The present invention discloses a process for the production of a fatty acid/L-carnitine derivative using monochloroacetic acid.
3-Hydroxy-4-trimethylammonio-butanoate (henceforth "L-carnitine") is a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine. In living cells, it is required for the transport of fatty acids from the cytosol into the mitochondria during the breakdown of lipids (or fats) for the generation of metabolic energy.
Fatty acid/L-carnitine derivatives like palmitoyl-L-camitine are synthesised according to the state of the art by reacting the educts L-carnitine and the chloride of the fatty acid in the presence of gaseous HCI and a tri-halide acetic acid.
The US 5,741,816 discloses a reaction of n-pentadecanoic acid with thionyl chloride and a subsequent reaction with L-carnitine in trichloroacetic acid.
However, there is still a need to improve upon these processes of the state of the art. In this regard, it would be advantageous to substitute the tri-halide acetic acid with an acid that has a lower molecular weight and a lower prize (currently at 4338 USD per tonne for trichloroacetic acid).
The problems stated above are solved by the process according to the invention, which uses monochloroacetic acid in the production of a fatty acid/L-carnitine derivative. Said reagent has the advantage of a lower molecular weight and a prize which is smaller by a factor of 5.4 (currently at 800 USD per tonne).
"Derivative" according to the invention is the reaction product of L-carnitine and a fatty acid or fatty acid chloride, namely an esterifled L-carnitine, whereby the hydroxyl moiety at carbon atom 3 of the L-camitine has reacted with the acid or acyl chloride moiety of the fatty acid or fatty acid chloride to form the ester moiety.
Preferably, the monochloroacetic acid is used in a concentration of between 3.3 and 4.4 mol/L, even more preferably in a concentration of between 3.5 and 4.3 mol/L.
The chloride of the fatty acid is preferably used in a concentration of between 1.25 and 1.85 mol/L, even more preferably in a concentration of between 1.6 and 1.85 mol/L, while L-camitine hydrochloride is preferably used in a concentration of between 1.2 and 1.5 mol/L, even more preferably in a concentration of between 1.2 and 1.4 mol/L
The gaseous HCI is preferably used in a concentration of between 3 and 4 mol/L, even more preferably in a concentration of between 3.25 and 3.75 mol/L.
The reaction according to the invention preferably takes place at a temperature of between 70°C and 80°C.
The invention will now be described in more detail by way of the following examples.
Comparative Example: Palmitoyl-L-camitine hydrochloride in trichloroacetic acid
120 g L-camitine and 368 g trichloroacetic acid are filled in the equipment and heated
up to 73 °C. After complete melting the solution is cooled down to 30 °C. 27.5g HCI
gas are added to the reactor and the reaction is stirred for 1h.
320.4 g palmitoyl chloride are slowly dosed over 1 hour and the solution is heated up
to 50 °C and stirred for 1.5 hours.
195.3 g isopropanol and 498 g ethyl acetate are added at room temperature to the
reaction mass, then cooled down to 0 °C. The solid is filtrated and washed with 65.1
g isopropanol and 191.8 g ethyl acetate (precooled at 0°C) and dried overnight.
The solid is recrystallized in 1050 ml isopropanol. The mixture is heated to 70°C.
Isopropanol and ethyl acetate are added to the system and cooled to 0°C. 202.9 g
palmitoyl-L-carnitine hydrochloride is obtained (74% yield). Its melting point is
determined at 164-184 °C
H-NMR (500 MHz, DMSO) δ 0.85 (t, 3 H); 1.25 (m, 24 H), 1.55 (m, 2 H), 2.35 (m, 2
H), 2.7 (d, 2 H), 3.12 (s, 9 H), 3.65 (d, 1 H), 3.85 (dd, 1 H), 5.45 (m, 1H)
Example 1: Palmitoyl-L-camitine hydrochloride in monochloroacetic acid
100 g L-carnitine and 180 g monochloroacetic acid are filled in the equipment and heated up to 70 °C. After complete melting the solution is cooled down to 30 °C. 24g HCI gas are added to the reactor, the reaction is stirred for 1 h at 50°C.
213 g palmitoyl chloride are slowly dosed over 1 hour and the solution is heated up to
70 °C and stirred for 2 hours.
