Concerning the Synthesis of Phencyclone (1,3-~iphen~l-Z-c~clopenta[I]phenanthrene-2-0ne) In a recent article Vaughn-Williams (1) presented two syntheses suitable for use in the undergraduate organic laboratory: (1) the preparation of pheneyclone (El) (2-5) by the hase-catalyzed eondensation of phenanthrenequinone (I) with dibenzyl ketone (Ill, and (2) the preparation of 2,3-dihydro-1,4-diphenyl-2,3-triphenylenediearboxylic anhydride (IV) (6) by the thermally-induced decarbonylation of the Diels-Alder adduct from ill and maleic anhydride.
We have attempted to reproduce the preparation of 111 and found that, in addition to experiencing certain mechanical difficultieP, the only product obtained was dihydropbencyclone (V) (5); at no time did we isolate any material identified asIII. Thus, it would appear that the synthesis of pheneyclone as described by VaughnWilliams presents some serious drawbacks as a useful preparation in the undergraduate laboratory. It is suggested that the original procedure of Dilthey (5). or some modification thereof (7, 8). might represent a reasonable substitute since: (1) less of one of the starting materials (phenanthrenequinone) is required, (2) the procedure is reproducible, and (3) the yield is quite reasonable (-90%). In any event, no matter uhot method is employed it is important to realize that euen the "reproducible" preparations of 111 require carefully controlled reaction conditions2 if formation of V is to be ouoided.
Literature Cited ill (2) (3) (4) (51 I61 (71 (81
Vaughn-Willlams H.R., J.CHEM.EDUC.. 48,263IL9711. Dilthey, W.. Chem Abafr. 28. L356iL9341. Maekenzie. K . J . , J Chem Soc., 473 (19601. Dittrnor. D. C.. burs. K..Balquist. J.M..andTaksshine. N..J 078.C h m , 37,225119721. Diifhey, W.,ferHorot. I.. andSchomrner, W.. J. prokt C h m , 143.189(19351. Dilfhey, W.,fer Horot. I.. andSchaeie7. A,. Jprokf Chem.. I48.53i19.171. Allen. C.F. H.. C0n.J. Chem 42.2151 (19641. Grove. W. S..unpublish~rosuIfs.Defailsofthepreparationof msnmadiiied by W.S.G.lvill be~uppliedbk,him toany interested
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Upon addition of approximately 2 ml of the alkali solution a precipitate appeared in the boiling reaction mixture resulting in violent bumping of the flask's contents. 2Allen (7) cautions that "The rate of addition is timed so that all the base has been added only when the temperature has dropped to 60%. (If too much of the base is admitted without efficient cooling, flocks of white contaminant became visible.)" 3 Present address: Smith Kline and French Laboratories, Philadelphia, Pa.
The Pennsylvania State Uniwrsity The Yark Campus York. Pcnnsylwnia 17103
Ernest A. Harrison, Jr. William S. Grave
Volume 52, Number 7, JuW 1975 / 461
