Nitriles from sulfonates

Nitdles may be prepared by several methods (1). The first nitrile to be prepared was propionitdle, which was obtained in 1834 by distilling barium ethyl sulfate with potassium cyanide. This is a general preparation of nitriles from sulfonate salts and is referred to as the Pelou2e reaction (2). Although not commonly practiced today, dehydration of amides has been widely used to produce nitriles and was the first commercial synthesis of a nitrile. The reaction of alkyl hahdes with sodium cyanide to produce nitriles (eq. 1) also is a general reaction with wide appHcabiUty ... 

Another important reaction in synthetic chemistry leading to C-C bond formation is the Michael addition. The reaction typically involves a conjugate or nucleophilic 1,4-addition of carbanions to a,/l-unsaturated aldehydes, ketones, esters, nitriles, or sulfones 157) (Scheme 21). A base is used to form the carbanion by abstracting a proton from an activated methylene precursor (donor), which attacks the alkene (acceptor). Strong bases are usually used in this reaction, leading to the formation of byproducts arising from side reactions such as condensations, dimerizations, or rearrangements. 

A large part of the usefulness of the Michael reaction in organic synthesis derives from the fact that almost any activated alkene can serve as an acceptor7—a, 3-unsaturated ketones, esters, aldehydes, amides, acids, lactones, nitriles, sulfoxides, sulfones, nitro compounds, phosphonates, phosphoranes, quinones,... 

Recently, the group of Herrera, Bernardi, and Ricci realized the enantioselective synthesis of protected a-amino nitriles from the corresponding a-amino sulfones 137, which act as effective precursors for the in situ generation of imines, by the use of acetone cyanohydrin (138) as a cyanide source using quinine-derived PTC 136 [64]. The aminonitriles 139 were produced with broad generality in 50-88% ee (Scheme 8.53). However, a similar protocol using KCN and TMSCN resulted in a lower ee value. 

The most widely explored method is the formation of tri- and tetrasubstituted cyclopropanes by reaction of vinylsulfonium salts with methylene compounds activated by ester, ketone, nitrile, or sulfone substituents. A series of examples is collected in Table 25. A variant of this method, where cyclopropanedicarboxylates cis-1 were actually obtained by intramolecular cyclization of the sulfonium salt Cj building block is also shown.Alkylthiocyclopropane derivatives 8 were obtained by the reaction of a ketene dithioacetal monosulfonium salt with carbanions derived from doubly activated methylene compounds. ... 

Nitro is just one of a number of groups that are also deactivating towards electrophiles and meta directing because of electron withdrawal by conjugation. Others include carbonyl groups (aldehydes, ketones, esters, etc.), nitriles, and sulfonates. The H NMR shifts of rings carrying these substituents confirm that they remove electrons principally from the ortho and para positions. 

Further examples of the preparation of nitriles from halides and sulfonates are included in section 190 (Nitriles from Halides and Sulfonates)... 

DSC studies have demonstrated the excellent thermal stabilities of novel diaryl nitrile and sulfone dyes (II-a,c). In addition, dye-doped Ultradel 9000D samples doped at 5 and 10%-iwt exhibit acceptable absorbance losses of < 3 dB/cm at 820 and 1320 nm. Higher doping levels give rise to absorbance losses which cannot be explained solely on the basis of Beers Law. It is clear that absorptive losses do not arise from the polymer itself Our study of dye-solvent (dye-matrfac) systems suggests that observed losses are not due to charge transfer interactions between dye and matrix (dye-solvent or dye-polymer). 

C-Methylation. Methyl iodide is an active alkylating agent employed in the C-methylation of carbanions derived from ketones, esters, carboxylic acids, amides, nitriles, nitroalkanes, sulfones, sulfoxides, imines, and hydrazones. The quantity of methyl iodide utilized in methylations varies from a slight (1.1 equiv) to a large excess (used as solvent). 

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (53). The first generation includes latices made with conventional (/) anionic surfactants like fatty acid soaps, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates (54) (2) nonionic surfactants like poly(ethylene oxide) or poly(vinyl alcohol) used to improve freeze—thaw and shear stabiUty and (J) cationic surfactants like amines, nitriles, and other nitrogen bases, rarely used because of incompatibiUty problems. Portiand cement latex modifiers are one example where cationic surfactants are used. Anionic surfactants yield smaller particles than nonionic surfactants (55). Often a combination of anionic surfactants or anionic and nonionic surfactants are used to provide improved stabiUty. The stabilizing abiUty of anionic fatty acid soaps diminishes at lower pH as the soaps revert to their acids. First-generation latices also suffer from the presence of soap on the polymer particles at the end of the polymerization. Steam and vacuum stripping methods are often used to remove the soap and unreacted monomer from the final product (56). 

Other Applications. Hydroxylamine-O-sulfonic acid [2950-43-8] h.2is many applications in the area of organic synthesis. The use of this material for organic transformations has been thoroughly reviewed (125,126). The preparation of the acid involves the reaction of hydroxjlamine [5470-11-1] with oleum in the presence of ammonium sulfate [7783-20-2] (127). The acid has found appHcation in the preparation of hydra2ines from amines, aUphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. It is also an important reagent in reductive deamination and specialty nitrile production. 

Sulfonate and sulfamoyl. A nitrile group is introduced into the 3- or 4-position of pyridine and into the 2- or 4-position of pyrimidine by displacement of a sulfonate group with potassium cyanide. Amines, water, or hydrazine displace 2- or 4-sulfonate groups from pyridine derivatives. 4-Quinolinylsulfonates (139)... 

---