Abstract
An expeditious and practical method for the reduction of amides
to amines is reported. The method is consisted of activation of
amides with Tf2 O followed by reduction with sodium borohydride
in THF at room temperature. Various amides/lactams gave
the corresponding amines in good to excellent yields, even with
hindered amides and secondary amides. This method also presents
other advantages such as TBDPS-group tolerance, short reaction time, simple
workup and purification procedure.
Key words
reduction - amides - amines - amide
activation - triflic anhydride
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General
Procedure for the Preparation of Amines from Amides
To
a solution of an amide (1.0 mmol) in anhyd CH2 Cl2 (10 mL)
was added Tf2 O (1.1 mmol) in an ice bath. After stirring for
30 min, NaBH4 (1.3 mmol) was added in one portion, and THF
(5 mL) was added dropwise. After stirring for 60 min at r.t., the
reaction was quenched with H2 O (5 mL). The solution was
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