1- Methylthio-8- naphthalene

In compound XXI, whose first irreversible oxidation peak potential is 0.47 V versus Ag/Ag, an S-S transannular interaction is likely to operate when compared with the oxidation potential, 0.7 V versus Ag/Ag" ", of l,8-bis(methylthio)naphthalene (XXIII). It is noteworthy to mention that 1,5-dithiocane (DTC), as in Eq. (40), the analogous saturated eight-membered ring compound of XXI, is oxidized reversibly, and it is suggested that the anchimeric assistance in oxidation of XXI and DTC is more effective in the latter [100]. When electrolyzed under controlled-potential conditions, XXI produces the corresponding monosulfoxide (80% yield). Cyclic voltammetric first peak potential of XXII was shown to be 400 and 670 mV, respectively, less positive than those of diphenyl sulfide and 1,3-bis[(methylthio)methyl]benzene [101]. 

All these procedures in the benzenoid series are based on electrophilic substitution while with napthalene compounds nucleophilic substitution has been employed as seen in the following examples. 2-Naphthol in anhydrous tetrahydropyran was treated rapidly over 2 mins, with butyllithium (2 moles) in pentane at 20-25°C. The solution was stirred for 4 hours, cooled to 0 C and after the addition of dimethyidisulphide in tetrahydropyran, the mixture was stirred for 2.5 hours to complete reaction to afford, after acidic work-up, 2-hydroxy-3-(methylthio)naphthalene in 83% yield (ref. 119). 

Methoxy-4-methyl-3-methylthio I Methyl methylthioacetate, SO2CI2 2 2-Methoxy-5-methylaniline 3 l,8-W.s-(Dimethylammo)naphthalene 81, [14]... 

Studying further the 1,5-interactions in peri-substituted naphthalenes (which culminated in the complete formation of a single bond in zwitterion 63 (Section 8.11.3.1.1) the corresponding methylthio derivative 242 was investigated <2006CEJ7724> also in this case the MeS sp -C attractive interaction controls the solid state structure of compound 242. 

Fused Rings and Polymers. Borazine analogues of naphthalene and substituted phenalenes are known the latter compound is formed by reaction of distannylamine and a large excess of tris(methylthio)borane (137). A general method for the preparation of the polycyclic borazines using fused carbon—heteroatom rings, where X = O, NR and n = 2,3, has been given (137). 

The mechanism for formation of the methylthio-containing aglycone of naphthalene is the same as that for the acetanilide (figure 3). Tissue C-S lyase activity does not function with preMAP [either naphthalene (11) or phenanthrene (74)J, presumably because preMAP structures lack the aromaticity required. 

Because of its more extended aromatic system naphthalene is expected to be more acidic than benzene, but the difference is hardly observed in synthetic experiments. Treatment of naphthalene with BuLi TMEDA in hexane results in the formation of comparable amounts of the 1- and 2-lithio compounds and a dilithio derivative (possibly 1,8-) so that this method is not interesting from a synthetic point of view. If the metallation is carried out with the ternary mixture BuLi f-BuOK, TMEDA in hexane at temperatures in the region of — 20 °C, subsequent addition of dimethyl disulfide affords a mixture of 1-methylthio-, 2-methylthio- and l,8-bis(methyl-thio)naphthalene. The mono- and disubstitution products can be separated by distillation. The favourable ratio of about 15 85, together with the fact that the 2-isomer is solid at room temperature (whereas the 1-isomer is a liquid), permits an easy purification of the predominant product by crystallization. For practical reasons (difficult separation from the products) the use of an excess of naphthalene is avoided (compare the metallation of benzene, Exp. 3), and consequently yields (based on BuLi) are not optimal, since part of the base may react with TMEDA. 

N,N -Bis(1-methylethyl)-6-(methylthio-1,3,5-triazine-2,4-diamine. SeePrometryn Bis (1-methylethyl) naphthalene. See Diisopropyl naphthalene 3-[2,4-Bis (i-methylethyl) phenyl]-2-propenoic acid, methyl ester. See Diisopropyl methyl cinnamate... 

The reaction of ortto-palladated (l-(dimethylantino)ethyl)-naphthalene with a perchlorate complex proceeds by the exo-pathway and produces (+)-exo-syn-methylthio-substituted phosphanorbomene P-S bidentate chelate 8.42, as shown in Eq. (8.7). Generation of the chelating cycloadduct involved an intramolecular cycloaddition mechanism, in which both the cychc diene and the hetero dienophile were coordinated simultaneonsly to the chiral palladium template during the course of the cycloaddition reaction [25]. 

Hjndc naphthalene dicarboxylic acid metbd 2,5-bis-(2-(methylthio)ethylthio)-l,4-benzenedicarboxylate... 

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