The present invention concerns the manufacturing method of pyrimidoisoquinoline derivatives or their salts. The present inventive pyrimidoisoquinoline derivatives or and pharmaceuticaliy acceptable salts thereof can be showed by the following structural formula. wherein R<1> is hydrogen, halogen or lower alkyl, R<2> is amino, nitro or acylamino and R<3> is carboxy or protected carboxy. The salts of pyrimidoisoquinoline(I) useable as medication contain salts of inorganic alkali or organic alkali(such as natrium salt, kalium salt, ethanolamine salt, 3(hydroxymethyl)-methyl ammonium salt and so on) and acid added salt(such as hydrochloric acid salt etc.). |