Benzyl chloroformate → Benzyl 3-bromopropylcarbamate

A solution of 3-bromopropylamine hydrobromide (547.5 g, 2.5 mol) in 500 mL of toluene and 600 mL of water was cooled to 6° C. and then aqueous potassium carbonate (1L, 5M, 5 mol) and benzyl chloroformate (1L, 2.63 mol) were added simultaneously at a rate such that the reaction temperature remained below 16° C. The mixture was allowed to warm to room temperature and then stirred for 80 minutes and 1.3L of additional water was added. The aqueous later was separated and extracted with toluene (1×300 mL). The combined organic layers were washed with 1N hydrochloric acid (2×300 mL), saturated sodium bicarbonate (1×300 mL) and saturated aqueous sodium chloride (1×300 mL), dried (Na2SO4) and filtered. The filtrate was concentrated under reduced pressure and the residue was extracted with hexanes (3×1L). The extract was concentrated under reduced pressure at 50° C. to give benzyl (3-bromopropyl)aminoformate (612.9 g, 2.25 mol) as a liquid.

1. customremained below 16° C
2. customThe aqueous later was separated
3. extractionextracted with toluene (1×300 mL)
4. washThe combined organic layers were washed with 1N hydrochloric acid (2×300 mL), saturated sodium bicarbonate (1×300 mL) and saturated aqueous sodium chloride (1×300 mL)
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. concentrationThe filtrate was concentrated under reduced pressure
8. extractionthe residue was extracted with hexanes (3×1L)
9. concentrationThe extract was concentrated under reduced pressure at 50° C.

ORD record

ord-88f5cc1e3dc24140868011f18a4e074e

Source dataset

uspto-grants-1997_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05688795