Thierry Prangé

Structures of marcfortine B and C (X-ray analysis), alkaloids from

Resume Marcfortine B and C are minor alkaloids isolated from the mycelium of Penicillium roqueforti . The structure of marcfortine B was established by spectral means and that of marcfortine C by X-ray diffraction analysis.

Synthetic studies on taxane diterpenes X-ray structure of a key intermediate

Abstract Michael condensation of the dienone (3) with the vinyllactone (19) leads to the compound (20). Attempts to construct the B ring of the taxane skeleton by direct cyclization of (20) are reported . The stereochemistry of (20) is established by X-ray structure determination.

Isolation and structure (x-ray analysis) of karinolide, a new quassinoid from Simaba Multiflora ☆

Karinolide is a structurally novel C20 quassinoid isolated from the French Guyanan Simaroubaceae, Simaba multiflora A.Juss. whose structure was established by X-ray diffraction analysis. 6α-Senecioyloxychaparrin , the known 6α-senecioloyxychaparrinone and 9-methoxycanthin-6-one were also isolated ; their structure were determined by spectral means.

Isolation and structure of sergeolide, a potent cytotoxic quassinoid from Picrolemma pseudocoffea

Abstract Sergeolide 2 , isolated from the French Guyanan Simaroubaceae, Picrolemma pseudocoffea Ducke, is a novel quassinoid possessing the normal C20 basic skeleton with a butenolide function attached to the A ring. Structure 2 was established by interpretation of the 400 MHz 1H-NMR and the 13C-NMR data. It is highly cytotoxic and is active against mouse leukemia P388. The previously known isobruceine B 1 was also isolated.

Antileukaemic quassinoids : structure (X-ray analysis) of bruceine C and revised structure of bruceantinol

Abstract The complete structure of bruceine C has been established by single crystal X-ray analysis of the tetra-O-acetyl derivative. The structure of bruceantinol, a potent antileukaemic quassinoid, has been revised and shown to be 4′-O-acetyl bruceine C.

Structure of laurycolactone A and B, new C18 - quassinoids from Eurycoma longifolia and revised structured of Eurycomalactone (X - ray analysis)

Abstract Laurycolactone A 2 and B 3 are new quassinoids with a C 18 basic skeleton isolated from the Vietnamese Simaroubaceae, Eurycoma longifolia Jack. The structure of Eurycomalactone, a C 19 quassinoid isolated previously from the same plant, has been revised and shown to be 4 . The structures have been established by spectral means and those of 2 and 4 confirmed by X-ray diffraction analysis.

Model studies in the taxane diterpene series - Part. I

Abstract Photochemical [2 + 2] cycloaddition of enol acetate 10a to cyclohexene led to a 3 : 1 mixture of the tetracyclic photoadducts A and B which, through reverse aldol reactions, under mild alkaline conditions produced two compounds : a tetracyclic ketone 13 and a tricyclic diketone 14 . Hydrolytic cleavage in methanolic hydrochloric acid of 15 and 16 resulting from irradiation of the enol ether 10b to cyclohexene gave rise to the rearranged tricyclic diketone 14 only. The trans stereochemistry 3α, 8β of the fused-ring system in 14 established by X-ray measurements, is different from the stereochemistry of the naturally occuring taxane derivatives.

New toxic quassinoid glucosides from Simarouba glauca (x-ray analysis)

Abstract Two new toxic quassinoid glucosides, 15- O -β- D -glucopyranosyl glaucarubolone 3 and 15- O -β- D -glucopyranosyl glaucarubol 4, have been isolated from Simarouba glauca seeds. Their structures were deduced from spectral data and that of 3 established by single-crystal X-ray analysis.

Quassinoids. Isolation from soulamea muelleri and structures of 1,12-di-o-acetyl soulameanone and Δ-picrasin b. X-ray analysis of soulameanone

Abstract The structures of soulameanone, 1,12-di-O-acetyl soulameanone and Δ 2 -Picrasin B, new quassinoids from Soulamea muelleri (Simaroubaceae), were determined by spectrometric methods and chemical correlation, and that of Soulameanone confirmed by single crystal X-ray analysis.

STRUCTURE (X-RAY ANALYSIS) OF MANICOLINE B, A MIXTURE OF TWO DIASTEREOISOMERS OF A NEW ALKALOID FROM DULACIA GUIANENSIS (OLACACEAE)

Abstract Manicoline B, isolated from the root bark of Dulacia guianensis (Olacaceae), was shown by X-ray analysis to be an equimolecular mixture of two diastereoisomers of a new alkaloid and to have structure (3).