Syntheses by Means of Dichlorovinylene Carbonate (4,5‐Dichloro‐1,3‐dioxol‐2‐one) as Dienophile and Photocyclophile

Abstract

With dipolarophiles the azomethine imines ( I ) give azapyrrolizidines in very good yields, inter alia, dimethyl 1.5.6.7tetrahydro-1,l-dimethyl-5 -oxopyrazolo [1,2-a]pyrazole-6,7dicarboxylate (5) [m.p. 138-139 "C] and perhydro-3,3-di- methyl-2-phenylpyrazolo[1,2-a]-[1,2,4]-triazole-1.7-dione ( 6 )

Long-range proton electron spin resonance splittings in anion radicals of bicyclo[2.2.1]hept-5-ene-2,3-diones

“…Found: C, 72.90; H, 5.32. 7.7-Dimethyl-2,3-dichlorobicyclo[2.2.1]hept-5-ene-2,3-diol Carbonate. Precursor to 7.…”

“…7.7-Dimethylbicyclo[2.2.1]hept-5-ene-2,3-dione (7). To a solution of the carbonate precursor (0.20 g) in 10 ml of 95% ethanol at 25 °C was slowly added 14.04 ml of a 0.23 M alcoholic NaOH solution with stirring.…”

“…By dehydrohalogenation of N-chloropiperidine three isomeric trimers have been obtained. 7 The a (1) and ß isomers (2) result from the normal trimerization reaction of the azomethine and differ only in the relative configuration of the three asymmetric methine carbons, whereas the iso compound is constitutionally isomeric to the a and ß compounds.8 a-and /3-tripiperideine each contain three asymmetric carbon atoms. The configurational isomers differ in their overall symmetry: one of the compounds is dissymetric (C3 symmetry, racemic mixture of RRR and SSS chirality), the other is asymmetric (C3 point group, also a racemic mixture in this case of RRS and SSR chirality).…”

Reactions of carbonyl compounds in basic solutions. Part 25.1 The mechanism of the base-catalysed ring fission of 3,4-diphenylcyclobut-3-ene-1,2-diones

“…1 However, a benzilic acid-type of rearrangement has been demonstrated in the base-catalysed reactions of cyclobutanediones to form 1-hydroxycyclopropane-1-carboxylic acids. 5 An important study by DeBoer 6 has shown that, when ethyl 3-hydroxy-1,2-diphenylcyclopropene-3-carboxylate † was † More correct name: ethyl 1-hydroxy-3,4-diphenylcyclopropene-1carboxylate. IUPAC preferred names have been used throughout this paper.…”