Phenanthrenes cyano

Bis(phenylazo)phenanthrene 174, for which the cyclic form 175 dominates reactivity at low concentrations, reacts with acrylonitrile in dry toluene at 55 °C for 48h to give the o o-adduct 2,4-diphenyl-3a,6a-(biphenyl-2,2 -yl)-6-exo-cyano-l,3a,4,5,6,6a-hexahydropyrrolo[2,3-r7 -2,3-triazol-2-ium-l-ide 176 (60% ) as the only product of cycloaddition. Reaction with other alkenes, for example, A -phenylmaleimide, leads to a mixture of endo- and o ti-products, cf. 177 and 178 <1996J(P1)1623>. 

ET induced allylation of dicyanoalkenes (e.g., 137) is regioselective the allyl radical couples to the carbon p to the cyano groups (—> 138). ° The efficiency of these reactions can be improved by using a cosensitizer, such as phenanthrene. °... 

In organic systems, observation of products from primary electron transfer from amines depends on the facility and selectivity of a-deprotonation. For example, irradiation of cyano-phenanthrene in the presence of diethylamine results in a mixture of reduction product and amine adduct, eq. 53 (161) ... 

In the presence of secondary amines, 9-cyanophenanthrene undergoes reduction and addition reactions on irradiation to yield 9,10-dihydro-9-cyano-phenanthrene and (63), respectively. The reaction has been studied in considerable detail in order to elucidate the effect of arene structure"" and amine structure " on aminyl and a-aminoalkyl radical formation. It is deduced that in benzene solution diethylamine undergoes exclusive N-H atom transfer to give... 

There have been several recent investigations into the mechanism of photo-cyanation of aromatic hydrocarbons. The process with naphthalene, biphenyl, and phenanthrene has been subjected to a kinetic analysis the reactions in dry or aqueous methyl cyanide are shown to involve two transient species, the first of which is an ionic complex formed from a triplet excimer of the arene, or, in the presence of an electron acceptor, from a triplet exciplex. Reaction of the transient complex with the cyanide ion yields the radical ArHCN, and in aqueous methyl cyanide this second transient reacts with itself to produce dihydrocyano- and cyano-compounds. In dry methyl cyanide the radical species is oxidized to the cyano product. 

The stilbene-dihydrophenanthrene photocycllsatlon reaction continues to find synthetic applications. The tetra-oxygenated methyl phenanthrene skeleton (161) has been prepared by photocyclisation of the stilbene (162) aromatisation of the intermediate dihydrophenanthrene occurs by elimination of methanol. 2 nq photocyclisation was observed In the absence of the cyano group in this compound 2 although the closely related structures (163) and (164) are said to cyclise to the phenanthrenes (165) and (166). Triarylethylenes are important... 

Photocleavage of benzyl-S bonds appears to proceed neither by an electron transfer pathway nor with participation of an exciplex. A meta effect seems to operate in these reactions as evidenced by the influence of 3-methoxy and of 3-cyano substituents on the efficiency of the cleavage process. Photolysis of 1,2-bis(phenoxymethyl)-, l,2-bis(phenylthiomethyl)-, and l,2-bis(phenylseleno-methyl)benzene induces a two-photon process to give o-quinonedimethane, which in the presence of dienophiles undergoes a cycloaddition reaction, and 4,8,10-trithiadibenzo[cd,ij]azulene 8-oxides gives the corresponding aldehydes and ketones together with 4,8,9-trithiacyclopenta[def]phenanthrene. The two... 

Photocyanation of aromatic compounds is dealt with in several papers this year. In the presence of an electron acceptor such as p-dicyanobenzene, aromatic hydrocarbons such as naphthalene (81), substituted naphthalenes, phenanthrene, or anthracene give mixtures of products on irradiation with sodium cyanide. The major products involve substitution of hydrogen by cyanide or addition of hydrogen cyanide to the aromatic hydrocarbon. When oxygen is present, the product mixture is less complex, and a good yield of cyano-substituted compound is obtained. It is proposed that the aromatic radical cation is involved in the... 

The polarized triplet-triplet absorption spectra of biphenyl, carbazole, and phenanthrene have been compared, and phenanthrene has been found to differ considerably from the other two molecules.290 T-T Absorption spectra of cyano-substituted benzenes,291 several aromatic vapours,292 tetracene in THF,293 and hexachloroacetone 294 have been reported, and an interesting use of the triplet state of anthracene as a probe for measuring the rates of lateral diffusion of molecules of biological interest has been described.295 Absorption spectra of... 

The photoreaction of l,l-dicyano-2-phenylefliene with allylsilane in the presence of phenanthrene in acetonitrile affords 5,5-dicyano-4-phenyl-l-pentene in good yield. Phenanthrene acts as a redox sensitizer in this process and allylation occurs at the position P to the cyano group. On the other hand, a similar photoallylation reaction of cyclo-... 

The photosubstitution of many polycyclic aromatic molecules demonstrate an a-effect. For example, photocyanation of naphthalene and Azulene give the 1-cyano derivatives and phenanthrene the 9-substituted compound. 

Nitriles can be hydrolyzed to carboxylic acids by refluxing in concentrated solutions of sulfuric acid or sodium hydroxide. For example, a solution of potassium hydroxide and ethylene glycol monoethyl ether is used to prepare 9-phenanthroic acid in 98% yield from 9-cyano-phenanthrene [21]. 

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