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.
Wanderung elektronegativer Gruppen an elektronendefiziente Zentren sind iiicht haufig ; meist handelt es sich urn die Umlagerung von Carbonester-und Carbonamid-Gruppen [Z]. Die Wanderung von Acylgruppen an positive Zentren wurde von House [3] bei der BF,katalysierten Umlagerung von M , 8-Epoxyketonen beobachtet ;
Under the conditions of the benzilic acid rearrangement diaryl und dialkyl 1,2,3‐triketones RCOCOCOR′ show two reactions: (1) Migration of RCO towards the more electronegative or less hindered CO group, yielding an α‐hydroxy‐β‐ketoacid which can undergo secondary reactions, and (2) direct cleavage between adjacent carbonyl groups forming RCOOH and R′CHOHCOOH, RCO being more electronegative or less hindered than R′CO. The balance between these reactions depends upon the steric and electronic properties of R and R′.
Juvenile Hormone, Biosynthesis, Cecropia Moth Adult 3-4 day old males of the giant silk moth H yalophora cecropia incorporate the label of [1-14C] propionate and [1-14C]butyrate in JH-I and JH-II. [1-14C]propionate is used for the bio synthesis of the hormones as an intact C3-unit. Three possible intermediates in the biosynthesis of JH-I-(E,E,Z)-7-ethyl-3,11-dimethyl-2,6,10-tridecatrienoic acid, its methyl ester, and the cor responding alcohol - were converted in low yields to the hormone. Methyl 7-ethyl-3,11-dimethyl-tridecanoate was not incorporated. Mevalonate applied to larvae before pupation was not used for the synthesis of a hypothetical JH-I precursor.
Bei Umsetzung mit KOH (2 Std. bei 20°C) und anschließender HC1‐Hydrolyse (0°) geht der sterisch gehinderte β‐Mesityl‐(alpha;,β‐dioxopropionsäureäthylester unter "benzilartiger" Umlagerung; CO2‐Entwicklung und Abspaltung der Estergruppe in Mesityltartronsäure über (91% Ausbeute als Ba‐Salz).
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