Dihydrobenzofuran → 2,3-Dihydrobenzofuran-5-carboxaldehyde

A solution of 9.4 ml (83.4 mmol) 2,3-dihydrobenzofuran in 250 ml methylene dichloride was cooled under nitrogen to 0° to -5° C. and 18 ml (167 mmole) titanium tetrachloride was added dropwise at 0° C. The resulting brown mixture was stirred 10 minutes and 8.3 ml (91.6 mmole) 1,1-dichloromethylmethyl ether was then added dropwise at 0° C. During this addition the reaction mixture became dark red in color. The mixture was allowed to warm to room temperature, stirred for 2 hours and poured slowly into a 2 liter beaker containing 700 ml saturated aqueous sodium bicarbonate solution The resulting mixture was filtered through diatomaceous earth and the solids washed with methylene dichloride. The separated organic layer was dried (Na2SO4) and the solvent evaporated to afford a residual oil, 10 g, (81%) which appeared homogeneous on silica gel thin-layer chromatography (TLC), eluting with an ethyl acetate/hexane/5% acetic acid, 1:5:5 by volume. Mass spectrum (m/e): 148 (M+), 147, 119.

1. additionDuring this addition the reaction mixture
2. stirringstirred for 2 hours
3. additionpoured slowly into a 2 liter beaker
4. filtrationwas filtered through diatomaceous earth
5. washthe solids washed with methylene dichloride
6. dry with materialThe separated organic layer was dried (Na2SO4)
7. customthe solvent evaporated
8. customto afford a residual oil, 10 g, (81%) which
9. washeluting with an ethyl acetate/hexane/5% acetic acid, 1:5:5 by volume

ORD record

ord-f0a401c2f49446cdb78279afe412c8a5

Source dataset

uspto-grants-1987_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04703052