Abstract: Novel pyrazolo[3,4-d]pyrimidine derivatives represented by the general formula (I) ##STR1## wherein R.sup.1 is an aryl or heteroaryl group which may be substituted by one to three members selected from the class consisting of halogen, C.sub.1-4 alkyl, C.sub.1-4 alkoxy, nitro, amino, N-C.sub.1-4 alkylamino, N,N-diC.sub.1-4 alkylamino, hydroxy, trifluoromethyl, carbamoyl, N-C.sub.1-4 alkylcarbamoyl and N,N-diC.sub.1-4 alkylcarbamoyl;R.sup.2 is C.sub.1-4 alkyl;R.sup.3 and R.sup.4 are independently hydrogen or C.sub.1-4 alkyl;R.sup.5 is hydrogen, C.sub.1-2 alkyl, C.sub.1-5 alkanoyl or C.sub.1-4 alkoxycarbonyl, the group R.sup.5 being attached at the 1- or 2-position of the pyrazole ring;X is C.sub.1-7 alkylene or a group of the formula:--(CH.sub.2).sub.m --Y--(CH.sub.2).sub.n --whereinm is 2 or 3,n is an integer of 0 to 3,and Y is oxygen, sulfur, imino or N-C.sub.

Abstract: Novel 3-aminopyrazolo[3,4-d]pyrimidine derivatives represented by the general formula (I) ##STR1## wherein R.sub.1 and R.sub.2 each represents an aliphatic hydrocarbon group; R.sub.3 and R.sub.4 each represents hydrogen, alkyl or acyl; R.sub.5 is alkyl, alkoxycarbonyl or formyl; and the dotted line designates the presence of two double bonds on the pyrazole ring, to which R.sub.5 is linked at either the 1- or 2-position and their salts, are useful for antiinflammatory, analgesic and antipyretic agents.

Abstract: Compounds of the formula ##STR1## wherein R is lower alkyl, and salts thereof. These compounds have excellent diuretic and antihypertensive actions in mammalian animals and are of use as therapeutic drugs for the treatment of edema and hypertension.

Abstract: Isoxazolo[3,4-d]pyrimidines of the formula ##STR1## wherein R.sup.1 and R.sup.2, respectively, are lower alkyl; R.sup.3 is lower alkyl or acyl; and R.sup.4 is hydrogen, lower alkyl, or acyl have antiflammatory, analgesic and antipyretic activities in mammals and low acute and subacute toxicities, as well. The compounds are particularly useful as an antiinflammatory, analgesic and antipyretic drug.

Abstract: Novel imidazole-5-acetic acid derivatives of the formula: ##STR1## wherein R.sup.1 is lower alkyl, cycloalkyl or, phenyl which may be substituted with one to three of halogen, nitro, amino, mono(lower alkyl)amino, di(lower alkyl)amino, lower alkyl, lower alkoxyl, benzyloxyl or/and hydroxyl; X.sup.1, X.sup.2 and X.sup.3 are each hydrogen, halogen, nitro, amino, lower alkyl, lower alkoxyl, benzyloxyl or hydroxyl; Y is halogen and R.sup.2 is hydrogen or lower alkyl; provided that X.sup.1 is halogen, lower alkyl, lower alkoxyl, benzyloxyl or hydroxyl when R.sup.1 is unsubstituted or substituted phenyl only with one halogen, di(lower alkyl)amino, lower alkyl or lower alkoxyl, and its salts have hypotensive activity.

Abstract: Novel imidazole derivatives of the formula: ##STR1## wherein R.sup.1 is lower alkyl or, phenyl-C.sub.1-2 alkyl which may be substituted with halogen or nitro;R.sup.2 is lower alkyl, cycloalkyl or, phenyl which may be substituted with halogen, lower alkyl, lower alkoxyl or di(lower alkyl)amino,one of R.sup.3 and R.sup.4 is of the formula: --(CH.sub.2).sub.n --COR.sup.5 in the formula R.sup.5 is amino, lower alkoxyl or hydroxyl and n is integer of 0, 1 or 2,and the other is hydrogen or halogen;provided that R.sup.1 is lower alkyl or phenethyl when R.sup.3 is halogen, n is 1 and R.sup.5 is lower alkoxyl or hydroxyl, and their salts have hypotensive activity.

