Tadayoshi Morita

Photodecarboxylation of chromone-2-carboxylic acid in aerated and deaerated ethanol solution

Abstract The typical photodecarboxylation of chromone-2-carboxylic acid occurs in aerated and deaerated ethanol solutions to afford 4-hydroxycoumarin and 2-(1′-hydroxyethyl)-chromone, respectively. The former proceeds through an addition of the ground state oxygen molecule, while the latter through the recombination between the ketyl radical and the 1-hydroxyethyl radical followed by the release of CO2. Chemiluminescence technique was successfully applied to detect ketohydroperoxide intermediates assumed in the photoreaction of the aerated system.

Synthesis and some properties of 7H-naphth[3,2,1-cd]azulen-7-ones and related compounds

7H-Naphth[3,2,1-cd]azulen-7-ones are synthesized by the intramolecular Friedel–Crafts cyclization of diethyl 4-phenylazulene-1,3-dicarboxylate derivatives with polyphosphoric acid (PPA). Treatment of 7H-naphth[3,2,1-cd]azulen-7-one with methyl trifluoromethanesulfonate or perchloric acid gives 7-methoxynaphth[3,2,1-cd]azulenium trifluoromethanesulfonate or 7-hydroxynaphth[3,2,1-cd]azulenium perchlorate. Both spectroscopic inspection and molecular orbital calculations for 7-hydroxynaphth[3,2,1-cd]azulenium ion show that the tropylium moiety is a main contributor to the ground state in the resonance structure. The syntheses of 7H-azuleno[1,8-bc]phenanthren-7-ones and 5,7-dihydrodinaphth[3,2,1-cd:1′,2′,3′-ij]azulene-5,7-diones are also described.

Magnetic circular dichroism of 3H-cyclohept[a]azulen-3-one

Abstract The absorption and MCD spectra of 3H-cyclohept[a]azulen-3-one were measured to show that it exists in different structures in CF 3 CO 2 H and CH 3 OH. A semi-empirical LCAO MO SCF CI calculation revealed the electronic transitions characteristic of the 7,5,7-ring system and interpreted the spectral change of 3H-cyclohept[a]azulen-3-one in CF 3 CO 2 H and CH 3 OH.