Abstract: New pyrazolo-pyrrolo-pyrimidine-dione (PPPD) compounds of formula (I), ##STR1## where R.sub.1, R.sub.2, R.sub.3, R.sub.4 and m are as defined in the specification, e.g., 4-(benzoylmethyl)-6-cyclohexyl-6,7-dihydro-2-phenyl-4H-pyrazolo[1,5-a]pyrr olo[3,4-d]pyrimidine-5,8-dione, have been found to be potentially useful to treat warm-blooded animal patients suffering from the symptoms of atherosclerosis and cholesterol buildup to relieve the same and for favorably altering the high density lipoprotein (HDL) to low density lipoprotein (LDL) ratio in blood samples of such patients.

Abstract: A compound of the formula: ##STR1## (wherein R is --SO.sub.2 R.sup.1 or --CONHR.sup.2 ; R.sup.1 is C.sub.1 -C.sub.5 alkyl, C.sub.8 -C.sub.12 phenylalkenyl, amino, dimethylamino, optionally substituted C.sub.8 -C.sub.12 aryl, or 5- or 6-membered heterocyclic group including at least one hetero atom selected from the group consisting of N, S, and O; R.sup.2 is amino, C.sub.1 -C.sub.8 alkylamino, C.sub.1 -C.sub.8 alkyl, or optionally substituted C.sub.8 -C.sub.12 aryl) or its pharmaceutically acceptable acid-addition salt, being useful as a drug for senile dementia, psychotropic, or antiamnesia agent is provided through several routes.