Dicyano compounds

Air-Stable boron-containing polymers can be prepared by the reaction of dicyano compounds with the / fZ-butylborane—trimethyl amine complex (449). 

The dicyano compound is then hydrogenated over a platinum catalyst to adiponitrile. 

Nitriles (see also Dicyano Compounds, Cyano Carbonyl Compounds, etc.) 10-105 Alkylation of nitriles... 

Unlike such unstable intermediates, the first, rare example of reversible dissociation of a carbon-carbon a bond into a stable carbocation and carbanion was reported for a nitro-dicyano compound (20) prepared from trimethyl- and triphenyl-cyclopropenylium tetrafluoroborate ([4" ]BF4 and [5 JBFJ) with the potassium salt of p-substituted-phenylmalononitrile anions (Arnett et al., 1983 Troughton et al., 1984 Arnett and Molter, 1985). Other ionically dissociative malononitrile derivatives have been prepared from such carbocations as the tropylium [S ] (Arnett and Troughton, 1983) and the tris(p-methoxyphenyl)methylium [93 j (Arnett and Troughton, 1983) ions. 

Previously proton NMR was used to show that both isomers existed in solution (146) This was due to the fact that two slightly different resonance positions were observed for the C-10-proton. Other than that no evidence for two species was available from the NMR spectrum. On the other hand, the 13C-spectrum shows significant differences in the chemical shifts of many nuclei in the two isomers. Fig. 37 compares the 13C-spectrum of aquo cyanocobyric acid with that for the dicyano derivative in which there is only one isomer. In the dicyano compound there are 38 resolvable peaks while there are. 60 in the aquocyano deriva-... 

Generally, during hydroboration polymerization of dicyano compounds, the formation of the borazine structures that have a six-membered boron-nitrogen ring (scheme 19a) and dihydroborated end groups (scheme 19b) as a structural defect is unavoidable. The borazine cross-linked structures often cause the gelation, and dehydroboration causes a decrease in molecular weight. 

Michalik et al. (86) have studied some similar systems (79). In these, the SMe proton resonances appear as symmetrical doublets at ambient temperature, which undergo coalescence in the temperature region of 151 to 180°C, corresponding to barriers to rotation about the C3=C4 bond of 21.6 to 23.3 kcal/mol. In comparable systems (i.e., with Ar = p-ClC6H4), the dicyano compound 79a has a AG of 21.9 kcal/mol the corresponding cyano ester 79b, 22.3 kcal/mol. Thus the cyano group acts as a more efficient acceptor than the ester group, an... 

When 23 reacts in this ANRORC process, in fact two intermediates, a cyanoimidoyl chloride (24) and a dicyanoazadiene (25), can be postulated (Scheme 11.16). When the dicyano compound 25 is the transient open-chain intermediate, scrambling of the radioactive carbon over both cyano groups takes place, and consequently after ring closure (route a), incorporation of the C-label into the pyrimidine ring should be expected (Scheme 11.16). 

Treatment of dicyano compound 41 with sulfur monochloride, N-ethyldiiso-propylethylamine and N-chlorosuccinimide in tetrahydrofuran at 0 °C for 3 days led to condensed 1,2-thiazine 42 in low yield (10%) together with polychlorinated... 

On treatment with sodium ethoxide in ethanol, dicyano compound 9 is... 

The template synthesis of phthalocyanine complexes [ZnL] by the condensation of dicyano compounds with urea in the presence of zinc chloride and ammonium molybdate has been described.1136,1137... 

The indium hydride compound, generated in situ from sodium borohydride and a catalytic amount of indium(m) chloride, selectively reduces carbon-carbon double bonds in conjugated alkenes such as a,a-dicyano olefins, a,/3-unsaturated nitriles, cyano esters, cyanophosphonates, diesters, and ketones (Scheme 107).372 This combined reagent system in acetonitrile reduces exclusively the a,/3-carbon-carbon double bond in a,/3,7,<5-unsaturated diaryl ketones, dicarboxylic esters, cyano esters, and dicyano compounds (Scheme 108).373... 

With adiponitrile, an open-chain dinitrile, however, such cyclization leading to a seven-membered cyclic imine occurs to a much lesser extent (see, e.g., eq. 7.25). The hydrogenative cyclizations have been utilized for the synthesis of pyrrolidine and piperidine derivatives from 1,2- and 1,3-dicyano compounds.118,119... 

So far, only a few examples of cationic photopolymerizations using PET corresponding to Scheme 3 have been described [10,13,165]. In the ternary system cyclohexene oxide, 9.10-dicyano anthracene and polynuclear aromatics, the polymerization of the former is initiated by the radical cations of the aromatic hydrocarbons formed via the PET with the dicyano compound. 

Hydrolysis of 4,5-dicyanoimidazole yields 4-amino-5-imidazole-car-boxamide which is converted by hypobromite into 4-amino-5-imidazole carbonitrile.444 Hydrolysis of the dicyano compound with aqueous alkali yields the corresponding 4,5-dicarboxylic acid.156 Reduction of the dicyanide with lithium aluminum hydride occurs with greater ease when the imino nitrogen carries a methyl substituent.156... 

One common possibility for the preparation of low molecular hemiporphyrazines is starting from o-dicyano compounds sudi as 1,2-dicyanbenzene and diamines sudi as 1,4-diaminobenzene or 2,6-diaminopyridine to obtain the ligand followed by introduction of metal ions (in the case using diaminopyridine) In order to get polymers, concepts of bifunctionality with various tetracyano compounds 103) and diamines 104) were used to prepare the polymer ligand 105)-, this is in some cases able to form polychelates 106) (Eq. 57, Table 17). 

The desired liquid crystals are generally synthesized from substituted ortho-dibromobenzene. In a Rosenmund-von-Braun reaction it is converted into the corresponding dicyano compound. Treatment with ammonia leads to the isoindoline from which the substituted phthalocyanine is obtained (Scheme 13). 

Dicyano compoimds undergo poly(cyclodiborazanes) (19), which have proven relatively stable towards air and thermal oxidation (eq. 19) (77-79). Some examples have been prepared where the dicyano compound allows for incorporation of a charge transferred structure (80). These exhibit extended r-conjugation through the cycloborazane unit. 

Polymers with diazatitanacyclohexadiene units (32) could be prepared by the reaction of bis(cyclopentadienyl)dimethyltitanium and dicyano compounds (scheme 18). Protonation of the polymers gave rise to polymers with P-amino-ot,P-unsaturated ketone-repeating units (33). Judging from the versatile reactivity of the diazatitanacyclohexadiene derivatives, the polymers (32) might also serve as attractive reactive materials. 

HYDROBORATION POLYMERIZATION OF DICYANO COMPOUNDS The organoboron polymers prepared by hydroboration polymerization of dienes or diynes are relatively unstable toward air as mentioned before. On the other hand, the preparation of stable boron-containing polymers has been an attractive target as polymeric materials, for which... 

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