L-Glutamic Acid → L-Pyroglutamic Acid
Reaction equation
[NH2:1][C@H:2]([C:8]([OH:10])=[O:9])[CH2:3][CH2:4][C:5](O)=[O:6]>O>[NH:1]1[C:5](=[O:6])[CH2:4][CH2:3][C@H:2]1[C:8]([OH:10])=[O:9]Participants
Reactant 1
Product 1
Reagents, catalysts & solvents 1
Procedure
The preparation process is described below by way of example. In a first stage, glutamic acid, for example, is melted at about 170-180° C., under which the cyclic amide, pyroglutamic acid (2-pyrrolidone-5-carboxylic acid) is formed by elimination of water. Instead of glutamic acid, it is also possible to use proline or a polar, high-boiling solvent such as N-methylpyrrolidone or sulfolane. Aspartic acid is then added, and the melt or the high-boiling solution is heated at 160-220° C. In this process polysuccinimide forms, which, in cases where glutamic acid is used, also contains glutamic acid units. The duration and temperature of heating is used to control the molecular mass of the growing polymer. The longer the heating time and the higher the temperature, the higher the molecular mass. In the next step, the organofunctional polysiloxane is added dropwise. The heating time after all of the polysiloxane has been added in turn influences the molecular mass of the copolymer formed. The melt is poured out and, after cooling, forms a glasslike mass, which can be readily pulverized by grinding. This is the water-insoluble form of the polypeptide-polysiloxane copolymer.
Sources & evidence
- ORD record
- ord-1a5da306f53c46358bf0ab1d121aa8ee
- Source dataset
- uspto-grants-2002_03
- Patent number
- US06358501B1
Reaction notes
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