A full continuous-flow preparation method of L-carnitine, including: mixing chlorine gas and a diketene solution via a first micromixer followed by transportation to a first microchannel reactor for continuous chlorination and esterification reaction to obtain 4-chloroacetoacetate; feeding the 4-chloroacetoacetate and a reductase to a second micromixer and a second microchannel reactor in sequence for continuous catalytic reaction to obtain (R)-4-chloro-3-hydroxybutyrate; simultaneously transporting the (R)-4-chloro-3-hydroxybutyrate and a trimethylamine solution to a third micromixer and a third microchannel reactor for continuous substitution and hydrolysis reaction; and subjecting the reaction mixture to desalination and concentration to obtain the L-carnitine.

A full continuous-flow preparation method of L-carnitine, including: mixing chlorine gas and a diketene solution via a first micromixer followed by transportation to a first microchannel reactor for continuous chlorination and esterification reaction to obtain 4-chloroacetoacetate; feeding the 4-chloroacetoacetate and a reductase to a second micromixer and a second microchannel reactor in sequence for continuous catalytic reaction to obtain (R)-4-chloro-3-hydroxybutyrate; simultaneously transporting the (R)-4-chloro-3-hydroxybutyrate and a trimethylamine solution to a third micromixer and a third microchannel reactor for continuous substitution and hydrolysis reaction; and subjecting the reaction mixture to desalination and concentration to obtain the L-carnitine.

A process for the manufacture of ω-aminoalkanoic acid of formula NH.sub.2—(CH.sub.2).sub.n—COOH, in which n is an integer from 9 to 11, by reaction of the corresponding ω-bromoalkanoic acid with ammonia, including the following stages: i) reaction of the ω-bromoalkanoic acid with an aqueous excess ammonia solution, and ii) separation of the ω-aminoalkanoic acid formed from the reaction mixture. The aqueous ammonia solution exhibits a concentration of 35% to 70% by weight, and stage i) is carried out under a pressure greater than atmospheric pressure, from 0.11 to 2.0 MPa absolute.

A process for the manufacture of ω-aminoalkanoic acid of formula NH.sub.2—(CH.sub.2).sub.n—COOH, in which n is an integer from 9 to 11, by reaction of the corresponding ω-bromoalkanoic acid with ammonia, including the following stages: i) reaction of the ω-bromoalkanoic acid with an aqueous excess ammonia solution, and ii) separation of the ω-aminoalkanoic acid formed from the reaction mixture. The aqueous ammonia solution exhibits a concentration of 35% to 70% by weight, and stage i) is carried out under a pressure greater than atmospheric pressure, from 0.11 to 2.0 MPa absolute.

The present invention provides an improved process for the preparation of 3-(4-chlorophenyl)-3-cyanopropanoic acid (compound (A)) and further its transformation to Baclofen (I). The process comprises reaction of compound (II) with Glyoxylic acid to obtain 3-(4-chlorophenyl)-3-cyanoacrylic acid (III); followed by the ‘in-situ’ reduction of (III) in the presence of a reducing agent to provide the compound (A).

Alternatively, the compound (A) is obtained by the process comprising reacting 2-(4-chlorophenyl)acetonitrile (II) with haloacetic acid (IV) in the presence of a base.

The compound 3-(4-chlorophenyl)-3-cyanopropanoic acid (A) undergoes hydrogenation in the presence of a metal catalyst and ammonia solution to provide Baclofen (I).

The present invention provides an improved process for the preparation of 3-(4-chlorophenyl)-3-cyanopropanoic acid (compound (A)) and further its transformation to Baclofen (I). The process comprises reaction of compound (II) with Glyoxylic acid to obtain 3-(4-chlorophenyl)-3-cyanoacrylic acid (III); followed by the ‘in-situ’ reduction of (III) in the presence of a reducing agent to provide the compound (A).

Alternatively, the compound (A) is obtained by the process comprising reacting 2-(4-chlorophenyl)acetonitrile (II) with haloacetic acid (IV) in the presence of a base.

The compound 3-(4-chlorophenyl)-3-cyanopropanoic acid (A) undergoes hydrogenation in the presence of a metal catalyst and ammonia solution to provide Baclofen (I).

Processes are disclosed for the synthesis of an α-amino acid or α-amino acid derivative, from a starting compound or substrate having a carbonyl functional group (C═O), with hydroxy-substituted carbon atoms at alpha (α) and beta (β) positions, relative to the carbonyl functional group. According a particular embodiment, an α-, β-dihydroxy carboxylic acid or carboxylate is dehydrated to form a dicarbonyl intermediate by transformation of the α-hydroxy group to a second carbonyl group (adjacent a carbonyl group of the starting compound) and removal of the β-hydroxy group. The dicarbonyl intermediate is optionally cracked to form a second, in this case cracked, dicarbonyl intermediate having fewer carbon atoms relative to the dicarbonyl intermediate but preserving the first and second carbonyl groups. Either or both of the dicarbonyl intermediate and the cracked dicarbonyl intermediate may be aminated to convert the second carbonyl group to an amino (—NH.sub.2) group, for producing the corresponding α-amino acid(s).

Processes are disclosed for the synthesis of an α-amino acid or α-amino acid derivative, from a starting compound or substrate having a carbonyl functional group (C═O), with hydroxy-substituted carbon atoms at alpha (α) and beta (β) positions, relative to the carbonyl functional group. According a particular embodiment, an α-, β-dihydroxy carboxylic acid or carboxylate is dehydrated to form a dicarbonyl intermediate by transformation of the α-hydroxy group to a second carbonyl group (adjacent a carbonyl group of the starting compound) and removal of the β-hydroxy group. The dicarbonyl intermediate is optionally cracked to form a second, in this case cracked, dicarbonyl intermediate having fewer carbon atoms relative to the dicarbonyl intermediate but preserving the first and second carbonyl groups. Either or both of the dicarbonyl intermediate and the cracked dicarbonyl intermediate may be aminated to convert the second carbonyl group to an amino (—NH.sub.2) group, for producing the corresponding α-amino acid(s).

Processes are disclosed for the synthesis of an α-amino acid or α-amino acid derivative, from a starting compound or substrate having a carbonyl functional group (C═O), with hydroxy-substituted carbon atoms at alpha (α) and beta (β) positions, relative to the carbonyl functional group. According a particular embodiment, an α-, β-dihydroxy carboxylic acid or carboxylate is dehydrated to form a dicarbonyl intermediate by transformation of the α-hydroxy group to a second carbonyl group (adjacent a carbonyl group of the starting compound) and removal of the β-hydroxy group. The dicarbonyl intermediate is optionally cracked to form a second, in this case cracked, dicarbonyl intermediate having fewer carbon atoms relative to the dicarbonyl intermediate but preserving the first and second carbonyl groups. Either or both of the dicarbonyl intermediate and the cracked dicarbonyl intermediate may be aminated to convert the second carbonyl group to an amino (—NH.sub.2) group, for producing the corresponding α-amino acid(s).

A compound that includes a menthol glycinate. The menthol glycinate includes a menthol connected to a glycine or glycine derivative, via an ester linkage. The groups on the N atom are referred to as R.sub.1 and R.sub.2, and R.sub.1 and R.sub.2 are independently selected from the group consisting of: H, alkyl and R.sub.1 and R.sub.2 together with the N atom to which they are attached form a 4-8-member ring. R.sub.1 and R.sub.2 each contain at most 20 carbon atoms.