Diaryl nitrile

Laser flash photolysis (LFP) studies have been carried out on the generation of N,C-diaryl nitrile imines from sydnones and from tetrazoles in solution at 77 K. They were found to have hfetimes of milliseconds and were quenched by dimethyl acetylenedicarboxylate (DMAD) (A q=5-9 x 10 M s ) and by carboxyhc acids (feq= lO -lO s ) (13). The strong dependence of v ax on the nature of the aromatic substituents in N,C-diaryl nitrile imines was interpreted by a hnear free energy relationship as due to intramolecular charge transfer (14). 

Cycloadditions have been carried out to 37/-indoles (222, 223) (125,126), N-arylmaleimides (224) (127,128), l,2), -azaphospholes (225) (129), 5(47/)-oxazo-lones (226) (130), and 4,5-dihydrooxazoles (230) (131). The primary cycloadducts from the reaction of oxazolones (e.g., 226 with diaryl nitrile imines), derived from tetrazoles in refluxing anisole, do not survive. They appear to lose carbon dioxide and undergo a dimerization-fragmentation sequence to give the triazole 228 and the diarylethene 229 as the isolated products (130). In cases where the two aryl substituents on the oxazole are not the same, then, due to tautomerism, isomeric mixtures of products are obtained. 

A rational extension of ortho-tolyl benzamide metalation [68], part of the broadly encompassing lateral metalation protocol [69] that can be DoM-connected, is the DreM equivalent, 154 —> 155 (Scheme 41), which provides a general regioselective route to 9-phenanthrols (156, 157, 158) [70] and may be extended to diaryl nitriles, hydroxylamine ethers, and hy-drazones 160, which provide the corresponding 9-amino derivatives 161 of similar generality 162-165 (Scheme 42), as may also be applied in natural product synthesis [71]. Further opportunities for DoM-cross-coupling and reduction/oxidation chemistry (159) have also been demonstrated [70a]. 

The decarboxylative coupling of potassium 2-(2-pyridyl)acetates with aryl halides can be carried out efficiently under palladium catalysis (Scheme 4.77) [80]. Based on DFT calculations, it was proposed that coordination of the pyridyl nitrogen to Pd is crucial to reduce the energy barrier of the rate-limiting decarboxylation step. a-Cyanoacetates also undergo similar decarboxylative arylation to produce a-aryl nitriles (Scheme 4.78) [81]. From the same combination of substrates, a,a-diaryl nitriles can also be selectively prepared by double arylation (Scheme 4.79) [82]. 

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). 

Alditol-l-yl substituted pyrroles or pyrazoles (e.g. 88 and 89) were obtained by addition to per-<7-acetylated 1,2-dideoxy-l-nitro-D- a/acm- and D-manno-l-hep-tenitols of the sodium salt of tosylmethyl isocyanide or the zwitterionic diaryl nitrile imines (e.g. PhC=N -N Ph), respectively. A general one-pot synthesis of alditol-l-yl substituted imidazoles (e.g. 90) involved reaction of aldoses with... 

The introduction of electronic asymmetry into this class of bis(diaryl)phosphinites has been used to design catalysts that can afford both enantiomers of naproxen nitrile. If the carbohydrate scaffold is based on methyl o-D-fructol uranosidc (29), (i )-naproxen nitrile is produced. In a similar manner to the results above, electron-donating aryl substituents on phosphorus afford... 

Nitrile oxides are generated by photolysis of 1,2-diaryl-substituted nitro-ethylenes through the formation of an oxazetine 2-oxide and its fragmentation (Scheme 1.7) (89). 

Diaryl- (85), diaroyl- (71), bis(4-substituted-l,2,5-oxadiazol-3-yl)furoxans (104) as well as exotic l,2,2,5,5-pentamethyl-4-(nitromethyl)-3-imidazoline 3-oxide-derived furoxan 22 (105) were obtained via corresponding nitrile oxides. 

N-Arylmaleimides are useful reagents for trapping and characterization of nitrile oxides (see, e.g., Ref. 165). However, their cycloadducts can also be target products. Thus, a series of 3,5-diaryl-4,6-dioxo-3a,4,6,6a-tetrahydropyrrolo- 3.4-r/]isoxazoles 95 was obtained by 1,3-dipolar cycloaddition of substituted benzonitrile oxides with N-(2,6-dialkylphenyl)maleimides. Certain compounds 95 showed bactericidal and fungicidal activity (264). 

Syntheses of l-aryl-3,3,3-trilluoro-l-propynes and their reactions with nitrile oxides to give 3,5-diaryl-4-tri(luoromethylisoxazoles have been carried out. In particular, l-(4-chlorophenyl)-3,3,3-trilluoro-l-propyne, on reaction with 4-chlorobenzohydroximoyl chloride in the presence of Et3N in PhMe, give a 45% mixture of 211 (R = R1 = 4-CIC6H4) and the regioisomer 212 in the ratio of 97 3, respectively (370). 

Reaction of 2-amino-5-aryl-thiadiazole (88 R = Ar) with aryl nitriles in the presence of aluminum chloride produced the aryl amidine (89) which was oxidized with lead tetraacetate to yield the 2,6-diaryl-[ 1,2,4]-triazolo[5,1 -( ]-1,3,4-thiadiazoles (90) <91 UC(B)435>. 

