Jeannette Varenne

Improved procedure for the preparation of deoxynucleoside phosphoramidites: Arylphosphoramidites as new convenient intermediates for oligodeoxynucleotide synthesis

Abstract A simplified procedure for the preparation of deoxynucleoside methyl- and arylphosphoramidites is described. Both types of phosphoramidites can be conveniently activated by N-methylaniline trifluoracetate for their use in oligodeoxynucleotide synthesis.

A new method for the synthesis of branched ribonucleotides

Abstract A new route, using phosphotriester intermediates, for the synthesis of branched ribonucleotides is described.

1,1-Bis-(4-methoxyphenyl)-1′-pyrenyl methyl (bmpm): a new fluorescent 5′ protecting group for the purification of unmodified and modified oligonucleotides

Abstract By replacing the phenyl by a pyrenyl in the dimethoxytrityl (DMTr) group commonly used for 5′-protection in oligonucleotide synthesis, we have obtained a fluorescent acid-labile protecting group which exhibits similar chemical properties to those of DMTr. Here we demonstrate the usefulness of the new protecting group in the purification of both charged and neutral DNA fragments.

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.

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.

Preparation and phosphorylation reactivity of n-nonacylated nucleoside phosphoramidites

Abstract N -nonacylated nucleoside phosphoramidites can be prepared in two steps from 2′-deoxynucleosides. Their use in phosphorylation reactions is exemplified.

Accumulation of cholesterol and cholesterol esters in the nephridia of a polychaeta annelida (Sabella pavonina savigny)

Abstract 1. 1. The localization and composition of the lipid content of the giant nephridia were studied in Polychaeta Sabella pavonina Savigny by cytological, histochemical and chemical methods. 2. 2. Cholesterol and its long-chain fatty acid esters (mainly palmitoleate and palmitate) were identified by TLC, electron impact and chemical ionization mass spectroscopy. Cholesterol palmitoleate, not yet described in the literature, was synthesized. 3. 3. Large numbers of lipid droplets containing cholesterol and its esters were seen to fill the infranuclear space of the proximal (P) and intermediate (C) nephridial epithelia, thus endowing them with a storage-like organ. 4. 4. Scattered small droplets were found in the apical cytoplasm of the distal apocrine nephridial epithelium (D). They contained cholesterol but no cholesterol esters.

Isolation and structure (X-ray analysis) of manicoline A, a new α-aminotropone from Dulacia guianensis(olacaceae)

Two alkaloids, manicoline A and B, have been isolated from the root bark of Dulacia guianensis(Olacaceae); the structure of manicoline A, a noval α-aminotropone, has been established by X-ray analysis.

Structures of virescenosides D and H, new metabolites of Acremonium luzulae(Fuckel) Gams

Two new metabolites, virescenosides D (3a) and H (4a), isolated from the fungus Acremonium luzulae(Fuckel) Gams, are shown to be the 4-deoxy-β-D-threo-hex-4-enodialdopyranoside and the 4-deoxy-β-D-threo-hex-4-enopyranoside of virescenol B (5b), respectively, on the basis of chemical and spectral evidence and, particularly, their partial synthesis from the known virescenoside B (1b).