Abstract: Compositions having antibiotic properties containing as antibiotic potentiators peptides of the formula ##STR1## wherein R.sup.1 represents a hydrogen atom or a lower alkyl, lower cycloalkyl, (lower cycloalkyl)-(lower alkyl), aryl or aryl(lower alkyl) group (said group being optionally substituted as the case may require by one or more amino, hydroxy, thio, methylthio, carboxy or guanidino groups so as to form the characterizing group of a naturally occurring L .alpha.-amino acid); R.sup.2 and R.sup.3 each represent the characterizing group of an .alpha.-amino acid of the type normally found in proteins with the proviso that R.sup.3 cannot represent a hydrogen atom when n is zero and R.sup.1 is a hydrogen atom or the phenyl group; R.sup.4 represents a hydroxy or methyl group; n stands for zero, 1, 2 or 3; and single asterisks denote that the configuration at the carbon atom so-marked is L when R.sup.2 or R.sup.

Abstract: This invention is directed toward pharmacologically active compounds of the formula ##STR1## wherein A represents a nitrogen atom which may be substituted by a methyl, cyclopropylmethyl, di(C.sub.1-4 alkyl) aminoethyl, methoxymethyl or hydroxyethyl group and B represents a carbonyl group or A and B together represent a grouping of the formula ##STR2## in which R.sup.a represents a hydrogen atom or a lower alkyl or hydroxymethyl group and X represents a nitrogen atom or C--R.sup.b wherein R.sup.b represents a hydrogen atom or a lower alkyl or hydroxymethyl group; R represents a halogen atom or a nitro or trifluoromethyl group; R.sup.1 represents a hydrogen atom or a lower alkyl group; R.sup.2 represents an acyl group derived from a naturally occurring amino acid (all such groups which contain an asymmetric carbon atom having the L- or D,L-configuration) and R.sup.3 represents a phenyl, halophenyl or 2-pyridyl groupAnd acid addition salts thereof.

Abstract: This invention is directed toward pharmacologically active compounds of the formula ##STR1## wherein A represents a nitrogen atom which may be substituted by a methyl, cyclopropylmethyl, di(C.sub.1-4 alkyl)aminoethyl, methoxymethyl or hydroxyethyl group and B represents a carbonyl group or A and B together represent a grouping of the formula ##STR2## in which R.sup.a represents a hydrogen atom or a lower alkyl or hydroxymethyl group and X represents a nitrogen atom or C-R.sup.b wherein R.sup.b represents a hydrogen atom or a lower alkyl or hydroxymethyl group; R represents a halogen atom or a nitro or trifluoromethyl group; R.sup.1 represents a hydrogen atom or a lower alkyl group; R.sup.2 represents an acyl group derived from a naturally occurring amino acid (all such groups which contain an asymmetric carbon atom having the L- or D,L-configuration) and R.sup.3 represents a phenyl, halophenyl or 2-pyridyl groupAnd acid addition salts thereof.

Abstract: This invention is directed toward pharmacologically active compounds of the formula ##STR1## wherein A represents a nitrogen atom which may be substituted by a methyl, cyclopropylmethyl, di(C.sub.1-4 alkyl)aminoethyl, methoxymethyl or hydroxyethyl group and B represents a carbonyl group or A and B together represent a grouping of the formula ##STR2## in which R.sup.a represents a hydrogen atom or a lower alkyl or hydroxymethyl group and X represents a nitrogen atom or C-R.sup.b wherein R.sup.b represents a hydrogen atom or a lower alkyl or hydroxymethyl group; R represents a halogen atom or a nitro or trifluoromethyl group; R.sup.1 represents a hydrogen atom or a lower alkyl group; R.sup.2 represents an acyl group derived from a naturally occurring amino acid (all such groups which contain an asymmetric carbon atom having the L- or D,L-configuration) and R.sup.3 represents a phenyl, halophenyl or 2-pyridyl group and acid addition salts thereof.

Abstract: This invention is directed toward pharmacologically active compounds of the formula ##STR1## wherein A represents a nitrogen atom which may be substituted by a methyl, cyclopropylmethyl, di(C.sub.1-4 alkyl)aminoethyl, methoxymethyl or hydroxyethyl group and B represents a carbonyl group or A and B together represent a grouping of the formula ##STR2## in which R.sup.a represents a hydrogen atom or a lower alkyl or hydroxymethyl group and X represents a nitrogen atom or C-R.sup.b wherein R.sup.b represents a hydrogen atom or a lower alkyl or hydroxymethyl group; R represents a halogen atom or a nitro or trifluoromethyl group; R.sup.1 represents a hydrogen atom or a lower alkyl group; R.sup.2 represents an acyl group derived from a naturally occurring amino acid (all such groups which contain an asymmetric carbon atom having the L- or D,L-configuration) and R.sup.3 represents a phenyl, halophenyl or 2-pyridyl groupAnd acid addition salts thereof.

Abstract: The present disclosure relates to peptide derivatives. More particularly, the disclosure is concerned with peptide derivatives of phosphonic and phosphinic acids, a process for the manufacture thereof and pharmaceutical preparations containing same.

Abstract: This invention is directed toward pharmacologically active compounds of the formula ##STR1## wherein A represents a nitrogen atom which may be substituted by a methyl, cyclopropylmethyl, di(C.sub.1-4 alkyl)aminoethyl, methoxymethyl or hydroxyethyl group and B represents a carbonyl group or A and B together represent a grouping of the formula ##STR2## in which R.sup.a represents a hydrogen atom or a lower alkyl or hydroxymethyl group and X represents a nitrogen atom or C--R.sup.b wherein R.sup.b represents a hydrogen atom or a lower alkyl or hydroxymethyl group; R represents a halogen atom or a nitro or trifluoromethyl group; R.sup.1 represents a hydrogen atom or a lower alkyl group; R.sup.2 represents an acyl group derived from a naturally occurring amino acid (all such groups which contain an asymmetric carbon atom having the L- or D,L-configuration) and R.sup.3 represents a phenyl, halophenyl or 2-pyridyl groupAnd acid addition salts thereof.