Enhancing reductive cleavage of aromatic carboxamides.
[reaction: see text] A set of aromatic and especially heteroaromatic N-benzyl carboxamides, derived from naphthalene, pyridine, pyrazine, and quinoline, and the corresponding tert-butyl acylcarbamates have been synthesized and studied by cyclic voltammetry with respect to facilitated reduction. The latter undergo regiospecific cleavage of their C(O)-N bonds under very mild reductive conditions with formation of Boc-protected (benzyl)amine in most cases in nearly quantitative yields. Examples of preparative cleavage by controlled potential electrolysis, activated aluminum, and NaBH(4) are given.
Ragnarsson
U
U
Department of Biochemistry, University of Uppsala, Biomedical Center, PO Box 576, SE-751 23 Uppsala, Sweden. urbki@bmc.uu.se
Grehn
L
L
Maia
H L
HL
Monteiro
L S
LS