Abstract: A process for preparing a compound of formula I: ##STR1## wherein R.sub.1 represents a hydroxy protecting group and R.sub.2 represents a carboxy protecting group, which comprises:hydrolyzing a compound of formula II ##STR2## wherein R.sub.1 and R.sub.2 are as defined above and R represents an alkyl, alkenyl or phenylalkyl group having from 1 to 18 carbon atoms, in the presence of an enzyme capable of selectively hydrolyzing the ester group of the 2-substituent thereof.

Abstract: The biotechnological resolution by means of stereoselective enzymatic thio-transesterification of the racemic mixture of the optical isomers of the compounds of formula (I): ##STR1## wherein: R, R' and R", alike or different form one another, represent a linear alkyl group of from C.sub.1 to C.sub.4, in the presence of an alcohol and an enzyme capable of selectively causing the reaction of thio-transesterification of the (L)-isomer to take place, with the (D)-isomer remaining substantially unchanged, and being then separated by means of per se known techniques.

Abstract: Biotechnological resolution by means of enzymatic transesterification of the relevant racemic mixture of the optical isomers of .alpha.-alkyl-substituted primary alcohols having the formula (I): ##STR1## wherein: R represents a linear or branched (C.sub.1 -C.sub.20)-alkyl or alkenyl group or an aryl group, also substituted or condensed with other groups, in particular a group of formula (II) or (III): ##STR2## wherein: R.sup.ii represents a (C.sub.1 -C.sub.8)-alkyl group, a (C.sub.1 -C.sub.4)-alkenyl group, an alkoxy, phenyl, phenoxy, benzoyl, or heterocyclic group;R.sup.iii represents a hydrogen or halogen atom;R.sup.iv represents a (C.sub.1 -C.sub.4)-alkyl group,and whereinR.sup.i represents a (C.sub.1 -C.sub.

Abstract: There is disclosed a process for the biotechnological resolution, by enzymatic esterification of the corresponding racemic mixture of the S(+) and R(-) optical isomers of the oxazolidinonic compounds having formula (I): ##STR1## wherein R represents a, linear or branched, C.sub.1 -C.sub.8 alkyl group, which process is characterized in that, the racemic 3-alkyl-5-hydroxymethyl-oxazolidin-2-one derivative of formula (I) is reacted with an esterifying compound, selected from esters having formula (III): ##STR2## wherein R represents a, linear or branched, C.sub.1 -C.sub.10 alkyl or alkenyl group and R" represents a linear or branched, C.sub.1 -C.sub.4 alkyl, alkenyl group, a haloalkyl (chlorine, bromine) group or a diacyl glycerolic group or from acids having formula (IV):R'"--COOH (IV)wherein R'" represents a, linear or branched, C.sub.1 -C.sub.20 alkyl or alkenyl group or from anhydrides having formula (V): ##STR3## wherein R.sup.IV represents a, linear or branched, C.sub.1 -C.sub.

Abstract: A process for preparing L(-)-carnitine chloride having the formula: ##STR1## comprising the steps of: (a) reacting a racemic ester of (R,S)-3,4-epoxybutyric acid having the formula: ##STR2## wherein R is an alkyl group having from 1-10 carbons, or a benzyl group, with an enzyme capable of selectively hydrolyzing enantiomer S(-),(b) separating said enantiomer S(-), from non-reacted ester, which is predominantly in the R(+) form;(c) reacting (1) the non-reacted ester obtained in step (b) with trimethylamine hydrochlorid or (2) the trimethylamine, to obtain thereby an ester having the formula: ##STR3## (d) hydrolyzing the ester obtain in step (c) in the presence of HCl to obtain thereby the L(-)-carnitine chloride having formula (I).The present invention is also directed to a novel class of compounds comprising R(+) enantiomers of the esters of 3,4-epoxybutyric acid.

Abstract: There is described the preparation of S(+) alpha-aryl-alkanoic acids by means of the reaction of a racemic ester(R,S) of the formula: ##STR1## wherein: R is a group selected from the group consisting of --C.tbd.CH, a --CH.dbd.CH.sub.2, --CN; --COCH.sub.3, --COO alkyl C.sub.1 C.sub.4 and --CH.sub.2 --O alkyl C.sub.1 -C4 group, Ar is a group selected from the group consisting of an aryl group and an aryl substituted or condensed with other groups, in particular a group selected from the group consisting of groups of the formula: ##STR2## wherein: R' is selected from the group consisting of C.sub.1 -C.sub.8 linear or branch of chain alkyl, C.sub.1 -C.sub.4 alkenyl, alkoxy, phenyl, phenoxy, tenoyl and heterocyclic;R" is selected from the group consisting of hydrogen or halogen;R"' is a C.sub.1 -C.sub.4 alkyl,with an esterase, produced by microorganisms capable of selectively hydrolizing the S(+) form of said racemic ester and by successively separating the S(+) acid from the unreacted ester.

Abstract: There are described compounds of formula: ##STR1## in which R=alkyl, alkoxy, alkylthio, halogen; n=0, 1 or 2; R.sup.1 =H, alkyl; R.sup.2 =H, alkyl, cycloalkyl, phenyl optionally substituted.The compounds of formula I and the salts thereof are active against the coccidiosis of the domestic and breeding animals, in particular of poultry.

Abstract: Method of producing derivatives of 6-.beta.-amidinopenicillanic acid, according to which a derivative of 6-aminopenicillanic acid is condensed with a reactive derivative of disubstituted amide in an inert anhydrous solvent and in the presence of a tertiary amine. In such a reaction, the reactive derivative of the disubstituted amide comprises a complex of an amide of carboxylic acid.