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Some 3-[(alkylthio)methyl]quinoxaline 1-oxide derivatives (1) have been synthesized and screened for antibacterial activity. 2-Acetyl-3-[(methylsulfonyl)methyl]quinoxaline 1-oxide (7a) was found to possess good in vitro activity against some pathogens important to veterinary medicine including Treponema hyodysenteriae, a causative agent in swine dysentery. In an in vivo experiment, this compound (7a) completely protected pigs against a swine dysentery challenge over a 21-day period.

A convenient, large‐scale synthesis of the antibiotic pyoluteorin, 2,3‐dichloro‐5‐(2′,6′‐dihydroxybenzoyl)‐pyrrole (1), is described. A key step in the synthesis involved a Friedel‐Crafts aroylation of pyrrole with 2,6‐dimethoxybenzoyl chloride (3) in methylene chloride. The desired intermediate, 2‐(2′,6′‐dimethoxybenzoyl)pyrrole (4), was obtained as the major product, along with a product of beta substitution (6). Compound 4 was converted to pyoluteroin (1) in four steps in an overall yield of 51%.