Pharmacologically active thiadiazole guanidine compounds

A compound of the formula:

• ##STR15## wherein A is such that there is formed together with the carbon atom shown an unsaturated heterocyclic nucleus, said unsaturated heterocyclic nucleus being a ring;
• X.sub.1 is hydrogen, lower alkyl, hydroxyl, trifluoromethyl, benzyl, halogen, amino or ##STR16## X.sub.2 is hydrogen or when X.sub.1 is lower alkyl, lower alkyl or halogen, k is 0 to 2 and m is 2 or 3, provided that the sum of k and m is 3 or 4;
• Y is oxygen, sulphur or NH;
• E is NR.sub.2 ;
• R.sub.1 is hydrogen, lower alkyl or di-lower alkylamino-lower alkyl;
• and R.sub.2 is hydrogen, nitro or cyano, or a pharmaceutically acceptable addition salt thereof.