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Good diastereoselectivity (85:15) was observed in the intramolecular cyclopropanation of the chiral unsaturated α-diazo-β-keto ester 9f , which possesses ( R )-pantolactone as a chiral auxiliary. The reaction was catalyzed by a chiral bis-oxazoline copper ( l ) complex 17 . The absolute stereochemistry of each generated diastereomer ( 10f and 11f ) was elucidated. Both enantiomers of the vitamin D 3 CD ring synthons ((−)- 21 and (+)- 22 ) were synthesized from (−)- 12 and (+)- 13 , respectively.

(-)-Trans-4-t-butyldimethylsilyloxymethyl-2-cyclopentenol (13), a key intermediate for the synthesis of (-)-carbovir (15), was synthesized by using enantioselective bicyclic ring construction of chiral α-diazo-β-keto ester 3 catalyzed by rhodium (II) acetate.

C3-C9 and C17-C24 subunits (2 and 3) of marine macrolide macrolactin A (1) were synthesized starting from known diol 5 and methyl (R)-3-hydroxybutylate 9 as chiral starting materials by straightforward manner.

Three new glucosidic constituents (1–3) were isolated from the methanolie extract of Perilla frutescens. Two of these compounds (t and 2) were jasmonoid glucosides and were determined to be 5’-β-D-glueopyranosyloxyjasmonic acid and 3-β-D-glucopyranosyl-3-epi-2-isocucurbic acid, respectively. The other one (3) was a new glucoside of phenylvaleric acid that was elucidated to be 3-β-D-glucopyranosyloxy-5-phenylvaleric acid. Its aglycone was also found for the first time in nature.

α,β,γ,δ-Unsaturated carbonyl compounds were converted regioselectively into γ-hydroxy-α,β-unsaturated carbonyl compounds by reduction-oxygenation with molecular oxygen and triethylsilane in the presence of cobalt(II) porphyrin as a catalyst followed by treatment with trimethyl phosphite. (±)-6-Hydroxyshogaol and related furanoids isolated from ginger were synthesized via this method.

A virG thyA double mutant of Shigella flexneri 2a was constructed as a candidate live-attenuated oral vaccine. In the keratoconjunctivitis model it did not provoke any adverse reaction by itself on guinea pigs' eyes and completely protected them from provoking keratoconjunctivitis. When (2.7–4.8) × 1010 of the vaccine was inoculated intragastrically after 1 day fasting in cynomolgus monkeys three times at weekly intervals, a watery stool was observed at 40% as a side-effect. Upon intragastric challenge after 1 day fasting with 7.5 × 109 of the virulent strain four weeks after the last vaccination, a statistically significant difference was obtained in the mortality rate but not in the morbidity rate between the vaccine and the control group, although the clinical findings were less severe in the vaccine group than in the control group. These results together with the histopathological and immunological findings indicate that the vaccine deserve further detailed studies.

In the course of our study on the antioxidative mechanism of (+)-catechin (1), we have examined the reaction products of 1 in the dark with radical initiator. Compound (2) was isolated as a major product by chromatographic methods and was identified as a known dehydro-dicatechin A on the basis of spectroscopic and chemical evidences. It was an oxidative dimeric flavan-3-ol, in which two units of 1 and the oxidative derivatives of 1 are linked each other. It can therefore be presumed that in the radical reaction in the dark, the A ring as well as the B ring of 1 could possess the H-atom donating ability, thus the chain radical reaction was terminated. Compound 2 was different from the reaction products under photoirradiation of 1. This is the first report on 2 derived from 1 without enzyme.

It is generally known that specimens of Carex species plants are resistant to insects and contain a variety of stilbene compounds. Some stilbene oligomers obtained from four kinds of Carex plants were analyzed by mass spectrometry. The electron impact mass spectra, secondary ionization mass spectra, and B/E linked scan spectra were measured to investigate their fragmentations.

Nisamycin, a new manumycin group antibiotic, was isolated from the culture broth of Streptomyces sp. K106. This strain was designated to genus Streptomyces by the taxonomic features. Nisamycin was purified by ethyl acetate extraction, silica gel column chromatography, preparative silica gel TLC, and Sephadex LH-20 column chromatography as a pale yellow powder. Nisamycin is active against Gram-positive bacteria and fungi, and exhibits a cytotoxic activity.

