Two atom insertions into the silacyclopropane and silacyclopropene rings: mechanistic considerations

Novel two atom insertion reactions into the SiC₂ rings of hexamethylsilirane and 1,1-dimethyl-2,3-bis(trimethylsilyl)-1-silirene involving the C bonds of styrene and α-methylstyrene, 1,3-butadiene and its 2-methyl and 2,3-dimethyl derivatives, and, in the presence of ultraviolet radiation, of aliphatic aldehydes and ketones, are reported. A radical mechanism is suggested tobe operative in these reactions. Also described are novel palladium-catalyzed reactions of the silirene with terminal and internal acetylenes.     

Über Differentialgleichungen in n. a. Banachräumen,insbesondere ihre Lösung mittels eines „Wegintegrales“

Ohne Zusammenfassung     

Characterization of carotenoids and carotenoid esters in red pepper pods (Capsicum annuum L.) by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry

Carotenoids and carotenoid esters were extracted from red pepper pods (Capsicum annuum L.) without saponification. Among the 42 compounds detected, 4 non-esterified, 11 mono- and 17 diesters were characterized based on their retention times, UV/Vis spectra and their fragmentation patterns in collision-induced dissociation experiments in atmospheric pressure chemical ionization mass spectrometry (APCI-MS). Positive and negative ion mode measurements were used for the characterization of major and minor carotenoids and their esters. Capsanthin esterified with lauric, palmitic and myristic acids represented the predominant compounds in the red pepper extracts. Additionally, three beta-cryptoxanthin and one zeaxanthin monoester were tentatively identified in red pepper pods for the first time. Furthermore, the specific fragmentation patterns of capsanthin-laurate-myristate and capsanthin-myristate-palmitate were used for the distinction of both regioisomers. The results obtained from LC-DAD-APCI-MSn experiments demonstrated that the carotenoid profile of red pepper pods is considerably more complex than considered hitherto.     

Zur Chemie von Polyhalocylohexanen. Mitteilung XXXI1: 1,1,4,4-Tetrachlor-cyclohexan vom Schmp. 125 bis 126° (1ep4ep) und 1,1,2,2,4,5-Hexachlor-cyclohexan vom Schmp. 109 bis 110° (1ep2ep4e5e)

Zusammenfassung Es werden die Konstitution und die Konfiguration des Tetrachlorcyclohexans vom Schmp. 125 bis 126° und des Hexachlorcyclohexans vom Schmp. 109 bis 110° bestimmt.Mitt. XXX: Österr. Chem.-Ztg.55, 102 (1954).