N,N'-Disubstituted amidines and carbon suboxide gave in excellent yield cm/ii/dro-4-hydroxy-6-oxo-l,2,3trisubstituted pyrimidinium hydroxides which underwent 1,4-dipolar type cycloadditions with dimethyl acetylenedicarboxylate. In the case of

The chemical stability of anion radical TCNQ‐. salts derived from low‐molecular weight and polymer 1,3‐disubstituted imidazoles and poly(trimethylammonium ethyl methacrylate) was investigated spectrophotometrically in dimethylformamide as a function of time, water content and the presence of oxygen. The low‐molecular weight TCNQ‐. salts are stable in anhydrous DMF also in the presence of oxygen. Polymer salts are decomposed already in anhydrous DMF in an ihert atmosphere. The decomposition products are the known α,α‐dicyano‐p‐toluoyl‐cyanide and the still unidentified compound with an intensive absorption at 330 nm. Along with protolytic reactions, direct oxidation with oxygen also participates in the decomposition of TCNQ‐. in aqueous DMF in the presence of oxygen.

The title six-membered mesoionic compound (1) undergoes cycloaddition reactions with acetylenic dipolarophiles to yield 1,2-disubstituted 4ff-quinolizin-4-ones (3), with extrusion of methyl isocyanate. With tetracyanoethylene and diethyl azodicarboxylate, no cycloadducts were obtained; rather, substitution occurred at the 3 position of the nucleus. Reaction of 2-jV-methylaminopyridine with carbon suboxide provided an extremely facile synthesis of the mesoionic compound 1.

cisand

High optical purity polystyrene (PS), poly(methy1 methacrylate) (PMMA) and styrene-methyl methacrylate statistical copolymers (S-MMA) were prepared. Light scattering measured on polymeric glasses depends on the chemical composition of the polymer and on the refractive index of the plastifier added. An isorefractive plastifier reduces considerably the scattering values for the copolymers S-MMA, while having no significant effect on the scattering of PMMA. A plastifier with a refractive index different from that of the polymer raises distinctly the light scattering values in all cases.It has been shown that the isorefractive plastifier has a favourable effect on attenuation loss of polymeric optical fibers (POF) obtained from the copolymer S-MMA 2/1. ZUSAMMENFASSUNG:Optisch hochreine Glaser wurden aus Polystyrol (PS), Polymethylmethacrylatund statistischen Styrol-Methylmethacrylat-Copolymeren (S-MMA) hergestellt. Die an diesen Glasern gemessene Lichtstreuung hangt von der chemischen Zusammensetzung des Polymeren und dem Brechungsindex des zugesetzten Weichmachers ab. Ein isorefraktiver Weichmacher verringert die Streuwerte der S-MMA-Copolymeren, hat aber keinen signifikanten Einflulj auf das Streuverhalten von PMMA. Ein Weichmacher mit einem vom Polymeren verschiedenen Brechungsindex verschlechtert die Streuwerte in allen untersuchten Fallen. Es wird gezeigt, dalj ein isorefraktiver Weichmacher die Dampfungseigenschaften von aus dem Copolymeren S-MMA 2/1 gezogenen polymeren Lichtleitern verbessert.