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The structures of ezomycins A1. and A2, antifungal antibiotics produced by a strain of Streptomyces, were determined as 1 and 2, respectively, by degradative and spectrometric studies.

Twelve new quarternary ammonium compounds were synthesized and their plant growth retarding activities were examined. Among the candidates, N,N,N-trimethyl-l-methyl-3-(3′,3′5′-trimethylcyclohexyl)- and N,N,N-trimethyl-l-methyl-3-(3′,3′,5′,5′-tetramethylcyclohexyl)-2-propenylammonium iodides were the most effective to suppress the growth of rice and cucumber seedlings, and their activities were far stronger than those of any growth retardants hitherto known.

A new insecticidal cyclodepsipeptide, bassianolide (1), was isolated from the mycelia of two entomophagous fungi and its structure was elucidated. Silkworm larvae exhibited an atonic symptom and were killed by administration of 1.

The kinetic behavior of the thiyl radical in the solution containing polyisoprenes and polybutadienes has been studied by the flash photolysis method. For benzothiazole-2-thiyl radical, the addition rate constants toward these polymers and the model compounds of the polymers were evaluated. The relative reverse rate constants and equilibrium constants were also estimated. The addition rate constants decrease with an increase in the degree of polymerization; the ratio of the addition rate constant for polyisoprene (3.1 × 104M−1 s−1 (in monomer unit); Mv = 674,000) to that for 2-methyl-2-butene (1.5 × 105M−1 s−1) is about 1/5. This indicates that the polymer chain effect appears in the free-radical addition reaction. The relative reverse rate constants for the polymers are also smaller than those for 2-methyl-2-butene, suggesting a kind of polymer effects; i.e., it can be presumed that the bonded-thiyl radicals migrate very rapidly to the neighboring double bonds in the polymer. Significant differences in the rate parameters were observed between polyisoprene and polybutadiene, between cis- and trans-polyisoprenes, and between 1,4- and 1,2-polybutadienes.

Chemorheological studies were carried out on three kinds of natural rubber vulcanizates, differing in the structure of their crosslinks, in nitrogen in the temperature range 100° to 230°C. The crosslinking site in these polymers consists of a carbon-carbon bond (sample 1), a carbon-sulphur-carbon bond (sample 2), and carbon-carbon and carbon-sulphur-carbon bonds (sample 3), respectively. The stress decay curve of all the samples was expressed by the sum of two exponential terms, that is, two different scission reactions took place in the polymer networks at the same time. Sample 1 underwent two different random scissions in the main chains above 180°C: one was the oxidative scission due to the oxygen molecules in the sample and the other was the thermal scission involving the peroxy and/or carbonyl groups on the polymer chains. The stress decay of sample 2 was based on the cleavages of two different types of crosslink which were mono- and disulphide linkages, whereas that of sample 3 was attributed to the scission both of crosslinkages and of the main chain. The scission of crosslinkages occurred at lower temperatures (above 120°C).

Structures of the antifungal antibiotics, ezomycins B1 (1), B2 (21), C1 (3), C2 (4), D1 (5) and D2 (6), were elucidated by degradative and spectrometric studies. Compound 3 was found to be the α-anomer of 1 and 4 was that of 2. Compounds 2, 4 and 6 were easily interconvertible under weak acidic conditions.

On hydrolysis with Dowex 50W, ezomycin A1 (1) C26H40N8O16S gave ezomycin A2 (2) C19H28N6O13 and l-cystathionine (3) as main products. Further acid hydrolysis of 2 afforded an amino uronic acid named ezoaminuroic acid (5), 3-amino-3,4-dideoxy-d-xylohexopyranuroic acid, and cytosine. Ezoaminuroic acid, l-cystathionine and cytosine were found to constitute ezomycin A1.

Stress relaxation of sulphur-cured natural rubbers of different crosslinked structures was investigated in an atmosphere containing variable amounts of oxygen. At high temperature, even very low contents of oxygen strongly affected the degradation of these vulcanizates. The stress relaxation of each vulcanizate was analysed in relation to the sol fraction and the swelling of sample degraded under the same condition. The scission mechanism of the vulcanizates depended on the quantity of oxygen in the atmosphere. Under nitrogen, the scission occured mainly near the crosslink site in all the samples. However, in the case of their being small amounts of oxygen present it took place near the crosslink site in the initial stages of degradation and then along the main chain at the later stages. In the atmosphere of comparative high oxygen content, the degradation seemed to result from the oxidative scission along the main chain. The degradation mechanisms of sulphur-cured natural rubbers were also discussed.

