Armstrong and Baeyer

Claus, Armstrong and Baeyer.—Still other formulas have been suggested on account of this difficulty, each endeavoring to avoid the necessity of oscillation in order to satisfy the four valencies of carbon. One of these was suggested by Claus and called the diagonal formula and another by Armstrong and Baeyer and known as the centric formula. 

The formula of benzene which has been discussed does not take into account the fourth valence of the carbon atoms. Many suggestions have been put forward in regard to the position of this fourth bond. The formulas of Kekul, Claus, Armstrong and Baeyer, and Thiele are as follows —... 

In the formula of Kekule the carbon atoms are joined alternately by double bonds. According to Claus, each carbon atom is in combination with the carbon atom opposite to it in the molecule. The so-called centric formula of Armstrong and Baeyer is meant to indicate that the combining powers of the carbon atoms which are not utilized in the ring formation and... 

Figure 10.7 Various proposed structures for benzene (a) Claus, (b) Lothar Meyer, (c) Armstrong, (d) Baeyer and (e) Dewar...

Two C2-symmetric 5-membered ring ketones 69 and 70 were reported by Armstrong and coworkers (Scheme 3.51) [84, 85]. Studies with these ketones showed that the 5-membered ring is more prone to Baeyer-Vilhger oxidation, and the activation of the carbonyl by electron-withdrawing substituents is important for the epoxidation. 

Kipping, a Manchester native, studied with Roscoe and Schorlemmer, then spent a year (1886) in Munich at Adolf von Baeyer s laboratory where Perkin, Jr., was Privatdozent and von Baeyer s assistant. Kipping completed his London doctoral degree in 1887 and was Armstrong s assistant from 1890 to 1897. See Partington, A History of Chemistry, IV 851. And Robert Robinson, Memoirs, 2223. 

On William Henry Perkin (1860-1929), ODNB, Waynfiete professor of chemistry 1913-1929, J. Greenaway, J. F. Thorpe and R. Robinson, The Life and Work of William Henry Perkin, Chemical Society, London, 1932 Robinson, J. Soc. Chem. Ind., 1929, 48,1008 J. Morrell, W. H. Perkin, Jr. at Manchester and Oxford , Osiris, 1993, 8, 104 Perkin, Baeyer Memorial Lecture , Memorial Lectures delivered before the Chemical Society, 1914-1932, Chemical Society, London 1933, 47 H. E. Armstrong, Perkin , Nature, 1929, 124, 623. 

See Fieser, L. F., and Fieser, M.x Organic Chemistry, 3rd ed., p. 529 for an explanation of Armstrong-Baeyer theory. New York Reinhold Publishing Coip. 1956. 

Kekule, who was the first to draw localized bond structures of benzene, was criticized by his contemporaries because the alternating single bond/double bond structure did not explain the number of isomers found in substituted benzenes (e.g., only one isomer of o-substituted benzene). A. Claus [12], J. Dewar [13], L. Meyer [14], H. E. Armstrong [15], A. v. Baeyer [16], and A. Ladenburg [17] proposed alternative structures (Figure 13.2). 

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