POLYSUCCINIMIDE

Only a few biopolymers have been incorporated between LDH lamellae. For instance, the incorporation of poly(Q ,/ aspartate) was reported [89] to proceed by the condensation of aminosuccinic acid via a polysuccinimide intermediate, which rearranges to give polyaspartate at 220 °C. It was found that the basal spacing decreases during the condensation process from 11.1 to 9.0 A, giving an available space of only 4.2 A for the accommodation of... 

J.J. Harrison and J. Ruhe, William R., Dispersant polysuccinimides derived from terpolymers, EP Patent 0831104, assigned to Chevron Chem. Co., March 25,1998. 

Title Preparation of High Molecular Weight Polysuccinimides... 

L-Aspartic acid solubilized with hydrochloric was polymerized with 30% polypho-sphoric acid at 180°C to prepare linear polysuccinimides having a Mw of 180,000 dal tons. When the polysuccinimide was hydrolyzed with dilute sodium hydroxide an a,p-polysodium aspartate hydrogel was generated. 

IM of NaOH per equivalent of succinimide. The alkaline conditions were held at pH 10 by auto-titration at 80°C in water bath. Under these mild conditions polysuccinimides were converted to polyaspartates within 1 hour. 

TABLE 1. Summary of weight average molecular weights from the preparation of polysuccinimides using L-aspartic acid using polyphosphoric acid. 

Poly(sodium aspartate-co-asparagine-co-succinimide), (II), was prepared by the author [3] by hydrolysis of polysuccinimide with ammonium and sodium hydroxides. A method for preparing branched polysuccinimide derivatives of the current investigation was also provided. 

Swift [4,5] prepared poly(succinimide-co-sodium aspartate) by copolymerizing aspartic acid with monosodium aspartate and polysuccinimide using L-aspartic acid in supercritical CO2. 

By initiating the polymerization of aspartic acid with a malimide end capping initiator, (III), Swift [6] prepared a functionalized polysuccinimide derivative. 

Optically active malimides have been prepared by condensing succinic anhydride with either (IR, 2R)- or (lS,2S)-2-benzyloxycyclopentylamine and then polymerizing into the corresponding polysuccinimide. When used on a silica gel support in a packed chromatographic column, the polysuccinimide separated selected racemic mixtures. 

These amino acid anhydrides are usuaiiy made with phosgene. The use of dimethyi carbonate shouid be tested in the preparation of the monomers. Poiyaspartic acid can be made by heating aspartic acid without soivent to form a polysuccinimide which is then hydrolyzed (12.34).186 It can also be made directly from maleic anhydride and ammonia. It promises to be useful as a scale inhibitor in water, an antiredeposition agent in detergents, and such. Gamma-irradiation converts it to a biodegradable superabsorbent material that takes up 3400 g water per gram of dry polymer.187 (Most superabsorbent polymers are based on acrylamide, a neurotoxin.)... 

As described in Section 6.2.5, a family of ion exchangers can be obtained from polysuccinimide silica poly(2-sulfoethyl aspartamide) is an aliphatic strong cation exchanger, and polyaspartic acid is a weak cation exchanger. The primary use of this family of products is in the area of protein and peptide separations. These packings exhibit a superior column efiiciency compared to th coimterparts based on organic polymers. 

Heating aspartic acid (I) with or without catalyst leads to a linear thermal polycondensation polymer known as polysuccinimide (II), conversions of monomer to polymer of greater than 95% being easily accomplished. Hydrolysis of polysuccinimide with base such as sodium hydroxide, leads to a random copolymer of a and aspartate units (III), with the 8 aspartate comprising about 70%—75% of the repeating units. 

Aminopropyl)morpholine (R -NH2 10 mmol) was added dropwise to polysuccinimide (20 mmol) dissolved in DMF (25 ml redistilled at reduced pressure under N2) and precooled to O C. The solution was stirred for 6h at room temperature it was then added dropwise to a stirred solution of diethylenetriamine fR -NH2 20 mmol) in the same solvent (20 ml), again cooled at 0"C. After stirring for another 5h at room temperature, the product polymer was precipitated from the viscous solution by Et20-petroleum ether (bp 65-70 C) and redissolved in H2O (50 ml). The pH was adjusted to 8 (IM HCl), and the solution was dialyzed and freeze-dried, to give copolyamide 4 in 61% yield 7/inh(H20), 12 ml g"i. The composition (x = y) was ascertained from elemental analytical and NMR data. 

The two structures starting from L-aspartic acid are shown in Scheme 10. Pathway A is the acid-catalyzed thermal condensation, and B is the noncatalyzed thermal condensation. The polysuccinimide intermediates hydrolyze at the points indicated to give mixtures of a, p poly (d,l- aspartic acid) salts. Regardless of the stereochemistry of the starting aspartic acid, d or l, the final polymeric product is always the dl racemate. 

A recent huge advance in this chemistry is reported by Sikes [142] and shown in Scheme 11. This advance allows the synthesis of water-soluble reactive intermediates by copolymerizing monosodium aspartate with aspartic acid in a preselected ratio. The intractable polysuccinimide intermediate obtained in other polymerizations mentioned earlier in other approaches is avoided, and the copolymer is soluble in water for further functionalization. Easier handling is very important for future characterization and development of applications. 

We used a synthetic polypeptide, a,P-poly[N-(2-hydroxyethyl)-D,L-aspartamide], which was prepared by aminolysis with aminoethanol of D,L-poly uccinimide obtained by thermal polycondensation The polysuccinimide is fully racemic and the aminolysis results in random opening of the succinimide rings, as demonstrated by the C-NMR spectrum As enzymes hydrolyze only the peptide bond... 

The polyaspartic acids a,P-poly[(2-hydroxyethyl)-fi(-/-aspartamide] with good biodegradability are used in detergents and cleaners. They are prepared by polycondensation of aspartic acid in the presence of phosphoric acid in a molar ratio of from 1 0.5 to 1 10 at a temperature of at least 120 C to give polysuccinimide. Subsequent hydrolysis of the polysuccinimide with bases is... 

Carriers similar to the conjugates shown in 32 were synthesized by Michael addition polymerizations or from polysuccinimide by a two-step ring-opening procedure. These carriers contain 1,2-dicarboxyl-fimctional anchoring sites in the side groups. They can be platinated to make structures like those in 49, derived from 48, and 50. 

Finally, a polymer featuring a 1-carboxyl-l-hydroxyl drug anchoring segment, which was synthesized by a two-step aminolysis of polysuccinimide, is given in 53. 

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