Piperazine and homopiperazine derivatives, pharmaceutical compositions containing them and process for preparing the same

The lipid peroxidation inhibiting piperazine and homopiperazine derivatives of the general formula (I) and the pharmaceutically acceptable acid addition salts thereof, Lip stands for hydrogen; C15-20 alkyl; C10-20 alkanoyl or C10-20 alkenoyl; trityl optionally substituted by halogen; adamantyl; 1- or 2-naphthyloxy or oxo-substituted tetrahydronaphthyloxy; or an amine protective group commonly used e.g. in the peptide chemistry; A and A are selected independently from the group consisting of a single bond and C2-3 alkylene optionally substituted by hydroxy or oxo; n is 1 or 2; and Het represents a group of the general formula (a), wherein R is amino or 1-pyrrolidinyl; or a 4-chloro-3-oxo-2,3-dihydro-5-pyridazinyl group of the formula (b); or a 4-amino-6,7-dimethoxy-2-quinazolinyl group of the formula (c); or a 4,7-diamino-6-phenyl-2-pteridinyl group of the formula (d); or a 2,7-diamino-6-phenyl-4-pteridinyl group of the formula (e); or a 2,4,7-triamino-6-pteridinylcarbonyl group of the ormula (f);