Rhodotorucine A is a lipophilic undecapeptide having a novel amino acid, S-farnesyl-cysteine, at the C-terminus. Sulfonium salt formation of rhodotorucine A and subsequent hydrolysis afforded trans-trans-farnesol, trans-nerolidol and α-bisabolol. Thus, the geometry of the side chain of S-farnesylcysteine was established unambiguously as all trans. The reaction mechanism was also discussed.

A new compound was isolated from leaves of peanut. Its structure was determined as o-(malonylamino)benzoic acid on the basis of physicochemical evidences.

Some different results from previous reports on acid degradation and catalytic reduction studies of the three components were obtained. From gibberellin Al only gibberellin C and no gibberic acid were obtained. From gibberellic acid (namely gibberellin X and A3) only gibberic acid and no gibberellin C were obtained. In addition to this, some experimental results of gibberellin A on animal tissues were also, presented.

A new crystalline steroid conjugate was obtained by partial acid hydrolysis of asterosaponin A, a steroidal saponin from the starfish, Asterias amurensis . The structure of the conjugate was established as 5α-pregn-9(11)-ene-3β,6α-diol-20-one-3-sulfate ( 2 ) on the basis of elemental analysis, IR and PMR spectra measurement and chemical reaction. Solvolysis of compound 2 yielded 5α-pregn-9(11)-ene-3β,6α-diol-20-one. Oxidation with chromium trioxide-pyridine complex followed by solvolysis afforded a new steroid, 5α-pregn-9(11)-ene-3β-ol-6,20-dione, whose structure was deduced by the measurement of ORD curve and PMR spectra. Thus, the location of carbohydrate moiety in asterosaponin A has been assigned to 6α-hydroxy group of the steroid conjugate.

In the previous papers(1)(2)(3) it was reported that several ω-(3, 4-dihydroxyphenyl) alkanoic esters and ω, ω'-bis-(3, 4-dihydroxyphenyl) alkanes were prepared and were found to have marked antioxydant activities. In the present paper, therefore, synthesis of ω-(2, 5-dihydroxyphenyl) alkanoic esters and ω, ω'-bis-(2, 5-dihydroxyphenyl) alkanes, the isomers of above compounds, were undertaken to search more effective antioxydants. 1) The synthesis of methyl γ-(2, 5-dihydroxyphenyl) butyrate (V): β-(2, 5-Dimethoxyphenyl) propionic acid (I) prepared by the treatment of hydroquinone dimethyl ether with succinic anhydride in the presence of AlCl3, was demethylated with HI to give β-(2, 5-dihydroxybenzoyl) propionic acid (IV). This was then reduced to γ-(2, 5-dihydroxyphenyl) butyric acid (III) by the CLEMENSEN reduction and was then esterified. 2) The synthesis of methyl e-(2, 5-dihydroxyphenyl) caproate (XIII): Hydroquinone dimethyl ether was condensed with polymeric adipic anhydride in the presence of AlCl3 to give δ-(2, 5-dimethoxybenzoyl) valeric acid (VIII). This acid was reduced by the CLEMENSEN reduction to give e-(2, 5-dimethoxyphenyl) caproic acid (X). The demethylation of (X) with HI gave e-(2, 5-dihydroxyphenyl) caproic acid (XI), which was esterified in the usual way. 3) The synthesis of 1, 6-bis-(2, 5-dihydroxyphenyl) hexane (XIV): Two moles of hydroquinone dimethyl ether were condensed with one mole of adipyl chloride in the presence of AlCl3 to give 1, 4-bis-(2, 5-dimethoxybenzoyl) butane (IX), which was reduced by WOLF-KISNER method to 1, 6-bis-(2, 5-dimethoxyphenyl) hexane (XIII) and was then demethylated. 4) The synthesis of 1, 10-bis-(2, 5-dihydroxyphenyl) decane (XVII): This compound was prepared in 'the same way as in (XIV), using sebacoyl chloride and hydroquinone dimethylether as starting materials. The antioxydant activities of these compounds will be discussed in the following paper. The authors wish to express their appreciation to Professor Dr. Y. SUMIKI for his guidance and advice.

