Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2003-01-03
2004-05-18
Hightower, P. Hampton (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S363000, C525S054110, C525S419000, C525S420000
Reexamination Certificate
active
06737501
ABSTRACT:
DESCRIPTION
1. Field of the Invention
The present invention relates to hydrophobically modified copolymeric polyglutamic acid derivatives and to a process for their preparation by condensation of glutamic acid or derivatives thereof with amines and coamino acids. The present invention also relates to the use of the hydrophobically modified copolymeric polyglutamic acid derivatives of the present invention.
2. Background of the Invention
Polypeptides, constructed from naturally occurring amino acids, are readily biodegradable and toxicologically safe. Moreover, polypeptides are valuable additives which, due to their properties, have received particular attention and are being used to an increasing extent.
Depending on the grade of amidation and hydrophobicity of the amine component, polyglutamides, in addition to their toxicological safety, their excellent mildness and biodegradability, are characterized by excellent properties as film formers and coatings, particularly in pharmacy and in the food sector. In addition, applications as biodegradable complexing agents, softeners and detergent builders are proposed.
The literature describes a large number of polypeptides and processes for their preparation, in particular those based on aspartic acid.
U.S. Pat. No. 5,057,597 describes the thermal polymerization of solid aspartic acid in a moving-bed or fluidized-bed reactor at temperatures of at least 180° C. to 250° C., where the reaction mixture remains flowable throughout the entire process.
U.S. Pat. No. 3,052,655 describes the preparation of copolymeric polypeptides which, in addition to aspartic acid, can also contain one or more other &agr;-amino acids. To prepare a liquid reaction mixture, the addition of an equimolar amount, based on the total amount of the amino acids, of concentrated phosphoric acid is required.
DE-A-36 12 102 discloses soluble and biodegradable copolymeric polypeptide amides, which, in the main chain, contain aspartic acid and/or glutamic acid units and units of other amino acids, and in which the hydrocarbon radical of the amide moiety can have 3 to 7 carbon atoms. These prior art compounds have molar masses of from 5,000 to 1,000,000 and are used, following reaction with amino alcohols or hydrazine, for binding biologically active substances.
EP-A-0 959 091 relates to copolymeric polyaspartic ester amides which have been modified with alkyl or alkenyl radicals having 6 to 30 carbon atoms, as well as their preparation and their use. As a result of the preparation process of the polyaspartic acid in which, in the first step, maleic monoesters are reacted with ammonia, and subsequent (partial) hydrolysis of the ester bonds, followed by the amidation of the free carboxyl groups, this prior art process forms products that still contain ester bonds.
According to DE-A-39 21 912, reaction products from polysuccinimide and amines having 1 to 8 carbon atoms in the hydrocarbon radical, which, in addition to the amide groups, also contain imide groups and optionally free carboxyl groups or ammonium salts thereof, can be used as coatings and/or retardants for medicaments and foods. The amidation of the polysuccinimide is carried out in dimethylformamide (DMF) as solvent, which in turn has to be removed afterward by laborious process steps and using large amounts of less acceptable solvents.
SUMMARY OF THE INVENTION
An object of the present invention is to provide simpler and more effective processes for the preparation of optionally copolymeric polypeptides, in particular those based on glutamic acid and aspartic acid, which, through simple variation of the starting materials and/or the reaction parameters, permits polymers with a predetermined distribution of the monomers within the molecule, i.e., from random distribution to the desired block formation, and also the setting of tailored molecular weights.
It has now been found that the foregoing object is achieved by a process for the preparation of optionally copolymeric polypeptides by simultaneous or stepwise reaction of glutamic acid and at least one further &agr;-amino acid and/or derivatives thereof with amines in the absence of solvents and catalysts under condensation conditions, optionally at subatmospheric pressure and with removal of the condensate from the reaction mixture.
The present invention therefore provides a process for the preparation of copolymeric polypeptides which comprises, in a first stage, reacting glutamic acid and/or derivatives thereof with amines in the absence of solvents and catalysts under condensation conditions, optionally at subatmospheric pressure and with removal of the condensate from the reaction mixture and, in a second stage, adding one or more further amino acids and/or derivatives thereof and/or one or more identical and/or further amines simultaneously or in any desired order, and reacting them with the reaction product of the first stage in the absence of solvents and catalysts.
The present invention further provides a process for the preparation of optionally copolymeric polypeptides, which comprises, in a first stage, reacting glutamic acid and/or derivatives thereof with one or more further &agr;-amino acids and/or derivatives thereof in the absence of solvents and catalysts under condensation conditions, optionally at subatmospheric pressure and with removal of the condensate from the reaction mixture and, in a second stage, reacting one or more amines simultaneously or in any desired order with the reaction product of the first stage in the absence of solvents and catalysts, under condensation conditions, optionally at subatmospheric pressure and with removal of the condensate from the reaction mixture.
The present invention further provides a process for the preparation of optionally copolymeric polypeptides, which comprises, in a first stage, reacting glutamic acid and/or derivatives thereof with one or more further &agr;-amino acids and/or derivatives thereof, with one or more amines simultaneously or in any desired order in the absence of solvents and catalysts, under condensation conditions, optionally at subatmospheric pressure and with removal of the condensate from the reaction mixture and, in a second stage, reacting glutamic acid and/or one or more further coamino acids and/or derivatives thereof and/or one or more identical and/or further amines simultaneously or in any desired order with the reaction product of the first stage in the absence of solvents and catalysts under condensation conditions, optionally at subatmospheric pressure and with removal of the condensate from the reaction mixture.
The present invention further provides a process for the preparation of optionally copolymeric polypeptides, which comprises, in a first stage, mixing at least one amino acid and/or derivatives thereof with amines in a ratio such that the mixtures are liquid at the condensation temperature, and heating them in the absence of solvents and catalysts to at least the melting temperature and, in a second stage, optionally metering in further coamino acids and/or amines simultaneously or in any desired order, and reacting the mixture with the mixture or the reaction product of the first stage under condensation conditions, optionally at subatmospheric pressure and with removal of the condensate from the reaction mixture.
DETAILED DESCRIPTION OF THE INVENTION
The present invention, which provides processes for producing hydrophobically modified polyglutamic acid derivatives, will now be described in more detail.
In accordance with the present invention, 30 to 90%, by weight, of the units present in the inventive copolymers consist of structural units of general formula (I), and 70 to 30%, by weight, of the units consist of structural units of general formula (II)
in which
A is a trifunctional radical with three carbon atoms and has one of the following structures
and in which
R
1
can have the meaning of R
2
, R
3
and R
4
, where
R
2
is identical or different amide radicals —C(O)NH—R
9
where
R
9
is straight-chain or branched, saturated and unsaturated alkyl r
Dietz Thomas
Messinger Erika
Muss Peter
Schick Ute
Weitemeyer Christian
Goldschmidt AG
Hampton Hightower P.
Scully Scott Murphy & Presser
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