Abstract: Y is O or S;R.sup.1 is hydrogen, halogen, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy;R.sup.2 is hydrogen, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.2 -C.sub.4 alkenyl, C.sub.2 -C.sub.4 alkenyloxy, C.sub.2 -C.sub.4 alkynyl, C.sub.2 -C.sub.4 alkynyloxy, mono-, di- or tri-halomethyl, trifluoromethoxy, C.sub.2 -C.sub.4 alkylthio, C.sub.3 -C.sub.4 branched alkylthio, nitro, or cyano;R.sup.3 is hydrogen, halogen, methyl, mono-, di- or tri-halomethyl;R.sup.4 isa) C.sub.3 -C.sub.8 cycloalkyl substituted by one or more C.sub.1 -C.sub.4 alkyl, preferably one or two methyl;orb) ##STR2## wherein R.sup.6 and R.sup.7 are independently, hydrogen or linear or branched, C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl, or C.sub.2 -C.sub.4 alkynyl, and R.sup.8 is C.sub.3 -C.sub.8 cycloalkyl substituted by one or more C.sub.1 -C.sub.4 alkyl; andR.sup.5 is an acyclic or cyclic side chain as defined herein.These compounds are useful for inhibiting the growth or replication of retroviruses such as HIV.

Abstract: Compounds of the formula ##STR1## wherein X is O or S;Y is O or S;R.sup.1 is hydrogen, halogen, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy;R.sup.2 is hydrogen, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.2 -C.sub.4 alkenyl, C.sub.2 -C.sub.4 alkenyloxy, C.sub.2 -C.sub.4 alkynyl, C.sub.2 -C.sub.4 alkynyloxy, mono-, di- or tri-halomethyl, trifluoromethoxy, C.sub.1 -C.sub.4 alkylthio, C.sub.3 -C.sub.4 branched alkylthio, nitro, or cyano;R.sup.3 is hydrogen, halogen, methyl, mono-, di- or tri-halomethyl;R.sup.4 isa) C.sub.3 -C.sub.8 cycloalkyl substituted by one or more C.sub.1 -C.sub.4 alkyl, preferably one or two methyl;orb) ##STR2## wherein R.sup.6 and R.sup.7 are independently, hydrogen or linear or branched, C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl, or C.sub.2 -C.sub.4 alkynyl, and R.sup.8 is C.sub.3 -C.sub.8 cycloalkyl substituted by one or more C.sub.1 -C.sub.4 alkyl; andR.sup.5 is an acyclic or cyclic side chain as defined herein.

Abstract: N-(2-Fluorophenyl)-1,2,3,4-tetrahydro-6-hydroxy-2,4-dioxo-5-pyrimidinecarbo xamide, useful for regressing or inhibiting the growth of leukemia and tumors in mammals. The compound has the formula: ##STR1## wherein R.sub.1 and R.sub.2 are selected from hydrogen or a cyclic or acyclic group which forms pyrimidine nucleosides or pseudo nucleosides, and the pharmacologically acceptable acid addition salts thereof.

Abstract: Method for reducing uric acid levels in mammals, comprising administering compounds having the formula: ##STR1## wherein A is selected from the group consisting of ##STR2## and --CH.sub.2 --; X is oxygen or sulfur; R.sub.6 is hydrogen, an alkoxy group having from one to four carbon atoms, or alkylthio, amino, dialkylamino, or NHR.sub.7 wherein R.sub.7 is alkyl, aryl or arylamino, the alkyl moieties of which have from 1 to 12 carbon atoms;R.sub.1 and R.sub.2 may each independently be hydrogen; alkyl, aryl, aralkyl, aralkenyl or aralkynyl, the alkyl, alkenyl or alkynyl moieties of which have from one to six carbon atoms, or a carbohydrate residue;R.sub.3 is hydrogen, C.sub.1 -C.sub.4 alkyl or aryl;R.sub.

Abstract: Novel 3-(2-haloalkyl)-1,4-oxathiins or 2-(2-haloalkyl)-1,4-dithiins, useful for regressing or inhibiting the growth of leukemia and tumors in mammals. The compounds have the formula.: ##STR1## wherein R.sub.1 is an alkyl group containing up to 4 carbon atoms, cyclohexyl or phenyl;R.sub.2 is hydrogen or ethyl;R.sub.3 and R.sub.4 are each hydrogen, methyl or ethyl, andwhen either R.sub.3 and R.sub.4 is methyl or ethyl, the other is hydrogen;X is halogen; andY is oxygen or sulfur andwhen Y is sulfur, R.sub.3 and R.sub.4 are both hydrogen.and pharmaceutical compositions comprising said compounds in admixture with a pharmaceutically acceptable substantially non-toxic carrier.