Amino groups introduction

Introduction of amino groups Introduction of conjugation Condensation with a triazole ring. 

The final step can involve introduction of the amino group or of the carbonyl group. o-Nitrobenzyl aldehydes and ketones are useful intermediates which undergo cyclization and aromatization upon reduction. The carbonyl group can also be introduced by oxidation of alcohols or alkenes or by ozonolysis. There are also examples of preparing indoles from o-aminophcnyl-acetonitriles by partial reduction of the cyano group. 

Ultraviolet photoelectron spectroscopy allows the determination of ionization potentials. For thiazole the first experimental measurement using this technique was preformed by Salmona et al. (189) who later studied various alkyl and functional derivatives in the 2-position (190,191). Substitution of an hydrogen atom by an alkyl group destabilizes the first ionization potential, the perturbation being constant for tso-propyl and heavier substituents. Introduction in the 2-position of an amino group strongly destabilizes the first band and only slightly the second. 

Use of dimethylaminoethyl (also rert-butylaminoethyl) methacrylate as a monomer permits the introduction of pendent amino groups which can serve as sites for secondary cross-linking, provide a way to make the copolymer acid-soluble, and provide anchoring sites for dyes and pigments. 

A.mina.tlon. Amination describes the introduction of amino groups into aromatic molecules by reaction of ammonia or an amine with suitably substituted halogeno, hydroxy, or sulfonated derivatives by nucleophilic displacement. Although reaction and operational conditions vary, the process always involves the heating of the appropriate precursor with excess aqueous ammonia or amine under pressure. 

Substituted Anthraquinones. Commercially important blue disperse dyes are derived from 1,4,5,8-substituted anthraquiaones. Among them, diaminodihydroxyanthraquiaone derivatives are most important in view of their shades and affinity. Representative examples are Cl Disperse Blue 56 [31810-89-6] (11) Cl 63285) (126), and Cl Disperse Blue 73 (113) (115). Introduction of a halogen atom ortho to the amino group improves affinity and lightfastness. 

Another important correlation between structure and properties in the pteridine series is seen in the solubilities, to which insufficient attention has been paid in general. Introduction of an amino group into pteridine (1) lowers the solubility in all solvents despite the fact... 

The addition of nucleophiles to double and triple bond systems is often a convenient way of effecting an intramolecular ring closure. Addition to cyano groups has received considerable attention, as in addition to ring formation it provides a convenient method for the introduction of an amino group. Reaction of methyl Af-cyanodithiocarbimidate with Af-methylaminoacetonitrile resulted in displacement of methanethiol and formation of (314). Sodium ethoxide treatment in DMF converted (314) into a 4-amino-5-cyanoimidazole... 

It is not only the activity that can be altered by incorporation of noncoded amino acids. Introduction of structures possessing certain chemical functions leads to the possibility of highly regioselective modification of enzymes. For example, selective enzymatic modification of cystein residues with compounds containing azide groups has led to the preparation of enzymes that could be selectively immobilized using click chemistry methods [99]. 

The relative insensitivity of Sp to changes in electronegativity of substituents which is observed for P fluoro-compounds is also evident for penta-arylphosphoranes. Thus the placement of />ara-substituents on the phenyl rings of pentaphenylphosphorane has very little effect and Sp is -f 88 1 p.p.m. for (16 Y = H, Me, or Cl). The effect on Sp of the introduction of an amino-group in the bis-biphenylenephosphorane system (17) is similar to that of an alkyl group (see Table 3). ... 

Osmium tetroxide used in combination with sodium periodate can also effect alkene cleavage.191 Successful oxidative cleavage of double bonds using ruthenium tetroxide and sodium periodate has also been reported.192 In these procedures the osmium or ruthenium can be used in substoichiometric amounts because the periodate reoxidizes the metal to the tetroxide state. Entries 1 to 4 in Scheme 12.18 are examples of these procedures. Entries 5 and 6 show reactions carried out in the course of multistep syntheses. The reaction in Entry 5 followed a 5-exo radical cyclization and served to excise an extraneous carbon. The reaction in Entry 6 followed introduction of the allyl group by enolate alkylation. The aldehyde group in the product was used to introduce an amino group by reductive alkylation (see Section 5.3.1.2). 

Introduction of an additional substituent such as alkyl, alkoxy, halogen, etc. at 3 -position has a large effect on color. That is, green color changes to red color when there is a tertiary amino group at 2 -position. Thus, 2 -dibenzylamino-6 -diethylamino-3 -methylfluoran (47 R1 = H, R2 = CH3 ),40 2 -dibenzylamino-6 -diethylamino-3 -ethylfluoran (47 R1 = H, R2 = C2H 5),34 3 -chloro-2 -dibenzylamino-6 -diethylaminofluoran (47 R1 = H, R2 = Cl),34 6 -((V-ethyl-4-methylanilino)-3 -methyl-2 -((V-methylanilino)flu-... 

Fig. 4.7 shows the titration with perchloric acid of a mixture of piperidine, ethylenediamine and p-toluidine. Fig. 4.8 illustrates the effect of different chain lengths on the titration (with perchloric acid) of diamines in nitrobenzene containing 2.5% (v/v) of methanol once the first amino group of EDA has been protonated, the resulting proton bridge with the lone pair of electrons of the second amino group lowers the basicity of the latter considerably the effect decreases on the introduction of more intermediate CH2 groups until complete disappearance when six are present. 

Nucleophilic substitution reactions, to which the aromatic rings are activated by the presence of the carbonyl groups, are commonly used in the elaboration of the anthraquinone nucleus, particularly for the introduction of hydroxy and amino groups. Commonly these substitution reactions are catalysed by either boric acid or by transition metal ions. As an example, amino and hydroxy groups may be introduced into the anthraquinone system by nucleophilic displacement of sulfonic acid groups. Another example of an industrially useful nucleophilic substitution is the reaction of l-amino-4-bromoanthraquinone-2-sulfonic acid (bromamine acid) (76) with aromatic amines, as shown in Scheme 4.5, to give a series of useful water-soluble blue dyes. The displacement of bromine in these reactions is catalysed markedly by the presence of copper(n) ions. 

As mentioned in the Introduction, a variety of unusual carbohydrate -protein linkages is found in Nature. These may be placed in several categories (i) carbohydrates O-glycosylated to jff-hydroxy amino acids (ii) carbohydrates S-glycosylated to cysteine (Hi) carbohydrates N-gly-cosylated to the N-terminal amino group of the protein or (iv) in some... 

Bidentate sites may be available in DNA itself. In the binding of Hg2+ and Ag+ we surmise that the binding is to amino-groups of cytidine and adenine and possibly the N(7) of guanine as all these positions are accessable in DNA. The introduction of a more kinetically permanent group such at [Pt(NH3)2]2+ attached to two such groups, e.g. two amino groups could lead to the formation of an inter-strand cross-link and an inhibition of DNA synthesis (90). 

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