Shigehiro Takase

Structure of malonylawobanin, the real anthocyanin present in blue-colored flower petals of commelina communis☆

Abstract The real anthocyanin in Commelina communis is not awobanin, but malonylawobanin, whose structure was determined to be 3-O-(6-O-( trans -p-coumaroyl)-β-D-glucosyl)-5-O-(6-O-malonyl-β-D-glucosyl) delphinidin ( 1 ).

WS009 A and B, new endothelin receptor antagonists isolated from Streptomyces sp. no. 89009. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

WS009 A and B novel endothelin receptor antagonists, have been isolated from the fermentation broth of Streptomyces sp. No. 89009. These antagonists were purified from the culture filtrate followed by Diaion SP-207, DEAE Toyopearl column chromatography and HPLC. WS009 A and B showed selective activity in an endothelin receptor binding assay with IC50 of 5.8 x 10(-6) M and 6.7 x 10(-7) M, respectively. On the basis of spectroscopic and chemical evidence, the structures of WS009 A and B have been established as 1 and 3, and are highly hydroxylated benz[a]anthraquinone chromophores.

Structure of FR 900483, a new immunomodulator isolated from a fungus

The structure of the immunomodulator FR 900483 (C5H9NO3) has been shown to be 1 on the basis of chemical and spectroscopic evidence and confirmed by a synthesis from D-glucose.

FR209602 and Related Compounds, Novel Antifungal Lipopeptides from Coleophoma crateriformis No. 738 : I. Taxonomy, Fermentation, Isolation and Physico-chemical Properties

Novel antifungal lipopeptides, FR209602, FR209603 and FR209604, were isolated from the fermentation broth of a fungal strain No. 738 which was identified as Coleophoma crateriformis from morphological and physiological characteristics. The antibiotics were purified by solvent extraction, HP-20, YMC-ODS and silica gel column chromatography and lyophilization. These compounds were structurally similar to FR901379 previously reported by ourselves which had a sulfate residue in the cyclic peptide portion.

Structure of amauromine, a new alkaloid with vasodilating activity produced by amauroascus sp.

Abstract Structure of amauromine (1a), a novel alkaloid with potent vasodilating activity has been established by chemical and spectroscopic evidences.

FR220897 and FR220899, Novel Antifungal Lipopeptides from Coleophoma empetri No. 14573

Novel antifungal lipopeptides, FR220897 and FR220899, were isolated from the fermentation broth of a fungal strain No. 14573. This strain was identified as Coleophoma empetri No. 14573 from morphological and physiological characteristics. FR220897 and FR220899 showed antifungal activities against Aspergillus fumigatus and Candida albicans attributed to inhibition of 1,3-β-glucan synthesis. Furthermore, FR220897 was effective in a murine model of systemic candidiasis.

Synthesis of debromo-8,8a-dihydroflustramine c1 , a model synthesis toward amauromine

Abstract Debromo-8,8a-dihydroflustramine C ( 4 ), a model compound of amauromine( 1 ), was synthesized utilizing thio-Claisen rearrangement of a sulphonium cation at the key step. This is the first synthesis of hexahydropyrrolo-[2,3-b]indole skeleton substituted with inverted prenyl group at position 3a.

FR227673 and FR190293, Novel Antifungal Lipopeptides from Chalara sp. No. 22210 and Tolypocladium parasiticum No. 16616

Novel antifungal lipopeptides, FR227673 and FR190293, were isolated from the fermentation broths of fungal strains Chalara sp. No. 22210 and Tolypocladium parasiticum No. 16616, respectively. These compounds have the same cyclic peptide nuclear structure as FR901379, with different side chains, and showed antifungal activity against Aspergillus fumigatus and Candida albicans attributed to inhibition of 1,3-β-glucan synthesis.

Total synthesis of amauromine

Abstract A total synthesis of amauromine ( 1 ) is described. Starting with L-tryptophan, diketopiperazine 4 was synthesized in nine steps. Thio-Claisen rearrangement of the sulphonium cation derived from the key intermediate 4 proceeded at the two sites simultaneously to provide 3 along with 12 . Reductive desulphurization on 3 using TiCl 4 -LiAlH 4 (1:2) resulted in concurrent cyclization to lead to amauromine ( 1 ).

WS-9659 A AND B, NOVEL TESTOSTERONE 5α-REDUCTASE INHIBITORS ISOLATED FROM A STREPTOMYCES

On the basis of spectroscopic and chemical evidence, the structures of WS-9659 A and B isolated as inhibitors of testosterone 5 alpha-reductase from a Streptomyces have been established as 1 and 2, respectively. The reductase inhibitory activities of the derivatives 5 and 6, and degradation products 3 and 8 were considerably less active and substantially inactive, respectively.