Resonance energies of aromatic hydrocarbons. Quantitative test of resonance theory

Abstract

1685 cm-"1; nmr (CDC13) H6 4.41 (s), H3 5.56 (s), OCH3 6.60 (s), gem-dimethyl 8.70 and 8.50 (s). Hydrogenation of 4c in methanol-THF using 5% Pd/C gave 4d.Having demonstrated the utility of this procedure in the synthesis of 6-methoxypenicillins, we focused our attention on the methoxylation of the cephalosporin molecule. The procedure, by analogy, presented two formidable problems: (1) chlorination at the C2 position and (2) 3 double bond isomerization.6 However, treatment of 6a with lithium methoxide (3.5It was now apparent that we could confirm the structure of 7-a-methoxycephalosporin C (7e) obtained OAc C02R2

The Scientific Legacy of Su-Moon Park: a Personal View

“…3 Park also met Professor William Herndon of the University of Texas at El Paso, who was a quantum chemist and an authority on conjugated π-bonded systems and graph theory. [4][5][6] From all three men, Park learned the art of identifying a fertile research area and then developing it intensively. From Song, he gained a deep appreciation of photochemistry.…”

On the computation of characteristic polynomial of a chemical graph

“…,a,, that are determined successively by Eq. (23), are, in fact, the coefficients of P(x), we point out that the following formula for Ak follows from Eq. (23) (24)…”

“…. ,a, determined by (23) are also the coefficients of P(x). This method can be directly used for the computation of the characteristic polynomial P(G;x) of a given graph Le Vemer-Faddeev's method can handle all kinds of complex (chemical) graphs including vertex-and edge-weighted graphs and Mobius graphs.…”

Giant Benzenoid Hydrocarbons. Superphenalene Resonance Energy

“…In this report Clar's model will be illuminated by using the Conjugated Circuits Model 18-10,38 -471 which is closely connected with Herndon's Resonance Theory [48,49] a variant of VB method that has already been considered by in a preliminary form by Simpson [50]. The model of Clar has conceptual novelties.…”