Poly amide hydrolysis

The polymeric drugs prepared from VBFU can also be expected to release 5-FU by amide hydrolysis as shown in Scheme 6. The hydrolysis of poly(VBFU) and poly(VBFU-co-MAn) was observed in a phosphate buffer solution (pH 7.0)... 

Figure 1. Schematic for the fabrication of a conductive organic circuit pattern. PAN refers to any in a series of nitrile-based polymers discussed below. Unconverted PAN may be an acceptable insulating phase. Alternatively, brief acid or base hydrolysis might convert it into the insulating poly(amide).

Alternating poly(amide-ester)s have been prepared from aminoalcohols and alkanedicarboxylic acids [67]. These are partially crystalline polymers with various rates of hydrolysis and subtilisin catalyzed degradations. 

Poly(amide enamine]s have been synthesized for this purpose and have been found to be susceptible to hydrolysis and biodegradation by both fungi and enz5mies. 

Poly(amide-enamine)s are synthesized because they degrade by surface erosion, unlike the degradation of other polymers like PGA which degrade homogeneously. These polymers are susceptible to hydrolysis and biodegradation by fimgi and enzymes (Huang et al, 1981). 

Many of these reactions are reversible, and for the stronger nucleophiles they usually proceed the fastest. Typical examples are the addition of ammonia, amines, phosphines, and bisulfite. Alkaline conditions permit the addition of mercaptans, sulfides, ketones, nitroalkanes, and alcohols to acrylamide. Good examples of alcohol reactions are those involving polymeric alcohols such as poly(vinyl alcohol), cellulose, and starch. The alkaline conditions employed with these reactions result in partial hydrolysis of the amide, yielding mixed carbamojdethyl and carboxyethyl products. 

The metabohc rate of poly(ester—amide) where x = Q has been studied in rats using carbon-14 labeled polymer. This study indicates that polymer degradation occurs as a result of hydrolysis of the ester linkages whereas the amide linkages remain relatively stable in vivo. Most of the radioactivity is excreted by urine in the form of unchanged amidediol monomer, the polymer hydrolysis product (51). 

The hydrolytic stability of water soluble poly[N-(4-sulfo-phenyDdimethacrylamide] (PSPDM) was studied at 90 C in aqueous solutions at pH 7, pH 1.2 (0.1M HC1), and pH 12.3 (0.1M NaOH). PSPDM, which possesses predominantly 5-mem-bered ring imides, was prepared by the cyclopolymerization and subsequent sulfonation of N-phenyldimethacrylamide. No detectable PSPDM imide hydrolysis occurred after 30 days at pH 7 or pH 1.2. Under basic conditions, however, complete hydrolysis to amic acid occurred after one day. The resulting Nsubstituted amide was extremely stable to further basic hydrolysis. 

In an attempt to hydrolyze PSPDM completely to head-to-head poly(methacrylic acid), higher temperature, and more strongly basic conditions were employed. PSPDM was heated at 125 C for four days in 5M NaOH. Like the 0.1M NaOH experiments, the imide was hydrolyzed to the amic acid and no further. The amide of the ring opened imide (V) is extremely resistant to basic hydrolysis. 

Five-membered ring imides in cyclopolymers of N-substituted dimethacrylamides such as PSPDM can be hydrolyzed to amic acids under moderately basic conditions. The resulting N-substituted amide is extremely resistant to basic hydrolysis. Consequently, this basic hydrolysis approach can still not be employed for the preparation of head-to-head poly(methacrylic acid). 

Acrylamide polymers in aqueous solution undergo thermal hydrolysis and cyclic imide formation. Acrylate, acrylamide and cyclic imide functional groups were detected when a poly(acrylamide) is heated at 150°C in water. The formation of intramolecular imide has been reported in literature. Moradi-Araghi, Hsieh and Westerman reported the formation of cyclic imide in acid, neutral and slightly basic media at 90° C.7 In acidic media, imide formation is favored. In neutral and basic media, both hydrolysis to acrylate and imide formation do occur, but hydrolysis is the dominant reaction. We speculate the high conversion of amine to amide is the result of transamidation, amidation and the nucleophilic addition of the amine to the glutarimide intermediate (Reaction 1). 

Chloromethyl polystyrene (Merrifield resin) has been prepared by chloro-methylation of polystyrene [23,27,53,54], by copolymerization of 4-chloromethylsty-rene with styrene [20,26,55,56], and by chlorination of poly(4-methylstyrene) [57,58], Aminomethyl polystyrene is most conveniently prepared by direct amidomethylation of polystyrene with (hydroxymethyl)amides or (halomethyl)amides under acidic conditions followed by hydrolysis [59-62], but it has also been prepared directly from chloromethyl polystyrene ([63,64] see also Section 10.1.1.1). 

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