The glycosidic constituents of two varieties of Perilla frutescens have been compared. A new phenylpropanoid glucoside named perilloside E has been isolated from the fresh leaves of the purple type plant. The structure was determined on the basis of spectral and chemical evidence.

Monodemethylation of fenitrothion catalyzed by any of five purified glutathione S-transferases from rat liver predominantly produced the (S P ) -(-)-enantiomer of desmethyl fenitrothion. Mouse liver cytosolic fraction demethylated fenitrothion in the presence of glutathione to produce predominantly the (R) P -(+)-isomer. The absolute configuration of the (+)-desmethyl fenitrothion was determined as (R) P by X-ray crystallography of its brucine salt

It is known that several kinds of pyrrolidine alkaloids with a bis-amide structure are isolated from extracts from leaves and roots of Meliaceae family plants. A fragment ion m/z 85 was found in common in mass spectra of all these compounds. The structure and fragmentation mechanism of the ion were elucidated through high-resolution mass spectra and B/E as well as B2/E linked scan spectra. The fragment ion was also found useful as an index for searching compounds having similar structures.

Three new monoterpene glucosides named perilloside B-D have been isolated from the fresh leaves of Perilla frutescens. The structures were determined on the basis of spectral and chemical evidence.

Homoconjugate 1,5-addition of various alcohols to doubly activated cyclopropane in the presence of acid catalysts was investigated. 22-Oxavitamin D3 D and CD ring synthons were synthesized effectively in short steps using the above reaction.

In addition to neoliacine and neoliacinic acid previously reported, three new germacranolides, named neoliacinolide A, B, and C, were isolated from the leaves of Neolitsea aciculata Koidz., and their structures were elucidated by spectroscopic analysis.

A novel quinone antibiotic named malbranicin was isolated from the culture filtrate and mycelium of Malbranchea cinnamomea TAIM 13T54, a thermophilic fungus. The antibiotic was elucidated to be 6-(1-acetylethyl)-2-methoxy-2,5-cyclohexadiene-1,4-dione by spectral analysis. Malbranicin exhibited antimicrobial and cytotoxic activities against Gram-positive bacteria and mammalian cell lines, respectively.

A new antifungal antibiotic, S-632-C, was extracted with ethyl acetate from the culture filtrate of Streptomyces hygroscopicus S-632 and isolated through a combination of column and preparative thin-layer chromatographies on silica gel. The structure of S-632-C was determined by analysis of 1H and 13C-NMR, MS, UV and IR spectra in comparison with those of S-632-A2 (9-methylstreptimidone). The signals were assigned on the basis of 2D NMR experiments, which involved 1H-1H DQF COSY, HMQC and HMBC spectral analysis. From these results, the chemical structure of S-632-C was elucidated as 6-(3,5-dimethyl-2-oxo-4,6-octadienyl)-4-carbamoylmethyl-3,4, 5,6-tetrahydro-2- pyrone. The antibiotic exhibited exclusively weak in vitro antifungal activity against Saccharomyces spp. and similar cytotoxic activity against KB carcinoma cells, as compared with the glutarimide antibiotic S-632-A2. In addition, this antibiotic had the ability to change the morphology of ras(ts)-transformed NRK cells to that of normal cells, also a characteristic S-632-A2 and B1.

Nisamycin, a novel manumycin group antibiotic, was isolated from the culture broth of Streptomyces sp. K106. Structural elucidation of nisamycin was achieved by detailed NMR spectral analyses and comparison of the NMR data of nisamycin with those of other manumycin group antibiotics. The structure was confirmed by chromic acid oxidation. The absolute stereochemistry of nisamycin was determined to be 4R, 5S and 6R from the CD spectra of nisamycin and chromic oxidation of nisamycin. In addition, some structure activity-relationships were examined.

