Degradation mechanism amides

Ionica, Filip and Dinulescu50 studied hypohalite halogenation of A-bonded acidic hydrogens, which proceeds considerably faster than corresponding carbon-H halogena-tions. They used Hoffmann degradation of amides as a proof of their mechanism (equation 32). Based on the overall stoichiometry of the reaction they suggested that if their... 

Edman degradation. Alanine amide was treated with phenyl isothiocyanate to form PTH-alanine. Write a mechanism for this reaction. 

Let us begin with a reaction that we encountered earlier as a method of synthesis of amines the Hofmann degradation of amides. Whatever the mechanism... 

Patricelli MP, Cravatt BF (1999) Fatty acid amide hydrolase competitively degrades bioactive amides and esters through a nonconventional catalytic mechanism. Biochemistry 38 14125-14130... 

The immediate direct quenching prevents the growth of large spher-ulites, which cause polymer brittleness and degrade mechanical properties of the solid state polymerized polymers. The method has been exemplified with poly(amide)s (PA)s and poly(butylene terephthalate) (PBT). 

If a polymer contains structures that can absorb terrestrial sunUght wavelengths (>290-300 nm), which leads to chemistry causing changes in molecular structure, photolysis can be an important degradation mechanism. Norrish I and II of carbonyl, ester, or amide containing polymers (e.g., oxidized PE, PES, and PAs) and the photo-Fries reaction in bi-sphenol A polycarbonate (BPA-PC) are well-known photolytic reactions [52]. These reactions are shown in Schemes 18.4-18.6. 

Although polymers in-service are required to be resistant toward hydrolysis and solar degradation, for polymer deformulation purposes hydrolysis is an asset. Highly crystalline materials such as compounded polyamides are difficult to extract. For such materials hydrolysis or other forms of chemolysis render additives accessible for analysis. Polymers, which may profitably be depolymerised into their monomers by hydrolysis include PET, PBT, PC, PU, PES, POM, PA and others. Hydrolysis occurs when moisture causes chain scissions to occur within the molecule. In polyesters, chain scissions take place at the ester linkages (R-CO-O-R ), which causes a reduction in molecular weight as well as in mechanical properties. Polyesters show their susceptibility to hydrolysis with dramatic shifts in molecular weight distribution. Apart from access to the additives fraction, hydrolysis also facilitates molecular characterisation of the polymer. In this context, it is noticed that condensation polymers (polyesters, -amides, -ethers, -carbonates, -urethanes) have also been studied much... 

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