Generation of 6-alkylidene/benzylidene-3,6-dihydropyrazin-2(1H)ones by reaction of 6-bromomethylpyrazin-2(1H)-ones with methoxide and further conversion into specific piperazine-2,5-diones and pyrazin-2(1H)-ones

Abstract

3-Aryl-, 3-benzyl- and 3-methoxy-6-(1-bromoalkyl/benzyl)-5-chloropyrazin-2(1H)-ones 6 have been synthesised and converted into new 6-alkylidene/benzylidene-5-chloro-3,6-dihydropyrazin-2(1H)-ones 7 by reaction with methoxide in THF. With 2 equiv. of alkoxide the corresponding 5-alkoxy derivatives 8 were obtained. Reaction of compounds of type 6, 7 or 8 with various nucleophiles generated 3,6-dihydropyrazin-2(1H)-ones, piperazine-2,5-diones and pyrazin-2(1H)-ones.