Hydroxyalkyl urea

In particular aminolysis with an alkanolamine such as monoethanolamine forms an hydroxyalkyl urea and an alcohol (reaction 20.9). 

The disadvantage of hydroxyalkyl urea formation is an intramolecular reaction which leads to an oxazolidone, a cyclic urethane (reaction 20.10) [33]. 

Allylation. A-(8-Hydroxyalkyl)ureas in which the (3-position is branching out by a methylene group are synthesized by Lewis acid-catalyzed reaction of stannylated allylureas. Different diastereomers can be obtained by proper choice of the Lewis acid. 

The more conventional method (NaN02-HCl) suffices to convert P-hydroxyalkyl ureas to oxazolidin-2-ones. A -Nitrosation of the products can be prevented by introducing an organic cosolvent (e.g., EtOAc). 

Primary cycloaUphatic amines react with phosgene to form isocyanates. Reaction of isocyanates with primary and secondary amines forms ureas. Dehydration of ureas or dehydrosulfuri2ation of thioureas results in carhodiimides. The nucleophilicity that deterrnines rapid amine reactivity with acid chlorides and isocyanates also promotes epoxide ring opening to form hydroxyalkyl- and dihydroxyalkylaniines. Michael addition to acrylonitrile yields stable cyanoethylcycloalkylarnines. 

Some commercial durable antistatic finishes have been Hsted in Table 3 (98). Early patents suggest that amino resins (qv) can impart both antisHp and antistatic properties to nylon, acryUc, and polyester fabrics. CycHc polyurethanes, water-soluble amine salts cross-linked with styrene, and water-soluble amine salts of sulfonated polystyrene have been claimed to confer durable antistatic protection. Later patents included dibydroxyethyl sulfone [2580-77-0] hydroxyalkylated cellulose or starch, poly(vinyl alcohol) [9002-86-2] cross-linked with dimethylolethylene urea, chlorotria2ine derivatives, and epoxy-based products. Other patents claim the use of various acryUc polymers and copolymers. Essentially, durable antistats are polyelectrolytes, and the majority of usehil products involve variations of cross-linked polyamines containing polyethoxy segments (92,99—101). 

There are few cases in which free /3-aldehydo esters have been condensed successfully with ureas. Commonly, alkoxymethylene esters are used. The initial reaction leads to an acyclic intermediate that may require a separate treatment to induce ring closure. The reaction of a /3-keto ester with urea may be a two-step process in which case acid catalysis can be used in the formation of an acyclic intermediate, with ring closure effected by strong alkali. When the ester component is a lactone or chromone, the product contains a hydroxyalkyl <2000JME3837> or 2-hydroxyphenyl substituent <2004S942>, as shown by the synthesis of the 5-(2-hydroxyethyl)-4-pyrimidinone 657 and the 6-(2-hydroxyphenyl)-pyrimidine 659. 

Several poly(urea urethane) oligomers 28 (Figure 12) were prepared by one-component polycondensation of iV-(hydroxyalkyl)-2 -oxo-1,3-diazepane-l-carboxamides, which act as intramolecular blocked isocyanates <2005PLM 1459>. These oligomers are semicrystalline materials and their melting points show the odd/even effect observed earlier for [ ]-polyamides, [ ]-polyurethanes, poly(ester amide)s, and poly (amide urethane)s. Further analysis showed that the polymers are stable up to ca. 205-230 °C, the polymers with the lower number of methylene groups in the amino alcohol decomposing at the lowest temperature. 

By glycolysis of urea groups a hydroxyalkyl carbamate (or hydroxyalkyl urethane) and an amine are formed (reaction 20.6). 

Urethane - polyisocyanuric foams (PU/PIR) foams) contain isocyanuric rings. Isocyanuric rings are glycolysed at lower reaction rates than the urea or urethane groups, with the formation of hydroxyalkyl carbamates and an amine (reaction 20.7) [11] ... 

The synthesis of substituted benzimidazolone analogues (Xi H) was started from appropriate 2-chloronitrobenzenes (VII) as outlined in Scheme 3. The reaction of VII with aminoalkanols in an inert solvent afforded N-hydroxy-alkyl-2-nitroanilines (VIII). Catalytic hydrogenation of the nitro group resulted in o-phenylene-diamines (IX) which reacted with urea to give the N-hydroxyalkyl-benzimidazol-2-ones (X). After treatment of Xwith thionylchlo-ride, the desired chloroalkylbenzimidazol-2-ones (I) could be isolated. 

Copolymers with hydroxyalkyl groups are commonly cured by butylated melamine- or urea-formaldehyde resins (see Chapter 13), e.g. ... 

A patent review [4] showed that early intumescent formulations incorporated in polymers contained a precursor of phosphoric or polyphosphoric acid, a pentaerythritol type char source, and melamine, as typical formulations of intumescent coatings. Further developments tried to reduce the complexity of the additive system, for example by using a binary combination of the add precursor with nitrogen-containing compounds, which also act as a char source. While the add source is generally APP, typical examples of the second component are produds of condensation of formaldehyde with substituted ureas products of readions between aromatic diisocyanates and pentaerythritol or melamine polymers containing the piperazine ring in the main chain, also combined with substituted s-triazine, hydroxyalkyl isocyanurate etc. 

Resinous products prepared from hexakis(methoxyl methyl) mela-mine-MA, urea-formaldehyde,and hydroxyalkyl-substituted urea-MA reactions have received some attention in coatings and moldings. 

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