30 植物性色素の二, 三の性状に就て

概要

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We have been studied on a few pigments derived from woods, and on a few its chemical behaviours we elucidate qualitatively on the basis of simple electronic theory as follows : 1) Colouring of the flavone pigments.It is proper to say that colouring of the flavone pigment will be originated from one whole conjugated system which is dispersed to benzopyron-ring and side phenyl radical. Accordingly light colouration or colourlessness of flavanone- and flavanonol-homologues is made clear through the consideration on the insulation effect of the 3-position methylene group in its malecule. On flovone glucoside it is recognized that combination of carbohydrate has a hypochromic effect resulting light colouration.2) Reactivity of carbonyl group in the flavone malecule.Flavone and flavonol pigments can not react with various cabonyl reagents. for the carbonyl group transmit its electron density to the oxy-gen atom in the pyron nucleus through resonance effect, while flavanone and some flavanonol compounds give crystalline oxime and semicarbazone through lacking of resonance system.3) Alkylation on the pigments.A long known experimental effect that the ortho-hydroxyl group to the carbonyl radical resists to its alkylation, is properly cleared off by the formation of chelation ring containing one hydrogen bond. Oo inert reactinity of 3-position hydroxyl group it may be admitted to give the similar pentacyclic ring formation.
日本森林学会の論文
1951-04-25