Dibutylamine → Methyl 4-(3-(dibutylamino)propoxy)benzoate

A solution of the mixture of methyl 4-(3-bromopropoxy)benzoate [17a] methyl 4,4′-[1,3-propanediylbis(oxy)]bisbenzoate [20] previous step (19.12 g) and dibutylamine (27.14 g, 35.7 mL, 210 mmol) in toluene (50.0 mL) was stirred under reflux conditions for 3 hours, cooled and extracted with 15% hydrochloric acid (3×40 mL). The combined aqueous layers were washed with of toluene (50 mL), basified to pH 8.5 with sodium bicarbonate and extracted with toluene (3×30 mL). The combined organic layers were dried over sodium sulfate, filtered and evaporated under reduced pressure at 60° C. (water bath). The residue was dissolved in hexane and passed through thin layer of silica gel. The solvent was evaporated under reduced pressure at 50-60° C. (water bath) to give 14.71 g (61.1% yield from 2 steps) of methyl 4-(3-dibutylaminopropoxy)benzoate [18a] as an oil.

1. temperaturecooled
2. extractionextracted with 15% hydrochloric acid (3×40 mL)
3. washThe combined aqueous layers were washed with of toluene (50 mL)
4. extractionextracted with toluene (3×30 mL)
5. dry with materialThe combined organic layers were dried over sodium sulfate
6. filtrationfiltered
7. customevaporated under reduced pressure at 60° C. (water bath)
8. dissolutionThe residue was dissolved in hexane
9. customThe solvent was evaporated under reduced pressure at 50-60° C. (water bath)

ORD record

ord-3e056dd5031b4a8dbee48c7ba1e8014d

Source dataset

uspto-grants-2007_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07312345B2