Allyl bromide → 3-Pent-4-enoyl-benzoic acid methyl ester

Temperature

100 °C

To a stirred solution of 3-tert-butoxycarbonylacetyl-benzoic acid methyl ester (11.1 g) and allyl bromide (3.0 mL) in DMF (40 mL) was added portionwise at 0° C. NaH (55% dispersion in mineral oil, 1.44 g). Stirring was continued at 0° C. for 20 min and at 20° C. for 30 min. The mixture was partitioned between AcOEt and brine, the pH being set to 7 by the addition of 3N HCl. The organic layer was dried and evaporated. The residual oil was stirred in a mixture of CH2Cl2 (30 mL) and TFA (30 mL) for 40 min at 20° C. The solvents were evaporated. The solution of the residue in AcOEt was extracted with ice-cold sat. Na2CO3 solution and the aqueous extracts were immediately acidified with 3N HCl and extracted with AcOEt. The solvent of this extract was evaporated and the residue heated in a mixture of toluene (40 mL) and 3N HCl (2 mL) to 100° C. for 1 h. The cooled mixture was diluted with AcOEt, washed with sat. NaHCO3 and brine, dried and evaporated to give 3-pent-4-enoyl-benzoic acid methyl ester (5.11 g) as a pale-yellow oil, MS (ISP) 236.2 [(M+NH4)+].

1. customThe mixture was partitioned between AcOEt and brine
2. additionthe pH being set to 7 by the addition of 3N HCl
3. customThe organic layer was dried
4. customevaporated
5. stirringThe residual oil was stirred in a mixture of CH2Cl2 (30 mL) and TFA (30 mL) for 40 min at 20° C
6. customThe solvents were evaporated
7. extractionThe solution of the residue in AcOEt was extracted with ice-cold sat. Na2CO3 solution
8. extractionextracted with AcOEt
9. customThe solvent of this extract was evaporated
10. additionThe cooled mixture was diluted with AcOEt
11. washwashed with sat. NaHCO3 and brine
12. customdried
13. customevaporated

ORD record

ord-2d16438fd10b4e98934d2f789112620b

Source dataset

uspto-grants-2003_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06544985B2