The structures of ezomycins A1. and A2, antifungal antibiotics produced by a strain of Streptomyces, were determined as 1 and 2, respectively, by degradative and spectrometric studies.

It has been confirmed that gibberellin A is a mixture of three components, gibberellin A1, gibberellin A2 and gibberellic acid (namely gibberellin X), by treating their methyl ester through the chromatography on A12O3 column. Attempts to separate them in free acid were made. The physical and chemical properties of each gibberellin as well as its physiological properties are described

Series of phenoxypyrimidines and phenoxytriazines were prepared to be evaluated as herbicides. Among them, 2-(2,6-dichlorophenoxy)-pyrimidine (XV), 2-phenoxy-4,6-dimethyl- pyrimidine (XVII), 2-(3-methyl-4-chlorophenoxy)-4,6-bis(ethylamino)-5-triazine (LIV), 2-(2,4-dichlorophenoxy)-4,6-bis(ethylamino)-s-triazine (LVIII), and 2-(2,6-dichlorophenoxy)-4,6-bis(ethylamino)-s-triazine (LX) showed high pre-emergent herbicidai activity to radish. On the other hand, 2-chloro-4-(2,6-dichlorophenoxy)-6-methylpyrimidine (XXX) revealed high efficiency to millet. Some structure-activity relationship is discussed.

To confirm the location of the lactone ring at ring A of gihberellin A3, selenium de-hydrogenation experiments were conducted in various ways. The results thus obtained and NMR spectrum studies rather support structure (III).

In the previous paper(1)(2) it was reported that some of the ω, ω'-bis-(3, 4-dihydroxyphenyl) alkanes showed remarkable antioxidant activites equal or superior to that of NDGA. Therefore, in the present paper syntheses of ω, ω'-bis-(3, 4-dihydroxyphenyl) butane and hexane were exa-mined from the practical standpoint. (1) the preparation of 1, 4-bis-(3, 4-dihydroxyphenyl) butane. The. synthetic method of ω, ω'-bis-(3, 4-dihydroxyphenyl) butane described in the previous paper(3) was so complicated that the examination of alternative processes seemed to be necessary. Firstly, ω-bromoacetoveratrone was treated with aqueous KOH in ethanol to yield 1, 2-diverat-roylethylene according to the BOGOSLOVSKII's method(4), but this attempt was unsuccessful. Then, the method of LUTL(7) to give 1, 2-dibenzoylethylene by the condensation/of benzene and fumaryl chloride was applied for veratrol but the corresponding dibenzoylethylene was not obtained. Next, in order to prepare 1, 4-diveratrylbutane via 1, 2-diveratroylethane, ω-bromoace-toveratrone was converted into car-cyanoacetoveratrone, m.p. 137_??_138° and the both compounds were condensed to give 1-cyano-1, 2-diveratroylethane, m.p. 148_??_149°, but the yield of the first step was so low such as 36% that this method should also be given up. Finaly, the processes from vsratrol and succinic anhydride to yield 1, 4-diveratrylbutane reported in the previous paper(3) were re-examined and the following results were obtained. The yield of 1-veratroyl-3-(3.4-dimethoxy-6-bromophenyl) propane from γ-(3, 4-dimethoxy-6-bromophenyl) butyric acid was found to increase from 13% to 60% when the chloroform solution of the latter compound was treated with SOCl2 in the presence of a trace of-dry pyridine. Then, 1, 4-diveratrylbutane was obtained in 90% yield by hydrogenating 1-veratryl-4-(3, 4-dimethoxy-6-bromophenyl) butane with Raney Ni and KOH in ethanol at 12 atm. and 63°. (2) The preparation of 1, 6-bis-(3, 4-dihydroxyphenyl) hexane. In this series, the ruduction of 1, 4-diveratroylbutane was found to be the most difficult step as was described in the previous paper(3) but it was solved by the following method. 1, 4-Di-veratroylbutane was hydrogenated to give 1, 6-diveratrylhexane with Pd-charcoal in ethanol-acetic acid at atmospheric pressure and room temperature., in the theoretical yield. Also with Cu-CrO in ethanol at 160° for 4 hrs with an initial pressure 40 atm. in 70% yield. 1, 6-Bis-(3, 4-dihydroxyphenyl) hexane was obtained by refluting 1, 6-diveratrylhexane with powdered AlCl3 in anhydrous chlorobenzene for 4 hrs at 140_??_150°. The authors wish to express their appreciation to Professor Dr. Y. SUMIKI for his guidance and advice

