Active hydrogen compounds amination

If the active hydrogen compound has two or three active hydrogens, the Mannich base may condense with one or two additional molecules of aldehyde and ammonia or amine, for example. 

According to this mechanism, it is the free amine, not the salt that reacts, even in acid solution and the active-hydrogen compound (in the acid-catalyzed process) reacts as the enol when that is possible. This latter step is similar to what happens in 12-4. There is kinetic evidence for the intermediacy of the iminium ion (13). 

For the reaction of isocyanate with active hydrogen compounds, tertiary amines or tin compounds act on... 

Compounds Z are active hydrogen compounds such as amines, anhydrides, and acids [30]. The curing reaction can also involve homopolymerization catalyzed by Lewis acids or tertiary amines. In most cases, reactions catalyzed by... 

Reaction between aldehydes, ammonia or amines, and an active hydrogen compound (Mannich)... 

The limit is reached with 1,3,5-triazine. This reacts very easily even with weak nucleophiles, and ring cleavage nearly always follows. Thus, it behaves as a formylating agent toward amines and other active hydrogen compounds. 

Catalysts may be Lewis bases like tertiary amines. The catalyst forms an initial coordination complex with the carbonyl carbon atom, with subsequent displacement by the active hydrogen compound ... 

Free radical initiators or active hydrogen compounds such as amines or alcohols are not very effective initiators for the polymerization of lactones. Polyesters of low molecular weight are produced by these techniques. For example, copolymerization of various lactones in the presence of water at 200 °C proceeded via a hydrolysis followed by the polycondensation reaction of the hydroxy acid, giving low molecular weight products [67-69]. Low molecular weight (=10,000) tri-block copolymer (CL-b-EO-b-CL) has been prepared from e-CL and poly(ethylene glycol) (Mn=10 3) by carrying out the polymerization at 165 °C for several hours in the absence of catalysts [70]. 

The polyaddition reaction is the most commonly used type of reaction for the cure of epoxy resins. The curing agents used in this type of reaction have an active hydrogen compound, and they include amines, amides, and mercaptans. With this reaction mechanism, the most important curing agents for adhesives are primary and secondary amines containing at least three active hydrogen atoms and various di- or polyfunctional carboxylic acids and their anhydrides. 

Step-Growth Polymerization. Only a relative few of the dozens of active hydrogen compounds that undergo reactions with the epoxy ring find widespread use in epoxy structural adhesives. The most common are amines, acid anhydrides, phenols, thiols, and carboxylic acids. 

Although formaldehyde has been most common, other aldehydes have also been used successfully for the formation of iminium ion. The Mannich reaction also proceeds with the other activated hydrogen compounds such as indole, furan, pyrrole and phenols. When primary amine is used, the Mannich base formed is a secondary amine and may undergo further condensation to yield tertiary amine. The Mannich base may eliminate an amine... 

In either case, the tertiary amine is apparently displaced by the active-hydrogen compound (alcohol, amine, etc.). 

In an elaborate study, Takahashi and co-workers investigated the exchange of allylic ethers and esters with a variety of active hydrogen compounds (255), including esters, ethers, carbanoid species, and amines. 

This reaction shows the addition of an active hydrogen compound, HA, across the N=C double bond of an isocyanate. Isocyanates also react with water and the initial product is carbamic acid which is unstable, losing carbon dioxide, and generates an amine that reacts with the excess isocyanate to produce urea as follows ... 

Mannich reaction.2 This reaction involves the condensation of an active hydrogen compound with formaldehyde and ammonia or a primary or secondary amine (usually as the hydrochloride) ... 

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