Katsura Munakata

Photochemical degradation products of pentachlorophenol

For the control of barnyard grass, Panicum crusgalli L., on the paddy fields in Japan, farmers utilize the herbicide, PCP-Na (sodium pentachlorophenoxide) on about the fifth day after transplanting of rice plant seedlings. On the day of the treatment the paddy field water is highly toxic to fish and many injuries by PCP herbicides to fish cultures occur during the transplantation season of rice plants, but the fish-killing activity in the water disappears several days after treatment. This fish toxicity in the water was prolonged by covering over the surface of field water by sheets and shutting out the sunshine. These phenomena taught the authors that sunshine promoted the degradation of PCP-Na in the water, just as in the case of the windowside PCP-Na solution turning from colourless to purple, after about ten days.

INSECT ANTIFEEDING SUBSTANCES IN PLANT LEAVES

ABSTRACT Insect antifeeding substances contained in plant leaves were widely surveyed by monitoring with ‘leaf-disc test’. Larvae of tobacco cutworm, Spodoptera litura F., were mainly the test insects and leaves of sweet potato, Ipomoea batatas Lamark var. edulis Makino, the insect baits. Leaves of Cocculus trilobus DC, Parabenzoin trilobum Nakai (= Lindera triloba Blume), Orixa japonica Thunberg, Clerodendron tricotomum, Caryopteris divaricata Maxim and other Verbenaceae plants have been systematically examined. Many kinds of insect antifeeding substances, i.e. alkaloids, sesquiterpenes, coumarines and diterpenes, were isolated and identified. These chemical structures have contributed to the knowledge of natural products chemistry and suggested the parent structure of insect antifeeding substances. The methodology for insect antifeeding substance research is discussed.

Structure of the diterpene clerodendrin A

Clerodendrin A (I), a bitter principle of Clerodendron tricotomum Thunb. and an antifeeding repellent, is a diterpene with the clerodon skeleton as in clerodin (II). On oxidation with sodium periodate the dihydro-tetraol (XXVI) gave the acetal (XXVII). The formation of the acetal revealed the relative configuration of the epoxide ring and the 18-hydroxy-group. The c.d. and o.r.d. curves of the αβ-unsaturated ketone (XXXII), obtained by treatment of (XXVII) with manganese dioxide, showed a positive Cotton sign. Therefore, compound (I) has the configuration antipodal to that of clerodin. This was confirmed by X-ray analysis of the p-bromobenzoate of the chlorohydrin (XXII).

Insect Feeding Inhibitors in Plants:Part III. Feeding Inhibitory Activity of Terpenoids in Plants

The insect feeding inhibitory activity of terpenoids in plants was surveyed and it was found that two sesquiterpenoids, pinguison and absinthin have the activity against Spodoptera littoralis Boisd. and the effectiveness of absinthin vary with the age or the rearing conditions of the insect.

Insect Feeding Inhibitors in Plants:Part I. Isolation of Three New Sesquiterpenoids in Parabenzoin trilobum Nakai

Three new sesquiterpenoids were isolated from Parabenzoin trilobum Nakai as feeding inhibitors against a polyphagous insect, Spodoptera littoralis Boisd and an oligophagous insect, Trimeresia miranda Butler. Host selection of polyphagous insects is also discussed.

Studies on Camellia sasanqua Thunb:Part II. Synthesis of Sasanquin

A glycoside “Sasanquin” ( = eugenol primeveroside), isolated by us from leaves of Camellia sasanqua, was synthesized. The glucoside linkage between eugenol and primeverose has been now confirmed as β-form.

An Insecticidal Alkaloid, Cocculolidine from Cocculus trilobus DC:Part I. The Isolation and the Insecticidal Activity of Cocculolidine

Cocculolidine isolated from leaves of Cocculus trilobus DC. (Kamiebi in Japanese), the host plant of Japanese fruit-piercing moths, exhibited insecticidal activity to leaf hoppers (Nephotettix bipunctatus cincticepts Uhler) and Azuki-been weevils (Callosobruchus chinensis Linne), however it had no activity to larvae of the fruit-piercing moth, Oraesia excavata Butler (Akaeguriba in Japanese), suggesting an interesting phenomenon of the host-parasite interrelationship.

An Insecticidal Alkaloid, Cocculolidine from Cocculus trilobus DC.: Part II The Structure of Cocculolidine

An insecticidal alkaloid, cocculolidine was extracted from fresh leaves of Cocculus trilobus DC. Von Braun reaction and a novel acid catalyzed degradation showed that this alkaloid had the same skeleton with those of erythrina alkaloids. Structure (I) was finally assigned to cocculolidine, being identified as a new lactone erythrina alkaloid containing α, β-unsaturated-γ-lactone. The mass spectra of I and dihydro-β-erythroidine were also discussed.

Production of Melilotic Acid by Action of Taphrina wiesneri Studies on Hypertrophic Disease of Cherry (Genus Prunus):So-called "Witch's Broom" Caused by Taphrina wiesneri . Part III

The in vitro action of Taphrina wiesneri on coumarin and its related compounds were examined. Melilotic acid, which accumulates in larger amounts in infected cherry leaves than in healthy leaves, was produced from coumarin, 3,4-dihydrocoumarin, o-coumaric acid or o-coumaryl glucoside by the action of acetone-dried cells of the fungus. From the results it is suggested that in cherry plants infected with the fungus melilotic acid may be formed from these precursors contained as ordinary components in cherry leaves. Possible mechanisms of the conversion of coumarin to melilotic acid are also discussed.

The Photochemical Reaction of Pentachlorophenol: Part III. The Chemical Structure of a Yellow C18-Compound

The chemical structure of a yellow C18-compound (IV), isolated from the decomposition products of sodium pentachlorophenoxide (Na-PCP) in an aqueous solution by sunlight, has been determined by chemical and spectroscopic evidences. Some of the chemistry and the absorption spectra of IV and its related compounds containing 3-cyclohexene-1,2-dione and spiroketal structures are also described.