The cleavage reaction of cyclopropane ring is one of the useful method in organic synthesis. Especially, the sequence of cyclopropanation-homoconjugate addition is one of the accessible methods for the synthesis of natural products possessing ring- and side-chain contiguous chiral centers. This report deals with the synthetic studies of biologically active natural products possessing such chiral centers by using the opening reaction of double activated cyclopropanes.Cyclopropane derivatives have been synthesized from methyl acetoacetate by alkylation, diazo transfer followed by copper-mediated cyclopropanation. The various adducts were obtained by homoconjugate addition of nucleophiles (Gilmann reagents, Grignard reagents, cyanide anion, methanol etc.) to cyclopropanes. The opening reaction proceed with inversion of absolute configuration at the apical carbon of the cyclopropane. The adducts were converted effectively into several biologically active natural products and/or known synthetic intermediates.

From (+)-catechin under radical reaction with 2,2′-azobis(2-methylpropionitrile), a novel intramolecular cyclization product was isolated and its structure has been characterized to be 2,4′,5′,12-tetrahydroxy-9,10-benzo-7-oxatricyclo[6.2.2.01,6]dodeca-2,5,9-trien-4-one by the spectroscopic analyses and the chemical transformation.

Homoconjugate 1,5-addition of various alcohols to doubly activated cyclopropane in the presence of acid catalysts was investigated. 22-Oxavitamin D3 D and CD ring synthons were synthesized effectively in short steps using the above reaction.

(−)-Pyrenophorin was synthesized by the Mitsunobu reaction of (2E,7S)-4,4-ethylenedioxy-7-hydroxy-2-octenoic acid which has been prepared via cobalt(II) porphyrin-catalyzed oxygenation of ethyl (2E,4E,7S)-7-acetoxy-2,4-octadienoate.

α,β,γ,δ-Unsaturated carbonyl compounds were converted regioselectively into γ-hydroxy-α,β-unsaturated carbonyl compounds by reduction-oxygenation with molecular oxygen and triethylsilane in the presence of cobalt(II) porphyrin as a catalyst followed by treatment with trimethyl phosphite. (±)-6-Hydroxyshogaol and related furanoids isolated from ginger were synthesized via this method.

The structure and stereochemistry of sargassumketone, a novel highly oxygenated ketone isolated from Sargassum kjellmanianum (the marine brown algae), have been elucidated on the basis of the spectroscopic and X-ray diffraction analysis.

Triflates of 2-hydroxymethytene t-butyl esters, derived from simple t-butyl esters, were treated with potassium t-butoxide in THF to generate alkylidenecarbenes. At room temperature, they underwent intramolecular 1,5 C-H insertion giving t-butyl cyclopentenecarboxylates.

(-)-Trans-4-t-butyldimethylsilyloxymethyl-2-cyclopentenol (13), a key intermediate for the synthesis of (-)-carbovir (15), was synthesized by using enantioselective bicyclic ring construction of chiral α-diazo-β-keto ester 3 catalyzed by rhodium (II) acetate.

Good diastereoselectivity (85:15) was observed in the intramolecular cyclopropanation of the chiral unsaturated α-diazo-β-keto ester 9f , which possesses ( R )-pantolactone as a chiral auxiliary. The reaction was catalyzed by a chiral bis-oxazoline copper ( l ) complex 17 . The absolute stereochemistry of each generated diastereomer ( 10f and 11f ) was elucidated. Both enantiomers of the vitamin D 3 CD ring synthons ((−)- 21 and (+)- 22 ) were synthesized from (−)- 12 and (+)- 13 , respectively.

From quercetin during autoxidation of unsaturated lipid and radical reaction, a novel doubly-linked oxidative product was isolated and its structure has been characterized to be 1,3,11a-trihydroxy-9-(3,5,7-trihydroxy-4H-1-benzopyran-4-on-2-yl)-5a-(3,4-dihydroxyphenyl)-5,6,11-hexahydro-5,6,11-trioxanaphthacene-12-one by spectroscopic analyses and chemical transformation after optical resolution by chromatography.

(±)-1′-Epiinvictolide [(3RS,5RS,6SR,1′SR)-3,5-dimethyl-6-(1′-methylbutyl)-tetrahydro-2H-pyran-2-one] was synthesized in 11 steps from methyl 2-oxo-6-exo-methylbicyclo[3.1.0]hexane-1-carboxylate, using a cuprous iodide-mediated homoconjugate addition of Grignard reagent as the key step.

