Primaiy amines

One of the best leaving groups is molecular nitrogen in alkyl diazonium ions. Diazonium ions are generated by nitrosation of primaiy amines. The diazonium ions generated from alkyl amines are veiy unstable and immediately decompose with loss of nitrogen. 

The most common and least expensive catalyst for producing primaiy amines from nitriles is sponge nickel. The generalized reaction, carried out in the presence of sponge nickel catalyst, is the following ... 

Amines are stable to electrochemical oxidation in acid solution because the nitrogen lone pair is protonated and inaccessible for reaction. This is not the case for N-acetylamines, which are oxidisable at a lead dioxide anode in aqueous sulphuric acid [99]. The primary electron tiansfer step involves the amide function and leads to a radical-cation, which loses a proton from the carbon atom adjacent to nitrogen. Subsequent steps lead to an acylimmonium ion, which is trapped by water. N-acetylated primaiy amines are converted to the corresponding carboxylic acid. 

Allylamines may be converted directly to oxazolidinones through condensation with CO2, to form carbamate salts, and treatment with iodine (equation 64 and Table 20).166 High stereoselectivity was obtained only in cases where the a-substituent was hydroxymethyl (entry 5) or the amine was secondary and the substituent was phenoxymethyl (entry 4). The results with primaiy amines are comparable to those for amide cyclizations shown in equation (57). 

NaAlH2(OCH2CH2OCH3)2, benzene or toluene, reflux, 20 h, 65-75% yield.2 Note that LiAlH4 does not cleave sulfonamides of primaiy amines those from secondaiy amines must be heated to 120°. 

Imines are formed from aldehydes or ketones with most primaiy amines. In general, they are only stable enough to isolate if either the C or N of the imine double bond bears an aromatic substituent. Imines formed from ammonia are unstable, but can be detected in solution. CH2=NH2, for example, decomposes at temperatures above -80 °C, but PhCH=NH is detectable by UV spectroscopy in a mixture of benzaldehyde and ammonia in methanol. 

Primaiy Amine (lysine residue) CEroteirO—NH2 NHS-Esler/Sulfo-NHS Ester Amide Bond ioti - -WH-C iotBin ... 

Synthesis of primaiy amines from alkyt halides with hexamelhylenefelramines. 

Primaiy amines react with esters to yield amides ... 

Chiral sulfinimines 1.148 are selectively reduced by DIBAH at -30°C. After treatment of the products with CF3COOH, chiral primaiy amines are obtained with an excellent enantiomeric excess [510, 512] (Figure 6.20). The reduction of recy-... 

Keywords maleic anhydride, phthalic anhydride, primaiy amine, microwave irradiation, A -carboxyalkyl maleimide, phthalimide... 

Keywords primaiy amine, Al-hydroxymethylene pyrazole derivative, microwave irradiation, A,Al-bis(pyrazole-1 -yl-methyl)alkylamine... 

In contrast to the early recognition of the importance of proline and proline-based secondary amine peptide catalysts as enzyme mimics, the potential of primary amines in asymmetric catalysis was much underestimated at that time, probably because of their known lower basicity in comparison to secondary amines. This is particularly surprising taking into consideration the fact that primary amino acid catalysis is of enormous importance in enzyme catalysis. For example, primaiy amines occur in the catalytic sites of several enzymes, such as type I aldolases, dehydratases, and decarboxylases. Therefore, primary amines as organocatalysts possess particular appeal. 

Scheme 1.5 Conjugation of carboxyl group containing molecules to primaiy amines using carbodiimide chemistry.

Scheme 1.8 Conjugation of primaiy amines with isothiotyanates.

Carbonates can be described as diester derivatives of carbonic acid, formed by condensation with hydroxyl compounds. However, carbo q lic acids do not possess the necessaiy reactivity to synthesize such products. Therefore bifunctional reactive molecules such as phosgene or carbonyldiimidazoles like N,N -carbonyldiimidazole (CDI) and disuccinimidyl carbonate (DSC) are commonly used (Scheme 1.13). These compounds readily react with nucleophiles to form stable conjugates. They react with hydro)q l-containing molecules to form the amino-reactive carbonate or carbamate intermediates. These intermediates react in a subsequent step with primaiy amines to form stable carbamate bonds (aliphatic urethanes). The reaction is usually carried out in alkaline media (pH 7-9) and in the absence of competing amino and... 

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