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18. Novel Redox-Active Cyclophanes Based on 3,3'-Biindolizines: Synthesis and Chirality.

Author

Sonnenschein H, Kreher T, Gründemann E, Krüger RP, Kunath A, and Zabel V

Abstract

The first compounds of a new series of redox-active cyclophanes were prepared by dehydrocyclization of bridged indolizines of type 1. The bridged dipyridino-compounds 2a and 2b obtained by reaction of 2 mol of lithiated alpha-picolines with dihalides were used as starting materials. Subsequent treatment of 2a,b with 2 mol of alpha-bromo ketones gave quaternary pyridinium halides. Ring closure in an alkaline medium (Chichibabin reaction) yielded the starting material for the synthesis of the macrocycles. Oxidative C-C coupling gave the diastereomeric cyclophanes of type 3. In all cases one pair of the enantiomers was obtained in excess. CV-investigations have shown that the main products are reversible redox systems. To clarify their conformations, compounds 3c, 3d/1, and3d/2 were subjected to X-ray analysis.

Published
1996
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19. [Effect of comprehensive preventive measures in children of dentists].

Author

Klinger G and Kreher T

Subjects
Adolescent, Adult, Child, Child, Preschool, DMF Index, Dental Plaque Index, Female, Humans, Male, Parent-Child Relations, Periodontal Index, Dental Caries prevention & control, Dentists, Periodontal Diseases prevention & control
Abstract

Preventive measures, continuously realized in children of dentists cause significantly lower values of Plaque index, Sulcus-bleeding-index, CPITN and caries in all groups of age in comparison to other groups.

Published
1990

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