Sodium-naphthalene complex formation

The addition product, C QHgNa, called naphthalenesodium or sodium naphthalene complex, may be regarded as a resonance hybrid. The ether is more than just a solvent that promotes the reaction. StabiUty of the complex depends on the presence of the ether, and sodium can be Hberated by evaporating the ether or by dilution using an indifferent solvent, such as ethyl ether. A number of ether-type solvents are effective in complex preparation, such as methyl ethyl ether, ethylene glycol dimethyl ether, dioxane, and THF. Trimethyl amine also promotes complex formation. This reaction proceeds with all alkah metals. Other aromatic compounds, eg, diphenyl, anthracene, and phenanthrene, also form sodium complexes (16,20). 

Anionic polymerization Initiated by electron transfer (e.g., sodium-naphthalene and styrene In THF) usually produces two-ended living polymers. Such species belong to a class of compounds called bolaform electrolytes (27) In which two Ions or Ion pairs are linked together by a chain of atoms. Depending on chain length, counterion end solvent, Intramolecular Ionic Interactions can occur which in turn may affect the dissociation of the ion pairs Into free ions or the llgand-lon pair complex formation constants. 

The formation of complexes 198 has been extended to provide access from the (r76-naphthalene)Ru complex 202 (80%). Compound 202 is used to produce ruthenium(O) complexes of type 198 by displacement of naphthalene in acetonitrile (127). Complex 202 is also obtained by reaction of [RuC12(COD)] with sodium naphthalene (128) [Eq. (17)]. 

Further experimentation showed that no complex formed when dispersed sodium was added to dimethoxyethane that had been carefully dried and purified by distillation from a sodium-naphthalene addition compound, yet ferric chloride was reduced almost as readily as when the so-called complex had been preformed (12). This was taken as evidence that the ether was acting also as a solvent for the ferric chloride and that the complex must have been dependent on impurities in the commercial-grade ether, which either reacted with sodium or acted as a catalyst for complex formation. Nevertheless, the ether was used as the medium for all iron powder runs because of its solvent action for ferric chloride and the smaller particle sizes which were obtained as a result of its use. 

The nature of the aromatic substituents is apparently not critical for SSRI activity, as indicated by the structure of duloxetine (23-5), where one ring is replaced by thiophene and the other by naphthalene. The synthesis starts as above by the formation of the Mannich base (23-1) from 1-acetyl thiophene with formaldehyde and dimethyl-amine. Treatment of that intermediate with the complex from lithium aluminum hydride and the 2R,3S entantiomer of dimethylamino-l,2-diphenyl-3-methyl-butane-2-ol gives the S isomer (23-2) in high enantiomeric excess. Treatment of the aUcoxide from (23-2) and sodium hydride with 1-fluoronaphthalene leads to the displacement of halogen and thus the formation of ether (23-2). The surplus methyl group is then removed by yet another variant of the von Braun reaction that avoids the use of a base for saponifying the intermediate urethane. Thus, reaction of (23-3) with trichloroethyl formate leads to the A -demethylated chlorinated urethane (23-4). Treatment of that intermediate with zinc leads to a loss of the carbamate and the formation of the free secondary amine duloxetine (23-5) [23]. 

The oil sample (approximately 0.3 g) is dispersed in a hydrocarbon solvent and reacted with a mixture of metallic s um catalyzed with naphthalene and diglyme at ambient temperature. This process converts organic halogens to their respective sodium halides. Halides in the treated mixture, including those present prior to the reaction, are then extracted into an aqueous buffer, which is then titrated with mercuric nitrate using diphenyl carbazone as the indicator. The end point of the titration is the formation of the blue-violet mercury diphenylcarbazone complex. 

Like radical polymerization in the presence of Cgo (Scheme 5.1), anionic copolymerization of C ) with styrene or C70 with p-methylstyrene has been reported (93, 94). In both cases, sodium naphthalenide in THF was used as the initiator. Fullerene-styrene copolymers were obtained, but their architectures are undefined, all that is known is that they are neither linear nor star Hke. In fact, the reaction is even more complex than in the case of radical initiation as, in addition to aU the possible reactions, electron transfer from the naphthalene radical-anion to the fullerene also takes place, generating Ceo (Na ), Furthermore, because the PS chains generated by electron transfer from the naphthalene radical-anion are dicarbanionc, Na PS Na, the formation of highly branched structures or even micro-gels is favored. 

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