The present disclosure provides a method for photocleavage of an amide bond, the method has mild reaction conditions and can realize the cleavage of amide bonds by using light. The method comprises the following steps: subjecting 2,4-dinitrofluorobenzene to a reaction with an amino group of a substance represented by structural formula I with an α-amino acid at the end to produce a compound 1 represented by structural formula II; then under light irradiation, subjecting the compound 1 to a cleavage reaction of amide bond; ##STR00001##
Wherein, R1 is the side chain group of α-amino acid; R2 is: aryl, aliphatic hydrocarbon, —CH(R)—COOH or polypeptide.

The present disclosure provides a method for photocleavage of an amide bond, the method has mild reaction conditions and can realize the cleavage of amide bonds by using light. The method comprises the following steps: subjecting 2,4-dinitrofluorobenzene to a reaction with an amino group of a substance represented by structural formula I with an α-amino acid at the end to produce a compound 1 represented by structural formula II; then under light irradiation, subjecting the compound 1 to a cleavage reaction of amide bond; ##STR00001##
Wherein, R1 is the side chain group of α-amino acid; R2 is: aryl, aliphatic hydrocarbon, —CH(R)—COOH or polypeptide.

A method for preparing pregabalin chiral intermediate (R)-3-(carbamoylmethyl)-5-methylhexanoic acid by a biological enzyme method. In particular, the method comprises: reacting compound (I) 3-isobutylglutaric acid, as a raw material, with a nitrogen-containing agent to produce compound (II) 3-isobutylglutarimide; and performing stereoselective ring-opening of compound (II) under the action of a biological enzyme to produce compound (III) (R)-3 -(carbamoylmethyl)-5-methylhexanoic acid:

##STR00001##

A method for preparing pregabalin chiral intermediate (R)-3-(carbamoylmethyl)-5-methylhexanoic acid by a biological enzyme method. In particular, the method comprises: reacting compound (I) 3-isobutylglutaric acid, as a raw material, with a nitrogen-containing agent to produce compound (II) 3-isobutylglutarimide; and performing stereoselective ring-opening of compound (II) under the action of a biological enzyme to produce compound (III) (R)-3 -(carbamoylmethyl)-5-methylhexanoic acid:

##STR00001##

An alternative and improved process for the preparation of Apremilast (Formula I) and Apremilast form B or a pharmaceutically acceptable salt thereof is provided. The novel process includes hydrogenation in acetone, Cyclization and acetylation followed by condensation in methyl isobutyl ketone (MIBK) and acetic acid mixture in specific volume ratios.

An alternative and improved process for the preparation of Apremilast (Formula I) and Apremilast form B or a pharmaceutically acceptable salt thereof is provided. The novel process includes hydrogenation in acetone, Cyclization and acetylation followed by condensation in methyl isobutyl ketone (MIBK) and acetic acid mixture in specific volume ratios.

The invention relates to a process for the preparation of one or more intermediate chemical compounds useful in the preparation of non-ionic contrast agents wherein the process is carried out continuously using one or more flow procedures.

The invention relates to a process for the preparation of one or more intermediate chemical compounds useful in the preparation of non-ionic contrast agents wherein the process is carried out continuously using one or more flow procedures.

The invention relates to a process for the preparation of one or more intermediate chemical compounds useful in the preparation of non-ionic contrast agents wherein the process is carried out continuously using one or more flow procedures.

A method of preparing a 2,6 disubstituted anilines includes, reacting a 2-amino isophthalic acid diester with sufficient Grignard reagent R.sub.2CH.sub.2MgX to form the corresponding diol product, dehydrating the diol product to the corresponding dialkene; and hydrogenating the diol product to form the corresponding aniline. The 2,6 disubstituted anilines can be used to produce N-Heterocyclic Carbenes (NHCs). The NHCs can find application in various fields such as organic synthesis, catalysis and macromolecular chemistry. Palladium catalysts containing the NHCs are also described.