Synthesis of Methylated Fluoranthenes

Whalley, Margaret (1949) Synthesis of Methylated Fluoranthenes. PhD thesis, University of Glasgow.

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A. 2:3:4-Trimethylfluoranthene has been synthesised from 1:2:3-trimethylnaphthalene and 0- bromo-nitrobenzene (page 57). B. Since starting materials for the existing syntheses of 1:2:3- trimethylmaphthalene were not available alternative methods of preparation were sought. Two have been found (a) from benzyl methyl ketone and ethyl cyano-acetate. (page 16). (b) from hemimellitene and succinie anhydride. (page 18). C. During the search for such alternative methods, three preparations of 1:3-dimethylnaphthalene-used in the synthesis of 2:4-dimethylfluoranthene (ref. 9) -were established (a) from benzyl methyl ketone and ethyl cyanoacetate (page 14). (b) from 1-phenyl-2:4:4-trimethylbutadiene (page 20). (c) from 1-phenyl-2:4-dimethylbutadiene (page 21). D. The possibility of preparing 2:3:4-trimethyl-fluoranthene from alpha-dlphenylene-beta-dimethyl-Delta-pentadiene (page 56) has been successfully investigated. a-Diphenylene-B-dimethyl-A-pentadiene was obtained by the action of magnesium 9-fluorenyl bromide on mesityl oxide (page 34) Treatment of the diene with hydriodic acid and boiling acetic acid gave three products (page 55):- (a) 2:3:4-trimethylfluoranthene-involving ring closure and migration of a methyl group but without reduction (page 56). (b) 2:4:4-trimethyl-1:2:3:4-tetrahydrofluoranthene involving ring closure and reduction but no methyl group migration (page 56). (c) 2-methyl-4 (9-fluorenyl)-pentane-involving reduction only (page 56). E. The same diene has been cyclised, with hydrogen bromide and stannic chloride, to 2:4:4 -tdimethyl-1:4 (13:4)-dihydrofluoranthene (page 58) from which various fluoranthene derivatives have been prepared by oxidation and reduction reactions (page 59-60). F. Further assurance of the structure of alpha-diphenylene-dimethyl-Delta-pentadiene (the same diene as in D and E) was sought in the reaction of lithium 9-fluorenyl on mesityl oxide since such lithium compounds almost invariably give high yields of carbinol produced by addition to the carbonyl group (1:2-addition) of aB unsaturated ketones. It has been established that the product was not the expected diene but methyl beta-9-fluorenyl-p-methyl-n-propyl ketone resulting from 1:4 -addition. (page 38). G. The reactions of both magnesium 9-fluorenyl bromide and of lithium 9-fluorenyl with such other alphabeta-unsaturated ketones as chalcone (page 36,39), benzylidene acetone (page 35, 41) , ethylidene acetone (page 35) and 3-methyl-pent-2-en-4-one (page35,43) have been examined. In some cases interpretation of the results proved difficult but it has been shown that in the case of magnesium 9-fluorenyl bromide there was no evidence of 1:4 addition (which would produce ketones). In contrast lithium 9-fluorenyl has been shown to react with the above aB-unsaturated ketones solely by 1:4-addition (yielding saturated ketones). H. Various further fluoranthene derivations have been prepared from the products obtained In G:- (a) 2:4-diphenylfluoranthene : by reduction, cyclisation and dehydrogenation of phenyl p-9-fluorenyl-B phenyl-mpthyl ketone (product of lithium 9-fluorenyl and chalcone) (page 41). (b) 2-phenyl-4-methylfluoranthene : similarly from methyl beta-9-fluorenyl-beta-phenylethyl ketone (product of lithium 9-fluorenyl and benzylidene acetone)(Page 42). (c) 2:3 : 2':3'-tetramethyl-4-4'-difluoranthyl from the ketone product of lithium 9-fluorenyl and 3-methyl-pent-2-ene-4-one by reduction (giving a pinacol) with subsequent cyclisation and dehydrogenation (page 44): and from the same ketone by reduction to the carbinol, a 2:3:4-trimethyltetrahydrofluoranthene. I. Lithium 1-indenyl has been shown to react with chalcone (page 65) and benzylidene acetone (page 65) solely by 1:4-addition giving saturated ketones. J. The preparation of lithium 10-benzanthryl and of benzanthrene 10-carboxylic acid has been achieved, (page 66).

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Organic chemistry
Date of Award: 1949
Depositing User: Enlighten Team
Unique ID: glathesis:1949-79724
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 31 Mar 2020 09:09
Last Modified: 31 Mar 2020 09:09

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