March, l!) 4 i
Ai SYriTHESIS
30.3
OF FLUORBNTIIENE BY CYCLODEHYDROGENATION
stilbenedicarboxylic and ~,1'-dibenzyldicarboxylic acid have been prepared. 2. Two esters of the stilbene series and one of .the dibenzvl series show tonka1 anesthetic mot)erties. 3. It is suggested that the activity i n the stilbene series is, in part, due to the extensive and conSummary tinuous conjugation which, if interrupted as in 1. Several dialkylaminoalkyl esters of 4,4'- the &benzyl analogs, results in decreased activity.
4,4'-Dialkylarrtinoalkyl Dibenzy1dicarboxylates.-The hydrochlorides of these compounds were prepared from the diacid chloride of 4,4'-dibenzyldicarboxylic acidI2 by method illdicated in the preparation of the analogous btilhene compounds above. The properties of these comp o u m ~ iprepared arc summarized in Table I I .
( 1 2 j F i x i e r and \Volffenstein, Bey., 37,3213 (1904).
[CONTRIBETIOX FROM THE
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CHICAGO, ILLINOIS
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RECEIVED SEPTEMBER 23, 1R4G
u.s. BUREAUO F MIXES, CENTRAL EXPERIMEST STATIOX]
Aromatic Cyclodehydrogenation. V. BY ?MILTONOR CHIN^
AND
A Synthesis of Fluoranthenel LESLIEREGGEL?
In a continuation of the cyclodehydrogenation3 but a pelleted chromia-alumina catalyst6 seems studies in this Laboratory,' we have found t h a t to be superior. 1-phenylnapht halene, I, can be readily converted Cook and Lawrence7 reported that the atto fluoranthene, 11. Since 1-(2',:3',4',3'-tetrahy- tempted liquid-phase dehydrogenation of the tlropheny1)-naphthalene, 111, which is an inter- tetrahydro compound, 111, to l-phenylnaphthamediate in the synthesis of I, can be converted di- lene, I, with a platinum catalyst gave only a small rectly to 11, the isolation of 1-phenylnaphthalene quantity of hydrogen, but the reaction did result is not required for the successful synthesis of in disproportionation into l-cyclohexylnaphthafuoranthene. The tetrahydro compound, 111, lene and 1-phenylnaphthalene. 1Ye have found that if a palladium-on-charcoal catalyst is used, nearly quantitative evolution of hydrogen occurs, and I-phenylnaphthalene can be isolated in 0 4 ~ , yield. The formation of I-cyclohexylnaphthalene can also be avoided by vapor-phase dehydrogenation of I11 over a palladium-on-charconl catalyst a t 33O0, but considerable fluoranthene is formed i n this process. Cook and Lawrence have c o m ~ n e n t c don ~ the unusual resistance which the tetrahydro compound I11 displays to hydrogenation under mild can be obtained in good yield in two steps from 1- conditions with a platinum catalyst. Previously, naphthylmagnesium bromide and cyclohexanone, we have foundYthat small-scale hydrogcn:i?ion of so that pure synthetic fluoranthene is now readily polynuclear compounds can be achieved in the available by a three-step pr0cess.j The cyclo- absence of a hydrogen atmosphere simply by redehydrogenations t o fluoranthene can be accom- fluxing an ethanol solution of the compound with plished with ;I palladium-on-charcoal catalyst, Raney nickel.9 11-e have tiow found tlint hydrogenation of 111 proceeds readily under thesr conf I , Pul)li.hed I,y rierriiis\;m < I f the Director, Kr, S Rureauof hlines. ditions, ant1 that l-cyclohesyliiaphtli~~l~,ii~ c ' u i lie I'resented h e f o r e the Organic Di\-ision a t the Atlantic City meeting of isolated from the products. t h e Ainericxti Chemical Society. April 8-12, I!l4(i.
0
( 2 1 Orjianic Chemist. Central Icxperiment S t a t i o n 17. S. Bureau of > l i n e s . Piit-hurjih, P a . I :1! 'The $1 u r d "c?clo-deh?~lri,gen;iti,,n" has been uqed previcusly. a s , f i x example. h y .[ \\- Cteni. In our studies with Raney nickel, n e ha.\? fininti t h a t e\eri in the presence of a hydrogen atmosphere, the hydrogen held o n the siirface of t h e nickel participates in t h e reacuon. F o r esample. in a quantitative study i t was found t h a t the apparent abwrptirm of hydrogen by cyclohexene is always less t h a n theoretical when hydrogenation is done in t h e presence o f K a n c y nickcl. e v e i i tli
