Reductive amination with zinc powder in aqueous media

Abstract

SummaryZinc powder in aqueous alkaline media was employed to perform reductive amination of aldehydes with primary amines. The corresponding secondary amines were obtained in good yields along with minor amounts of hydrodimerization byproducts. The protocol is a green alternative to the use of complex hydrides in chlorinated or highly flammable solvents.

Butenafine and analogues: An expeditious synthesis and cytotoxicity and antifungal activities

“…HRMS (ESI): m / z observed: 248.1394; C 18 H 17 N [M+H] + requires: 248.1439; error (ppm): 1.8. Data for 4ad are in accordance with those reported elsewhere [48] .…”

Transfer hydrogenative reductive amination of aldehydes in aqueous sodium formate solution

“…Addition of 0.5 equiv of HCO 2 H produced 40% of 5 and 19% of 6 (entry 2). Under these conditions, the selectivity toward the desired amine product over benzyl alcohol was inferior, however, delightful results were observed after adding additional HCO 2 H. The selectivity of 5 versus 6 was enhanced as more HCO 2 H was added, however, the tradeoff was that the conversion of benzaldehyde was reduced (entry [4][5][6][7][8][9][10][11]. This phenomenon indicates that the hydrogenation of benzaldehyde was significantly suppressed at lower pH, whereas the reverse reaction of imine formation was accelerated under the same conditions.…”

“…Afterward, several groups have developed different methods of aqueous reductive amination based on either hydride reagents or hydrogenation using gaseous H 2 . [6][7][8][9][10][11] However, these reactions usually suffer some drawbacks, such as the requirement of high temperatures and moderate to high pressures, or poor atom economy. Xiao and co-workers [12][13][14][15][16] have pioneered in the catalytic transfer hydrogenation reactions in water.…”

New potential of the reductive alkylation of amines

“…This reaction is most efficient for aromatic aldehydes and aniline and benzylamine derivatives; the reaction of aliphatic aldehydes and amines leads to lower yields of target products. 28 …”