Mugio Nishizawa

A new olefin cyclization agent, mercury(II) trifluoremethanesulfonate—amine complex

Abstract A new reagent, mercury(II) trifluoromethanesulfonate—amine complex, has been developed for effective cyclization of various farnesol derivatives in good yield and high selectivity.

(+)-8-Hydroxycalamenene: a fish-poison principle of Dysoxylum acutangulum and D. alliaceum

Abstract A fish-poison principle of Dysoxylum acutangulum and D. alliaceum has been identified as (+)-8-hydroxycalamenene, a new natural sesquiterpene phenol. This compound shows not only significant toxicity against fish but also antibacterial activity.

Malonate half-esters of homolanostanoid from an asian Ganoderma fungus

Abstract From the fruit body of an Indonesian Ganoderma species (Polyporaceae), malonic acid half-esters of two new homolanostanoid triterpene hydroxyacids have been isolated along with carboxyacetylquercinic acid, and characterized as their methyl esters. The stereochemistry of carboxyacetylquercinic acid was established by the X-ray crystallography of its methyl ester, and the structures of the two new components were determined by spectral analysis and comparisons with the methyl ester of carboxyacetylquercinic acid. An anti-tumour promoting activity of these quercinic acid derivatives is also reported.

The structure of Lansioside A : A novel triterpene glycoside with amino-sugar from lansium domesticum

Abstract Lansioside A, a novel triterpene amino-sugar glycoside, is isolated from Lansium domesticum and its full structure including absolute configuration is established by the chemical derivation and spectral study.

Biomimetic cyclization of ambliofuran and analog by using mercury(II) triflate/N,N-dimethylanilline complex: Synthesis of (±) -Ambliol-A

Abstract Biomimetic cyclization of ambliofuran with mercury(II) triflate/N,N-dimethylaniline complex is initiated from the internal double bond (Δ7) in high selectivity, whereas the corresponding sulfone is cyclized from terminal (Δ15) olefin to give marginatan skeleton.

Total synthesis of (±) Baiyunol

Abstract On the basis of highly efficient cationic cyclazation of 13-oxoambliofuran with mercury(II) triflate/ N , N -dimethylaniline complex, the first total synthesis of (±)-baiyunol, an aglycon of a sweet substance. Is accomplished in a short-step sequence.

Total synthesis of (±)-α,γ-onoceradienedione and lansic acid

Abstract Unsymmetrical onoceranoid triterpenes,α,γ-onoceradienedione and lansic acid, have been synthesized effectively by means of mercury(II) triflate/amine complex-induced olefin cyclization.

STUDIES ON THE SESQUITERPENOIDS OF HYPOLEPIS PUNCTATA METT. II

Abstract Hypacrone ( 1 ), a new seco-illudoid sesquiterpene, was isolated from a fern, Hypolepis punctata Mett., as its characteristic acrid principle. The structure is proposed on the spectral basis and the transformation into pterosins, illudoid constituents of the same plant.

Isolation of individual type II cyanolipids from Nephelium lappaceum

Abstract Three kinds of type II cyanolipids were isolated as pure forms from Nephelium lappaceum using HPLC. The full structures were established by spectral and chemical investigations.

Studies on the sesquiterpenoids of hypolepis punctata mett.—II : The total synthesis of hypacrone

Hypacrone (1), a new seco-illudoid, was synthesized by several steps, including a cross aldol condensation of two major moieties, a diketone (2) and a cyclopentenone derivative (11).