Naphthalene-1,5-dithiol

The treatment of 1,8-dihydroxynaphthalene 426 (X = X = O) with bromochloromethane and K2C03 in DMF gives rise to naphtho[de]-l,3-dioxine 427 (X = X = O, R = R = H) in good yield [83ZN(B)1000]. Acylation of 1,8-naphthalene dithiol 426 (X = X = S) with carboxylic acid chlorides in pyridine leads to mono-S-acyl-derivatives 427 (X = X = S, R = OH) existing in a cyclic form. In sulfuric acid, the latter compounds are converted into naphtho[de]-1,3-dithiinium cations (77BCJ2193). 

In a recent report [77], Furukawa et al. found a novel method for generation of N-tosyl imines which have been trapped as [4+2]-cycloadducts. 1,8-Naphthalene dithiol can be converted in two steps into sulfilimines 210 [Eq. 

Ethylene and propylene episulfides polymerize in THE at 0-70°C in the presence of sodium naphthalene, and (importantly) the polymer contains no naphthalene residues. The reaction involves one-electron transfer followed by dimerization of the resulting radical to give a dithiolate ion. This ion then polymerizes an episulfide by anionic mechanism (Boileau et al. 1967 Scheme 7.14). 

Several transition metal ions form stable complexes with aliphatic 1,2-dithiols, which absorb in the near-lR. Known as dithiolenes, their nickel complexes in particular have been found to have valuable properties. The physical properties of dithiolenes can be readily tailored by variations on the substituents attached to the dithiols, see (4.13). Although they have low molar absorption coefQcients, when compared to cyanines etc., they do have one big advantage in that they show very little absorption in the visible region." Stracturally analogous dyes can be made from aromatic dithiols and oxothiols (4.14), and the much more bathochromic naphthalene derivatives (4.15), but they are much weaker absorbers. 

Following interaction between lithiated naphthalene derivatives and chalcogene, heteroring closure requires the participation of an oxidant. In this case, oxygen of the air may play such a role. On air oxidation, 1,8-dithionaphthol is converted into naphtho[a/]dithiol 216 (65JOC3997). 

The well-known instability of the disulfide anion radicals, (R SR2)-, is apparently explained by the antibonding electron population, presumably in the framework of the disulfide bond. In some cases, however, these anion radicals turned out to be more or less stable (Breitzer et al. 2001). Two examples in Schemes 3-22 and 3-23 deserve to be distinguished. Firstly, one-electron reduction of naphthalene-1,8-disulfide using sodium in dimethoxyethane generates the corresponding anion radical, Scheme 3-22. Second, the oxidation of a [l,n]-dithiol by Ti(III)-H202 at pH 7 produces the cyclic disulfide according to Scheme 3-23 ... 

Sodium disulfide reacts with octachloronaphthalene to form tetrachloronaphtho[l,8-cd 4,5-c d ]bis[l,2-dithiole] (27b) and naphthalene or tetracene provides related fused 1,2-dithioles (27a) and (27c) by treatment with sulfur reagents (76JA252). 

Benzocyclopropene reacts with a variety of radical reagents (for example A -bromosuccinimide carbon tetrachloride bromotrichloromethane bromoform/benzoyl peroxide alkyl sulfide and ethane-1,2-dithiol with photolysis) to afford products derived from cleavage of the cyclopropane ring. The preferential mode of reaction consists of a chain reaction initiated by radical addition at Cl a followed by opening of the cyclopropyl radical to afford a benzyl radical. Yields are generally low except for the addition of the alkylsulfanyl radical, e.g. formation of 1, and no products derived from addition to the central tt-bond are formed. Cyclopropa[A]naphthalene reacts similarly with radicals and gives 2-methylnapthalene derivatives, while no addition to the central 7i-bond is observed. ... 

Both halo and nitro functions attached to naphthalene are displaced by the anion of benzene-1,2-dithiol in DMF under argon. 

The complex in Figure 11.18 successfully induces photoinduced proton reduction, hut with very low activities. Provide two reasons why using naphthalene monoimide dithiolates as the linker between the photosensitizer and the active site for proton reduction was considered desirable. What spectral argument was used to reason that the ground state zinc porphyrin moiety does not interact electronically with the diiron portion of this complex ... 

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