NITROGEN DERIVATIVE OF OXO COMPOUND, MANUFACTURE AND MEDICINE

Compounds of the formula in which R1 and R2 independently of one another denote hydrogen, lower alkyl or aryl or, taken together, denote lower alkylene, one of the radicals R3 and R4 represents the group =N-R (Ia), in which R represents the group -O-Ra (Ib) and Ra represents hydrogen, lower alkyl, carboxy-lower alkyl or lower alkoxycarbonyl-lower alkyl or R represents the group -N(Rb)-Rc (Ic) and Rb and Rc independently of one another represent hydrogen or lower alkyl or one of the radicals Rb and Rc represent hydrogen and the other radical represents the group -C(=X)-Rd, in which X denotes oxo and Rd denotes lower alkoxy, di-lower alkylamino-lower alkyl, tri-lower alkylammonio-lower alkyl, lower alkyleneamino-lower alkyl, oxa-lower alkyleneammonio-lower alkyl, thia-lower alkyleneamino-lower alkyl, aza-lower alkyleneamino-lower alkyl which is optionally aza-substituted by lower alkyl or denotes pyridinio-lower alkyl or X denotes oxo or thioxo and Rd denotes amino, or both radicals Rb and Rc, taken together, denote lower alkylene, oxa-lower alkylene, thia-lower alkylene or aza-lower alkylene which is optionally aza-substituted by lower alkyl, and the other of the two radicals R3 and R4 has the same meanings or denotes oxo, and the ring A has no other substituents or is additionally substituted by lower alkyl, lower alkoxy and/or halogen, and salts of compounds of this type have salt-forming properties are active in retrovirus-induced Rauscher leukaemia of the mouse and can therefore be used therapeutically, for example in the control of immune diseases or autoimmune diseases likewise caused by retroviruses.