Fragin (I) was synthesized as the racemate by use of isobutyryl chloride or isobutyl-aldehyde as a starting material.

Stress relaxation mechanisms were investigated for various curing systems in natural rubber, especially the ‘complex’ crosslinking irradiation cure systems containing sulphur or tetramethylthiuram disulphide (TMTD) in both air and nitrogen mainly at 100°C. With the systems, the chemical stress relaxation in air showed that in the main oxidative scission was the major cause of stress decay. However, the number of moles of main chain scission, qm(t) seemed to be dependent on the chemical structure of the crosslink. In the TMTD curing system and irradiation-TMTD curing systems, qm(t) is independent of the ratio, ρ, of the effective chain density Nc(0) based on the carbon-carbon crosslinkages to Nm(0) based on mono- and di-sulphide linkages. Stress decay in air of both accelerated-sulphur cures and irradiation-sulphur cures was shown to be due to both the interchange reaction of polysulphide linkages and random scission of the main chain. On the other hand, in nitrogen there are two simultaneous reactions at the crosslink:interchange and thermal scission.

The outline of this report has already been published in this Journal as a communication to the Editors. The relation among four isomers, gibberellin A1, gibberellin C, pseudogibberellin A1 and isogibberellin A1 was clarified. The partial structure of gibberellin C is presented.

Helminthosporol was isolated as a natural plant growth-regulator produced by Helminthosporium sativum and its structure was assigned as I. Oxidation of I with chromium trioxide-pyridine complex gave helminthosporal (II). The glycol (III), obtained by the reduction of I or II, yielded I by the oxidation with activated manganese dioxide. I spontaneously changed into helminthosporic acid (IV), when the former in organic solvent was let to stand in the air.

Various 3-halo-6-phenoxypyridazines, with or without nitro groups on their benzene rings, and 3-anilino-6-phenoxypyridazines were prepared together with some related compounds to be evaluated as herbicides. Ultraviolet spectra of some nitrophenoxypyridazines thus obtained were also examined.

STRUCTURE OF PESTALOTIN, A NEW METABOLITE FROM PESTALOTIA CRYPTOMERIAECOLA Yasuo Kimura, Kenji Katagiri and Saburo Tamura Department of Agricultural Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, Japan (Received in Japan 15 July 1971; received in UK for publication 20 July 1971) During the course of our screening search for gibberellin synergists among microbial metabolites, we succeeded in isolating an active principle named pestalotin from culture filtrate of a phytopathogenic fungus, Pestalotia cryptomeriaecola. Here we wish to report the structure of this compound. Pestalotin (I), CllH1804, M+ 214, mp 88-89'C, exhibited IR absorption bands at 1710 and 1635 cm -' and an UV absorption maximum at 233 nm (~=12200 in EtOH). The NMR spectrum of I showed the presence of an olefinic proton (6 5.14, 1H; d, 532 Hz) and a methoxyl group (6 3.75, 3H; s). On the basis of these spectral data, I is considered to be a derivative of 4-methoxy-5,6-dihydro-a-pyrone (1, 21.

Series of 3-chloro-6-phenoxy- and 3,6-bisphenoxypyridazines were prepared from 3,6-dichloropyridazine to be evaluated as herbicides. Certain thioethers were also prepared.

Ezomycine sind fungicide Antibiotica, die von verschiedenen Streptomyces-Arten produziert werden und das Wachstum der phytopathogenen Pilze Sclerotinia und Botrytis hemmen.