Amino group resonance effect

Notice that the MO picture gives the same qualitative picture of the substituent effects as described by resonance structures. The amino group is pictured by resonance as an electron donor which causes a buildup of electron density at the /3 carbon, whereas the formyl group is an electron acceptor which diminishes electron density at the /3 carbon. 

C. Resonance Effect of the Amino Group and Related Groups. 518... 

Groups that are particularly strong electron releasers do not achieve this by an inductive effect, but they have heteroatoms with lone pair electrons that are able to stabilize resonance structures by transferring the charge to the heteroatom, i.e. an electron-releasing resonance effect. An amino group is typical of this type of substituent. 

It can be seen that lone pair donation creates another favourable resonance form only when electrophilic attack is ortho or para to the amino group. There is a small electron-withdrawing inductive effect... 

A number of studies have examined the antioxidant activities of chitosan from various sources. Park et al. (2004a) prepared three kinds of partially deacetylated hetero-chitosans such as 90% deacetylated, 75% deacetylated, and 50% deacetylated chitosan from crab chitin, and their antioxidant properties were measured using electron spin resonance spectrometry. Park and coworkers found that their antioxidant activities were dependent on the DD, and the 90% deacetylated chitosan showed the highest free radical scavenging activities. Yen et al. (2008) also found that a sample with more amino groups at the C-2 position showed the highest antioxidant activity. Tomida et al. (2009) examined the protective effects of seven different MW chitosans on plasma protein from oxidation by peroxyl radicals. In the ability to protect plasma protein from... 

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