A new general approach to the 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one skeleton via diisobutylaluminum hydride reduction of 2,3-dioxo-1,4-benzoxazines

Article abstract of DOI:10.1055/s-1993-25936

A series of naturally occurring hemiacetals 2a-d was synthesized by the chemoselective diisobutylaluminum hydride reduction of 2,3-dioxo-4H-1,4-benzoxazines 1a,b and their N-hydroxy derivatives 1c,d precursors. The procedure described represents a new general approach to the 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one skeleton giving rise to the bioactive natural hydroxamic acids 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (2c) and 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (2d) in only three steps starting from nitrophenols.