Regioisomer formation has to be considered in the preparation of quinoxalines having different substituents at the 2- and 3-position. Oxalomonoimidic acid dimethyl ester or oxalompnoimidic acid diethyl ester, chloro(methyl- , imino)acetic acid ethyl ester, chloro[(Z)-hydroxyimino]acetic acid ethyl ester and (Z)-2-[(E)-hydroxyimino]acetohydroximoyl chloride were applied to the synthesis of 3-aminoquinoxalin-2(1H)-one derivatives, and the isomer ratio was investigated concerning the reactivity of the ring-closure reagent. The structures of reaction products . were identified using 1H, 13C and 15N NMR techniques. A direct synthesis of quinoxaline-2,3(1H,4H)-dione 3-oximes is described.
|Number of pages||5|
|Journal||Journal of the Chemical Society - Perkin Transactions 1|
|Publication status||Published - Dec 1 1999|
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