453
boronic acid (1 mmol) was added and the mixtures degassed. The
reaction mixtures were refluxed for 3.0 h. The reactions were
monitored by TLC. The reaction mixtures were then evaporated in
vacuo. The resultant residues were purified by flash chromatogra-
phy (silica gel) to afford the desired product as colourless solid. Rf
0.58 (E.A 20%/PE 80%). Mp 142e143 ꢀC; IR (KBr, cmꢁ1): 3071, 2956,
1765, 1724, 1573, 1245, 1193, 1107, 1028, 838; 1H NMR (300 MHz,
24 h and then quenched into water (150 mL). The organic layer was
then extracted with EtOAc (50ꢂ3 mL) and the combined organic
layer was evaporated in vacuo. The resultant residues were purified
by flash chromatography (silica gel) to afford the desired product as
pale yellow solid. Rf- 0.70 (E.A 20%/PE 80%); 284 mg, 86%. Mp:
150e152 ꢀC; IR (KBr, cmꢁ1): 3041, 2979, 1727,1573,1268,1179, 1104,
1038, 858; 1H NMR (300 MHz, DMSO-d6)
d
¼8.05 (d, J¼7.5 Hz, 1H,
DMSO-d6)
J¼7.8 Hz, 2H, AreH), 6.16 (s, 1H, CH), 4.14 (s, 2H, CH2), 3.79 (s, 3H,
OCH3), 2.26 (s, 3H, CH3); 13C NMR (75 MHz, DMSO-d6)
d
¼7.67 (s, 1H, AreH), 7.24e7.46 (m, 4H, AreH), 6.91 (d,
AreH), 7.71e7.76 (m, 1H, AreH), 7.68e7.69 (m, 1H, AreH),
7.35e7.50 (m, 4H, AreH), 5.10 (s, 1H, CH), 2.36 (s, 3H, CH3); 13C NMR
d¼159.9 (Cq),
(75 MHz, DMSO-d6)
d
¼165.1 (Cq), 161.3 (Cq), 153.5 (Cq), 147.0 (Cq),
158.0 (Cq), 155.8 (Cq), 151.3 (Cq), 133.5 (Cq), 132.7 (CH), 130.1 (CH),
128.6 (CH), 125.1 (CH), 118.4 (Cq), 116.4 (CH), 114.5 (Cq), 114.3 (CH),
55.0 (OCH3), 35.8 (CH2), 20.4 (CH3). MS (EI) m/z (relative intensity)
280 (100, Mþ); HRMS (ESI, quadrapole): m/z calcd for C18H16O3
280.1099; found 280.1098. Anal. Calcd for C18H16O3: C, 77.12; H,
5.75. Found: C, 77.12; H, 5.76%.
139.3 (Cq), 134.6 (CH), 134.0 (CH), 130.9 (CH), 125.1 (CH), 123.8 (Cq),
123.6 (CH), 117.1 (CH), 114.9 (Cq), 93.2 (CH), 20.5 (CH3); MS (ESI) m/
z: 332 (100, MþHþ); HRMS (ESI, quadrapole) calcd for C16H11BrO3:
329.9892, found: 329.9890. Anal. Calcd for C16H11BrO3: C, 58.03; H,
3.35; Br, 24.13. Found: C, 58.04; H, 3.35; Br, 24.12%.
4.5.10. 4-(2-Bromo-4-chlorophenoxy)-coumarin 9c. In a 250 mL
flask 4-chlorocoumarin (5.0 mmol) in acetonitrile (50 mL) was
placed and to this were added K2CO3 (5.5 mmol) and 2-bromo-4-
chlorophenol (5.0 mmol). The reaction mixture was refluxed for
24 h and then quenched into water (150 mL). The organic layer was
then extracted with EtOAc (50ꢂ3 mL) and the combined organic
layer was evaporated in vacuo. The resultant residues were purified
by flash chromatography (silica gel) to afford the desired product as
white solid. Rf 0.65 (E.A 20%/PE 80%); 277 mg, 79%. Mp: 172e173 ꢀC;
IR (KBr, cmꢁ1): 3049, 2982, 1731, 1576, 1268, 1178, 1102, 1035, 828;
4.5.7. 4-(4-Methyl)benzyl-7-methyl coumarin 8d. In
a 30 mL
Schlenk tube equipped with a magnetic stirring bar, complex 1
(5.0 mol %) and 4-bromobenzyl-7-methylcoumarin (1 mmol) were
taken in THF (2 mL) and Na2CO3 solution (2.0 M, 1 mL). The solu-
tions were degassed (three freezeethaw cycles) and stirred for
10 min. After this time period, to the solution 4-methylphenyl bo-
ronic acid (1 mmol) was added and the mixtures degassed. The
reaction mixtures were refluxed for 3.0 h. The reactions were
monitored by TLC. The reaction mixtures were then evaporated in
vacuo. The resultant residues were purified by flash chromatogra-
phy (silica gel) to afford the desired product as yellow solid. Rf 0.73
(E.A 20%/PE 80%). Mp 104e105 ꢀC; IR (KBr, cmꢁ1): 2922, 1731, 1619,
1H NMR (300 MHz, CDCl3)
d
¼7.96 (d, J¼7.5 Hz,1H, AreH), 7.65e7.67
(m, 1H, AreH), 7.55e7.58 (m, 1H, AreH), 7.27e7.38 (m, 2H, AreH),
7.13 (d, J¼8.0 Hz, 2H, AreH), 5.23 (s, 1H, CH); 13C NMR (75 MHz,
1259, 1143, 1014, 812; 1H NMR (300 MHz, DMSO-d6)
d¼7.73 (d,
CDCl3)
d
¼164.7 (Cq), 162.0 (Cq), 153.7 (Cq), 148.2 (Cq), 133.9 (CH),
J¼7.9 Hz, 2H, AreH), 7.13e7.39 (m, 5H, AreH), 6.19 (s, 1H, CH), 4.17
133.2 (Cq), 133.1 (CH), 129.5 (CH), 124.3 (CH), 124.0 (CH), 123.1 (CH),
116.9 (CH), 116.7 (Cq), 114.7 (Cq), 93.8 (CH); MS (ESI) m/z: 352 (100,
MþHþ); HRMS (ESI, quadrapole) calcd for C15H8BrClO3þHþ:
350.9424, found: 350.9425. Anal. Calcd for C15H8BrClO3: C, 51.24; H,
2.29; Br, 22.73; Cl, 10.08. Found: C, 51.24; H, 2.28; Br, 22.73, Cl,
10.07%.
