Total Synthesis of Natural Products of Microbial Origins(Recent Topics of the Agricultunal Biological Science in Tohoku University)

Microorganisms are an important rich source of secondary metabolites, which could be useful leads to valuable agrochemicals and/or medicinal drugs. This mini-review describes our recent achievements on the total synthesis of biologically active natural products of microbial origins: pteridic acids A and B (strong plant growth promoters), epoxyquinols A and B (anti-angiogenic compounds), communiols A-F, G, and H, and macrotetrolide α (antibiotics), pyricuol and tabtoxinine-β-lactam (phytotoxins)

Enzyme-catalyzed synthesis and odor evaluation of both enantiomers of perfume compounds

Synthesis of both enantiomers of some perfume compounds, and their difference in aroma characteristics are described. Enantiomeric pairs of methyl jasmonate and its 4,5-didehydro congener, principal components of jasmin absolute, were prepared from the corresponding commercially available racemates using lipase-catalyzed optical resolution. The E-value for the reaction is as high as 370. The nature-identical isomers produced superior aroma activity relative to unnatural ones. Racemic lavandulol from a commercial source, was also resolved using several enzymatic transesterifications followed by hydrolysis with PPL. Odor evaluation revealed that the nature-identical isomer should play a key role in lavender oil. Cis-α-irone and cis-γ-irone, used as important violet components for perfumery, were synthesized in optically active forms through fractional crystallization of the diastereomeric salts with α-phenethylamine. The nature-identical irones also had better floral characteristics like ionone

Effects of Olibanum and Tea-tree, used in Aromatherapy today, on the Body and Mind

Olibanum (frankincense), used as a religious offering, has been one of the most valuable and respected substances since ancient times. Tea-tree, with a long history as a folk medicine for Australian aborigines, has been used in modern aromatherapy since the late 1970’s. In this paper, comparisons of olibanum and tea-tree in aromatherapy and their effects on the body and mind are discussed

Synthetic studies of ancistrocladinium A and B, antileishmanial compounds isolated from a Congolese Ancistrocladus Species

Synthetic studies of ancistrocladinium A and B, antileishmanial compounds isolated from a Congolese Ancistrocladus sp., are described. Buchwald‒Hartwig coupling reaction between the dihydroisoquinoline and the naphthyl triflate failed. The main framework of ancistrocladinium A was constructed by 1,2‒addition of the amine to the naphthoquinone in the presence of celium trichloride as a catalyst. On the other hand, 1,4‒addition of the amine to the naphthoquinone proceeded without catalyst to form the framework of B. These products will be valuable leads for antileishmanial agents

7,8beta-dihydroponasterone A, a new phytoecdysteroid from the needles of the Japanese Yew, Taxus cuspidata

A new plant ecdysteroid 7,8beta-dihydroponasterone A, together with ponasterone A, were isolated from the methanol extract of the needles of the Japanese yew, Taxus cuspidata. Their structures were elucidated on the basis of spectroscopic analysis including ¹H NMR, 13C NMR, ¹H-¹H COSY, NOESY, HMQC and HMBC and confirmed by high-resolution FABMS data

A New pseudo-Alkaloid Taxane and a New Rearranged Taxane from the Needles of Taxus canadensis

A new taxane with an amino side chain on C-5 and a new 11(15→1)abeotaxane having a tetrahydrofuran ring along carbon atoms C-2, C-3, C-4, C-20 identified for the first time from the needles of the Canadian yew, Taxus canadensis. Their structures were characterized as 2α,7β ,9α,10β ,13-pentaacetoxy-11β -hydroxy-5α-(2 -hydroxy,3 -N,N-dimethylamino-3 -phenyl)-propionyloxytaxa-4(20),12-diene (1) and 13α,20β -diacetoxy-5α,7β ,9α,10β -tetrahydroxy-2α,20-epoxy-11(15→1)abeotaxa-11,15-diene (2) on the basis of 1D, 2D NMR spectroscopy and high-resolution FABMS analysis. Taxane 1 contains a rare C-12, C-13 double bond and a basic side chain, while taxane 2 bears a rare isopropenyl group at C-1

Synthesis of Sulfo-Sialic Acid Analogues: Potent Neuraminidase Inhibitors in Regards to Anomeric Functionality

The design, synthesis and application of N-acetylneuraminic acid-derived compounds bearing anomeric sulfo functional groups are described. These novel compounds, which we refer to as sulfo-sialic acid analogues, include 2-decarboxy-2-deoxy-2-sulfo-N-acetylneuraminic acid and its 4-deoxy-3,4-dehydrogenated pseudoglycal. While 2-decarboxy-2-deoxy-2-sulfo-N-acetylneuraminic acid contains no further modifications of the 2-deoxy-pyranose ring, it is still a more potent inhibitor of avian-origin H5N1 neuraminidase (NA) and drug-resistant His275Tyr NA as compared to the oxocarbenium ion transition state analogue 2,3-dehydro-2-deoxy-N-acetylneuraminic acid. The sulfo-sialic acid analogues described in this report are also more potent inhibitors of influenza NA (up to 40-fold) and bacterial NA (up to 8.5-fold) relative to the corresponding anomeric phosphonic acids. These results confirm that this novel anomeric sulfo modification offers great potential to improve the potency of next-generation NA inhibitors including covalent inhibitors

New Limonoids from the Seeds of Xylocarpus granatum

Three novel limonoids, 2,3-dideacetylxyloccensin S (1), 30-deacetylxyloccensin W (2), and 7-hydroxy-21β-methoxy-3-oxo-24,25,26,27-tetranortirucalla-1,14-diene-23(21)-lactone (3), were isolated from the seeds of the Chinese mangrove, Xylocarpus granatum. The structures were elucidated on the basis of 1D- and 2D-NMR (including 1H- and 13C-NMR, DEPT, 1H,1H-COSY, HSQC, HMBC, and NOESY) data and confirmed by HR-MS

Enzyme-catalyzed synthesis and odor evaluation of both enantiomers of perfume compounds

Synthesis of both enantiomers of some perfume compounds, and their difference in aroma characteristics are described. Enantiomeric pairs of methyl jasmonate and its 4,5-didehydro congener, principal components of jasmin absolute, were prepared from the corresponding commercially available racemates using lipase-catalyzed optical resolution. The E-value for the reaction is as high as 370. The nature-identical isomers produced superior aroma activity relative to unnatural ones. Racemic lavandulol from a commercial source, was also resolved using several enzymatic transesterifications followed by hydrolysis with PPL. Odor evaluation revealed that the nature-identical isomer should play a key role in lavender oil. Cis-α-irone and cis-γ-irone, used as important violet components for perfumery, were synthesized in optically active forms through fractional crystallization of the diastereomeric salts with α-phenethylamine. The nature-identical irones also had better floral characteristics like ionone