Nitrogen containing functional groups imines

Fluorinations of other functionalities containing C = N bonds, such as 2//-azirines and imines, are included in this section. Certain 2Ff-azirines and imines yield a-fluoro ketones. With other 2Ff-azirines, /i,/(-difluoro amines are the main reaction products. In a strict sense, these reactions cannot be considered as examples of substitution of nitrogen-containing functional groups no substitution takes place when /S. -difluoro amines are the reaction products. However, these methods have been included. 

Under strictly anhydrous conditions, the iminophosphorane intermediate that is formed as a result of the Staudinger reaction can react with aldehydes and ketones in an intermolecular fashion (as in the synthesis of imine 36 described above) or intramolecularly with a variety of carbonyl containing functional groups to afford a host of products. Nitrogen containing ring systems such as cyclic imines (44) represent just one of the many products one can prepare and the reaction is particularly well suited for the facile synthesis of five, six, and seven-membered rings. In addition to aldehydes and ketones, carboxylic acids, esters, thio-esters, and amides can also react in an intramolecular fashion to trap an iminophosphorane to afford a variety of heterocycles. Examples from the current literature are described in Section 2.5.5. 

Figure 2.2 Types of nitrogen-containing functionalities on the carbon materials (a) pyrrole- like group (b) nitrile (c) secondary amine (d) nitro group (e) nitroso group (f) terciary (g) amine (h) pyridine-like group (i) imine (j) amide (k) lactam (1) pyri-done (m) quaternary amine.

Several functional groups containing carbon-nitrogen double bonds can participate in radical cyclizations. Among these are oxime ethers, imines, and hydrazones.337 Hydrazones and oximes are somewhat more reactive than imines, evidently because the adjacent substituents can stabilize the radical center at nitrogen.338 Cyclization at these functional groups leads to amino- substituted products. 

Pyridoxal phosphate (PLP) is at the heart of chemistry conducted by a number of enzymes. Many of us know the coenzyme pyridoxal phosphate by the closely related vitamin from which it is derived in our diet—pyridoxine, or vitamin 06. Wheat is a good dietary source of vitamin 06. Although pyridoxal phosphate (see below and the model) is a member of the aldehyde family, when it is involved in biological chemistry, it often contains the closely related functional group with a carbon-nitrogen double bond, the imine group. 

Several functional groups contain nitrogen. A nitrogen atom can form single, double, or triple bonds to a carbon atom. At least one C—N O bond is present in an amine. The other two O bonds from nitrogen are to either hydrogen or carbon atoms. Compounds with C=N double bonds are called imines those with C N triple bonds are called nitriles. 

A condensation reaction is a reaction between two reactants that yields one larger product and a second, smaller product such as water. This type of reaction has been illustrated in the reactions of many functional groups containing oxygen or nitrogen. Products of condensation reactions include ethers, acetals, esters, imines, and amides. 

Several pyridine containing ligands of this type have been reported by Toftlund [2]. A combination of two aliphatic and four imine nitrogen functions seems to provide a ligand field at the crossover point. A versatile class of ligands of this type is based on aliphatic diamines substituted with four alkylpyridine groups. The simplest compound of this type is tetrakis(2-pyri-dylmethyl)-l,2-ethanediamine (tpen) (18). 

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