1- cyano-2- naphthalene derivatives

Maeda et al. examined intramolecular [2 + 2] photocycloadditions of 1-cyano-naphthalene derivatives (I) in microchannel reactors [4]. They use microreactors made of polydimethylsiloxane (PDMS) and Pyrex glass. With a photolithographic method, channels of 300 pm width, 50 pm depth and 45-202 mm length are fabricated. For the photoreaction (Scheme 16.2), flow rates of 0.03-0.005 mLh are applied and a xenon lamp with a UV-29 Alter (> 290 nm) is used as a light source. The authors report that under the conditions prevailing in the microreactor, higher regioselectivity and efficiency are achieved compared with batch process conditions. 

Heteroaromatic naphthalene derivatives generally have a lower HOMO-LUMO gap than the analogous phenylene-based compounds, leading to a bathochromic shift of the PL emission maxima. By superimposing the PL spectra of 364 (X = 469 nm/498 nm) and the corresponding triflone 365 (X = 485 nm), it can be shown that replacement of cyano by triflyl does not shift the spectral position of the nathylenevinylenes. 

Mizuno et al. recently have reported a novel intramolecular [3 + 2] cydoaddition of l-cyano-2-(4-pentenyl)naphthalene derivatives 119 [90]. The direct photolysis of 119 in acetonitrile gave the [3 + 2] cycloadducts 120 in good yields (Scheme 4.60). 

Due to their reduced aromatic character, naphthalene derivatives also frequently undergo ortho cycloaddition with alkenes (Sch. 4). 1-Cyano-naphthalene 13 reacts with cyclohexadiene to yield the regioisomeric ortho adducts 14 and 15 in good yields [34]. Two regioisomers 17 and 18 were also obtained from the intramolecular reaction of the 1-cyanonaphthalene derivative 16 [35]. The proportion of the two isomers depends on the solvent polarity. 

Intermolecular addition accounts for the formation of the products 181 in Scheme 23. Here, irradiation brings about addition of the cyano group of the naphthalene derivative to the phenol immediately adjacent to the hydroxy group. The resultant (2 + 2)-cycloadduct is unstable and ring-opens readily to yield the azocines . 

Bender and his coworkers " have examined the influence of the position of a cyano substituent on the outcome of the reactions of the naphthalene derivatives 237, 238 and 239. Typical of the reactions is the direct irradiation (A > 290 nm) of 237, resulting in its conversion into the three products shown in Scheme 16. The semibullvalene 240 is also photochemically reactive and is converted into the cyclo-octatetraene in 75% yield on fur-... 

Very recently, BASF AG applied for patents on UV absorbers based on 4-cyano-naphthalene-dicarboximide derivatives, such as 4-cyano-N(2,6-diisopropylphenyl)naphthalene-l,8-dicarboximide [139], and pyridindione derivatives such as 1,4-dimethyl-5-dimethylaminomethylene-2,6-dioxo-3-cy ano-1,2,5,6-tetrahydropyridine [140]. It remains to be seen how the patenting process will proceed, and whether a commercial product will result. 

Hanack and coworkers [161] reported related cyano-substituted naphthalene vinylene derivatives 126 and 127. Interestingly, replacing the phenylene unit in CN-PPV 113 with naphthalene in polymers 126 and 127 results in significant blue shift of the emission maxima from 710 to 595 nm (for 126a) and 500 nm (for 127). In addition, the efficiency, tested for double-layer device ITO/l/127/Mg Al(3 97), was rather low (3>el = 0.017%). 

Only the silica-based stationary phases with covalently bonded alkyl chain, cyano and propylamino ligands have found practical applications in HPLC. Besides these common ligands, the experimental use of naphthalene, pyrene and nitroaromatic as ligands has also been reported. Silica-based stationary phases with covalently bonded cyclodextrins or cyclodextrin derivatives have been frequently employed in the separation and quantitative determination of isomer pairs. 

Aspartame and its degradation products aspartylphenylalanine, aspartic acid, and phenylalanine can also be separated after reaction with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide (sodium or potassium cyanide) in borate buffer (50 mM, pH 8). This reaction affords highly fluorescent and stable l-cyano-2-substituted-benz[/]isoindole (CBI) derivatives that can be detected at 420 nm excitation and 490 nm emission. The CBI derivatives are separated on a TSK ODS-120T column using a gradient of 30-80% B (acetonitrile water, 9 1 v/v) in A (50 mM acetate buffer, pH 6.0) (75). 

Simple benzannelation of benzene leads to naphthalene. Related to our synthesis, a great number of benzene derivatives with an acidified methylene group that are ready for condensation with (7), e.g., desoxybenzoin (activated by carbonyl), benzyl-phenylsulphones (activated by sulphonyl), esters of phenylacetic acids, and best-suited, the phenylacetonitriles (activated by cyano) can easily be transformed to arylaminobutadienes 54) and cyclized to naphthalenes (56) ... 

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. 

Pyrazole-, Thiazole>, and Imidazole>fused Thiophens.—Starting from (410) and carrying out nucleophilic substitution with thioglycolate followed by ring-closure, as described for (384) and (408), the thieno[2,3-d]pyrazole system (411) was synthesized. Their ionization constants have been determined and the transmission of the influence of the substituents R has been studied and found to be more feeble than in naphthalene d benzo[b]thiophen. From the cyano-derivative (412), thiophen-fused derivatives such as (413) and (414) have been synthesized. Electrophilic... 

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