Heterocyclic bridged

Formation of helical-like peptides stabilized due to heterocyclic bridges formed between coils by natural and artificial amino acids 99T11711. 

Figure 11 Dinuclear platinum compounds based on heterocycle bridges.

DTES WITH OTHER HETEROCYCLIC BRIDGES BASED ON THENOINES AND RELATED STRUCTURES... 

Considerable attention has been given to the construction of heterocyclic bridges of dihetarylethenes based on ethane-1,2-dione, 2-hydroxyethan-l-one, and 2-chloroethan-l-one derivatives. In many cases, readily available 2,5-dimethylthiophene is used as the starting compound. 2-Hydroxy-l,2-bis(2,5-dimethyl-3-thienyl)ethan-l-one 213, one of the key substrates, was synthesized according to Scheme 62 (01IZV113). 

The above diketones are also convenient and versatile starting compounds for the synthesis of photochromes containing heterocyclic bridges. Thus, ethane-l,2-dione 223 with aldehydes and ammonium acetate in acetic acid gave imidazoles 271 (Scheme 75) (05ZOR1375). 

Giuffrida, G. and Campagna, S. (1994) Influence of peripheral ligands on the metal-metal interaction in dinuclear metal complexes with V-heterocyclic bridging ligands, Coord. Chem. Rev. 135/136, 517-531. 

O. Olkhovyk and M. Jaroniec, Periodic mesoporous organosilica with large heterocyclic bridging groups, J. Am. Chem. Soc. 127, 60-61 (2005). 

A series of compounds isomeric with morphinans, and described as metamorphinans (144), has been reported.<133) They were made from meta-thebainone (143),(149) which is readily accessible from thebaine,(134,135) and have the heterocyclic bridge between C-9 and C-14. 

Chemists at the rival Bayer company established the structure Indanthrone consists of two anthraquinone units joined through a heterocyclic bridge containing two nitrogens. This enabled industrial research laboratories to discover anthraquinone-based intermediates for other vat dyes. In 1904, an assistant of Bohn synthesized benzanthrone (48), later an important intermediate in processes involving aminoanthraquinone-derived colorants72. 

Functionalized benzo[b]furan-based heterocycles were made from Fischer carbene complexes and heterocycle-bridged enynes in good to acceptable yields <05TL2211>. 

A simple reaction that creates both chiral centres in one step was already in the literature.3 It is a cross between a Mannich and a Prins reaction involving the condensation of an unsaturated amine 24 with glyoxylic acid (25 available as an aqueous solution - fortunately the reaction works in water) to give a heterocyclic bridged lactone 26 with the right relative stereochemistry (but of course racemic). 

Bredt s Rule is further assessed in a report by Shea, which covers both carbocyclic and heterocyclic bridged systems. 

Heterocyclic bridging ligands in controlling electronic and magnetic properties in polynuclear complexes 98ACR842. 

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