Search

The synthesis of (±)-cyclocymopol (1) is described. Brominative cyclization with 2,4,4,6-tetrabromocyclohexadienone of cymopol bismethoxymethyl ether (7), which was obtained by monogeranylation of 2,5-dibromohydroquinone bismethoxymethyl ether (5), resulted in the formation of an undesired tricyclic compound 9. In contrast, an analogous reaction of cymopol dimethyl ether (6) provided the requisite cyclocymopol dimethyl ether (4). A two-step reaction of 4 involving oxidative demethylation with cerie ammonium nitrate or silver dipicolinate and reduction with sodium hydrosulfite gave rise to (±)-cyclocymopol (1).

A novel synthesis of the enone 12 starting from (+)-dihydrocarvone (3) and its transformation into (+)-7-hydroxycostal (1) are described. The ketone 10, obtained from 4 through a four-step sequence was converted to 12 by acid-catalyzed elimination and subsequent regioselective hydrogenation. Alternatively, the methoxyhydroperoxide 13 generated by the ozonolysis of 4 was subjected to the Criegee rearrangement, providing a mixture of 10 and 14, which on acid treatment, gave 11. Transformation of 12 into 19 was accomplished via a five-step reaction sequence. The reaction of 19 with the lithium alkoxide of 2-lithio-2-propenol afforded (+)-7-hydroxycostol (2), whose oxidation with manganese dioxide gave rise to (+)-7-hydroxycostal (1).

The synthesis of ( – )-cis-neocnidilide (1), a stereoisomer of neocnidilide (2) having inhibiting activity against mycotoxin-producing fungi, is described. ( ±)-(E)-1,3-Nonadien-5-ol was kinetically resolved to give (S)-13, which was converted to (S)-triene ester 8. The intramolecular Diels-Alder reaction of 8 afforded a mixture of 12 and 10. The dihydro derivative 14, obtained by catalytic hydrogenation of 12, was transformed via trimethylsilylketene acetal into α-bromolactone 19, which upon treatment with DBU in toluene, gave rise to ( – )-cis-neocnidilide (1).

The synthesis and biological activity of ( + )-pyrenolide B (1) and related compounds are described. The known (Z)-2-decen-9-olide (7) prepared via decan-9-olide (6) from 2-ethoxycarbon- ylcyclononanone (4) was converted to 9 by the deconjugative process, which, upon oxidation with m-chloroperbenzoic acid, led to the epoxy lactone 10. Base-promoted epoxide ring opening of 10 and subsequent oxidation furnished keto lactone 8, which, on treatment with phenylselenenyl chloride and subsequent oxidative elimination, provided ( + )-pyrenolide B (1). The antimicrobial activity of (±)-1, 6, 7, 8, 9, 10a, 10b and 11a was examined against fungi and yeast.

The interaction of some anthracycline antibiotics (adriamycin, daunomycin, aclacinomycin-A) with bacteriophage ϕX174 was investigated. Adriamycin and daunomycin inactivated the infectivity of both free ϕX174 phage and naked single-stranded ϕX174 DNA without DNA strand scission, but aclacinomycin-A did not show this action. The phage inactivation reaction was reversibly inhibited by Superoxide dismutase, catalase or other oxygen radical scavengers. The inactivation of ϕX174 by adriamycin and aclacinomycin-A was stimulated by the addition of Cu2+, while the ϕX174 inactivation by daunomycin was inhibited by the addition of Cu2+. The ϕX174 inactivation by adriamycin and aclacinomycin-A in the presence of Cu2+ was caused by degradation of DNA, and this inactivation reaction was inhibited irreversibly by oxygen radical scavengers. These results indicate that anthracycline antibiotics bind to ϕX174 DNA in the form of free radicals and that during the auto-oxidation of these antibiotics in the presence of Cu2+, o...

The synthesis of (S)-(+)-methyl β, γ-dihydroxy-α-methylenebutyrate and (S)-(-)-tulipalin B, antibacterial substances isolated from Spiraea thunliergii Sieb. has been accomplished starting from isopropylidene-D-glyceraldehyde.

1-O-Palmitoyl-d-glucopyranose was prepared by the selective 1-O-acylation of 4,6-O-benzylideneglucose followed by hydrogenolysis of the protecting group. 1-O-Oleoyl-d-glucopyranose was synthesized from the corresponding benzylidene derivative by selective hydrolysis in acetic acid. This procedure constitutes a useful method for the synthesis of 1-O-acyl-d-glucopyranoses containing unsaturated carboxylic acids. However, 4,6-O-benzylidene-l-O-linolenoyl-d-glucopyranose was converted to 3-O-linolenoyl-d-glucopyranose by the acidic hydrolysis due to acyl migration.Synthesized glucosyl esters were inactive in the bean second-internode bioassay. However, it was found that 3-O-linolenoyl-d-glucopyranose had a promoting activity on germination of pollen and growth of pollen tube.

