Naphthalene and derivs

Other important expls obtd on nitration of products of distillation of coal tar were Di- and Tri nitrobenzene (Vol 2 of Encycl, pp B46ff and Nitronaphthalenes, which will be described under Naphthalene and Derivatives... 

Naphthalene and Derivatives. The time-temperature relationship is especially important in this series from the standpdnt of isomer distribution. Low temperatures (SO C and below) and/or diort reaction periods favor alpha substitution, while higher tena(peratures (about 160 C) and/or a longer time favor beta substitution. Even when the more stable beta isomer is the final product, the less stable (but more easily formed) alpha isomer is produced first, but imdergoes desulfonation and resulfonatimi to the beta sulfonate. The data for naphth ene are shown in Table 7-11. The same considerations hold in the disulfonation of naphthalene and in the preparation of the naphthd- and naphthylaminesuHonic acids. 

The sequential nucleophile/electrophile addition can also be applied to the dearomatization of naphthalene and derivatives. Treatment of [Cr(CO)3(l,4-dimethoxynaphthalene)] with 2-methyl-2-litihiodithiane affords a single regio-isomeric dihydronaphthalene (Scheme 24) [35, 40]. In the second example in Scheme 26, an a-nitrile anion is used. HMPA is essential in this case to favor alkylation of the metal as opposed to anion dissociation [40]. 

Figure 16.13 presents the studies of Rehm and Weller [29] of the quenching of fluorescence of naphthalene and derivatives by amines in acetonitrile solution for the range of... 

Fused Systems.—Naphthalene and Derivatives. A new method of aromatization of partially hydrogenated aromatic hydrocarbons overcomes the difficulty of the competing Diels-Alder reaction of reactive arenes. The method is based on deprotonation-hydride elimination in which potassium fencholate (277) serves as the base and fenchone (278) as the hydride acceptor, catalytic amounts only of fencholate being required since it is regenerated in the aromatisation step. In this way, the conversion of 1,2-dihydronaphthalene into naphthalene and of 9,10-dihydroanthracene into anthracene proceeds almost quantitatively. 

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