Aromatic dinitriles

Aromatic dinitriles such as isophthalonitrile and terephthalonitrile were also hydrogenated over Raney Co in the presence of ammonia to give high yields of the corresponding diamines49-52 (eqs. 7.2649 and 7.2750). Hydrogenation of o-phthalonitrile,... 

Cull, S.G., Woodley, J.M., and Lye, G.J. 2001. Process selection and characterisation for the biocatalytic hydration of poorly water solnble aromatic dinitriles. Biocatalysis and Biotransformation, 19 131-54. 

Rhodococcus spp. have also been used to hydrolyze only one of two nitrile groups in aromatic dinitriles in 86% yield.233 Rhodococcus rhodochrous has been used to hydrolyze aliphatic dinitriles, such as adiponitrile, to... 

Arylbenzonitriles can be prepared by condensing arylidenemalononitriles with dienamines. So 43 was reacted with the morpholine derivative 174 to yield biphenyl-2-carbonitrile 175. When 43 was condensed with 1-phenylethylidenemalononitrile 176, tricyano-cyclohexadiene 177 was obtained, which in turn afforded the aromatic dinitrile 178 by HCN elimination. ... 

An older publication by the Zeneca Fine Chemicals Manufacturing Organization describes the use of immobilized whole cells of Rhodococcus sp, SP 361 for the hydrolysis of aromatic dinitriles (Scheme 53) [134]. It was found that flu-orinated aromatic dinitriles (163) were regioselectively hydrolyzed by nitrile... 

When aromatic dinitriles are used, high melting polymers with good thermal stability form. 

High-temperature Polymers. Huang and Ou (4) of this Institute synthesized five aromatic dinitriles ... 

R.A. Brand, M. Bruma, R. Kellman, C.S. Marvel, Low-molecular-weight polybenzimidazoles from aromatic dinitriles and aromatic diamines, J. Polym. Sci. Part A Polym. Chem. 16 (9) (1978) 2275-2284. 

Crosby, J., Moilliet, J., Parratt, J.S., and Turner, NJ. (1994) Regioselective hydrolysis of aromatic dinitriles using a whole cell catalyst. J. Chem. Soc., Perkin Trans. 1, 1679-1687. 

Enone formation-aromatization has been used for the synthesis of 7-hydro-xyalkavinone (716)[456]. The isotlavone 717 was prepared by the elimina-tion[457]. The unsaturated 5-keto allyl esters 718 and 719, obtained in two steps from myreene. were subjected to enone formation. The reaction can be carried out even at room temperature using dinitriles such as adiponitrile (720) or 1,6-dicyanohexane as a solvent and a weak ligand to give the pseudo-ionone isomers 721 and 722 without giving an allylated product(458]. 

Molecular ion The mass spectra of aromatic nitriles and dinitriles show intense molecular ions (see Figure 21.3). 

Aliphatic dinitriles (loss of CH2CN) Aromatic compounds Cyclic carbonate compounds Segmented fluoroalcohols (i.e.. loss of H2F2)... 

Knoevenagel-type condensation of 1,4-xylylene dinitriles and aromatic dialdehydes gives access to cyano-containing poly(para-phenylene-cyanovinylene)s (74). The insoluble parent systems (74a R, R = H) have been reported by... 

A nitrilase from the hyperthermophile Pyrococcus abyssi, which exhibits optimal growth at 100 °C, was cloned and overexpressed. Characterization of this nitrilase revealed that it is operational as a dimer (rather than the more common multimeric structure for nitrilases), with optimal pH at 7.4 and optimal apparent activity at 80 °C with Tm (DSC) at 112.7 °C. The substrate specificity of the nitrilase is narrow and it does not accept aromatic nitriles. The nitrilase converts the dinitriles fumaronitrile and malononitrile to their corresponding mononitriles [58],... 

The present procedure of in situ generation and trapping of 2,3-dicyanobutadiene in the presence of olefins overcomes these problems and affords the [4 + 2]-cycloadducts in good yields, particularly in the case of olefins possessing a strained double bond.2 Substituted 1,2-dicyanocyclohexenes prepared by the in situ [4 + 2]-cycloadditions can be dehydrogenated to new aromatic ortho-dinitriles. For example, 2,3-dicyanofluorene is prepared in... 

