Abstract: A process for the preparation of 1,1-cyclohexanediacetic acid monoamide comprising the amination of 1,1-cyclohexanediacetic acid anhydride by reaction with aqueous NH3 at a temperature lower than 30° C. by using a NH3/anhydride molar ratio lower than 3, and the product precipitation through the acidification of the reaction mixture; a precipitation process of 1,1-cyclohexanediacetic acid monoamide; and a process for the synthesis of gabapentin comprising the above preparation of 1,1-cyclohexanediacetic acid monoamide, the Hofmann transposition of the same monoamide, the purification of a gabapentin salt and the crystallization from organic solvent.

Abstract: The present invention relates to an improved process for the preparation of gabapentin and, more particularly, to an improvement of the preparation reaction of 1,1-cyclohexanediacetic acid monoamide, intermediate utilized in the preparation of gabapentin.

Abstract: A process which allows the re-use of compounds of formula ##STR1## in diltiazem synthesis through a process of conversion to a mixture of enantiomers III-(2R,3R) and III-(2S,3S) is described.

Abstract: The present invention relates to a process for the separation of the enantiomers of threo-2-hydroxy-3-(2'- aminophenylthio)-3-(4"-methoxyphenyl)-propionic acid, which is an important intermediate in the synthesis of pharmacologically active compounds, by means of the direct crystallization of the relevant cyclohexylaminic salt.According to a preferred form of practical embodiment of the present invention, the optically pure acid is recovered as the hydrochloride of the corresponding methyl ester.

Abstract: The present invention relates to a novel process for synthetizing 2-aryl-3-hydroxy-cis-2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and their derivatives, an optically pure compounds or as their racemic mixtures, having the following general formula (I): ##STR1## by using, as synthesis precursors, methyl esters of 2-hydroxy-3-arylthio-3-arylpropionic acids in their threo form, as their hydrochlorides, or as free bases, of generally formula (II): ##STR2## and treating such precursors with an excess of sodium methoxide, at low temperature, in diethyleneglycol, dimethylether, diemthylformamide and ethyl acetate.