Aldehydes nitrogen derivatives

The neutral nitrogen compounds include tertiary aliphatic nitro compounds and aromatic nitro compounds amides (simple and substituted) nitrogen derivatives of aldehydes and ketones (hydrazones, semicarbazones, etc.) nitriles nitroso, azo, hydrazo and other intermediate reduction products of aromatic nitro compounds. The imides, primary and secondary nitro compounds, oximes and primary sulphonamides are weakly acidic nitrogen compounds. All the above nitrogen compounds and also the secondary sulphonamides, with few... 

Review "Alkylation of Ketones and Aldehydes via Nitrogen Derivatives"... 

J. K. Whitesell and M. A. Whitesell, Alkylation of Ketones and Aldehydes via their Nitrogen Derivatives , Synthesis, 517-536 (1983). 

Whereas isolated imines are relatively unstable and readily undergo hydrolysis to form carbonyl compounds, alkylated imines and imino derivatives are found as stable compounds in a variety of situations. Thus a number of nitrogen derivatives of aldehydes and ketones, such as the oxime, semicarbazone and hydrazone, contain an imino fragment. 

Compound classes, not previously described (eg. 5- and 6-membered heteroarenes) Compound classes, for which, in the meantime, significant improvements and progresses have been made, for example carbonic acid derivatives, carboxylic acids and carboxylic acid derivatives, aldehydes, carbonyl derivatives, halogen compounds, peroxides, sulfur, selenium, tellurium, nitrogen and phosphorus compounds. 

Enatnines, itnines, hydrazones and oximes represent the common nitrogen derivatives of ketones and aldehydes (Scheme 1). Both hydrazones and oximes were of importance before the availability of modem spectral techniques for the conversion of liquid carbonyl-containing compounds into solid materials that could be correlated with known samples by melting point and mixed melting point methods. While these applications have all but disappeared, these derivatives, as well as enamines and imines, have emerged as important intermediary species in overall transformations that effect substitution a to the original carbonyl group. Much of this work is based on the seminal contributions of Stork. 

Whitesell, J. K., Whitesell, M. A. Alkylation of ketones and aldehydes via their nitrogen derivatives. Synthesis 1983, 517-536. 

Nitrogen derivatives of aromatic aldehydes and enamines in syntheses of heterocycles 03MI49. 

It would be a fair summary of the present situation to say that lithium enolates of ketones or esters are now usually preferred to aza-enolates for nucleophilic alkylation, but that lithium derivatives of cyclohexyl or /-butyl imines are preferred for the nucleophilic alkylation of aldehydes. We shall treat lithium enolates later, along with the equally popular silyl enol ethers, but there is one more nitrogen derivative which should come first. 

Directed functionalizations at the a-carbon atom of aldehydes and ketones have been carried out via reactions of their nitrogen derivatives, including aldimines, ketimines, hydrazines, and oximines. The general procedure involves metallation of the nitrogen derivative, subsequent reaction with an electrophile and final conversion of the obtained derivative into the derivative of the starting aldehyde or ketone. The reaction sequence is depicted in the following general scheme ... 

The chemistry of the metallated nitrogen derivatives of aldehydes and ketones has been reviewed by Mukaiyama [4] and Whitesell-Whitesell [5]. 

In this chapter, some procedures with simple aldimines and ketimines are described. They show representative conditions for the metallation of these nitrogen derivatives, their subsequent reactions with a number of electrophiles and the final hydrolytic cleavage of the C=N bond with formation of derivatives of the starting aldehydes or ketones. 

The most common type of nitrogenous derivatives is that which is formed by the reaction of the aldehyde (or hemiacetal) group of the sugars with compounds containing amino groups ... 

Raw Material and Energy Aspects to Pyridine Manufacture. The majority of pyridine and pyridine derivatives are based on raw materials like aldehydes or ketones. These are petroleum-derived starting materials and their manufacture entails cracking and distillation of alkanes and alkenes, and oxidation of alkanes, alkenes, or alcohols. Ammonia is usually the source of the nitrogen atom in pyridine compounds. Gas-phase synthesis of pyridines requires high temperatures (350—550°C) and is therefore somewhat energy intensive. 

Inductive and resonance stabilization of carbanions derived by proton abstraction from alkyl substituents a to the ring nitrogen in pyrazines and quinoxalines confers a degree of stability on these species comparable with that observed with enolate anions. The resultant carbanions undergo typical condensation reactions with a variety of electrophilic reagents such as aldehydes, ketones, nitriles, diazonium salts, etc., which makes them of considerable preparative importance. 

Two substituents on two N atoms increase the number of diaziridine structures as compared with oxaziridines, while some limitations as to the nature of substituents on N and C decrease it. Favored starting materials are formaldehyde, aliphatic aldehydes and ketones, together with ammonia and simple aliphatic amines. Aromatic amines do not react. Suitable aminating agents are chloramine, N-chloroalkylamines, hydroxylamine-O-sulfonic acid and their simple alkyl derivatives, but also oxaziridines unsubstituted at nitrogen. Combination of a carbonyl compound, an amine and an aminating agent leads to the standard procedures of diaziridine synthesis. 

A class of nitrogen-containing compounds that was omitted from the section just discussed includes imines and their- derivatives. Irnines are formed by the reaction of aldehydes and ketones with ammonia. Imines can be reduced to primary amines by catalytic hydrogenation. 

Enamines derived from aldehydes disubstituted on the jS carbon such as those derived from isobutyraldehyde (16) are alkylated on nitrogen by alkyl... 

A fundamental problem in the alkylation of enamines, which is inherent in the bidentate system, is the competition between the desired carbon alkylation and attack at the nitrogen. With unactivated alkyl halides (3,267), this becomes especially serious with the enamines derived fromcycloheptan-one, cyclooctanone, cyclononanone, and enamines derived from aldehydes. Increasing amounts of carbon alkylation are found with the more reactive allyl and benzyl halides (268-273). However, with allyl halides one also observes increasing amounts of dialkylation of enamines. 

The addition of phenylisocyanate to aldehyde-derived enamines resulted in the formation of aminobutyrolactams (438,439). As aminal derivatives these produets can be hydrolyzed to the linear aldehyde amides and thus furnish a route to derivatives of the synthetically valuable malonaldehyde-acid system. With this class of reactions, a second acylation on nitrogen becomes possible and the six-membered cyclization products have been reported (440). Closely related to the reactions of enamines with isocyanates is the condensation of cyclohexanone with urea in base (441). 

The neutral species of 1,3,6-triazanaphthalene, unlike those of its isomers, decomposes at pH 7.1 to give 4-aminopyridine-3-aldehyde, on standing at 20°. The nitrogen atom in position 5 of pteridine must confer extra stability on the hydrated cation, because 1,3,8-triaza-naphthalene (from which it is derived by replacing C-5 by a nitrogen atom) is more easily ring-opened by cold acid. 

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