Anticoccidials. VI. An improved synthesis of 1,6-dihydro-6-oxo-2-pyrazinecarboxylic acid 4-oxide and some related derivatives and determination of anticoccidial activity.

Abstract

1,6-Dihydro-6-oxo-2-pyrazinecarboxylic acid 4-oxide (1) was synthesized by 2 different methods. The first is a hydrolysis of methyl 6-chloro-2-pyrazinecarboxylate 4-oxide, which was in turn obtained from methyl 6-chloro-2-pyrazinecarboxylate by reaction with m-chloroperbenzoic acid. The 2nd is an oxidation of 6-hydroxymethyl- 2(1H)-pyrazinone 4-oxide with nickel peroxide. Compound 1 was converted to amine salts, esters and amides. 6-Methoxy, 6-mercapto and 1-alkyl derivatives were also prepared. The compounds prepared were tested for anticoccidial activity in chickens against Eimeria tenella and marked activity was seen with compound 1 and amine salts of 1. The activity of 1 was counteracted by the simultaneous administration of an equal weight of orotic acid or adenine.