105623-61-8

A naturally occurring cyclic hydroxamic acid, isolated from Pseudomonas species, and its analogues were synthesized via six steps starting from 2-hydroxy-3-methoxypyridine.The antimicrobial activity of the synthesized compounds is described.

6-Alkoxy-5,6-dihydro-4H-1,2-oxazines (2) and (5) have been prepared by the reaction of chloro oximes (1) with enol ethers in the presence of sodium carbonate.The 3-phenyloxazine (2) rearranges to the nitrone (3) in methanolic HCl.In contrast, the 3-acyloxazines (5a-e) are converted into 3-alkoxypyridine 1-oxides (7) in aqueous alcoholic HCl.With HCl in acetic acid the oxazine (5a) is converted into 2-chloromethyl-3-hydroxypuridine hydrochloride (10a); analogous reactions take place with oxazines (5b) and (5d).Possible mechanisms for these reactions are discussed.