Arlette Tubul

Synthesis of 1,3-divinyl-2-methyl-2-alkylcyclopentanes by dialkylation of ethyleneketals with 1,8-bis(trimethylsilyl)-2,6-octadiene

Abstract Dialkylation of ethyleneketals by 1,8-bis(trimethylsilyl)-2,6-octadiene led to 1,3-divinyl-2-methyl-2-alkylcyclopentanes (mixture of isomers) in moderate yield.

Influence of the nature of the Lewis acid on the rearrangement of 1-phenyl-7-oxanorbornadiene derivatives

Abstract 1-phenyl-7-oxanorbornadiene derivatives are rearranged into 6-hydroxyfulvenes or 4-phenylphenols derivatives when they are reacted with Lewis acids. The course of the reaction, which is highly selective, depends exclusively on the nature of the Lewis acid used.

Polyclonal antibody-catalysed aldimine formation

Abstract An antiserum catalysed imine formation from pyridoxal and phenylalanine is described, under conditions in which the uncatalysed reaction is not observed. This polyclonal antibody preparation shows Michaelian kinetic characteristics and presents a very good specificity for the pyridoxal structure.

Synthesis and Spectrokinetic Studies of a New Family of Photochromic 2H‐Chromenes (=2H‐1‐Benzopyrans): Dimethyl 6‐Aryl‐2,2‐dimethyl‐2H‐chromene‐7,8‐dicarboxylates

A series of dimethyl 6-aryl-2,2-dimethyl-2H-chromene-7,8-dicarboxylates were synthesized, and the photochromic properties of this new family of dimethyl-2H-chromenes were studied under continuous irradiation. The presence of the methoxycarbonyl groups was shown to stabilize the colored forms. This stabilization depended on the solvent, and in two cases the formation of long-lived opened forms was observed. Under irradiation with a mercury lamp, this family of 2H-chromenes showed a strong resistance to photodegradation.

Dialkylation of β and γ-diketone monoethyleneketals by 1,8-bis(trimethylsilyl)-2,6-octadiene.

Dialkylation of β-diketone monoethyleneketals by 1,8-bis(trimethylsilyl)-2,6-octadiene leads to bi- or tricyclic alcohols (one stereoisomer) 3 or 7a resulting from a participation reaction. On the other hand, dialkylation of 2,5-hexanedione monoethyleneketal gives a divinylbicyclic ether 10

Synthetic route to tricyclic carbon compounds by Friedel–crafts acylation

Acylation of cyclohexene by cyclohexenyl- or cyclopentenyl-acetyl chloride gave des-A-11-oxo or des-D-7-oxo steroids.

Un nouveau carbène ambiphile : 1′ α-cyclohexylidène-cyclobutylidène.

Abstract α-Cyclohexylidene-cyclobutylidene, a new ambiphilic carbene, undergoes addition to 1,1-diethoxyethylene and t. butylfumarate and insertion into activated carbon-hydrogen bonds.

Synthesis and Spectrokinetic Studies of a New Family of Dimethyl [2H]-Chromenes: Dimethyl 6-Aryl-2,2Dimethyl-[2H]-Chromene-7,8-Dicarboxylates

Abstract The synthesis of a series of dimethyl 6-aryl-2,2-dimethyl-[2H]-chromene-7,8-dicarboxylates is described. The photochromic properties of this new family of dimethyl-[2H]-chromenes have been studied in solution, under continuous irradiation. The presence of the methoxycarbonyl groups was shown to stabilise the coloured forms. The fading rates are generally low in comparison with the standard “naked” chromenes in the same experimental conditions. This stabilisation depends on the solvent used. We could observe the presence of one permanent opened form. Moreover, it seems that the synthesised molecules have a strong resistance toward photodegradation.

7-Oxabicyclo[2.2.1]heptadiene derivatives: reactivity towards Brønsted acids

7-Oxabicyclo[2.2.1]heptadiene derivatives can be converted to phenols, fulvenes and/or the products from a retro-Diels–Alder-like reaction by treatment with Bronsted acids; the outcome of the reaction depends on the experimental conditions and the nature of the Bronsted acid used.