Unsaturated nitriles compounds

By-Products. Almost all commercial manufacture of pyridine compounds involves the concomitant manufacture of various side products. Liquid- and vapor-phase synthesis of pyridines from ammonia and aldehydes or ketones produces pyridine or an alkylated pyridine as a primary product, as well as isomeric aLkylpyridines and higher substituted aLkylpyridines, along with their isomers. Furthermore, self-condensation of aldehydes and ketones can produce substituted ben2enes. Condensation of ammonia with the aldehydes can produce certain alkyl or unsaturated nitrile side products. Lasdy, self-condensation of the aldehydes and ketones, perhaps with reduction, can lead to alkanes and alkenes. 

One development involves the use of vitamin B 2 to cataly2e chemical, in addition to biochemical processes. Vitamin B 2 derivatives and B 2 model compounds (41,42) cataly2e the electrochemical reduction of alkyl haUdes and formation of C—C bonds (43,44), as well as the 2inc—acetic acid-promoted reduction of nitriles (45), alpha, beta-unsaturated nitriles (46), alpha, beta-unsaturated carbonyl derivatives and esters (47,48), and olefins (49). It is assumed that these reactions proceed through intermediates containing a Co—C bond which is then reductively cleaved. 

Thermolysis of 4- and 5-azidopyrazoles has been studied by Smith (B-70MI40402, 81AHC(28)232). These compounds undergo fragmentation with formation of unsaturated nitriles via the nitrenes (474a) and (474b Scheme 42). 

The direct synthesis of o.g-unsaturated nitriles can be accomplished by treating the appropriate carbonyl compound with potassium hydroxide in... 

Interaction of carbonyl compounds with a, (3-unsaturated nitriles as a convenient route to carbo- and heterocycles 98UK442. 

A vinyl ether and an aryl hydrazide react to give compound 72 (83JHC1657). A large number of compounds have been made from a,P-unsaturated nitriles. Crotononitriles react with A-acetylcyanoacetohydrazide and with cyanocinna-monitrile to give compounds such as 73 (91GEP3926770), and compound 74 (90JOC2259), respectively. 

Enamines react with acceptor-substituted alkenes (Michael acceptors) in a conjugate addition reaction for example with o ,/3-unsaturated carbonyl compounds or nitriles such as acrylonitrile 8. With respect to the acceptor-substituted alkene the reaction is similar to a Michael addition ... 

The Michael reaction occurs with a variety of a,/3-unsaturated carbonyl compounds, not just conjugated ketones. Unsaturated aldehydes, esters, thio-esters, nitriles, amides, and nitro compounds can all act as the electrophilic acceptor component in Michael reactions (Table 23.1). Similarly, a variety of different donors can be used, including /3-diketones, /3-keto esters, malonic esters, /3-keto nitriles, and nitro compounds. 

There is generally little or no competition from 1,2 addition (to the C=0). However, when R is allylic,l,4 addition is observed with some substrates and 1,2 addition with others. The compound R2CuLi also add to a,P-unsaturated sulfones but not to simple aP-unsaturated nitriles. Organocopper reagents RCu (as well as certain R2CuLi) add to ocP-unsaturated and acetylenic sulfoxides. ... 

Unsaturated Nitriles, Nitro Compounds, and Sulfonic Acids and... 

Much of the early work into the rhodium(II)-catalysed formation of oxazoles from diazocarbonyl compounds was pioneered by the group of Helquist. They first reported, in 1986, the rhodium(II) acetate catalysed reaction of dimethyl diazomalonate with nitriles.<86TL5559, 93T5445, 960S(74)229> A range of nitriles was screened, including aromatic, alkyl and vinyl derivatives with unsaturated nitriles, cyclopropanation was found to be a competing reaction (Table 3). 

A useful synthesis of polysubstituted pyridines (i.e., 11) is based on the legioselective addition of Uthiated -enaminophosphonates to unsaturated carbonyl compounds. These pyridines can also be obtained via a one-pot reaction from metalated phosphonates and sequential addition of nitriles and unsaturated caibonyl compounds <96TL(37)4577>. 

Whereas secondary nitroalkanes such as 1-nitrocyclohexane 1766 are reduced to the corresponding oximes, for example 1767 [24], primary nitro compounds such as a-nitro-o-xylene 1768 or unsaturated nitro compounds such as 1770 are transformed into nitriles such as 1769 and 1771 [24] (Scheme 12.6). 