1000 g Acetone are added at room temperature. The solid is filtered out, washed with
500 g acetone and dried at 60 °C and 14 mbar overnight.
The solid is recrystallized with 450g Acetone. 202.9 g palmitoyl-L-camitine
hydrochloride is obtained (74% yield). Its melting point is determined at 164-184 °C
H-NMR (500 MHz, DMSO) δ 0.85 (t, 3 H); 1.22 (m, 24 H), 1.5 (m, 2 H), 2.3 (m, 2 H),
2.7 (d, 2 H), 3.1 (s, 9 H), 3.65 (d, 1 H), 3.85 (dd, 1 H), 5.45 (m, 1H)
Example 2: Lauryl-L-Camitine hydrochloride
20.0 g L-Carnitine hydrochloride and 25.3 g monochloroacetic acid are filled in the
equipment and heated up to 70 °C. After complete melting the solution is cooled
down to 50 °C.
29.6 g lauryl chloride is slowly dosed over 1 hour and the solution is heated up to 70
°C and stirred for 3 hours.
After dosing 30.7 g isopropanol at room temperature and termination of the
exothermic reaction, 135.2 g ethyl acetate is added and the suspension is cooled
down to 3 °C overnight.
The solid is filtered out and washed with 147.8 g isopropanol/ethyl acetate (1:2.7)
and dried at 50 °C and 24 mbar overnight.
34.2 g lauryl-L-Carnitine hydrochloride is obtained.
A yield of 99.4% is achieved. The melting point of the final product is determined at
177 °C
H-NMR (500 MHz, DMSO) δ 0.86 (t, 3 H), 1.24 (m, 16 H), 1.52 (m, 2 H), 2.31 (m, 2
H), 2.68 (d, 2 H), 3.1 (s, 9 H), 3.61 (d, 1 H), 3.8 (dd, 1 H), 5.45 (m, 1H)
Example 3: Octanoyl-L-camitine hydrochloride
20.0 g L-Carnitine hydrochloride and 25.3 g monochloroacetic acid are filled in the
equipment and heated up to 70 °C. After complete melting the solution is cooled
down to 50 °C.
22.0 g octanoyl chloride is slowly dosed over 30 minutes and the solution is heated
up to 70 °C and stirred for 3 hours.
After slowly dosing 30.8 g isopropanol at room temperature and termination of the
exothermic reaction, 104.5 g ethyl acetate is added and the suspension is cooled
down to 3 °C overnight.
The solid is filtered out and washed with 147.8 g isopropanol/ethyl acetate (1:2.7)
and dried at 50 °C and 24 mbar overnight.
25.4 g octanoyl-L-carnitine hydrochloride is obtained.
A yield of 81.1% is achieved. The melting point of the final product is determined at
178-181 °C.
H-NMR (500 MHz, DMSO) δ 0.85 (t, 3 H), 1.25 (m, 8 H), 1.5 (m, 2 H), 2.3 (m, 2 H),
2.7 (d, 2 H), 3.1 (s, 9 H), 3.65 (d, 1 H), 3.8 (dd, 1 H), 5.45 (m, 1 H)

WE CLAIM
1. A process for the production of a fatty acid/L-carnitine hydrochloride derivative, whereby the educts are reacted in the presence of monochloroacetic acid.
2. The process according to claim 1, whereby the educts are the chloride of a fatty acid and L-carnitine.
3. The process according to claim 1 and/or 2, whereby the fatty acid is selected from the group consisting of palmitic acid, lauric acid and octanoic acid.
4. The process according to any of claims 1-3, whereby the monochloroacetic acid is used in a concentration of between 3.3 and 4.4 mol/L, preferably in a concentration of between 3.5 and 4.3 mol/L.
5. The process according to any of claims 1-4, whereby the chloride of the fatty acid is used in a concentration of between 1.25 and 1.85 mol/L, preferably in a concentration of between 1.6 and 1.85 mol/L.
6. The process according to any of claims 1-5, whereby L-carnitine is used in a concentration of between 1.2 and 1.5 mol/L, preferably in a concentration of between 1.2 and 1.4 mol/L.
7. The process according to any of claims 1-6, whereby the reaction takes place at a temperature of between 70 and 80 °C.