Abstract: Novel N.sup.2 -substituted phenyl-2,6-diaminonebularines of the formula ##STR1## wherein either one of R.sup.1 and R.sup.2 is carbamoyl which may be substituted or acyl group and the other is hydrogen atom, halogen atom or lower alkoxyl group, and their acid addition salts have an excellent coronary vasodilator action.

Abstract: Compounds of the formula ##STR1## wherein R is a phenyl or cyclohexyl group which may be substituted by halogen, lower alkyl or lower alkoxy, or their acid addition salts, are produced in good yield by reacting a compound of the formula ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3, independently of each other, are a hydroxyl group which may be proctected, which is prepared in 2 or 3 steps from 5-amino-1-.beta.-D-ribofuranosylimidazole-4-carboxamide, with a compound of the formulaR--N.dbd.C.dbd.N--R.sup.4wherein R has the same meaning as defined above and R.sup.4 is hydrogen or the same group as R, and, if necessary, subjecting the resulting compound to a treatment for removal of protective groups on its hydroxyl groups.

Abstract: Novel N.sup.2 -substituted phenyl-2,6-diaminonebularines of the formula ##STR1## wherein R.sup.1 is halogen, lower alkyl or lower alkoxy and R.sup.2 is hydrogen, halogen, lower alkyl or lower alkoxy, and their acid addition salts have excellent coronary vasodilator action.

Abstract: Novel imidazole derivatives of the formula ##STR1## wherein R.sup.1 is hydrogen, nitro or amino, R.sup.2 is a phenyl, furyl or thieyl group which may be substituted by halogen, lower alkyl, lower alkoxy or di-lower-alkylamino, R.sup.3 is hydrogen or lower alkyl and X is halogen, and their physiologically acceptable salts, have excellent diuretic and hypotensive actions.

Abstract: Isoxazolo[3,4-d]pyrimidines of the formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3, respectively, are hydrogen, lower alkyl, cycloalkyl, or aryl which may be substituted by halogen, are useful as antiinflammatory-analgesic drugs, and the industrially feasible production thereof is provided.

Abstract: Isoxazolo[3,4-d]pyrimidines of the formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 respectively, are hydrogen, lower alkyl, cycloalkyl, or aryl which may be substituted by halogen, are useful as antiinflammatory-analgesic drugs, and the industrially feasible production thereof is provided.

Abstract: Novel 3-(disubstituted)aminoisothiazolo[3,4-d]pyrimidines of the formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are respectively alkyl, alkenyl, aryl, aralkyl or aralkenyl, each of which may be substituted, or R.sup.1 and R.sup.2 form together with the adjacent nitrogen a heterocyclic ring which may be substituted, R.sup.4 is hydrogen or alkyl and X is oxygen or imino with a proviso that when X is imino R.sup.4 is hydrogen, show an eminent adenosine-3',5'-cyclic phosphate phosphodiesterase-inhibitory activity, and exhibit excellent pharmacological actions such as anti-inflammatory and sedative activities.

Abstract: Novel 3-(disubstituted)aminoisothiazolo[3,4-d]-pyrimidines of the formula ##SPC1##Wherein R.sup.1, R.sup.2 and R.sup.3 are respectively alkyl, alkenyl, aryl, aralkyl or aralkenyl, each of which may be substituted, or R.sup.1 and R.sup.2 form together with the adjacent nitrogen a heterocyclic ring which may be substituted, R.sup.4 is hydrogen or alkyl and X is oxygen or imino with a proviso that when X is imino R.sup.4 is hydrogen, show an eminent adenosine-3',5'-cyclic phosphate phosphodiesterase-inhibitory activity, and exhibit excellent pharmacological actions such as antiinflammatory and sedative activities.