[(Mes3Sn)2MoO4], ein monomeres Triorganozinnmolybdat

[(Mes₃Sn)₂MoO₄], a Monomeric Triorganotin Molybdate Mes₃SnBr (Mes = 1, 3, 5‐trimethylphenyl) reacts with (NBu₄)₂[Mo₆O₁₉] in the presence of (NBu₄)OH (in CH₃CN as solvent) to form [(Mes₃Sn)₂MoO₄]. Alternatively the title compound can be obtained from the reaction of [MoO₂(acac)₂] (acac = 2, 4‐pentadionate) with Mes₃SnOH in isopropanol. [(Mes₃Sn)₂MoO₄] forms monoclinic crystals, space group C2/c, with a = 2271.6(3) pm, b = 825.2(1) pm, c = 2739.9(5) pm, β = 90.96(2)°. The crystal structure consists of isolated molecules in which a tetrahedral MoO₄ unit is connected to two terminal Mes₃Sn groups. The Mo‐O distances range from 169.6(4) to 181.1(3) pm and the Sn‐O distance is 204.8(3) pm.     

Die gasförmigen Komplexe NiAl2Cl8 und NiAl3Cl11

Gaseous Complexes NiAl₂Cl₈ and NiAl₃Cl₁₁ Spectral photometric measurements of equilibria which are established by reaction of solid NiCl₂ with gaseous Al₂Cl₆ have been made. Results see ?Inhaltsübersicht”?.     

Cyclotetrasilazane als precursor für cyclotrisilazane und bis(cyclodisilazan-1-yl)silane

Di-lithiated octamethylcyclotetrasilazane (OMCTS, 1) reacts with halosilanes in different ways. Ring contraction with formation of the isomeric cyclodisilazanes 2, 3 occurs in the reaction with chloro- and fluorotrimethylsilanes. Substitution (6) and ring contraction with formation of the isomeric six-membered ring 7 occurs with chlorodimethylsilane. 2, 3, 6 and 7 are excellent precursors of silyl-bridged, SiH-functional, four-membered ring systems (4, 5, 9–11). The mechanism of the isomerization reactions are discussed.     

Borazin—metallkomplexe : VI. Über ligandenaustauschreaktionen an borazin—metallkomplexen: synthese von B-trimethylborazin-tricarbonylchrom

Me₃B₃N₃H₃Cr(CO)₃ has been obtained by ring-ligand exchange starting from Et₃B₃N₃Me₃Cr(CO)₃ and Me₃B₃N₃H₃. The new compound has been characterised by means of their IR, NMR, UV and mass spectroscopic data.     

Open- and closed-shell states in few-particle quantum mechanics. II. Classification of atomic states

The system developed in the first paper of this series for the classification of states as open- or closed-shed type is applied to atomic states. These may be classified in the isoelectronic limit (Z → ∞) from knowledge of the true wave function in this limit. One-matrix occupation numbers are tabulated for a number of states of the first-row atoms in the limit Z → ∞ and the states classified. A classification for finite Z is possible in the framework of the Z-dependent perturbation theory by use of a thoerem for the stability of a closed-shed with respect to small perturbations. Such a stability does not hold in general for open-shel states.     

Semiconductor gas sensors in bioreactor control

A simple semiconductor gas sensor (TGS 812) is used for the on-line measurement and control of indole during the production of l-tryptophan from indole and l-serine with immobilized E. coli cells. Indole is estimated in the reactor gas space. In combination with an automatic indole supply system, a feed-batch process became possible. The indole concentration was monitored and kept within the optimal range (300–600 mg l^?1). A simple gas-sensing electrode dipped in the reaction medium provides direct measurement of organic solvents and gases in the liquid. Such a system is suitable for on-line determination of ethanol (10–70 g l^?1) during continuous production of ethanol with immobilized yeast cells.     

Totalsynthese von (+)-D-Homoöstron-3-methyläther

Total Synthesis of (+)-D-Homoestrone 3-methyl ether A novel total synthesis of (+)-D-homoestrone 3-methyl ether ( 21 ) is described starting from (S)-8a-methyl-3,4,8,8a-tetrahydro-2H, 7H-naphthalene-1,6-dione ( 1 ) as a chiral synthon for the rings C and D. The key step involves alkylation of the derived 3 with m-methoxyphenacyl bromide ( 4 ) as an AB-building block to give the dioxo-secosteroid 5 . Hydrogenation of 5 affords the trans-decalone 11 . As by-products the epimeric cis-decalones 12 and 13 were characterized. Cyclization of 11 leads under kinetic control predominantly to the Δ⁹⁽¹¹⁾-tetraene 14 . Catalytic hydrogenation of 14 and subsequent modification in ring D give the title compound 21 . It was found that 14 and also the derived Δ⁸-isomer 15a add hydrogen from the α-face of the molecule to an extent of about 80%. The 8α-D-homoestrone derivatives 20a and 23 as well as the 9β-isomers 19a and 22 were characterized.     

Hydrazones and new Oximes of 4-Aminobicyclo[2.2.2]octanones and their Antiprotozoal Activities

Summary. 4-Aminobicyclo[2.2.2]octan-2-ones and -ols showed activity against the causative organisms of East African sleeping sickness and Malaria tropica. Several imino derivatives of the ketones were more active. Now hydrazono analogues and 3-hydroximino derivatives of the ketones and alcohols were synthesized. The structures of the obtained isomers were elucidated by NMR spectroscopy. A single phenylhydrazone exhibited quite good antitrypanosomal activity in the range of already known imino analogues.     

Hydrazones and new Oximes of 4-Aminobicyclo[2.2.2]octanones and their Antiprotozoal Activities

4-Aminobicyclo[2.2.2]octan-2-ones and -ols showed activity against the causative organisms of East African sleeping sickness and Malaria tropica. Several imino derivatives of the ketones were more active. Now hydrazono analogues and 3-hydroximino derivatives of the ketones and alcohols were synthesized. The structures of the obtained isomers were elucidated by NMR spectroscopy. A single phenylhydrazone exhibited quite good antitrypanosomal activity in the range of already known imino analogues.