申请人:ELI LILLY AND COMPANY
公开号:EP0018144A1
公开(公告)日:1980-10-29
A process for the preparation of substituted 2-aminopyrazines is described, of the formula
wherein
R1 is hydrogen or C1-C4 alkyl;
R2 is hydrogen, halo, C,-C3 alkyl, or trifluoromethyl;
n is 0, 1, or 2, with the proviso that when n=2, only one ortho position may be substituted; and
R3 is C1-C4 alkyl, which comprises cyclizing a hydroxyimino-substituted aminoacetonitrile of the following formula
wherein R1, R2, R3, and n have the same values as set forth hereinbefore, with an acid selected from the group consist ing of polyphosphoric acid, about 85% phosphoric acid and a mixture of phosphoric acid with phosphorus pent oxide.
描述了一种制备取代的 2-氨基吡嗪的工艺,其式为
式中
R1 是氢或 C1-C4 烷基;
R2 是氢、卤代、C,-C3 烷基或三氟甲基;
n 是 0、1 或 2,但当 n=2 时,只能取代一个正交位置;以及
R3 是 C1-C4 烷基,其中包括环化下式的羟基亚氨基取代的氨基乙腈
其中 R1、R2、R3 和 n 的值与前文所述相同,用选自聚磷酸、约 85%磷酸和磷酸与五氧化磷混合物的酸。