A new water soluble palladium(O) complex was also prepared. This compound and a previously reported related species were examined as catalysts in the hydrogenation of unsaturated nitriles in water. It was found that the pH of the solvent plays a crucial role in determining both yield and reaction course.869... 

Cyclopropanes 93 are obtained in satisfactory yields from both a,p-unsaturated carbonyl compounds and nitriles, when these substrates are allowed to react with... 

In addition to the types of structures shown thus far, there are several others that are both interesting and important. One such type of structure contains unsaturated rings. Because R-C=N is called a nitrile, compounds containing the -P=N group were originally called phosphonitriles. An unstable molecule having the formula N-PH2 is known as phosphazine. Although this molecule is unstable,... 

Lowe H, Hessel V, Hubbard S, Lob P (2006) Addition of secondary amines to a, 3-unsaturated carbonyl compounds and nitriles by using microstructured reactors. Org Proc Res Dev 10 1144-1152... 

This aldol condensation is assumed to proceed via nucleophilic addition of a ruthenium enolate intermediate to the corresponding carbonyl compound, followed by protonation of the resultant alkoxide with the G-H acidic starting nitrile, hence regenerating the catalyst and releasing the aldol adduct, which can easily dehydrate to afford the desired a,/3-unsaturated nitriles 157 in almost quantitative yields. Another example of this reaction type was reported by Lin and co-workers,352 whereas an application to solid-phase synthesis with polymer-supported nitriles has been published only recently.353... 

Whether the dianion of azohenzene is able to deprotonate MeCN (pK 31.3) has been discussed [62, 64, 68]. However, on a preparative scale generation of CH2CN takes place at the potential of the second reduction of azohenzene, and reactions initiated by cyanomethylation of benzamide [108], carbonyl compounds (or their Schiff bases) or Q , 8-unsaturated nitriles either present in situ [69, 109] or added subsequently [110-112] have been studied. A mixture of products is normally obtained. 

Both butenolides 50 and 51, one tethered to an a, -unsaturated ester, the other to an unsaturated nitrile, failed to undergo cyclization. Instead, the C=C 7i-bond of the butenolide was reduced, leading cleanly and efficiently to saturation of that bond, and to compounds 54 and 55, respectively. In contrast, the corresponding alkylidene malonate 52, as well as the alkylidene malononitrile 53, both cyclize to afford a mixture of the cis-anti-cis and cis-syn-cis linearly fused lactones 56 and 57. 

During the coverage period of this chapter, reviews have appeared on the following topics reactions of electrophiles with polyfluorinated alkenes, the mechanisms of intramolecular hydroacylation and hydrosilylation, Prins reaction (reviewed and redefined), synthesis of esters of /3-amino acids by Michael addition of amines and metal amides to esters of a,/3-unsaturated carboxylic acids," the 1,4-addition of benzotriazole-stabilized carbanions to Michael acceptors, control of asymmetry in Michael additions via the use of nucleophiles bearing chiral centres, a-unsaturated systems with the chirality at the y-position, and the presence of chiral ligands or other chiral mediators, syntheses of carbo- and hetero-cyclic compounds via Michael addition of enolates and activated phenols, respectively, to o ,jS-unsaturated nitriles, and transition metal catalysis of the Michael addition of 1,3-dicarbonyl compounds. ... 

Otherwise, dibromomalonates (and nitriles) react with a-unsaturated carbonyl compounds in the presence of only 1 equiv of dibutyl telluride, giving cyclopropane derivates. 

For the synthesis of nonannulated 2-amino-4H-pyrans, acyclic carbonyl compounds 24 are used in Methods 1,2, and 3. Generally, readily accessible ketones 24, as well as unsaturated nitriles 25 contain electron-withdrawing substituents (R, X). Consequently, densely functionalized pyrans 22 are formed. UNs, widely used for aminopyran preparation, include 30-34... 

There are some examples of pyran synthesis by Method 2, which involves the reactions of unsaturated ketones with methylene-active nitriles. In a typical case of Method 2, the Michael reaction of a,j5-unsaturated carbonyl compounds 26 (77TL1835, 78JHC57,... 

The cyano derivative of indandione 228 acting as an unsaturated nitrile reacts differently with 1,3-dicarbonyl compounds, depending on their nature (89CB1323). Acetylacetone and ethyl benzoylacetate provide spiro(indan-2,2 -pyrans) 229 acetoacetic esters give propellans 230 (proven by X-ray analysis). But only dimedone 103b among the ketones studied yields spirochromene 231 (Scheme 88). 

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