Orientation in azole rings containing three or four heteroatoms

3 Orientation in azole rings containing three or four heteroatoms 

Such compounds contain two or three pyridine-like heteroatoms. For the symmetrical systems (82) and (83), no ambiguity occurs, but for systems (84)-(87) there are at least two alternative reaction sites. It appears that reaction takes place at the nitrogen atom furthest away from the pyrrole-like heteroatom, as shown in (84)-(86) where evidence is available from reactions with alkylating reagents (Section 3.4.1.3.9). 

Similar ambiguities arise in the reactions of azole anions. At least as regards alkylation reactions in the 1,2,3-triazole series (88), the product appears to depend on the reagent used. In the 1,2,4-triazole series (89) a single product is formed, whereas tetrazole (90) gives mixtures. 

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Orientation in azole rings containing three or four heteroatoms Effect of azole ring structure and of substituents Proton acids on neutral azoles basicity of azoles Proton acids on azole anions acidity of azoles Metal ions... 

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