Abstract: The invention relates to a method for enhancing erosion uniformity on the sputtering surface of a magnetron cathodic sputtering target. The invention is characterised in that it consists in adding to said target intended to be coupled to a magnetron maintained fixed as compared to this target, at least one ferromagnetic piece for complete or partial insertion into said target or by juxtaposition thereto, so as to bring about, at the entire sputtering surface, a curvature reduction of the magnetic induction lines generated by the magnetron.

Abstract: Purified form of streptogramines, characterised in that it contains at least one component from group B streptogramines of general formula (I), wherein R1 is Me or Et, R2 is H or OH, and R3 is substituted benzyl of general formula (III), such that 1) if R2 is H, R is NR4R5, wherein one of R4 and R5 is H or an Me radical and the other is Me, and R′ is Cl or Br, or R is (C3-5)alkenyl if R4 and R5 are Me, or 2) R is H and R′ is halogen, alkylamino or dialkylamino, an ether-oxide residue, alkylthio, (C1-3)alkyl or trihalogenomethyl, or R is halogen, (C2-4)alkylamino, (C2-4)dialkylamino or methyl ethyl amino, pyrrolidino alkenyl alkyl amino, dialkylamino, an alkyl cycloalkylmethyl amino radical or in ether-oxide residue, alkylthio, alkylthiomethyl, (C1-6)alkyl, aryl or trihalogenomethyl, and R′ is H, or R is halogen, amino, alkylamino or dialkylamino, an ether-oxide residue, an alkylthio radical, (C1-6)alkyl or trihalogenomethyl and R′ is halogen, alkylamino or dialkylamino, an ether-oxide

Abstract: A method for preparing streptogramins of the formula (I): ##STR1## wherein R.sub.1 is methyl or ethyl, R.sub.2 is H and X and Y together form an oxo radical, or R.sub.1 is ethyl, R.sub.2 and X are H and Y is H or OH, or else R.sub.1 is ethyl, R.sub.2 is OH and X and Y together form an oxo radical, by demethylation of a synergistin derivative of the formula (II): ##STR2## wherein R.sub.1, R.sub.2, X and Y are as defined above, by means of a treatment with a periodate in an acetic medium, followed by a treatment in an aqueous medium.

Abstract: This invention relates to a purified form of streptogramins, having of a combination of one or more group B components of streptogramins, of general formula: ##STR1## in which A.sub.1 is a radical of general formula: ##STR2## for which R' is H or OH and Y is H, a methylamino radical or a dimethylamino radical,R is an ethyl radical or, when R' is H, R can also represent--CH.sub.3, andR.sub.1 and R.sub.2 are H, or alternativelyA.sub.1 is a radical of formula: ##STR3## R is an isobutyl radical, and R.sub.1 is OH and R.sub.2 is --CH.sub.3,and one or more group A minority components of streptogramins, of general formula: ##STR4## in which R" is H or a methyl or ethyl radical, in the state of cocrystallizate, of a coprecipitate or of a physical mixture of the powders.

Abstract: This invention relates to a purified form of streptogramins, consisting of a combination of one or more group B components of streptogramins, of general formula: ##STR1## in which A.sub.1 is a radical of general formula: ##STR2## for which R' is H or OH and Y is H, a methylamino radical or a dimethylamino radical, R is an ethyl radical or, when R' is H, R can also represent --CH.sub.3, and R.sub.1 and R.sub.2 are H, or alternatively A.sub.1 is a radical of formula: ##STR3## R is an isobutyl radical, and R.sub.1 is OH and R.sub.2 is --CH.sub.3, and one or more group A minority components of streptogramins, of general formula: ##STR4## in which R" is H or a methyl or ethyl radical, in the state of cocrystallizate, of a coprecipitate or of a physical mixture of the powders.