The synthesis of 22 substituted tricarbonyl compounds is reported. They were obtained either by oxidation of β‐dicarbonyl compounds with SeO2 or nitrous oxides or by oxidation of the α‐bromo‐β‐dicarbonyl compounds with DMSO. The procedures using SeO2 or DMSO are more rapid and give in general better yields than other methods described in the literature.
Summary. Secondary deactivated aliphatic diazo compounds (diazo-ketones R-CO-CN,-R'; diazo-esters ROOC-CN,-R'; 1,1, I-trifluoro-2-diazopropane) are hydrolyscd by the A -S E~ mechanism comprising rate determining protonation of the substrate, followed by decomposition. Product analysis shows that the dccomposition of the secondary diazonium ions is monomolccular, without intervention of a nucleophile.The corresponding primary diazo compounds (R-CO-CHN,, ROOC-CHN, and CF,-CHN,) are hydrolysed by the A-2 mechanism comprising preequilibrium protonation; the primary diazonium ion reacts with a nucleophilc in a bimolecular displaccmcnt step .The only exception observcd is found in p-nitrophenyl-diazomethane, which follows A -S E~ mechanism.The observations are discussed in terms of the stability of the corrcsponding secondary resp. primary cc-keto-carbonium ions.Primare Diazoketone R-CO-CHN, werden bei der sauren Hydrolyse rasch und reversibel protoniert, worauf das gebildete Diazonium-Ion im geschwindigkeitsbestimmenden Schritt zu den Produkten zersetzt wird Wir fanden, dass auch anderweitig desaktivierte Diazoalkane wie 2,2,2-Trifluordiazoathan CF3-CHN, rasch und reversibel protoniert werden. Der Nachweis der Reversibilitat erfolgte wie in anderen Fallen [a]
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.