Thiazine derivatives and preparation thereof

Abstract

Thiazine derivatives of the formula [I]: ##STR1## wherein R.sup.1 and R.sup.2 are both H or form a naphthalene ring together with the benzene ring; R.sup.3 and R.sup.4 are both H, or one of them is halogen and another is H; X is S or O; R.sup.5 and R.sup.6 are each i) H, ii) lower alkyl, iii) cycloalkyl, iv) substituted phenyl, v) naphthyl, vi) lower alkyl which is substituted by substituted or unsubstituted phenyl, or vii) S-containing heterocyclic group; one of Z.sup.1 and Z.sup.2 is O and another is H.sub.2 ; A is lower alkylene; R.sup.7 and R.sup.8 are each i) H, ii) lower alkyl, iii) lower alkenyl, iv) lower alkynyl, or v) lower alkyl which is substituted by substituted or unsubstituted phenyl, or both form together N-containing heterocyclic group; provided that when both of R.sup.1 and R.sup.2 are H, Z.sup.2 is O and either one of R.sup.5 and R.sup.6 is substituted phenyl, naphthyl or S-containing heterocyclic group, or their salts, which have calcium antagonistic activity within the cerebral tissues and are useful for prophylaxis and treatment of ischemic encephalopathia and/or cerebral neurocyte dyscrasia, and process for preparing said compounds.