The present invention provides pyrazine derivatives of formula Iand pharmaceutically acceptable salts thereof, wherein the designation of R1, R2, R3 and R4 is provided herein. The invention also provides syntheses for preparation of such compounds. The invention further provides methods of use of these compounds and pharmaceutical compositions containing them for treatment and/or prevention of diseases and for manufacture of medicaments. These compounds and pharmaceutical compositions have antioxidative and thrombolytic effects, and thus can be used for the treatment and/or prevention of cerebral stroke caused by ischemia, and used for manufacture of medicaments for the treatment and/or prevention of nervous system diseases caused by excessive amount of radicals and/or thrombosis, infectious diseases, metabolic system diseases, cardiovascular and cerebrovascular diseases, and age-related degenerative diseases.
