Ammonia → (RS)-1-(3,5-Difluorophenyl)ethylamine

Participants

Reaction Steps

To a stirred mixture of 3′,5′-difluoroacetophenone (86.8 g, 0.556 mol) and 2 M NH3 in EtOH (1.4 L, 2.8 mol) was added titanium(IV) isopropoxide (326 mL, 1.11 mol) dropwise over 15 min stirring was continued at ambient temperature for 20 h. The mixture was cooled in an ice-water bath and sodium borohydride (31.5 g, 0.834 mol) was added in portions over 60 min. The reaction mixture was stirred for an additional 1 h, and then quenched with aqueous NH4OH (2 M, 1.3 L) followed by EtOAc (1 L). The resulting mixture was aged for 18 h and filtered through a pad of celite, washing with EtOAc (1 L). To the filtrate was added EtOAc (2 L) and H2O (1 L) containing NaCl (ca. 100 g). The mixture was shaken and allowed to separate. The organic layer was concentrated in vacuo to a volume of about 500 mL and partitioned between EtOAc (2 L) and saturated aqueous Na2CO3 (300 mL). The organic layer was dried (Na2SO4), filtered, and concentrated in vacuo to give the title compound. MS: m/z=182 (M+CH3CN−NH2).

Provenance & Evidence