A new procedure for the synthesis of 2-amino-3-cyano-5-substituted pyrazines 9, useful intermediates for the synthesis of pteridines, is described. Oximation of@-keto esters 2 followed by reaction with aminomalononitrile provides 2-amino-6-carbalkoxy-3-cyano-5- substituted pyrazine 1-oxides 5. Protection of the amino group as its ((dimethy1amino) methylene) amino derivative 9 followed by SN~ decarbalkoxylation provides pyrazines 10 ...