3-Benzofurancarboxaldehyde

3 -methyl benzofuran (200 mg, 0.19 ml, 1.5 mmol) and Se03 -methyl benzofuran (200 mg, 0.19 ml, 1.5 mmol) and Se02 (200 mg, 1.8 mmol, 1.2 eq.) weresuspended in 1, 4-dioxane (3 ml) and heated to reflux for 24 hours. The reaction mixture was allowed to cool, then diluted with EtOAc/hexane (2:1 v/v, 10 ml) and filtered through a short plug of silica to remove selenium residues. The silica plug was washed with EtOAc (2 x 3 ml) and the combined organic filtrate was evaporated to dryness and purified by silica gel column chromatography (hexane/EtOAc 96:4) to afford a yellow oil (162 mg, 1.1 mmol, 74 % yield) . XH NMR (300 MHz, CDC13) delta 10.18 (s, 1H) , 8.26 (s, 1H) , 8.19 (m, 1H) , 7.54 (m, 1H) , 7.41 (m, 2H) ; ESI m/z = 147.0 (MH)+, calc . for C9H702 = 147.04.Compound E-3 (16 g, 121 mmol) was dissolved in 1, 4-dioxane solution (100 mL), and then add selenium dioxide (17.5g, 157mmol), then, the mixture was stirred and refluxed for 16 hours. The reaction was cooled to room temperature, and the mixture was diluted with ethyl acetate /hexane (2:1, 100 mL). After stirring for 10 min, the insoluble material was removed by filtration and washed with ethyl acetate. The combined filtrates were concentrated under reduced pressure and purified by silica gel column chromatographyThe product was obtained as a yellow solid 7.3 g, yield 41%3-Methylbenzofuran 3 (5.08 g, 38.5 mmol) is treated with SeO2 (5.10 g, 46.2 mmol) in accordance with Method D affording the title compound (3.08 g) after column chromatography (silica gel, 5% EtOAc in heptanes) as a light yellow wax: 1H NMR (360 MHz, CDCl3, deltaH) 10.19 (IH, s), 8.28 (IH, s), 8.20 (IH, dd), 7.57 (IH, dd), 7.43 (IH, app td), 7.40 (IH, app td).; Method D[00102] In accordance with the procedure of Zaidlewicz et al. (Heterocycles, 2001, 55, 569-577), a suspension of the 3-methylbenzofuran (1 equiv) and SeO2 (1.2 equiv) in 1, 4- dioxane (6 vol) is warmed to reflux and stirred 24 h. At this juncture, reaction progress is

Molecular Weight:146.14
XLogP3:1.8
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:146.036779430
Monoisotopic Mass:146.036779430
Topological Polar Surface Area:30.2
Heavy Atom Count:11
Complexity:156
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes