Immobilizing bifunctional phosphines with ethoxysilane groups on silica often leads predominantly, and sometimes quantitatively, to P(V) side products that occupy space on the surface but cannot bind metal complexes. Although this side reaction is well-known, and dreaded because it leads to leaching of adsorbed catalysts that are not bound covalently, the exact nature of the surface-bound side product was not yet known. With the help of polycrystalline model compounds of the types [R3PEt]+X- and [R3POEt]+X- (R=alkyl, aryl; X=Cl-, Br-, I-, BF4-) and their solid-state NMR characteristics [delta(31P), CSA], it is demonstrated that the side product is an ethylphosphonium salt bound to the surface by a siloxide anion, [R3PEt]+[Si-O]-.

When dissolved in the mixture FS0,H-SbF,-SO,, a-diazo-ketones are protonated on oxygen, and not on carbon as previously reported.

Die Alkylierung der niedrigkettigen Alkane (III) mit dem aus Ethylen (I)/HF‐TaF5 intermediär erzeugten Ethylkation (II) zu den Ethylalkanen (IV) wird untersucht.

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The 3-phenylazepino[5,4,3-c,d]indole derivatives 5 and 9-11, representing heterocyclic analogs of the selective dopamine D-1 receptor ligands of the 3-phenylbenzazepine class, were synthesized starting from the indole-4-carboxylate 7. Receptor binding studies employing bovine striatal membranes demonstrated that the test compounds 5, 10, and 11 are able to displace the D-1 selective radioligand [3H]-SCH 23390 as well as the D-2 antagonist [3H]-spiperone. Compound 5b turned out to be the most potent and selective ligand (ki = 1.8 microM for D-1 and ki = 8.9 microM for D-2). It is assumed that the moderate selectivity of 5b is due to the conformational inequality of the 7-membered rings when compared to the benzazepines. This results in a spatial arrangement of the phenyl substituent which is not able to interact with a 'subtype selectivity-inducing site'.