Abstract: A novel process for the synthesis of Lacosamide using D,L-serine as starting material is described, where the methylation reaction of hydroxyl is carried out using an inexpensive base such as NaOH and an inexpensive alkylating agent, non-toxic and non-carcinogenic, such as methyl p-toluenesulfonate; the R enantiomer is isolated from the racemic mixture of Lacosamide after selective hydrolysis of the acetamide, salification of the racemic mixture with a chiral acid (HX*) in an organic solvent, resolution of the diastereoisomeric mixture, preferably by precipitation of the R enantiomer, and subsequent acetylation of the optically pure intermediate.

Abstract: A novel process for the synthesis of Lacosamide using D,L-serine as starting material is described, where the methylation reaction of hydroxyl is carried out using an inexpensive base such as NaOH and an inexpensive alkylating agent, non-toxic and non-carcinogenic, such as methyl p-toluenesulfonate; the R enantiomer is isolated from the racemic mixture of Lacosamide after selective hydrolysis of the acetamide, salification of the racemic mixture with a chiral acid (HX*) in an organic solvent, resolution of the diastereoisomeric mixture, preferably by precipitation of the R enantiomer, and subsequent acetylation of the optically pure intermediate.

Abstract: A process for preparing 2?,3?-didehydro-2?,3?-dideoxynucleosides and 2?,3?-dideoxynucleosides is described, which comprises the reductive elimination reaction of a compound of formula in which X, Y, P? is H or a protecting group and B is a natural or modified, optionally substituted purine or pyrimidine base or a five- or six-membered monocyclic or eleven- or twelve-membered bicyclic, optionally substituted heterocyclic system containing at least one nitrogen atom, by reaction with zinc metal and a suitable activating agent, characterized in that the divalent zinc is removed by precipitation, from an organic phase, of the corresponding zinc sulfide, by adding a solution of a mineral sulfide to the organic phase.

Abstract: A process is described which permits the preparation of Ritonavir with only five intermediate stages using the same starting materials as those used in the process described in WO 94/14436; the process described here is also particularly satisfactory from the point of view of environmental impact because nearly all of the carbon atoms used are subsequently incorporated in the final molecule. Finally, the improvement afforded by this novel process is linked with the fact that an inexpensive reagent, such as bis-trichloromethyl carbonate (BTC), is used in two of the five stages.