Iridoidglucoside aus Leucocarpus perfoliatus G. DON. 174. Mitteilung über organische Naturstoffe

Iridoidglucosides from Leucocarpus perfoliatus G. DON . The known iridoid glucoside boschnalosid (1) was isolated from Leucocarpus perfoliatus in addition to the hitherto unknown yuheinosid, for which structure 2 was deduced.     

Kolorimetrische Schnellbestimmung der Kristallviolettbase (KVB)

Zusammenfassung Es wird eine Methode zur kolorimetrischen Bestimmung der Kristallviolettbase in benzolischen Lösungen beschrieben. Das Prinzip gründet sich auf der Salzbildung der farblosen Base mit der ebenfalls in Benzol löslichen Pikrinsäure. Dabei resultiert das tief blauviolett gefärbte KV-Pikrat, dessen Konzentration mit dem Spektralphotometer ermittelt wird.Mit 4 Abbildungen     

Structure d'alcaloïdes indoliques doubles d'un type nouveau

The Structure of bis-indoline alkaloids of a novel type The structure of folicangine 4 , a bis-indoline alkaloid from the leaves of Voacanga africana, is obtained by correlation with voafolidine 3a and isovoafolidine 3b . It requires an ether bridge between the two parts of the molecule, as in subsessiline (amataine 5a ). Subsessiline-lactone, from the leaves of Voacanga thouarsii has structure 5b proved by correlation with 5a . The CD. curves of double-indole alkaloids of vobtusine type are given (Table 3).     

Chromium imine and amine complexes as homogeneous catalysts for the trimerisation and polymerisation of ethylene

Cr(III) complexes of tridendate imine and amine ligands with N, P, O, S donor atoms 1 and 2 have been prepared and tested as catalysts in the oligomerisation and polymerisation of ethylene giving excellent selectivity towards 1-hexene and polymerisation to polyethylene when activated with cocatalysts. X-ray structure analyses of the precatalysts 1a-c, 1i, and 2b are investigated. The metal-ligand binding in 1a and 1b is nearly the same, which leads to similar catalytic activities of these precatalysts.     

On the Gorenstein property of Rees Algebras

Let (A,M) be a noetherian local ring. For certain equimultiple ideals I in A we try to relate the Gorenstein property of the Rees algebraⁿ and of A itself. In particular we n0 treat the case of equimultiple prime ideals of height two and the case I=M. The results underscore a natural conjecture, s. Thm. 2.6. and 3.2.     

Optisch aktive übergangsmetall-komplexe: LXXXIII. Konfigurationsstabile tetraedrische NiNi′CC′-cluster

The reaction of Ni(C₅H₅)₂ and Ni(C₅H₄COOCH₃)₂ with the acetylene (?)-(R)-C₆H₅CCCONHCH(CH₃)(C₆H₅)(C₆H₅), “CC′”, yields tetrahedral Ni₂C₂ clusters. Besides the compounds with two identical Ni corners (Ni₂CC′ types) also compounds with two different Ni corners (NiNi′CC′ types) are formed. These consist of two diastereomers which, for a given (R)-configuration in the acid amide substituent, differ only in the cluster chirality. They are separated chromatographically and turn out to be configurationally stable with respect to a change of the cluster chirality.