Abstract: 5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivatives represented by the following general formula [I] ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are either the same or different and mean individually a hydrogen atom or lower alkyl group, Y denotes a specific phenyl-containing substituted amino group, and their salts. These compounds have excellent immuno-modulating activities.

Abstract: A compound of the formula ##STR1## wherein Z is N or NH, is a single or double bond, R.sub.1 is hydrogen, C.sub.1-20 alkyl or optionally substituted phenyl, A is lower alkylene, R is carboxyl, lower alkoxycarbonyl, ##STR2## or 1-cycloalkyl-tetrazole-5-yl, R.sub.2 is lower alkyl, hydroxy-lower alkyl or optionally substituted phenyl-lower alkyl, R.sub.3 is lower alkyl or cycloalkyl, or R.sub.2 and R.sub.3 together constitute ##STR3## and R.sub.5 and R.sub.6 are hydrogen or optionally substituted phenyl, or a pharmacologically acceptable salt thereof, has platelet aggregation inhibitory activity and/or cyclic AMP/phosphodiesterase inhibitory activity.

Abstract: A compound of the formula ##STR1## wherein R.sup.1 is hydrogen or lower alkyl, R.sup.2 is hydrogen, lower alkoxy or halogen, and A is lower alkylene, or a pharmacologically acceptable salt thereof, has sympatholytic .alpha.-receptor blocking activity and is useful for the treatment of hypertension.

Abstract: 5,6-dihydroimidazo[2,1-b]thiazole-2-carboxamide derivatives represented by the following general formula [I] ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are either the same or different and mean individually a hydrogen atom or lower alkyl group, Y denotes a specific phenyl-containing substituted amino group, and their salts. These compounds have excellent immuno-modulating activities.

Abstract: A method for inhibiting blood platelet aggregation in humans, and promoting vasodilation in humans, by administering to a human in need of the same an effective amount of 2-hydroxy-3-isopropyl-5,6-dimethylpyrazine or a hydrate or a pharmaceutically acceptable non-toxic salt thereof. Administration can be orally in an amount of about 0.02-12 mg/kg body weight per day, or parenterally in an amount of about 0.01-6 mg/kg of body weight per day.

Abstract: Compounds of the formula wherein R is ##STR1## in which R.sub.1, R.sub.2 and R.sub.3 are the same or different and are selected from the group consisting of hydrogen, chlorine, bromine, lower alkyl, lower alkoxy and naphthyl, provided that when R.sub.1 is lower alkyl, R.sub.2 and R.sub.3 are hydrogen, chlorine, bromine or lower alkoxy, or a pharmaceutically acceptable salt thereof, have anti-carrageenin edema activity, and are useful as anti-inflammatory agents and immuno modulators. They are produced by reacting an amide of the formula ##STR2## wherein R has the same meanings hereinabove, with N,N'-ethylene thiourea.

Abstract: Compounds of the formula ##STR1## wherein R is ##STR2## in which R.sub.1, R.sub.2 and R.sub.3 are the same or different and are selected from the group consisting of hydrogen, chlorine, bromine, lower alkyl, lower alkoxy and naphthyl, provided that when R.sub.1 is lower alkyl, R.sub.2 and R.sub.3 are hydrogen, chlorine, bromine or lower alkoxy, or a pharmaceutically acceptable salt thereof, have anti-carrageenin edema activity, and are useful as anti-inflammatory agents and immuno modulators. They are produced by reacting an amide of the formula ##STR3## wherein R has the same meanings hereinabove, with N,N'-ethylene thiourea.