Dihydrobenzofuran → 2,3-Dihydrobenzofuran-5-carboxaldehyde

A solution of 9.4 ml (83.4 mmole) 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-dichloromethyl methylether was then added dropwise at 0° C. During this addition the reaction mixture became dark red. The mixture was allowed to warm to room temperature, stirred for two 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%) of which appeared homogeneous on silica gel 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 two hours
3. additionpoured slowly into a 2 liter beaker
4. filtrationThe resulting mixture was 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%) of which
9. washeluting with an ethyl acetate/hexane/5% acetic acid 1:5:5 by volume

ORD record

ord-aafc79dcdb3e4c1cbfeb7b371aa10ea0

Source dataset

uspto-grants-2000_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06110951