9.10- Dihydroanthracene preparation

In the following preparation, this reaction is exemplified by the union of anthracene with maleic anhydride, to form 9,io-dihydroanthracene-9,io-e do-a -succinic anhydride note that as a result of this reaction both the outer rings of the anthracene system become truly aromatic in character. 

Uses Dyes starting material for the preparation of alizarin, phenanthrene, carbazole, 9,10-anthraquinone, 9,10-dihydroanthracene, and insecticides in calico printing as component of smoke screens scintillation counter crystals organic semiconductor research wood preservative. 

Applied to the synthesis of hydrocarbons the following results have been obtained by this new method. 9 10-Diphenyl-9 10-dihydroanthracene is formed by the condensation of benzene and chloroform, whilst in the ordinary Friedel-Crafts reaction (A., 194, 254 227, 107) triphenyl-methane (Preparation 6) is the main product, traces of chlorarylmethanes and tetraphenylethane (B., 26, 1952) being also formed. The same compound is also obtained from benzal chloride and benzene. Carbon tetrachloride and benzene give 9 9 10 10-tetraphenyl-9 10-dihydroanthracene as do also phenylchloroform and benzene. In the older reaction triphenylchloromethane (p. 432) is the chief product. 

Cyclotriveratrylene was first prepared by Gertrude Robinson in 1915 (Scheme 7.2). Robinson was interested in following up earlier work on the synthesis of anthracene derivatives and concluded that her product (empirical formula, C7H10O2, was 2,3,6,7-tetramethoxy-9,10-dihydroanthracene (7.43), the dimer of the intermediate veratryl cation (7.42). During the 1950s, CTV was again reformulated erroneously as a hexamer (7.44) and it was not until 1963 that the onset of a variety of modern techniques established a trimeric formula. 

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

The application of strong bases to hydrocarbons which contain a sp3 hybridized carbon and a conjugated system may abstract a proton and form a fully conjugated carbanion. This reaction has several synonyms such as deprotonation, proton abstraction or metalation reactions. The most common bases are alkyl lithium derivatives, e.g., butyl lithium21 24). Sometimes the addition of tetramethylethylenediamine (TMEDA) or potassium ferf-butoxide is required especially when dianions and polyanions are prepared 24e,f). Ether solvents or hydrocarbon solvents are most common. This process can be demonstrated by the preparation of anthraene dianion 22 from 9,10-dihydroanthracene (1)25). The metalation reaction can also be carried out in the NMR tube. 

Dynamic two-dimensional and NMR studies of the conformationally restricted amide iV-(l-naphthoyl)-d5-2,6-dimethylpiperidine reveal correlated rotation about the aryl-CO and amide bonds. 9-(l-Adamantylamino-methyl)-9,10-dihydroanthracene was prepared via condensation of 1-adaman-tylnitrile with 9-anthryllithium and its hydride reduction. An NMR study confirmed a boat conformation for the central ring, with the substituent of C9 in a pseudo-axial position. The structure of bis[(l,3)2-oxaadamantano]-18-crown-6 (I) and its potassium picrato complex were studied using NMR, X-ray structure analysis and molecular mechanics calculations. In the gas phase and in CDCI3 solution, in both I and the corresponding complex cation the most stable conformation of C2h symmetry is found. 

Another method for preparing hydrogenated fuUerenes is that of transfer hydrogenation [89—93]. This consists of transferring hydrogen from 9,10-dihydroanthracene to at 623 K, to yield mainly C(,QH3g, but sometimes... 

Benzynes and substituted benzynes react with isoindoles to give the 9,10-dihydroanthracene-9,10-imines (92).33 A considerable number of substituted compounds of this type have been prepared.27 Triptycene derivatives (i.e., the benzyne adducts of the anthracene system) have been encountered as unexpected products from the reaction of benzyne with 2-benzyl-1,3,4,7-tetramethylisoindole.114... 

Bromine adducts in which not all the C=C bonds are saturated are more easily prepared from polycyclic aromatic hydrocarbons. Thus 1,2,3,4-tetra-bromo-l,2,3,4-tetrahydronaphthalene is obtained by brominating pure naphthalene in anhydrous CC14 at 0° with irradiation (30% yield)134 or in CC14 at room temperature with irradiation and addition of peroxide (ascaridole) (12% yield).135 Anthracene adds bromine in CS2 at 0°, giving 9,10-dibromo-9,10-dihydroanthracene,136,137 and phenanthrene in ether138 or carbon disulfide139 gives 9,10-dibromo-9,10-dihydrophenanthrene when warmed, these two products pass into 9-monobromo derivatives by loss of HBr. 

Uses. A marked improvement in the low temperature flow property of a fuel oil having a bp 120-150°C by adding a novel compound prepared by reacting pri-, sec- or tert-aliphatic amine containing alkyl group of 1-30 C-atoms with 9,10-dihydroanthracene-9,10-endo-aP-succinic anhydride (or acid) there of together with a polymer having ethylene structure present relates compound temperature fluidity middle distillate composition petroleum fuel. 

After last year s preliminary report on the synthesis of pentatetraene by a retro-Diels-Alder reaction involving flash thermolysis of (131), Ripoll has now published the full details and has also shown that the similar decomposition of ll-vinylidene-9,10-ethano-9,10-dihydroanthracene (132) at 750°C-10mm-Hg pressure gives an 85% yield of butatriene (133). To complement these developments, a timely publication has appeared on the theoretical basis and the instrumentation necessary for flash thermolyses, suitable for such experiments on a preparative scale. 

A soln. prepared from Li and anthracene in tetrahydrofuran under Ng irradiated several hrs. at room temp, with a high-pressure Hg-arc lamp, and the mixture decomposed with methanol -> 9-(5-hydroxy-n-butyl)-9,10-dihydroanthracene. Y 65%. F. e. s. K. Suga, S. Watanabe, and T. Fujita, Chem. Ind. 1970, 402. 

Dihydroanthracene-9,10-a,p-succinic Acid Anhydride Preparation Using a Monomode Microwave Apparatus... 

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