Conjugated rings

FULLY CONJUGATED RINGS REACTIVITY AT RING ATOMS... 

FULLY CONJUGATED RINGS REACTIVITY OF SUBSTITUENTS 2.12.4.1 Fused Benzene Rings... 

FULLY CONJUGATED RINGS REACTIVITY AT RING ATOMS 3.02.2.1 General Survey of Reactivity... 

It has been pointed out that a different array of atomic orbitals might be conceived of in large conjugated rings. The array, called a Mobius twist, results in there being one point in the ring at which the atomic orbitals would show a phase discontinuity. ... 

The possibility of extra stabilization in conjugated systems that have conjugated components exocyclic to the ring has also been examined. The substituents complete conjugated rings but are not part of the cyclic system. Some representative structures are shown in Scheme 9.4. 

With more than one heteroatom in a nine-membered fully conjugated ring system in principle there are a number of possibilities when nitrogen is present, whereas with oxygen and sulfur solely 1,4,7-triheteronine systems 1 and 3, respectively, are conceivable. Furthermore there arc mixed systems possible with different heteroatoms, i.e. 4, 5. 

CHj—), which do not form a conjugated ring system. Thus, these compounds are colorless (as are all porphyrinogens). However, the porphyrinogens are readily auto-oxidized to their respective colored porphyrins. These oxidations are catalyzed by light and by the porphyrins that are formed. 

The isolated double bonds in the dihydro product are much less easily reduced than the conjugated ring, so the reduction stops at the dihydro stage. Alkyl and alkoxy aromatics, phenols, and benzoate anions are the most useful reactants for Birch reduction. In aromatic ketones and nitro compounds, the substituents are reduced in preference to the Dissoiving-Memi... 

Synthesis and Reactivity of Fully Conjugated Rings Containing Phosphorus 531... 

Synthesis and Reactivity of Non- and Partly Conjugated Rings Containing... 

Reactivity of Fully Conjugated Rings 12.18.4.1 Electrophilic Attack at Nitrogen... 

There are no reported examples of fully conjugated rings. 

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