What is Hexylamine and its Applications?

Hexylamine, also known as 1-hexanamine, is a colorless or pale yellow liquid at room temperature and pressure. It has a distinct ammonia odor and is soluble in water to a certain extent, as well as miscible with most organic solvents. Hexylamine belongs to the class of organic amine compounds and exhibits some alkalinity. In organic chemistry, it can be used as a ligand and an intermediate in organic synthesis, commonly employed in the preparation of dyes and biochemical reagents.

Structural Properties

Hexylamine contains an amino functional group in its structure, which gives it nucleophilic properties and allows it to participate in nucleophilic substitution reactions. It can also undergo condensation reactions with aldehydes, ketones, and other organic compounds, forming corresponding imine products. Hexylamine is easily oxidized to nitrogen oxides by oxidizing agents due to the strong electron-donating nature of its amino functional group.

Applications

Hexylamine serves as an intermediate in organic synthesis, commonly used in the synthesis of organic functional molecules. The nitrogen atom in its structure can undergo dehydration condensation reactions with two molecules of carbonyl compounds, producing various pyrrole compounds. This reaction is often referred to as the "Hantzsch pyrrole synthesis," which is a simple and efficient method for synthesizing a variety of pyrrole compounds under mild conditions.

Figure 1: Hexylamine Applications

A mixture of 1,2,4-triphenylbutane-1,4-dione (0.5 mmol), hexylamine (0.5 mL), and a 5% aqueous solution of phosphoric acid (19 mol%, 0.1 mL) was sequentially added to a dry 25 mL Schlenk flask equipped with a stirring bar. The reaction mixture was then stirred at 140 ℃ under an air atmosphere for 8 hours. The progress of the reaction was monitored by TLC. After the reaction was complete, the reaction mixture was cooled to room temperature, and 1 M hydrochloric acid was added to neutralize the solution. The organic layer was extracted three times with ethyl acetate, and the combined organic layers were washed with water, dried over magnesium sulfate, filtered to remove the drying agent, and the resulting filtrate was concentrated under vacuum. The residue obtained was purified by silica gel column chromatography to obtain the desired product compound.

References

[1] Ibrahim, Yusuf Ajibola; et al. Journal of Molecular Structure (2022), 1252, 132123

[2] Reichert, Elaine C. Journal of the American Chemical Society (2023), 145(6), 3323-3329