Abstract: The present invention is directed to N-[(2,4-difluorophenyl)methyl]-6-hydroxy-3-methyl-5,7-dioxo-2,3,5,7,11,11a-hexahydro[1,3]oxazolo[3,2-a]pyrido[1,2-d]pyrazine-8-carboxamide of the formula: or a pharmaceutically acceptable salt or stereoisomer thereof, and pharmaceutical compositions comprising the same. The present invention has HIV integrase inhibitory activity.

Abstract: A process for preparing a compound represented by formula (Y1) or (Y2) wherein Rx is an optionally substituted carbocyclyl lower alkyl, or the like or a salt thereof, using a novel process for preparing a pyridone derivative represented by formula (X4) wherein R1d, R2d, and R4d are as defined herein.

Abstract: The present invention provides a compound of formula (I): wherein —X? is —CR7? or —N?, ring B is a substituted or unsubstituted carbocycle or a substituted or unsubstituted heterocycle, R1 is substituted or unsubstituted alkyl or the like, R2 a and R2 b are each independently hydrogen, substituted or unsubstituted alkyl or the like, R3 and R4 are each independently hydrogen, halogen, substituted or unsubstituted alkyl or the like, R5 is hydrogen, substituted or unsubstituted alkyl or the like, each R6 is independently halogen, hydroxy, substituted or unsubstituted alkyl or the like, R7 is hydrogen, halogen, hydroxy, substituted or unsubstituted alkyl or the like, p is an integer of 0 to 3, or a pharmaceutically acceptable salt thereof which has an effect of inhibiting amyloid ? production, especially an effect of inhibiting BACE1, and which is useful as a therapeutic or prophylactic agent for diseases induced by production, secretion and/or deposition of amyloid ? proteins.

Abstract: The invention relates to tetrahydropyridinyl and dihydropyrrolyl compounds of Formula (I): and pharmaceutically acceptable salts, prodrugs, or solvates thereof, wherein X, Y, Z, R1, R2, m, and n are defined as set forth in the specification. The invention is also directed to the use of compounds of Formula (I) to treat a disorder responsive to the blockade of calcium channels, and particularly N-type calcium channels. Compounds of the present invention are especially useful for treating pain.

Abstract: The object of the present invention is to provide a novel compound which has various biological activities and is useful for medical and animal drugs. The present invention provides a compound represented by the formula: ##STR1## wherein R.sup.1 is COOR.sup.4, CONR.sup.5 R.sup.6, CO--R.sup.7 --OR or CH.sub.2 OR.sup.8 ; R.sup.2 is hydrogen atom, alkyl, aralkyl, heteroaryl, heteroarylalkyl, COR.sup.13, COOR.sup.14, CONR.sup.15 R.sup.16 ; R.sup.3 is hydrogen atom or OR.sup.3 ; a broken line ( - - - ) represents the presence of a double bond when R.sup.3 is oxygen atom and the absence of a double bond when R.sup.3 is OR.sup.3, or a salt or metal chelete thereof.

Abstract: The compounds of the present invention inhibit HMG-CoA reductase, and subsequently suppress the synthesis of cholesterol. And they are useful in the treatment of hypercholesterolemia, hyperlipoproteinemia, and atherosclerosis. The compounds have the formula ##STR1## wherein R.sup.1, R.sup.2, and R.sup.3 each is independently hydrogen, optionally substituted lower alkyl, or optionally substituted aryl; R.sup.4 is lower alkyl, aralkyl, aryl, or heteroaryl, each of which is optionally substituted; X is vinylene or ethylene; Y is ##STR2## where R.sup.5 is hydrogen, lower alkyl, aryl, aralkyl, or a cation capable of forming a non-toxic pharmaceutically acceptable salt.

Abstract: A compound of the formula: ##STR1## (wherein R.sup.1 is hydrogen, C.sub.1 -C.sub.5 alkyl, C.sub.1 -C.sub.5 alkoxy, C.sub.1 -C.sub.5 alkoxycarbonyl, or trifluoromethyl; R.sup.2 is hydrogen, C.sub.1 -C.sub.5 alkoxycarbonyl, C.sub.6 -C.sub.12 aryloxycarbonyl, C.sub.1 -C.sub.5 alkanoyloxy-C.sub.1 -C.sub.5 alkyl, C.sub.1 -C.sub.5 alkoxycarbonyloxy-C.sub.1 -C.sub.5 alkyl, C.sub.1 -C.sub.5 acylamino-C.sub.1 -C.sub.5 alkyl, 2-hydroxy-1-C.sub.2 -C.sub.5 alkenyl, phthalimido-C.sub.1 -C.sub.5 alkyl, halogeno-C.sub.1 -C.sub.5 alkoxycarbonyl-C.sub.1 -C.sub.5 alkyl, hydroxy-C.sub.1 -C.sub.5 alkyl, C.sub.1 -C.sub.5 alkylthio-C.sub.1 -C.sub.5 alkyl, or C.sub.1 -C.sub.5 alkylsulfinyl-C.sub.1 -C.sub.5 alkyl; ##STR2## m is an integer of 0 or 1; R.sup.3 and R.sup.4 each is hydrogen, halogen, cyano, C.sub.1 -C.sub.5 alkyl, amino, C.sub.1 -C.sub.5 alkoxy, C.sub.6 -C.sub.12 aryl-C.sub.1 -C.sub.5 alkoxy, C.sub.1 -C.sub.5 alkoxycarbonyl, fluoro-C.sub.1 -C.sub.5 alkoxy, C.sub.1 -C.sub.

Abstract: A 2'-halopenicillin compound is prepared from a penicillin-1-oxide compound by the action of an acid halide in the presence of a base. The product on heating rearranges to a 3-halo-3-methylcepham compound which itself gives a 3-methyl-3-cephem compound on further heating. A 2'-halopenicillin compound gives a 3-methyl-3-cephem compound on heating. The 2'-halopenicillin compounds, 3-halo-3-methylcepham compound and 3-methyl-3-cephem compounds are antibacterials which are also useful as intermediates for the synthesis of other penicillins and cephalosporins.