Amide groups neutral

Water-soluble pAM neutral polymer interacts with ions of the solution through the complex formation between amide groups and hydrated ions. 

The amide group of coelenteramide is an extremely weak acid thus, it will be rapidly protonated in a neutral protic environment, changing into its neutral (unionized) form. If the rate of the protonation of the excited amide anion is sufficiently fast in comparison with the rate of its de-excitation, a part or most of the excited amide anion will be converted into the excited neutral species within the lifetime of the excited state of the amide anion, resulting in a light emission from the excited neutral coelenteramide (kmax about 400 nm). 

Substituent effects on ks. The replacement of an a-methyl group at the 4-methoxycumyl carbocation CH3-[14+] by an a-ester or a-amide group destabilizes the parent carbocation by 7 kcalmol-1 relative to the neutral azide ion adduct (Scheme 11 and Table 3) and results in 5-fold and 80-fold decreases, respectively, in ks for nucleophilic addition of a solvent 50/50 (v/v) methanol/water.33 These results follow the trend that strongly electron-withdrawing substituents, which destabilize a-substituted 4-methoxybenzyl carbocations relative to neutral adducts to nucleophiles, do not lead to the expected large increases in the rate constants for addition of solvent.28,33,92-95... 

The neutral amino acids (class IV) have hydroxyl groups serine, threonine) or amide groups asparagine, glutamine). Despite their nonionic nature, the amide groups of asparagine and glutamine are markedly polar. 

An X-ray crystallographic study of 33 shows this compound to be neutral with two Me3SiCH2 groups -bonded to zinc while the amide group is /z -bonded via its nitrogen... 

Pinori, M. Di Gregorio, G. Mascagni, P. A New Anchor Group for the Solid-phase Synthesis of C-terminal Peptide Amides Under Neutral Conditions, in Innovation and Perspectives in Solid Phase Synthesis, Epton, R., Ed. Mayflower Worldwide Kingswinford, 1994 pp. 635-638. 

Unlike amines, which also contain nitrogen (Section 23.12), amides are neutral rather than basic. Amides do not act as proton acceptors and do not form ammonium salts when treated with acid. The neighboring carbonyl group causes the unshared pair of electrons on nitrogen to be held tightly, thus preventing the electrons from bonding to H+. 

Conjugation of the nitrogen lone pair with the adjacent phosphoryl or carbonyl function was tested by the 13C NMR parameters of the N-phosphorylated and N-acetylated aniline, as well as of their complexes with Lewis acids. (h ). The inductive and resonance constants for the neutral and charged amide groups were determined using the dual substituent parameter (dsp) approach. ( 5). Results are given in the Table. 

Other neutral hosts have also been prepared based upon the hydrogen-bond donating ability of appropriately arranged amide groups,71-74 highly fluorinated macrocycles,75 or even +S=08- and 8+P=Os- dipoles.76... 

Amides are carboxylic acid derivatives. The amide group is recognized by the nitrogen connected to the carbonyl group. Amides are neutral compounds the electrons are delocalized into the carbonyl (resonance) and thus, are not available to bond to a hydrogen ion. 

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