1,3-Dibromopropane → 4(3-Bromopropylthio)-gamma-oxobenzenebutanoic acid

Temperature

25 °C

A mixture of the product of Example 1, Step E (5 g), 1,3-dibromopropane (20 g) and K2CO3 (10 g) was refluxed in methylethylketone (100 ml) for 20 hours. The cooled reaction mixture was filtered, the solvent evaporated and the residue purified by chromatography over silica gel. The resulting ester of the title compound was hydrolyzed by dissolving in a mixture of 25 ml of methanol and 15 ml of 1N NaOH and stirring at 25° C. for 4 hours. The reaction mixture was diluted with 100 ml of water, acidified with citric acid and extracted with 2×100 ml of EtOAc. The combined organic layers were washed with brine, dried over Na2SO4 and evaporated to yield the title compound which was sufficiently pure for use in the next step, m.p. 91°-94°.

1. customThe cooled reaction mixture
2. filtrationwas filtered
3. customthe solvent evaporated
4. customthe residue purified by chromatography over silica gel
5. dissolutionby dissolving in a mixture of 25 ml of methanol and 15 ml of 1N NaOH
6. additionThe reaction mixture was diluted with 100 ml of water
7. extractionextracted with 2×100 ml of EtOAc
8. washThe combined organic layers were washed with brine
9. dry with materialdried over Na2SO4
10. customevaporated

ORD record

ord-952951c35a474d32985220bdea40cbaf

Source dataset

uspto-grants-1992_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05135940