Tetrahydrodicyclopentadiene,

The synthesis of adamantane (15), tricyclo[3.3.1.1 ]decane [281-23-2] by heating tetrahydrodicyclopentadiene (14) [6004-38-2] in the presence of aluminum trichloride illustrates another aspect of the synthetic utiHty of DCPD (80). Adamantane is the base for dmgs that control German measles and influenza (80-81) (see ANTIVIRAL AGENTS). 

Fluonnation over cobalt trifluonde over a temperature gradient of 200 to 250 °C converts ern-dicyclopentadiene to a mixture of endo- and exo-perlluoro-tetrahydrodicyclopentadiene and perfluorobicyclo[5.3 Ojdecane [21] (equation 14). 

When the removal of the ether is complete, the condenser is drained of water and the receiving flask is immersed in an ice bath. The condenser is heated by steam, if necessary, to prevent solidification of the distillate in the condenser. The distillation is resumed affording e i/o-tetrahydrodicyclopentadiene, bp 191-193, about 50 g (98%). The melting point varies with the purity of the starting diene but is usually above 65. ... 

A 125-ml standard taper Erlenmeyer flask is equipped for magnetic stirring and charged with 50 g (0.37 mole) of tetrahydrodicyclopentadiene (Chapter 5, Section I). A standard taper inner joint or a short condenser is greased and inserted into the flask... 

I. Tetrahydrodicyclopentadiene (Chapter 5, Section I) A Camphor quinone (Chapter 1, Section XI) A p-Toluenesulfonylhydrazide A, EK... 

Tetrahydrodicyclopentadiene, t259 Tetrahydro-2,5-dimethoxyfuran, d525 Tetrahydrofurfuryl alcohol, t70... 

Dicyclopentadiene, conversion to endo-tetrahydrodicyclopentadiene and to adamantane, 43, 8 a,a-Dichlorotoluene, conversion to ,a-difluorotoluene, 44, 40... 

Chemical/Physical. In an alkaline medium or solvent, carrier, diluent or emulsifier having an alkaline reaction, chlorine will be released (Wlndholz et ah, 1983). Technical grade chlordane that was passed over a 5% platinum catalyst at 200 °C resulted in the formation of tetrahydrodicyclopentadiene (Musoke et al, 1982). 

Tetrachloroterephthalic, see Chlorthal-dimethyl Tetraethyl monothiopyrophosphate, see Diazinon Tetraethyl p3U ophosphate, see Diazinon Tetrahydrodicyclopentadiene, see Chlordane Tetrahydronaphthalene, see Naphthalene... 

Monitoring by GC provided evidence [25] for several intermediates in the isomerisation of tetrahydrodicyclopentadiene (39) to adamantane (40), Scheme 2.15, a thermodynamically controlled process (discovered serendipitously) [26]. Molecular mechanics calculations indicated that the slow step of the rearrangement could occur prior to formation of exo-41, which rearranges in a few minutes to 40 on treatment with AlBr3 in CS2 at 25°C. When the reaction of exo-41 was conducted at — 10°C and monitored by GC over a period of 100 minutes, the presence of two additional intermediates (42 and 43) was revealed [25]. 

When the removal of the ether is complete, the condenser at the top of the column is replaced by a wide-diameter adapter the bottom of which is placed in a receiver flask immersed in an ice bath. The adapter is heated (Note 2) to prevent premature solidification of the distillate. The distillation is continued and the e o-tetrahydrodicyclopentadiene, b.p. 191-193°, is collected. 

The evolution of heat initially observed is due to the exothermic rearrangement of ewdo-tetrahydrodicyclopentadiene to its cico-isomer. ... 

Preparation B. Ault and Kopet2 describe as an introductory organic experiment a procedure for the preparation of adamantane by isomerization of endo-tetrahydrodicyclopentadiene by the method of Schleyer but the product is isolated from a hexane extract of the reaction mixture as the beautifully crystalline inclusion complex with thiourea.3 As noted in 1, 1164, the ratio in this complex is 3.4 molecules of host per molecule of guest hydrocarbon. Although the reaction time is only 1 hour, the yield (15%) is about the same as that reported for a reaction time of 8-12 hours. 

On the other hand, R-exchanged zeolites have also been used in combination with a metal function, for carrying out the isomerization and hydrocracking of paraffins and cycloalkanes. This is the case for isomerization of n-hexane to isohexane and 2,2-dimethyl-butane (Rabo et al. 1961) the isomerization of n-undecane to mixed Ci 1 isomers at 275°C on Pt/Ce-Y zeolite (Weitkamp et al. 1985) the isomerization of c (7o-exo-tricyclo[5.2.1.02,6]-decane or exo-tricyclo[6.2.1.02,7]-undecane into adamantane or 1-methyladamantane, respectively, on R-Y at 150-270°C (Lau and Maier 1987) the isomerization of tetrahydrodicyclopentadiene into adamantane on Re-Y in a H2/HC1 atmosphere at 250°C (Honna et al. 1986) or the double bond relocation of 2-alkyl acrolein into fran.j-2-methyl-2-alkenals over Ce,B-ZSM-5 (Fisher et al. 1986). Recently, it has been reported that Ce-promoted Pd/ZSM-5 is an active and selective catalyst in the dehydroisomerization of a-limonene to / -cymene (Weyrich et al. 1997). 

The scope of the thermodynamically driven (stabilomer approach) cycloalkane rearrangements with Lewis acids, of which tetrahydrodicyclopentadiene-adamantane transformation is a prototype, has been greatly amplified . Not only have many new adamantane-land polycycloalkanes been synthesized, but their rearrangements have been studied to provide new hydrocarbons. A few examples of cycloalkanes, synthesized through the stabilomer approach, are depicted in Table Some of these rear-... 

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