Abstract: The present invention relates to a compound of the formula (1): wherein R1 is group of the formula (2): (wherein X is nitrogen atom or C(R5), Y is nitrogen atom or C(R6), R5 and R6 are each independently hydrogen atom, etc.) etc., m is 1 to 6, L1 is single bond, etc., R2 is hydrogen atom, substituted or unsubstituted alkyl group, etc., R3 is hydrogen atom, etc., L2 is single bond, etc., R4 is hydrogen atom, substituted or unsubstituted aryl group, etc., or pharmaceutically acceptable salt thereof, being useful for preventing or treating Alzheimer's disease.

Abstract: The present invention relates to a compound of the formula (1): wherein R1 is group of the formula (2): (wherein X is nitrogen atom or C(R5), Y is nitrogen atom or C(R6), R5 and R6 are each independently hydrogen atom, etc.) etc., m is 1 to 6, L1 is single bond, etc., R2 is hydrogen atom, substituted or unsubstituted alkyl group, etc., R3 is hydrogen atom, etc., L2 is single bond, etc., R4 is hydrogen atom, substituted or unsubstituted aryl group, etc., or pharmaceutically acceptable salt thereof, being useful for preventing or treating Alzheimer's disease.

Abstract: A novel dipeptide compound inhibiting the enzymatic activity of HIV protease and an anti-AIDS medicine comprising this dipeptide compound as an effective component represented by formula (I) wherein R1, R2, and R3 independently represent C1-4 alkyl, alkoxyl, hydrogen etc . . . (provided that not all of the R1, R2, and R3 are hydrogen), R2 and R3 may form a ring together, R4 represents C1-4 alkyl or hydrogen; X is a methylene group or a sulfur atom; Y represents e.g., a five or six member monocycle or aryloxyalkyl having up to 12 carbon atoms (provided that the aromatic ring may be substituted by alkyl etc . . . ); and Z represents a C1-6 aliphatic hydrocarbon or an aromatic hydrocarbon having up to 12 carbon atoms (provided that this aromatic ring may be substituted by alkyl etc . . . , or at least one carbon atom in the aromatic hydrocarbon may be replaced by a hereto atom).

Abstract: A cyclic tetrapeptide derivative represented by the general formula (I): wherein: R11, R12, R21 and R22 independently denote a monovalent group selected from hydrogen, a linear or branched alkyl group with 6 or less carbon atoms, benzyl group, 4-methoxybenzyl group, 3-indolylmethyl group, (N-methoxy-3-indolyl) methyl group, (N-formyl-3-indolyl)methyl group, etc.; R3 denotes a divalent group selected from a linear chained hydrocarbon group with 3 or 4 carbon atoms, or the linear branched hydrocarbon group having a branched chain added to the chain, or a divalent group substituted with a heteroatom; R4 denotes a divalent chained hydrocarbon group with 4 to 6 carbon atoms, or a divalent group derived from said hydrocarbon group by addition etc.

Abstract: A novel dipeptide compound inhibiting the enzymatic activity of HIV protease, an anti-AIDS medicine comprising this dipeptide compound as an effective component.

Abstract: &bgr;-Amino-&agr;-hydroxycarboxylic acid derivatives represented by the following formula and salts thereof which are useful as human immunodeficiency virus (HIV) protease inhibitors: The compounds are effective for treating a patient suffering from AIDS and AIDS related diseases.

Abstract: &bgr;-Amino-&agr;-hydroxycarboxylic acid derivatives represented by the following formula and salts thereof which are useful as human immunodeficiency virus (HIV) protease inhibitors: The compounds are effective for treating a patient suffering from AIDS and AIDS related diseases.

Abstract: A novel tripeptide compound represented by the following general formula (I) exhibiting superior HIV protease inhibition activity, and an anti-AIDS medicine comprising this compound as an effective component and a pharmaceutically acceptable salt thereof. (R)-N-(2-methylbenzyl)-3-{(2S,3S)-3-[N-(2-chromonecarbonyl)-L-asparaginyl]amino-2-hydroxy-4-phenylbutanoyl}-5,5-dimethyl-1,3-thiazolidine-4-carboxamide can be given as a typical example of this compound.

Abstract: The present invention provides synthetic methodology to produce novel dipeptide compounds and pharmaceutically acceptable salts thereof which exhibit excellent HIV protease inhibitory activity and excellent bioavailability from digestive tracts. Methods of using the dipeptide compounds and pharmaceutically acceptable salts thereof also are provided.

Abstract: The present invention provides a novel dipeptide compound or pharmaceutically acceptable salt thereof which exhibits an excellent HIV protease inhibitory activity and an excellent bioavailability from digestive tracts, and an anti-AIDS agent comprising said dipeptide compound as an effective ingredient. ##STR1## (wherein R.sub.1 represents 5-membered or 6-membered monocyclic hydrocarbon group or heterocyclic group wherein more than one carbon atom of said monocyclic hydrocarbon group is substituted with hetero atom. X represents methylene group (--CH.sub.2 --), chloromethylene group(--CH(Cl)--), oxygen atom sulfur atom or sulfonyl group (--SO.sub.2 --). R.sub.21 and R.sub.22 each represents hydrogen atom or aliphatic hydrocarbon group having 1-6 carbons. R.sub.3 represents aliphatic hydrocarbon group or monovalent group derived from aromatic monocyclic hydrocarbon having 1-6 carbons.

Abstract: The present invention provides a novel dipeptide compound or pharmaceutically acceptable salt thereof which exhibits an excellent HIV protease inhibitory activity and an excellent bioavailability from digestive tracts, and an anti-AIDS agent comprising said dipeptide compound as an effective ingredient.General formula (I): ##STR1## (wherein R.sub.1 represents 5-membered or 6-membered monocyclic hydrocarbon group or heterocyclic group wherein more than one carbon atom of said monocyclic hydrocarbon group is substituted with hetero atom. X represents methylene group (--CH.sub.2 --), chloromethylene group(--CH(Cl)--), oxygen atom sulfur atom or sulfonyl group (--SO.sub.2 --). R.sub.21 and R.sub.22 each represents hydrogen atom or aliphatic hydrocarbon group having 1-6 carbons. R.sub.3 represents aliphatic hydrocarbon group or monovalent group derived from aromatic monocyclic hydrocarbon having 1-6 carbons.

Abstract: A process for producing peptide derivatives of formula (1) or salts thereof: ##STR1## which comprises condensation of peptide derivative of formula (2): ##STR2## with carboxylic acid of formula (3): ##STR3## or condensation of a peptide derivative of formula (4): ##STR4## with a protected amino acid of formula (5'): ##STR5## wherein R.sup.1 and R.sup.2 are a lower alkyl group or hydrogen atom, R.sup.3 is a lower alkyl group, X is a methylthiomethyl, methanesulfonylmethyl, carbamoylmethyl, or a lower alkyl group, Ar is an aryl or heteroaryl group, and A.sup.4 is Ar--O--CH.sub.2 --CO. The peptide derivatives and salts thereof are useful as the human immunodeficiency virus (HIV) protease inhibitors.