Nitriles photochemical synthesis

Solvent Aniline, DMF, various nitriles medium- [78, 79] pressure Hg-lamp photochemical synthesis of Ru(Por)L2... 

Synthesis of 4(6)-amino-l,3,5-triazine-2-ones and 2-thiones starting from benzotriazole derivatives has been reported <01JOC6797>. The first template photochemical synthesis of a 1,3,5-triazine derivative as a receptor capable of differentiating between thymine and uracil has been described <01CC1446>. A new solid phase synthesis of trisubslituted 6-amino(substituted)-2,4-dioxo-3,4-dihydro-l,3,5-triazines from a resin-bound amine component has been reported <01JCO278>. The synthesis of thirteen lris(azol-l-yl)-13,5-triazines, as a new class of multidentatc ligands, has been described <01H(55)905>. Tris(pyrazolyl-13,5-triazincs) 14 have been prepared by cyclotrimerization of aromatic nitriles, in piperidine and in solvent-free conditions <01T4397>. 

Autoxidation of secondary acetonitriles under phase-transfer catalytic conditions [2] avoids the use of hazardous and/or expensive materials required for the classical conversion of the nitriles into ketones. In the course of C-alkylation of secondary acetonitriles (see Chapter 6), it had been noted that oxidative cleavage of the nitrile group frequently occurred (Scheme 10.7) [3]. In both cases, oxidation of the anionic intermediate presumably proceeds via the peroxy derivative with the extrusion of the cyanate ion [2], Advantage of the direct oxidation reaction has been made in the synthesis of aryl ketones [3], particularly of benzoylheteroarenes. The cyanomethylheteroarenes, obtained by a photochemically induced reaction of halo-heteroarenes with phenylacetonitrile, are oxidized by air under the basic conditions. Oxidative coupling of bromoacetonitriles under basic catalytic conditions has been also observed (see Chapter 6). 

Synthesis of the 1,3,2,4-analogues is confined to SNS+ reacting with a nitrile. Fewer synthetic options, coupled with the conversion of the 1,3,2,4-radical to the 1,2,3,5-counterpart, by thermal or photochemical isomerism (Section 6.11.4.1), account for a limited number of examples in this section. 

The photolysis of enaminonitriles provides a convenient and direct one-step synthesis of imidazoles. l,6-Dihydroimidazo[4,5-d]imidazole was prepared by the photochemical rearrangement of 3-aminopyrazole-4-carbonitrile (76JOC19) and by photolysis of 4-aminoimidazole-5-carbonitrile (74JA2014) (equation 71). The precise nature of the reaction intermediates (if any) formed on irradiation of enaminonitriles remains to be determined. However, the direct photochemical inversion of the nitrile to isocyanide is a possibility. 

A one pot, three components synthesis of tetrasubstituted imidazoles has been reported, where an isoxazole gives photochemically an acyla-zirine 7. This intermediate is trapped under basic conditions by an a-(alkylideneamino) nitrile 8 formed in situ from an aldehyde and an a-aminonitrile. The C2-C3 cleavage in the azirine ring is unusual (Scheme 15). ... 

The synthesis and photochemical reactions of polyurethanes containing [CpFe(CX))2]2 molecules has been examined. Reactions of [CpFe(CX))2Rl, R = alkyl in cyclodextrins with CO and SO2 have been studied. Some cationic ruthenium nitriles, [(Cp)L2Ru(NCAryl)], L = phosphine as phosphite have been prqiared to use in Langmuir-Blodgett films. ... 

Azetines.—1-Azetines are an uncommon group of compounds, a recent synthesis has been described and a simple member of the group, 2-phenyl-1-azetine, has been reported to undergo ready decomposition. The photochemical addition of benzonitrile to 2,3-dimethylbut-2-ene has been previously reported and the azabutadiene (168) was obtained 2-phenyl-3,3,4,4-tetramethyl-l-azetine (167) was proposed as an intermediate a- and jS-naphthonitriles were reported to undergo an addition reaction but not to the nitrile, and the tricyclic adducts (169) and (170) were obtained instead. Yang and co-workers have re-examined this reaction, and from 1-naphthonitrile they obtained azetine (171) whereas benzonitrile gave (167). 

Bruce and co-workers furthermore used the photochemical acylation for the synthesis of the benzodiazepine skeleton (Scheme 53). Benzodiazepines (e.g., diazepam [Valium]) are widely used as antianxiety agents, which makes them attractive target molecules. Transformation of 6 (R = Ph) into its bis-triflate (149) and subsequent reaction with N-methylethylenediamine afforded the diazepine 148. The conversion of the remaining triflate into either nitriles or esters was subsequently accomplished using suitable organopalladium compounds. ... 

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