A crude mixture of enzymes isolated from Rhodococcus sp. is used for selective hydrolysis of aromatic and aliphatic nitriles and dinitriles (117). Nitrilase accepts a wide range of substrates (Table 8). Even though many of them have low solubility in water, such as (88), the yields are in the range of 90%. Carboxylic esters are not susceptible to the hydrolysis by the enzyme so that only the cyano group of (89) is hydrolyzed. This mode of selectivity is opposite to that observed upon the chemical hydrolysis at alkaline pH, esters are more labile than nitriles. Dinitriles (90,91) can be hydrolyzed regioselectively resulting in cyanoacids in 71—91% yield. Hydrolysis of (92) proceeds via the formation of racemic amide which is then hydrolyzed to the acid in 95% ee (118). Prochiral 3-substituted glutaronitriles (93) are hydrolyzed by Phodococcus butanica in up to 71% yield with excellent selectivity (119). 

The cyclization reactions of a,oj-dinitriles under the influence of anhydrous hydrogen halides (Eq. 3) at 0-25° have proved to be of considerable synthetic value. A range of aromatic heterocyclic systems becomes available, since it is possible for the exo-imine double... 

The reaction of aliphatic, aromatic and arylaliphatic nitriles and dinitriles with formaldehyde, aliphatic and aromatic aldehydes in the presence of acids leads to the A,Af -alkylidene- and Af,AT -arylalkylidene-bis-amides 9a and has been known since 187634. 

The application of nitrilases is broad. A purified nitrilase from Bacillus pallidus was employed to hydrolyse a wide variety of aliphatic, aromatic and heteroaromatic nitriles and dinitriles (Scheme 6.33) [102]. Nitrilases have also been patented for the hydrolysis of a-substituted 4-methylthio-butyronitriles, however, no stereoselectivity was reported [103]. 

The fusion of alkali arylsulfonates with potassium cyanide forms aromatic nitriles by a replacement of the sulfo group. For the most part, the yields are low, although the reaction has been applied successfully in the preparation of naphthonitriles and cyanopyridines. Sometimes potassium ferrocyanide is substituted for the alkali cyanide with better results. Ten isomeric cyanonaphthalenesulfonates have been converted to the dinitriles by fusion with this reagent in yields ranging from 8% to 75%. Migration of the cyano group from the beta to the alpha position has been observed in the formation of these Compounds. ... 

The submitter states that a number of aromatic mono-and dinitriles have been prepared by this procedure vvith slight or no modification in the temperature. The reaction mixtures were usually worked up by the acetone-ammonia method described in Note 6. Among the compounds prepared by this method are o-nitrobenzonitrile, o-bromobenzonitrile, w-methoxy-benzonitrile, 4,4 -dicyanodiphenylsulfone, 4,4 -dicyanostilbene, a,7-di-(4-cyanophenoxy)propane. With the last, a temperature of 185 190° for 20 minutes gave the best results. The yields before purification ranged between 75% and 95% and after purification between 63% and 79%. Aliphatic acids give low yields of the corresponding nitriles and, in some cases, chlorinated by-products. 

The preparation of aromatic nitriles by an 5rn1 process was described recently.Suitably substituted diazo sulfides, either isolated or only generated in situ, reacted with tetrabutylammonium cyanide under photon or electron stimulation (equation 21), leading to aryl cyanides with yields that are comparable with those of the Sandmeyer reaction. Bromo- and chloro-substituted aryl diazo sulfides afforded the corresponding dinitriles in high yields. 

Using supported y-Mo2N as a surface-mediated catalyst, a new proposal for the manufacture of aromatic nitriles and dinitriles from the relatively cheap aldehydes was made [16, 17]. Thus, isophthalic dinitrile can be produced in a gas-phase amm(on)dehydrogenation (cf. Section 3.3.12.2) at 400 °C according to eq. (11) with 80% conversion when a 50-fold excess of ammonia is used [16]. It is obvious that imine intermediates are formed (from the aldehyde and ammonia) which then dehydrogenate under the reaction conditions. 

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