Eine breit anwendbare Synthese fluoreszierender kondensierter α-Pyrone

In a two step procedure and in usually good yield an -pyrone ring can be annelated to (enolized) cyclic -dicarbonyl compounds like 4-hydroxy-2-pyrones, 4-hydroxycoumarins, 4-hydroxy-2-quinolones and more complex malonylheterocycles, but also to -naphthole.In a first step the combined action of triethyl orthoformate and arylamines upon the dicarbonyl system affords the anilinomethylene derivativesB in usually high yields.B is reacted with an active methylene nitrile (like alkyl cyano-acetates) and one equivalent of a strong base (like sodium methoxide or potassium hydroxide) in a polar aprotic solvent (like dimethylformamide). Subsequent acidification with dilute aqueous acid gives the corresponding -pyroneD with yields from 18 to 84%.The reaction sequence is broadly applicable, which is demonstrated by the synthesis of a series of known (3, 7, 16, 31) and novel (10, 19, 22, 25, 28, 34) heterocyclic systems. Most of them exhibit strong fluorescence in the visible with emission maxima between 450 and 510 nm.

208. Mitt.:H. Wittmann undF. Günzl, Z. Naturforsch.33b, 1540 (1978).     

Die Brüder Otto und Robert Margulies

It is difficult to understand that nearly no information can be found in encyclopedias and books about the history of the chemical industry about the Margulies family (father Benedikt and sons Otto and Robert), pioneers in industrial chemistry. The Margulies brothers realized the importance of catalysis and electrochemistry as a basis for industrial chemical processes. They initiated the fixation of N₂ from the air which resulted in the synthesis of Ammonia by Haber and Bosch and they also developed the first industrial process for the production of Hydrogen Peroxide and built the first industrial production unit in Austria. There is no monument to honor the pioneers, no price is named after them and they had very little benefit from what they initiated or made available on an industrial scale. This article is dedicated to their memories.