The invention relates to compounds of the general formulae
in which R1, R2, R3, R4 and x have the meaning defined in the specification. These compounds are valuable novel intermediates for the preparation of novel 1,2-dihydropyrido[3,4-b]-pyrazines.
本发明涉及通式如下的化合物
其中 R1、R2、R3、R4 和 x 具有说明书中定义的含义。这些化合物是制备新型 1,2-
二氢吡啶并[3,4-b]-
吡嗪的重要新型中间体。