A. G. Pinkus Baylor University Waco. TX 76703
Origin of Cyclic Structural Formulas
Cyclic formulas were not possible before the development of extended formulas for molecules showing linkages between atoms. Theories on tetravalence of carbon and linkaees hetween aturns which were ccmn~ivrrlintlrpcndently by Kekuli. 11 I and Couoer 12-41 and nuhlished in 1858 were ~rohahlvthe import& stage in the development of modern struciural formulas in chemistrv since rapid progress in chemical knowledge hegini rviththat dute..4lth;uch the origin of the r~n,r)(,s;~l of the cyclic formula for hen~enein 18fi3 hv Kekule i5) i s well-known in the story of his daydream of t h i latter in thr Frenrh ver& ( $1 of the action mure extensivr chemic al thwrv. paper . . 1.31. These are the tirat three cyclic formulas appearing in print seven years before the well-known Kekul6 formula for benzene.
-
Acknowledament 'l'he author expresses appreriation to Baylor IJniversity for 3 sahhatical leave durinr whirh work on this r)nvt.r was lamel\, accomplished. Literature Cited 11) Kekuli, A., Ann.. 106.129 118581. 12) (a) Cuupr,A.,Cumpl. Rend., &, ,157 118581.1hl RepuhlishedssEnglishtranslstion in AlernhicCluh Reorints. No. 21. "On a Newchemical Thcorv and Rerearcheion Salicylic A e i d , " ~ . d < ~ b1983 ~ ~ ~and h , !cI"Clarrie~in t h e ~ h e o ; yolChemical Combination.(lVol. I. Benfey, 0. T.,Ed.. Dover Pubiicationr. 1962, pp. 132 I( (31 Druner. A. S.. Phil. Mae J. S c i . 141. 16. LO4 ii8581. Reouhlirhed in rofs2b s n d c .
in refs2h
.
and
