Reaction #63587

Reaction equation

3,3-bis(4-fluorophenyl)tetrahydro-2H-pyran-2-one

hydrobromic acid

→

α-(3-bromopropyl)-4-fluoro-α-(4-fluorophenyl)benzeneacetic acid

Solvents

acetic acid

Conditions

Workup

1. 1
   workup.ADDITIONThe reaction mixture was poured onto water
2. 2
   FiltrationThe precipitated product was filtered off
3. 3
   workup.DISSOLUTIONdissolved in 2,2'-oxybispropane
4. 4
   WashThe organic phase was washed with water
5. 5
   Otherdried
6. 6
   Filtrationfiltered
7. 7
   Otherevaporated
8. 8
   workup.ADDITIONThe residue was boiled in a mixture of 42 parts of 2,2'-oxybispropane and 42 parts of petroleumether
9. 9
   FiltrationThe product was filtered off
10. 10
    Othercrystallized from 2,2'-oxybispropane

Procedure

A mixture of 5.8 parts of 3,3-bis(4-fluorophenyl)tetrahydro-2H-pyran-2-one and 30 parts of a solution of hydrobromic acid in glacial acetic acid was stirred over week-end at room temperature. The reaction mixture was poured onto water. The precipitated product was filtered off and dissolved in 2,2'-oxybispropane. The organic phase was washed with water, dried, filtered and evaporated. The residue was boiled in a mixture of 42 parts of 2,2'-oxybispropane and 42 parts of petroleumether. The product was filtered off and crystallized from 2,2'-oxybispropane, yielding 1.27 parts of α-(3-bromopropyl)-4-fluoro-α-(4-fluorophenyl)benzeneacetic acid; mp. 161° C. (intermediate 16).

Source