Putrescine Dihydrochloride → N'-(2,4-difluorophenyl)butane-1,4-diamine

Temperature

110 °C

1,4-Diaminobutane dihydrochloride (0.97 g, 6 mmol), sodium t-butoxide (1.87 g, 19.5 mmol), rac-BINAP (61.0 mg, 0.09 mmol), and Pd(dba)2 (35.0 mg, 0.06 mmol) are charged to a flame dried screw-cap vial. The vial is vacuumed and back filled with nitrogen. Then anhydrous toluene (15 mL) is added, followed by the addition of 1-bromo-2,4-difluorobenzene (0.34 mL, 3.00 mmol). The mixture is stirred under nitrogen at 110° C. overnight. The reaction mixture is diluted with 80 mL of diethyl ether and filtered through a pad of celite 545. The filtrate is extracted with 6N aqueous HCl (10 mL×3). The combined aqueous layers are washed twice with diethyl ether and adjusted with 1M aqueous NaOH to pH>12. The aqueous layer was extracted with diethyl ether three times. The combined ether phase is dried over anhydrous Na2SO4, filtered, and concentrated to obtain N′-(2,4-difluorophenyl)butane-1,4-diamine as a brown oil: 1H NMR (CDCl3) δ 1.55 (m, 2H), 1.66 (m, 2H), 2.74 (t, 2H), 3.12 (t, 2H), 6.55 (m, 1 H), 6.73 (m, 2H).

1. customdried
2. customscrew-cap vial
3. additionback filled with nitrogen
4. additionThen anhydrous toluene (15 mL) is added
5. filtrationfiltered through a pad of celite 545
6. extractionThe filtrate is extracted with 6N aqueous HCl (10 mL×3)
7. washThe combined aqueous layers are washed twice with diethyl ether
8. extractionThe aqueous layer was extracted with diethyl ether three times
9. dry with materialThe combined ether phase is dried over anhydrous Na2SO4
10. filtrationfiltered
11. concentrationconcentrated

ORD record

ord-541bf923969d4d12853860da84c113ae

Source dataset

uspto-grants-2010_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07723343B2