Three new germacranolide glycosides, pittosporanoside B1, B2 and B3, have been isolated from Pittosporum tobira Ait, and their structures have been determined by spectral and X-ray crystallographic analyses.

A new chlorine-containing metabolite has been isolated from two fungi, and its structure including absolute stereochemistry was established by spectroscopic and X-ray crystallographic studies.

Three new gymnomitrane sesquiterpenoids have been isolated from the liverwort Marsupella emarginata var. patens together with the known (−)-gymnomitrene and (−)-ar-curcumene. Their structures and absolute configurations have been determined on the basis of chemical and spectroscopic evidence as well as from the results of an X-ray analysis of a derivative. We also describe the ring expansion reaction of the gymnomitrane framework and the chemosystematics of the genus Marsupella.

Penicillium sp. NTC-47, which had been isolated from a soil sample, produced novel dihydroquinolinones when cultured with okara (the insoluble residue of whole soybean). These metabolites, 1 and 2, were crystalline products with molecular formulas of C17H17NO5 and C17H17NO4, respectively. The structure of 1 was established to be 3-methoxy-4,5-dihydroxy-4-(4'-methoxyphenyl)-quinolinone by spectroscopic evidence and by an X-ray crystal-lographic analysis. Spectral data indicated the structure of 2 to be 5-deoxy-l. Compound 1 demonstrated toxicity against brine shrimp with an LC50 value of 20μg/ml, but 2 exhibited no activity at a dose of 100 μg/ml.

A new oleanane triterpene was isolated from okara fermented with Penicillium simplicissimum ATCC 90288. Its structure was established to be 7β, 15α, 24-trihydroxyolean-12-en-3, 11, 22-trione by spectroscopic techniques and an X-ray crystallographic analysis.

The homoconjugate addition of various organocopper reagents to doubly activated cyclopropane (1) was investigated. The otpimized yield (81 %) was obtained when using higher-order cyano cuprate in the presence of trimethylsilyl cyanide, and the reaction was applied to synthesize (±)-juvabione intermediate 9.

Three glucosides (1-3), together with known phenylpropanoids and polyacetylenes were isolated from Oenanthe javanica Blume (DC.). Glucoside 1, named oenanthoside A, is a new phenylpropanoid glucoside and was determined to be 2,3-methylenedioxy-5-allylphenyl beta-D-glucopyranoside, mainly by NMR techniques. Glucosides 2 and 3 were identified as eugenyl beta-D-glucopyranoside and pinoresinol beta-D-glucopyranoside, respectively. These were found for the first time in this plant.

Fungitoxic sesquiterpenoid chokols A, B, C, F, and K, chokolic acid B, and chokolal A were synthesized from chokol G by modifying the side chain.

The fungitoxic sesquiterpene (±)-chokolic acid A (1) was synthesized stereoselectively by starting from 2-methoxycarbonyl-(3-isopropenyl)cyclopentanone (2) in a 9% overall yield from 10 steps.

A new monoterpene glucoside named perilloside A has been isolated from the fresh leaves of Perilla frutescens . Its structure has been characterized on the basis of spectral and chemical evidence.

(±)-Homosarkomycin (2) and (±)-rosaprostol (3) were synthesized from (±)-methyl 2-oxo-bicyclo[3.1.0]hexane-1-carboxylate (1) by using the nucleophilic ring opening reaction on the double-activated cyclopropane ring as the key step.

A new friedelane triterpene alcohol, maytensifolin-C, has been isolated from the stems of Maytenus diversifolia . Its structure was established as 6β-hydroxyfriedelan-3,16,21-trione by spectroscopic methods and single-crystal X-ray analysis.

The structures of the title compounds were determined by X-ray crystallographic analysis. The results lead to a revision of the previously proposed structure for photochemical cycloadduct of 9,9-ethylenedioxy-6-methoxycarbonyl-5-methyl-2-oxabicyclo[4.4.0]dec-4-en-3-one with acetylene.