Process for the hydrogenation of aromatic compounds
AssigneeEvonik Degussa GmbH
InventorsRolf Hartung, Franz Hitzel-Zerrahn, Thomas Müller, Jörg Pietsch
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Abstract
The present invention focuses on a process for the hydrogenation of aromatic or heteroaromatic compounds and in particular on the ring hydrogenation of compounds having the formula (I). Aromatic amino acids and amino alcohols can be successfully ring-hydrogenated using a platinum-rhodium mixed catalyst. The products can be used inter alia as mimetics in bioactive peptide active ingredients.
Claims20
A process for the hydrogenation of a compound, comprising hydrogenating a C6-C18 aromatic substituted amino acid or C6-C18 aromatic substituted amino alcohol in the presence of a platinum-rhodium mixed catalyst, wherein said C6-C18 aromatic substituted amino acid or C6-C18 aromatic substituted amino alcohol is of formula (I):
- wherein
- n is 0, 1 or 2;
- R1 is a (C6-C18) aryl, or a (C7-C19) aralkyl, wherein aryl groups are optionally substituted with halogen, (C1-C8) alkoxy, (C1-C8) acyl, or (C1-C8) acyloxy;
- R2 is H, OH, (C1-C8) alkyl, (C2-C8) alkoxyalkyl;
- R3 and R4 are each independently H, a (C1-C8) alkyl, a (C6-C18) aryl, or together denote an ═O function;
- P1 and P2 are each independently hydrogen, an amino protective group or together stand for a bifunctional amino protective group;
- P3 is hydrogen, a hydroxyl protective group, or a carboxyl protective group;
- and
- the carbon atom marked with * is an asymmetrical carbon atom;
- and wherein;
- said process produces a yield of greater than 94% after a reaction time of about 6 to 8 hours;
- and
- the hydrogenation reaction is performed in the presence of a solvent consisting of a mixture of water and an alcohol.
A process for the hydrogenation of a compound selected from the group consisting of:
- L-phenylalanine, D-phenylalanine, L-phenylglycine, D-phenylglycine, L-tyrosine or D-tyrosine, comprising hydrogenating said compound in the presence of a platinum-rhodium mixed catalyst wherein said process produces a yield of greater than 94% after a reaction time of about 6 to 8 hours, and wherein:
- a) the hydrogenation reaction is performed in the presence of a solvent consisting of a mixture of water and an alcohol;
- b) the ratio of platinum to rhodium in said platinum-rhodium mixed catalyst is between 20:1 and 1:1 (w/w);
- said platinum-rhodium mixed catalyst is used in a quantity of 0.1 to 20 wt %, relative to the compound undergoing hydrogenation.
A process for the hydrogenation of a compound selected from the group consisting of:
- L-phenylalanine, D-phenylalanine, L-phenylglycine, D-phenylglycine, L-tyrosine or D-tyrosine, comprising hydrogenating said compound in the presence of a platinum-rhodium mixed catalyst wherein said process produces a yield of greater than 94% after a reaction time of about 6 to 8 hours, and wherein the hydrogenation reaction is performed in the presence of a solvent consisting of a mixture of water and an alcohol.
Dependencies are inferred from the claim text.