Synthesis and Reactions of α‐Bromo‐ N ‐alkoxyimidates

The reaction of alkyl hydroxamates 2 with (C 2 H 5 ) 3 O · BF 4 in CH 2 Cl 2 affords N ‐alkoxyimidates 3 . The direct alkylation of hydroxamic acids 1 with 1,2‐dibromoethane gives the 5,6‐dihydro‐1,4,2‐dioxazine derivatives 4 . The reactions of the acyclic imidates 3 as well as the cyclic N ‐alkoxyimidates 4 with N ‐bromosuccinimide in CCl 4 produces the α‐bromoimidates 5a – d and 6a – d . The α‐bromine atom in the bromides 5b , d and 6a , b , d can be displaced by fluorine and azido substituents to yield the α‐fluoro‐ N ‐alkoxyimidates 7b , d and 10a , b , d and the α‐azido compounds 8b , d and 11a , b , d , respectively. The reduction of the azides 8b , d and 11a , b , d affords the α‐aminoimidates 9b , d and 12a b , d , respectively. The reaction of the bromides 6a – d with benzene derivatives 14a – d in the presence of AgBF 4 affords the aromatic substitution products 15a – d . Acid‐catalyzed hydrolysis of 15a , c gives the arylsubstituted carboxylic acids 16 and 17 .