(s, 2H, CH2), 2.47 (s, 3H, CH3), 2.27 (s, 3H, CH3); 13C NMR (75 MHz,
DMSO-d6)
d
¼160.0 (Cq), 155.5 (Cq), 153.3 (Cq), 142.7 (Cq), 135.8 (Cq),
133.9 (Cq), 129.2 (CH), 128.8 (CH), 125.3 (Cq), 125.2 (CH), 116.6 (CH),
113.6 (CH), 36.4 (CH2), 20.9 (CH3), 20.6 (CH3). MS (EI) m/z (relative
intensity) 264 (100, Mþ); HRMS (ESI, quadrapole): m/z calcd for
C18H16O2þHþ 265.1229; found 265.1226. Anal. Calcd for C18H16O2:
C, 81.79; H, 6.10. Found: C, 81.78; H, 6.12%.
Acknowledgements
4.5.8. 4-(4-Methoxy)benzyl-7-methyl coumarin 8e. In
a 30 mL
A.R.K. would like to thank DST, India for financial support under
the DST-Fast Track Fellowship Scheme (Fellowship No SR/FT/CS-58/
2010). The authors would like to thank SAIF facility in TIFR, Mumbai
for NMR characterization of all the compounds. We thank
Schlenk tube equipped with a magnetic stirring bar, complex 1
(5.0 mol %) and 4-bromobenzyl-7-methylcoumarin (1 mmol) were
taken in THF (2 mL) and Na2CO3 solution (2.0 M, 1 mL). The solu-
tions were degassed (three freezeethaw cycles) and stirred for
10 min. After this time period, to the solution 4-methoxyphenyl
boronic acid (1 mmol) was added and the mixtures degassed. The
reaction mixtures were refluxed for 3.0 h. The reactions were
monitored by TLC. The reaction mixtures were then evaporated in
vacuo. The resultant residues were purified by flash chromatogra-
phy (silica gel) to afford the desired product as colourless solid. Rf
0.64 (E.A 20%/PE 80%). Mp 116e117 ꢀC; IR (KBr, cmꢁ1): 2992, 1736,
1602, 1512, 1248, 1144, 1023, 858; 1H NMR (300 MHz, DMSO-d6)
ꢀ
ꢀ
Fundacion Seneca (project 08670/PI/08) for financial support.
Supplementary data
Supplementary data associated with this article can be found in
References and notes
d
¼7.67e7.76 (m, 1H, AreH), 7.11e7.37 (m, 4H, AreH), 6.92 (d,
J¼7.9 Hz, 2H, AreH), 6.31 (s, 1H, CH), 4.13 (s, 2H, CH2), 3.75 (s, 3H,
OCH3), 2.40 (s, 3H, CH3); 13C NMR (75 MHz, DMSO-d6)
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d
¼160.5 (Cq),
158.5 (Cq), 156.3 (Cq), 153.8 (Cq), 143.2 (Cq), 130.5 (CH), 129.3 (Cq),
125.7 (CH), 116.8 (CH), 116.6 (Cq), 114.5 (CH), 113.9 (CH), 55.5
(OCH3), 36.5 (CH2), 21.4 (CH3). MS (ESI) m/z (relative intensity) 281
(100, MþHþ); HRMS (ESI, quadrapole): m/z calcd for C18H16O3
280.1099; found 280.1075. Anal. Calcd for C18H16O3: C, 77.12; H,
5.75. Found: C, 77.11; H, 5.77%.
4.5.9. 4-(2-Bromo-4-methyl-phenoxy)-coumarin 9b. In a 250 mL
flask 4-chlorocoumarin (5.0 mmol) in acetonitrile (50 mL) was
placed and to this were added K2CO3 (5.5 mmol) and 2-bromo-4-
methylphenol (5.0 mmol). The reaction mixture was refluxed for
3. Donnelly, D. M. X.; Sheridan, M. H. In The Flavonoids, Advances in Research Since
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