Borohydride reduction of the imine groups in a pyruvate-derived cobalt(III) complex, (OC-6-33')-[Co(Aim(2)trien)](2)[ZnCl(4)], occurs with high diastereoselectivity. The major diastereoisomeric product, (OC-6-33'-ARSSR,CSRRS)-[Co(A(2)trien)]Cl has been isolated and crystallographically characterised. The results from base-induced isomerisation of the major isomer allow us to conclude that most ...

Far-UV-induced formation of dimeric pyrimidine photoproducts within DNA is a major cause of the carcinogenic effects of solar light. The chemical structure of this class of lesion has been mostly determined by studies on model compounds. The present work is aimed at providing mass spectrometry data on the thymine-thymine photoproducts, including the diastereoisomers of the cyclobutane dimer, th...

We report here a total synthesis of nocardicin A. The antibiotic was obtained as a mixture of diastereoisomers that possessed approximately one quarter of the antibacterial activity of the naturally occurring material. Recently a new B-lactam antibiotic, nocardicin A, has been reported.1,2) This is the first example of a monocyclic B-lactam derivative having antimicrobial activity. We report he...

The syntheses of two new ligands, 3,4-di(2-pyridyl)-1,2,5-oxadiazole (dpo) and 3,4-di(2-pyridyl)-1,2,5-thiadiazole (dpt), are described. Complexes with palladium and copper have seven-membered chelate rings with coordination through the two pyridine nitrogens, whereas in the silver nitrate complex of dpt the ligand acts as a bridge between metal centres. Studies of the mononuclear ruthenium com...

The driving force of homoand heterochiral complex formation in mixtures of chiral compounds is, probably, the effort of the system to separate the most symmetric associates from the less symmetric ones. A possible way to achieve separation of these associates is distribution between two phases. Therefore, during the separation of (a certain part) diastereoisomers similar trends can be observed ...

Lignans are a large class of natural products that have been isolated from many plants. They reveal diverse biological activities, especially antiviral and antitumor properties. From Piper cubeba, lignans of several classes can be isolated from the roots, rhizomes, stems, leaves, seeds, and fruits. Among its various chemical constituents, (-)-cubebin and (-)-hinokinin are found in significant q...

Abstract The relationship between extractant stereochemistry and their extraction performance has only poorly been established. In order to address a part of this concern, we investigated the Pu(IV) liquid‐liquid (LLE) by using N , ‐di‐(2‐ethylhexyl)butyramide (DEHBA), as well those its position isomers. DEHBA ( ββ ‐isomer) ‐(2‐ethylhexyl)‐ ‐(oct‐3‐yl)butyramide (EHOBA or αβ were synthesized mi...