Sodium Hydroxide → 1-Butoxy-2-(3-bromopropylamino)-1-cyclobutene-3,4-dione

Solid 3-bromopropylamine hydrobromide (31.0 g, 0.1416 mole) was added with stirring to a solution of sodium hydroxide (5.77 g, 0.140 mole) in methanol (152 mL) and stirred at ambient temperature for 15 minutes. The solution was cooled to 0°-5° C. and then added with stirring to the solution of Step A. The mixture was stirred at 22° C. for 1.5 hours then concentrated under reduced pressure (40° C.) to about 120 mL volume. Toluene (120 mL) was added and the mixture was washed with water (240 mL). The organic layer was dried (sodium sulfate), filtered, and the solvent was evaporated under reduced pressure to give 38.64 g (95.0 % yield) of the title compound as an off-white solid. The product was used without further purification in the subsequent reaction.

1. temperatureThe solution was cooled to 0°-5° C.
2. additionadded
3. stirringThe mixture was stirred at 22° C. for 1.5 hours
4. concentrationthen concentrated under reduced pressure (40° C.) to about 120 mL volume
5. additionToluene (120 mL) was added
6. washthe mixture was washed with water (240 mL)
7. dry with materialThe organic layer was dried (sodium sulfate)
8. filtrationfiltered
9. customthe solvent was evaporated under reduced pressure

ORD record

ord-7c269784d08a48ceb0a47cb800ec50a2

Source dataset

uspto-grants-1990_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04927970