Leino, Teppo O. et al. published their research in Journal of Organic Chemistry in 2015 | CAS: 65350-59-6

1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) belongs to pyridine derivatives. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Product Details of 65350-59-6

Synthesis of 1,3,6-Trisubstituted Azulenes was written by Leino, Teppo O.;Baumann, Marcus;Yli-Kauhaluoma, Jari;Baxendale, Ian R.;Wallen, Erik A. A.. And the article was included in Journal of Organic Chemistry in 2015.Product Details of 65350-59-6 This article mentions the following:

We have developed a short, general synthetic route to 1,3,6-trisubstituted azulenes. The key intermediate, 6-methylazulene, was synthesized from readily available and inexpensive starting materials in 63% yield over two steps. The Me group of 6-methylazulene was then used as a synthetic handle to introduce different substituents at the 6-position via two different methods. Subsequently, the 1- and 3-positions were substituted with addnl. functional handles, such as formyl, chloromethyl ketone, and iodide. The efficiency of the synthetic route was demonstrated by preparing a collection of three different products with the best demonstrated yield 33% over seven steps. In the experiment, the researchers used many compounds, for example, 1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6Product Details of 65350-59-6).

1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) belongs to pyridine derivatives. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Product Details of 65350-59-6

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem