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Amino groups dimerization reactions

Reactions. Reactions of cyanamide are either additions to the nitrile group or substitutions at the amino group. Both are involved in the dimerization to dicyandiamide. [Pg.367]

Most of the reactions occurring at the amino group of the cyanamide molecule requite the anionic species, —N=C=N or HN C=N, sometimes in equivalent amount and occasionally as provided by base catalysis. Therefore, the process conditions for dimerization should be created to avoid the use of any metal salt, such as mono sodium phosphate (4). [Pg.367]

FIGURE 3.15 Protection of amino groups as urethanes by reaction with succinimido carbonates (path A).33-36 The mixed carbonate is a weaker electrophile than the chloroformate. The V-alkoxycarbonylamino-acid anion does not react with the reagent (path B) in the presence of the weak base hence no dimer is formed. R = triethyl or dicyclohexyl. [Pg.81]

Imipenem (5.46) has not completely fulfilled such expectations [122], Indeed, this compound is unstable in both acidic and alkaline media. In weakly acidic solutions, imipenem undergoes complex oligomerization, a reaction initiated by the intermolecular attack of the carboxy group on the /3-lactam Fig. 5.17) and yields, finally, a diketopiperazine compound. In weakly alkaline solution, an intermolecular reaction between the /3-lactam and (iminome-thyl)amino group was observed Fig. 5.18). This reaction proceeds via an unstable dimer that breaks down to thienamycin (5.45) and a /3-lactam ring-opened compound bearing a Ai-formyl group [123],... [Pg.219]

If methyleneindoline-o)-aldehydes are condensed with cyclic amines substituted by an amino group in the aromatic ring, dyes are obtained that can be dimerized either by reaction with cyanuric chloride in a molar ratio of 2 1 or with phosgene. On account of their high substantivity these dyes are suitable for dyeing bleached sulfite pulp [22],... [Pg.257]

Also acetic acid may arise from a reaction of this type. Most important compounds of this pathway are pyruvic aldehyde, diacetyl, hydro-oxyacetone and hydroxydiacetyl which can easily react with amino acids. The Strecker degradation is a reaction where the amino acid is de-carboxylated and loses its amino group. Reaction products are the Strecker aldehyde and - as an intermediate - an aminoketone which forms a pyrazine by dimerization. This pathway is considered to be most important for the origin of pyrazines in thermal aromas. However, only limited knowledge is available about the fate of the Strecker aldehydes. As we will demonstrate they are very reactive. [Pg.146]


See other pages where Amino groups dimerization reactions is mentioned: [Pg.214]    [Pg.189]    [Pg.562]    [Pg.805]    [Pg.204]    [Pg.74]    [Pg.493]    [Pg.608]    [Pg.79]    [Pg.154]    [Pg.181]    [Pg.221]    [Pg.222]    [Pg.952]    [Pg.163]    [Pg.624]    [Pg.314]    [Pg.132]    [Pg.127]    [Pg.307]    [Pg.292]    [Pg.294]    [Pg.11]    [Pg.788]    [Pg.204]    [Pg.329]    [Pg.310]    [Pg.778]    [Pg.782]    [Pg.189]    [Pg.800]    [Pg.48]    [Pg.63]    [Pg.237]    [Pg.834]    [Pg.948]    [Pg.63]    [Pg.237]    [Pg.285]    [Pg.184]    [Pg.398]    [Pg.258]    [Pg.189]    [Pg.196]    [Pg.132]   
See also in sourсe #XX -- [ Pg.349 ]




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Amino group reactions

Dimerization reactions

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