We described product analysis of DNA synthesized in chloroplast lysate from liverwort Marchantia polymorpha L. cell suspension cultures. Characteristics of in vitro DNA synthesis by chloroplast lysate using bacteriophage ϕX174 single-stranded DNA were very similar to those in the case of double-stranded calf thymus DNA reported previously. Autoradiographic analysis clearly showed the incorporation of radioactive [α-32P]-dCTP into DNA molecules associated with bacteriophage ϕX174 single-stranded template DNA, indicating conversion of bacteriophage ϕX174 single-stranded DNA to double-stranded DNA (RF III, double-stranded linear molecule). Experiments on the fate of [32P]-labeled single-stranded DNA also showed a clear conversion of the single-stranded DNA to double-stranded DNA. Furthermore, patterns of sucrose density gradient centrifugations (neutral and alkaline) showed the production of two major components in in vitro DNA synthesis by chloroplast lysate. This also indicated conversion of bacteriophage ...

Lysate of chloroplasts prepared from liverwort Marchantia polymorpha L. cell suspension cultures incorporated [3H]-dTTP into acid insoluble materials when DNA was added exogenously as a template. The incorporation was highly dependent on the addition of template DNA, four deoxynucleoside triphosphates and magnesium ions (maximum incorporation at 5mM). Magnesium ions could be replaced by manganese ions. DNA synthesis inhibitors, Nethylmaleimide (NEM) and ethidium bromide (EtBr), strongly inhibited the incorporation. Dideoxythymidine triphosphate (ddTTP), an inhibitor of DNA polymerases β and γ, inhibited the incorporation at the concentration of 50μM (molar ratio of ddTTP/dTTP= 17). On the other hand, the incorporation by the chloroplast lysate was resistant to arabinofuranosyl cytosine triphosphate (araCTP) and aphidicolin as well as the RNA polymerase inhibitors, rifampicin and α-amanitin. The chloroplast lysate highly utilized denatured calf thymus DNA and bacteriophage ΦX174 singlestranded DNA as templates when added exogenously, while a synthetic homopolymer, poly(rA)- oligo(dT)12-18, did not stimulate the incorporation at all. Autoradiographic analysis of DNA synthesized in isolated chloroplasts showed that the chloroplast DNA synthesis took place at several specific sites on the chloroplast DNA from cells of the liverwort, Marchantia polymorpha.

A biomimetic synthesis of ( – )-aplysistatin (1) is described. The Wittig reaction of the keto ester 5 with homogeranyl triphenylphosphonium ylid gave the desired intermediate 3. Successive treatment of 3 with activated manganese dioxide, sodium chlorite and aq. trifluoroacetic acid led to the unsaturated β-hydroxy lactone 2, which was subjected to brominative cyclization to yield ( –)-aplysistatin (1).

( — )-Neocnidilide (1), an antifungal substance isolated from Cnidium officinale Makino and its antipode 11 were respectively synthesized from (S)- and (i?)-(ii)-l-ethenylpentyl 2,4-pentadienoate (...

The interaction of some anthracycline antibiotics (adriamycin, daunomycin, aclacinomycin-A) with bacteriophage oX174 was investigated. Adriamycin and daunomycin inactivated the infectivity of both free oX174 phage and naked single-stranded oX174 DNA without DNA strand scission, but aclacinomycin-A did not show this action. The phage inactivation reaction was reversibly inhibited by superoxide dismutase, catalase or other oxygen radical scavengers. The inactivation of oX174 by adriamycin and aclacinomycin-A was stimulated by the addition of Cu2+, while the oX174 inactivation by daunomycin was inhibited by the addition of Cu2+. The oX174 inactivation by adriamycin and aclacinomycin-A in the presence of Cu2+ was caused by degradation of DNA, and this inactivation reaction was inhibited irreversibly by oxygen radical scavengers. These results indicate that anthracycline antibiotics bind to ΦX174 DNA in the form of free radicals and that during the auto-oxidation of these antibiotics in the presence of Cu2+, oxygen radicals were generated to cause the degradation of oX174 DNA.

The synthesis of (S)-(+)-methyl β,γ-dihydroxy-α-methylenebutyrate and (S)-(−)-tulipalin B, antibacterial substances isolated from Spiraea thunbergii Sieb. has been accomplished starting from isopropylidene-d-glyceraldehyde.

Some α-methylene-β-butyrolactones and congeners were synthesized and their growth inhibitory activities were assayed on rice seedlings and Avena coleoptile sections. In the latter bioassay, the inhibitory activities of the synthetic α-methylene-γ-lactones were comparable to those of heliangine and pyrethrosin, the natural inhibitors possessing α-methylene-γ-lactone moiety.

Oxidations of epigallocatechin in the presence of catechol or pyrogallol with tea oxidase as well as with an oxidizing reagent and the isolation of the oxidation products, categallin (II) and pyrogallin (III), in crystalline form are described. Their absorption spectra are compared with those of pigment P(I) obtained by the oxidation of epigallocatechin and epicatechin, and their structural relationships are discussed.

A study is made on the oxidation of a mixture containing epigallocatechin and epicatechin with tea oxidase as well as a oxidizing reagent, in order to understand the formation of red pigments in tea manufacture. As the reaction proceeds a remarkable colored substance is formed, which can be obtained in reddish orange needles (from water) and is supposed to be a troponoid compound having a 3′,4′-dihydroxybenzotropolone nucleus as suggested by a tentative structural formula III from a consideration of its spectral characteristics.