1-Hydro-3-vinylhexamethylcyclotetrasiloxane and its polymerization

1,3-Dimethyl-3-vinyl-1,3-dichlorosiloxane is prepared by partial cohydrolysis of methylvinyldichlorosilane and methyldichlorosilane, and its cohydrolysis with sym-tetra-methyldichlorodisiloxane gives 1-hydro-3-vinylhexamethyl-cyclotetrasiloxane. A study is made of the kinetics of the polymerization of the latter in CCL₄ in the presence of H₂PtCl₆ · 6H₂O     

Buchbesprechungen

Ohne Zusammenfassung     

Tetracyclines Communication 33. Synthesis of 8-chloro-5-methoxy-3,10-dioxo-1,2,3,4,4a,9,9a,10-octahydroanthracene [5-chloro-1,3,4,4a,9a,10-hexahydro-8-methoxy-2,9-anthracenedione]

Summary 8-Chloro-5-methoxy-3,10-dioxo-1,2,3,4,4a,9,9a,10-octahydroanthracene (Ib) was synthesized; this can serve as an intermediary in the preparation of the tetracyclic analog (IIb) of aureomycin,Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 806–810, May, 1965 Original article submitted April 22, 1963For preceding communication see [1],The authors thank L. B. Senyavina for infrared spectrum measurements.     

Die Pentafluoro-orthoselen- und -orthotellurgruppe,eine 19F-Kernresonanzuntersuchung

A ¹⁹F-NMR Study of the (Pentafluoro)orthoselenium and -tellurium Group In ¹⁹F-nmr the (pentafluoro)orthoselenium and (pentafluoro)orthotellurium groups show characteristic AB₄ spectra. Chemical shifts give information about the different bondings. The axial fluori ne atom is often more influenced, a certain trans effect may be discussed. The values of is otopic splittings, coming from ⁷⁷Se agree with these observations, isotopic splittings from ¹²³Te und ¹²⁵Te are much less important. Comparison is done with selected compounds containing a (pentafluoro)orthosulphur group.