The invention relates to a new process for producing useful intermediates for the manufacture of NEP inhibitors or prodrugs thereof, in particular NEP inhibitors comprising a γ-amino-δ-biphenyl-α-methylalkanoic acid, or acid ester, backbone, such as N-(3-carboxyl-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-(2R)-methyl butanoic acid ethyl ester or salt thereof.

The present disclosure is directed synthetic methods for the preparation of 4-valyloxybutyric acid. The synthetic methods described herein employ a diverse array of protecting group strategies and reaction conditions. Additionally, the present disclosure is directed to compounds useful as synthetic intermediates in the preparation of 4-valyloxybutyric acid.

The present disclosure is directed synthetic methods for the preparation of 4-valyloxybutyric acid. The synthetic methods described herein employ a diverse array of protecting group strategies and reaction conditions. Additionally, the present disclosure is directed to compounds useful as synthetic intermediates in the preparation of 4-valyloxybutyric acid.

The invention relates to an overall enantio-specific synthesis of 4-chlorokynurenine compounds, in particular L-4-chlorokynurenine, with improved yields. Large-scale syntheses are disclosed. The invention also relates to novel intermediates in the synthesis of L-4-chlorokynurenine.

The invention relates to an overall enantio-specific synthesis of 4-chlorokynurenine compounds, in particular L-4-chlorokynurenine, with improved yields. Large-scale syntheses are disclosed. The invention also relates to novel intermediates in the synthesis of L-4-chlorokynurenine.

The invention relates to an overall enantio-specific synthesis of 4-chlorokynurenine compounds, in particular L-4-chlorokynurenine, with improved yields. Large-scale syntheses are disclosed. The invention also relates to novel intermediates in the synthesis of L-4-chlorokynurenine.

The present invention provides a composition comprising anti-1-amino-3-.sup.18F-fluorocyclobutyl-1-carboxylic acid (.sup.18F-FACBC) having an improved impurity profile compared with previous such compositions. Also provided is a method to obtain said composition.

The present invention provides a composition comprising anti-1-amino-3-.sup.18F-fluorocyclobutyl-1-carboxylic acid (.sup.18F-FACBC) having an improved impurity profile compared with previous such compositions. Also provided is a method to obtain said composition.

The invention relates to a process for the preparation of Melphalan (4-[bis(2-5 chloroethyl)amino]-L-phenylalanine of formula (I) said process comprising the reaction of a 4-amino-L-phenylalanine protected at the carboxy and amino aminoacidic groups with an agent able to convert the aromatic amino group into a group of formula: —N(CH.sub.2CH.sub.2OS(O).sub.nO—).sub.2, wherein n is 1 or 2 followed by conversion of the .fwdarw.N(CH.sub.2CH.sub.2OS(O).sub.nO—).sub.2 group into a —N(CH.sub.2CH.sub.2Cl).sub.2 group. The invention also provides novel intermediates useful for the preparation of Melphalan. ##STR00001##

The invention relates to a process for the preparation of Melphalan (4-[bis(2-5 chloroethyl)amino]-L-phenylalanine of formula (I) said process comprising the reaction of a 4-amino-L-phenylalanine protected at the carboxy and amino aminoacidic groups with an agent able to convert the aromatic amino group into a group of formula: —N(CH.sub.2CH.sub.2OS(O).sub.nO—).sub.2, wherein n is 1 or 2 followed by conversion of the .fwdarw.N(CH.sub.2CH.sub.2OS(O).sub.nO—).sub.2 group into a —N(CH.sub.2CH.sub.2Cl).sub.2 group. The invention also provides novel intermediates useful for the preparation of Melphalan. ##STR00001##