Recherches sur le benzofuranne,LVII. Sur une chloration inhabituelle de l'hétérocycle au cours de la réduction des (nitro-4 phényl)-2 ou -3 benzo-furannes par le chlorure stanneux

Reductions of 2-(4-nitrophenyl)- and 3-(4-nitrophenyl)benzo-furans by stannous chloride in presence of hydrochloric acid yield not only the expected 2-(4-aminophenyl)- and 3-(4-amino-phenyl)-2-chlorobenzofurans but also the 2-(4-aminophenyl)-3-chloro- and 3-(4-aminophenyl)-2-chlorobenzofurans the structures of which have been ascertained by their ¹³C nmr spectra, by comparison with those of 2-phenyl- and 3-phenylbenzofurans. These interfering chlorinations are most likely due to a radical mechanism.     

Isomerès optiques du naftidrofuryl ( = 2-[(naphth-1-yl)méthyl]-3-(tétrahydrofur-2-yl)propanoate de 2-(diéthylamino) éthyle)

Optical Isomers of Naftidrofuryl( = 2-(Diethylamino)ethyl 2-[(Naphth-1-yl)methyl]-3-(tetrahydrofur-2-yl)propanoate) The four optical isomers of naftidrofuryl ( 1 ) were prepared in two ways, by separation and resolution of the two diastereoisomeric racemates and by synthesis from the enantiomers of tetrahydrofuran-2-methanol ( 6 ); see Scheme}. The absolute configuration of one of the isomer as a tartrate monohydrate was established by X-ray crystallography thus allowing the deduction of the absolute configurations of the other three optical isomers.     

Couplages J des groupes méthyle dans les phényltriméthylsilanes p-substitués: Effets de solvants

The J coupling constants of a series of p-substituted phenyltrimethylsilanes were measured in CH₂Cl₂ and CCl₄ solutions. The solvent effect is discussed; it is too large to allow any straightward conclusion on ring-substituent interaction.     

Synthèse du virensate de méthyle

Synthesis of Methyl Virensate The synthesis of methyl virensate (=methyl 4-formyl-3,8-dihydroxy-1,6,9-trimethyl-11-oxo-11H-dibenzo-[b, e][1,4]dioxepin-7-carboxylate; 18 ) by the condensation of the substituted β-orcinol and orcinol units 9 and 10 followed by formylation and demethylation of the depsidone 13 is described.