Claude Benezra

Contact allergy to Frullania and LaurusNobilis: cross‐sensitization and chemical structure of the allergens

Cross‐sensitization between two plant allergens, Frullania and Laurus Nobilis (L.), has been demonstrated in Strasbourg. A review of the haptens isolated from Frullania outlines the importance of the purification of allergen to ascertain the nature of the causative agent. New results on laurel oil point to the possibility of a common denominator (the α methylene γ‐butyrolactone moiety) between this plant and Frullania; former results are re‐interpreted and analyzed. In conclusion, the importance of physicochemical methods used to purify and isolate haptens, and help in their definition, is stressed.

Steroylphosphonates III: Dimethyl phosphonates in the estrone series☆

Abstract In order to test the hormonal activity of steroidal phosphonates on chicken embryos, several compounds have been prepared by addition of trimethyl phosphite (or dimethyl phosphonate) to 2-methylene-17β-hydroxy -4-androsten-3-one 10 and 2-methylene-17β-hydroxy-4-estren-3-one 3 . Structures of the compounds are discussed. Neat trimethyl phosphite can be added directly (without proton donor) to Δ4-2-methylene-3-ketosteroids; possible mechanisms are discussed. The aromatization of 2-di-methylphosphonomethyl-17β-hydroxy-1, 4-androstadien-3-one 17-acetate 14 with 48% aqueous HBr gave exclusively (and unexpectedly) the “para” phenol: 2-dim.ethylphosphonomethyl-4 methyl-1, 3, 5(10) -estratriene-1,17β-diol 15 the structure of which was conclusively established by Nuclear Overhauser Effect (NOE) experiments. Biological assays on chicken embryos with 2-dimethylphosphonomethyl-3-hydroxy-l, 3, 5(10)-estratrien-17-one 9 and compound 15 were negative.

The Diels–Alder addition of dimethyl vinylphosphonates to cyclopentadienes: stereochemistry of the reaction using nuclear magnetic resonance spectroscopy

The configurations of the adducts of dimethyl vinylphosphonate with cyclopentadiene, hexachlorocyclopentadiene, dimethoxytetrachlorocyclopentadiene, and pentachlorocyclopentadiene are established by n.m.r.

Polymeric Separation Media. New Functionalized Polymers for the Selective Removal of Haptens from Complex Organic Mixtures

Among the numerous properties of functional polymers, one which has been of interest to us recently is their ability to “fish out”1 selectively one type of functionality from a complex reaction mixture. Our first contribution2 to this field was the development of a polystyryl boronic acid resin which was capable of binding selectively cis-diols. For example, the separation of cis 1,2-cyclohexanediol from its trans isomer could be carried out efficiently by treatment of the commercially available mixture of isomers with the boronic acid resin using either a batch or a column technique2. Boronate formation occurs exclusively with the cis diol which is thus retained by the polymer from which it can be cleaved later by addition of moist solvent or alcohol. This method can also be used with 1,3 or 1,4 diols and is of particular value with carbohydrate derivatives3–4 Other noteworthy applications of functional polymers, in which their ability to extract a component from a complex mixture is used for synthetic purposes, include the preparation of a threaded macrocycle5, the synthesis of an unsymmetrical tetraarylporphyrin6, and the preparation of a dideoxy-sugar of biological importance such as methyl α-D-paratoside1.