The synthesis of quinazoline derivatives by the addition of N(3)-C(4) fragment units has not previously been a major synthetic route, but 2,4-dialkyl, alkyl/aryl, and diaryl quinazolines 865 are now readily available by a new procedure that involves activation of A -arylamides 864 with trifluoromethanesulfonic anhydride and 2-chloropyridine, and subsequent addition of nitriles <2006JA14254>. Either normal or microwave heating can be used to perform the final ring-closure step. 

Werden anstelle von a-Halogen- oder a-Hydroxy-ketonen a-Halogen-carbonsaure-nitrile ein-gesetzt und ist die Amidin-Komponente N,N -Diary -substituiert, so erhalt man in guten Aus-beuten 4-Amino-l,3-diaryl-imidazolium-Salze113 z.B. ... 

Wabnitz, T.C., Rizzo, S., Gotte, C., Buschauer, A., Benincorid, T. and Reiser, O. Enantioselective Hydrogenation of Diaryl-substituted ot, -Unsaturated Nitriles. Tetrahedron Lett, 2006, 47, 3733-3736. 

More decisive evidence is provided by the interconvertibility of N-aryl-JV-arylamidinothioureas (28) and Hector s bases by oxidation-reduction.63, B4,67b The former compounds are accessible (as salts) (i) by the condensation of arylthioureas (24) with arylcyanamides (23),63 (ii) by the extrusion of sulfur from the recently described40,41 s-diaryldithioformamidine hydrobromidesB4a (22), (tit) by the oxidation of arylthioureas (24) with 0.5 moles of hydrogen peroxide in the presence of mineral acids,B4a and (iv) by the mild reduction of Hector s bases by hydrogen sulfide in acid media.B4a The first of these four reactions limitB the structure of the products to the three alternatives 25, 28, and 30. Of these, 25 is excluded by the non-identity of the product with authentic67 N-phenyl-i -phenylamidinothiourea (25 R = Ph). The monosulfide structure (30) is not reconciled as readily with the observedB4a hydrolytic fission of the products into diaryl-guanidines (29) and thiocyanic acid as is structure 28. Indeed, as in the case of thioamides and nitriles (see Section II, C, 1), the present condensation may involve the primary formation of an intermediate diimido-monosulfide (30) and its isomerization to 28. 

The lower members of the homologous series of 1. Alcohols 2. Aldehydes 3. Ketones 4. Acids 5. Esters 6. Phenols 7. Anhydrides 8. Amines 9. Nitriles 10. Polyhydroxy phenols 1. Polybasic acids and hydro-oxy acids. 2. Glycols, poly-hydric alcohols, polyhydroxy aldehydes and ketones (sugars) 3. Some amides, ammo acids, di-and polyamino compounds, amino alcohols 4. Sulphonic acids 5. Sulphinic acids 6. Salts 1. Acids 2. Phenols 3. Imides 4. Some primary and secondary nitro compounds oximes 5. Mercaptans and thiophenols 6. Sulphonic acids, sulphinic acids, sulphuric acids, and sul-phonamides 7. Some diketones and (3-keto esters 1. Primary amines 2. Secondary aliphatic and aryl-alkyl amines 3. Aliphatic and some aryl-alkyl tertiary amines 4. Hydrazines 1. Unsaturated hydrocarbons 2. Some poly-alkylated aromatic hydrocarbons 3. Alcohols 4. Aldehydes 5. Ketones 6. Esters 7. Anhydrides 8. Ethers and acetals 9. Lactones 10. Acyl halides 1. Saturated aliphatic hydrocarbons Cyclic paraffin hydrocarbons 3. Aromatic hydrocarbons 4. Halogen derivatives of 1, 2 and 3 5. Diaryl ethers 1. Nitro compounds (tertiary) 2. Amides and derivatives of aldehydes and ketones 3. Nitriles 4. Negatively substituted amines 5. Nitroso, azo, hy-drazo, and other intermediate reduction products of nitro com-pounds 6. Sulphones, sul-phonamides of secondary amines, sulphides, sulphates and other Sulphur compounds... 

The reaction of p-iodo- or p-bromo-anisole or of 1-iodonaphthalene with the anion formed from the a,(3-unsaturated nitrile (36) gives 60-70% combined yields of the isomeric nitriles (37) and (38) together with small amounts of the diarylated derivatives (39).135... 

Cross-coupling reactions of ArCOAr. Reaction of Yb(0) with diaryl ketones changes the reactivity of the carbonyl group from electrophilic to nucleophilic. Thus in the presence of this lanthanoid metal, diaryl ketones couple with other ketones, nitriles, and epoxides to give pinacols, a-hydroxy ketones, and 1,3-diols, respectively, via the intermediate a. 

Nitrile oxides are generated from nitrolic acids [RC(N02)=N0H] by elimination of the elements of nitrous acid. This can occur spontaneously, on heating, or by the action of sodium bicarbonate, and it thereby provides access to symmetrically substituted dialkyl-, diaryl-, and diacyl-furoxans. 

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