Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Pyrido (2,3-B) pyrazine derivatives
 A compound of the formula: ##STR1## wherein R.sup.1 is pyridyl(lower)alkyl, N-oxidopyridyl(lower)alkyl or imidazolyl(lower)alkyl, PA0 R.sup.2 is aminophenyl, [protected amino]phenyl, [[[halophenyl](lower)alkenoyl]amino]phenyl, [[pyridyl(lower)alkenoyl]amino]phenyl, [[[N-oxidopyridyl](lower)alkenoyl]amino]phenyl, [[[protected aminopyridyl](lower)alkenoyl]amino]phenyl, [thiazolylcarbonylamino]phenyl which may have pyridyl, naphthyl having lower alkoxy and halogen, [dihalophenyl](lower)alkenyl, [N-oxidopyridyl](lower)alkenyl, [aminopyridyl](lower)alkenyl, [protected aminopyridyl](lower)alkenyl, [carboxypyridyl](lower)alkenyl, [protected carboxypyridyl](lower)alkenyl, [[pyridyl(lower)alkenyl]pyridyl](lower)alkenyl, [[carboxy(lower)alkenyl]pyridyl](lower)alkenyl, [[protected carboxy(lower)alkenyl]pyridyl](lower)alkenyl, [pyridyl(lower)alkenyl]pyridyl, lower alkylbenzothiazolyl or [halopyridylcarbonyl]amino, PA1 with proviso that when R.sup.2 is [[4-pyridyl(lower)alkenoyl]amino]phenyl, aminophenyl, [lower alkanoylamino]phenyl or [dihalophenyl](lower)alkenyl, then PA2 R.sup.1 is N-oxidopyridyl(lower)alkyl or imidazolyl(lower)alkyl, and a pharmaceutically acceptable salt thereof, which is useful as a medicament. 
Fujisawa Pharmaceutical Co., Ltd.
A A A A A A A A A C A Y A A A A A A A
A61P A61P A61P A61P A61P A61P A61P A61P A61P C07D A61P Y02P A61P A61P A61P A61P A61P A61P A61P
inventional inventional inventional inventional inventional inventional inventional inventional inventional inventional inventional additional inventional inventional inventional inventional inventional inventional inventional
Akihiko Norihiko Shinya
Sawada Shimazaki Watanabe