Heterocyclic aromatic compounds pyridine resembles benzene

Cyclic compounds that contain at least one atom other than carbon within their ring are called heterocyclic compounds, and those that possess aromatic stability are called het erocyclic aromatic compounds Some representative heterocyclic aromatic compounds are pyridine pyrrole furan and thiophene The structures and the lUPAC numbering system used m naming their derivatives are shown In their stability and chemical behav lor all these compounds resemble benzene more than they resemble alkenes... 

Other kinds of substances besides benzene-like compounds can also be aromatic. For example, the cyclopentadienyl anion and the cycloheptatrienyl cation are aromatic ions. Pyridine, a six-membered, nitrogen-containing heterocycle, is aromatic and resembles benzene electronically. Pyrrole, a hve-membered heterocycle, resembles the cyclopentadienyl anion. 

The chemistry of furfural is mainly determined by the aldehyde function and the heteroaromatic furan ring. Many chemical transformations are therefore similar to those of aromatic aldehydes. However, the aromatic character of the heterocycle is low when compared to isocyclic compounds such as benzene derivatives or other related heterocycles such as pyrroles and pyridines. Therefore, the furan ring also resembles to a diene which significantly enriches the chemistry of furfural [112]. Many applications of furfural to organic synthesis are reported in the literature... 

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See also in sourсe #XX -- [ ]

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