Abstract: Disclosed herein are processes for the preparation of fused heteroaryl dihydro pyrimidine compounds, or salts or stereoisomers thereof, which are useful for the treatment and prophylaxis of hepatitis B virus infections using compounds of formula IX or stereoisomers thereof, wherein a disclosed process comprises a. reacting a compound formula II with hydrogen in the presence of a solvent and a palladium catalyst or a platinum catalyst, to form a compound of formula III: b. reacting the compound of formula III, or a salt or stereoisomer thereof, with a hydrolase selected from the group consisting of an amidase and a peptidase, or a mixture thereof, to form a compound of formula I: or a salt or stereoisomer thereof, c.

Abstract: The invention relates to a novel process for the preparation of a chiral piperazine-2- carboxylic acid or of a salt thereof of the formula (I). The chiral piperazine-2-carboxylic acid derivatives of the formula (I) are key intermediates for the preparation of fused heteroaryl dihydro pyrimidines which are useful for the treatment and prophylaxis of hepatitis B virus infections.