Pseudobases, heterocyclic

III. Structure and Mechanism of Formation of Derivatives of the Heterocyclic Pseudobasic Carbinolamines... 

The heterocyclic pseudobasic carbinolamines show a very varied reactivity. However, the structure of a large number of their transformation products, in particular those from which conclusions have been drawn as to the structure of the initial pseudo base, are incorrect even in the most recent literature. 

Covalent Hydration of Nitrogen-Containing Heterocycles and Heterocyclic Pseudobases... 

Heterocyclic Pseudobases J. W. Bunting, Adv. Heterocycl. Chem., 1979, 25, 1-82. Heterocyclic Pseudo Bases D. Beke, Adv. Heterocycl. Chem., 1963, 1, 167-188. 

If the thiophene ring bears one or more N02 groups, it becomes susceptible to nucleophilic attack by alkoxide ion an anionic cr-complex is thus produced which can be isolated in some cases. This is called a Meisenheimer adduct, and corresponds to the first step in many nucleophilic substitution reactions on activated thiophene substrates. The similarity between these adducts and heterocyclic pseudobases has been pointed out (79AHC(25)l). Kinetic data lead to similar rate equations for both processes both are characterized by negative entropies of activation of similar magnitude. 

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