Tetrahydroanthracenes

Tetrahydroanthracene is the linear benzologue of Tetralin. This compound behaves identical to Tetralin in the presence of dibenzyl with respect to ring contraction, giving a single methyl signal at 19.6 ppm (Figure 5). Contrary to... 

The use of an extended arene (tetrahydroanthracene) in [OsCl(en)(ri6-tha)]+ (29) gave rise to a similar potency (112). This is in contrast with the data for ruthenium-arenes, where the same substitution gave rise to a 10-fold increase in activity. Further work therefore needs to determine if the extended Os-arenes can intercalate into DNA in a manner similar to Ru-arenes. Replacement of the iV /V-chelating ligand en for other AyV-bidentates with pyridine, aliphatic amine, or azopyridine donor atoms leads to loss of activity, probably because of slower hydrolysis and higher acidity of the coordinated water (112). 

The complex [Rh(MeOH)2(diphos)]+ (diphos = l,2-bis(diphenylphosphino)eth-ane) has been reported to hydrogenate polynuclear aromatic hydrocarbons under mild conditions (60 °C, 1 bar H2) [17]. A kinetic study of the hydrogenation of 9-CF3CO-anthracene to the corresponding 1,2,3,4-tetrahydroanthracene was consistent with a rapid conversion of the precursor to [Rh( 76-anthracene)(diphos)]+ and a rate-determining step involving the reaction of the latter complex with H2... 

The procedure given here is a modification of the first synthesis of the tetrahydroanthracene diepoxides.5 7 These compounds have also been prepared from another 1,4-benzadiyne equivalent, namely 1,5-diamino-1,5-dihydrobenzo[1,2-d 4,5-d ]bistriazole which, although it has certain advantages,12 is not as available as 1,2,4,5-tetrabromobenzene. 

Volume 75 concludes with six procedures for the preparation of valuable building blocks. The first, 6,7-DIHYDROCYCLOPENTA-l,3-DIOXIN-5(4H)-ONE, serves as an effective /3-keto vinyl cation equivalent when subjected to reductive and alkylative 1,3-carbonyl transpositions. 3-CYCLOPENTENE-l-CARBOXYLIC ACID, the second procedure in this series, is prepared via the reaction of dimethyl malonate and cis-l,4-dichloro-2-butene, followed by hydrolysis and decarboxylation. The use of tetrahaloarenes as diaryne equivalents for the potential construction of molecular belts, collars, and strips is demonstrated with the preparation of anti- and syn-l,4,5,8-TETRAHYDROANTHRACENE 1,4 5,8-DIEPOXIDES. Also of potential interest to the organic materials community is 8,8-DICYANOHEPTAFULVENE, prepared by the condensation of cycloheptatrienylium tetrafluoroborate with bromomalononitrile. The preparation of 2-PHENYL-l-PYRROLINE, an important heterocycle for the synthesis of a variety of alkaloids and pyrroloisoquinoline antidepressants, illustrates the utility of the inexpensive N-vinylpyrrolidin-2-one as an effective 3-aminopropyl carbanion equivalent. The final preparation in Volume 75, cis-4a(S), 8a(R)-PERHYDRO-6(2H)-ISOQUINOLINONES, il lustrates the conversion of quinine via oxidative degradation to meroquinene esters that are subsequently cyclized to N-acylated cis-perhydroisoquinolones and as such represent attractive building blocks now readily available in the pool of chiral substrates. 

Khalil Shahlai, Samuel Osafo Acquaah, and Harold Hart 201 USE OF 1,2,4,5-TETRABROMO-BENZENE AS A 1,4-BENZADIYNE EQUIVALENT anti- AND syn-1,4,5,8-TETRAHYDROANTHRACENE 1,4 5,8-DIEPOXIDES... 

We know that C6-cyclization of 1-(naphthyl-2)-butene is possible without metal catalysts. The products are dihydrophenanthrene over quartz and 1,2,3,4-tetrahydrophenanthrene plus phenanthrene over alumina (50). The latter apparently catalyzes the redistribution of hydrogen in dihydrophenanthrene. Neither anthracene nor dihydro- or tetrahydroanthracene are formed over quartz or alumina from 1-(naphthyl-2)-butene. Plate and Erivanskaya concluded from this that the 2-alkylnaphthalene - anthracene reaction does not involve naphthylbutene intermediate (27). 

Treatment of l,2-di(l-acetoxypropynyl)benzene (238) with Sml2 generates 1,2-dipropadienylbenzene (239), which spontaneously cyclizes to give 2,3-naphthoquino-dimethane (240). Then facile Diels-Alder reaction of 240 with fumarate (241) gives the tetrahydroanthracene derivative 242 [52]. 

Changing the arene can also have a significant effect on the rate and extent of hydrolysis. For example, there is a 2-fold difference in the hydrolysis rate between the biphenyl complex [Ru(ri6-biphenyl)Cl(en)]PF6, and the tetrahydroanthracene complex [Ru(ri6-5,8,9,10-tetrahydroanthracene)Cl(en)]PF6 or the dihydroanthracene complex [Ru(ri6-9,10-dihydroanthracene)Cl(en)]PF6, demonstrating that variations in the steric and electronic effects of arene ligands can modulate the aquation rate [68]. 

Orchin (149) has described a novel method for the preparation of small quantities of tetrahydroanthracene from 9,10-dihydroanthracene or from anthracene. 

To about 0.54 g. of 9,10-dihydroanthracene in 25 ml. of ethanol, 8 g. of Raney nickel catalyst was added. After refluxing for 2J hours in an atmosphere of nitrogen, the mixture was filtered and the filtrate was concentrated. On cooling, about 0.33 g. of 1,2,3,4-tetrahydroanthracene was obtained. The mother liquor, when treated with 0.3 g. of s-trinitro-benzene, yielded about 0.25 g. of the 1,2,3,4-tetrahydroanthracene-tri-nitrobenzene complex. The total yield was 81% of the theoretical. When about 0.34 g. of anthracene in 50 ml. of ethanol was treated with 10 g. of Raney nickel, a 71 % yield of the same product was obtained. 

Dihydroanthracene is obtained in high yield in the hydrogenation over copper-chromium oxide in ethanol at 100°C (eq. 11.79)254 or in decalin at 150°C.255 Tetrahydroanthracene is obtained in high yield in the hydrogenation over copper-chromium oxide at 240-260°C and 9.5 MPa H2.255... 

---