Methylparaben → Methyl 4-(allyloxy)benzoate

To a nitrogen flushed 5 L three neck round bottom flask fitted with a mechanical stirrer, condenser, and a nitrogen inlet was charged 608 g (4 mol of methyl 4-hydroxybenzoate, 520 ml (727 g, 6.00 mol, 1.5 eq) of allyl bromide, 663 g (9.6 mol of anhydrous potassium carbonate, and 2.3 L of acetone. The mixture was refluxed with vigorous stirring for 90 min. Additional potassium carbonate, (50 g) was added, and 25 g added again after an additional 50 min. After 20 min (total reaction time of 160 min), the suspension was allowed to cool to ambient temperature and stirred overnight. The mixture was filtered and the cake washed with 3 L of acetone. The solution was concentrated to obtain 788.6 g (theoretical yield 768.9 g) of a pale yellow, almost colorless oil which was used without purification in the next step. The product was a single spot on TLC (silica-1:1 EtOAc/Hex) and the NMR was consistent with methyl 4-allyloxybenzoate.

1. customTo a nitrogen flushed 5 L three neck round bottom flask
2. customfitted with a mechanical stirrer, condenser, and a nitrogen inlet
3. temperatureThe mixture was refluxed
4. addition25 g added again after an additional 50 min
5. waitAfter 20 min (total reaction time of 160 min)
6. stirringstirred overnight
7. filtrationThe mixture was filtered
8. washthe cake washed with 3 L of acetone
9. concentrationThe solution was concentrated
10. customto obtain 788.6 g (theoretical yield 768.9 g) of a pale yellow, almost colorless oil which
11. customwas used without purification in the next step

ORD record

ord-5cc668b0149c47dfa6ea35cd2e14f536

Source dataset

uspto-grants-1996_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05538991