Synthesis, Crystal Structure and Hirshfeld Surface Analysis of 3-butylquinazolin-4(3H)-one Hydrochloride

Introduction

One of the key tasks of modern chemistry is the targeted synthesis of new highly efficient biologically active compounds and their use in agriculture and medicine to combat diseases. In recent years, biologically active substances have been identified among substituted derivatives of quinazolin-4(3H)-one. Therefore, developing effective and environmentally safe preparations based on inexpensive raw materials and improving their physicochemical and biological properties remains an important scientific direction.

Experimental. 3-Butylquinazolin-4(3H)-one was dissolved in acetone with thorough stirring using a magnetic stirrer. When hydrogen chloride (HCl) gas was introduced into the solution through a tube, a white precipitate formed. The resulting solid was filtered, and the filtrate was washed 2–3 times with acetone. As a result, pure 3-butylquinazolin-4(3H)-one hydrochloride was obtained with an 88% yield. R_f = 0.66 (system: water : methanol, 1:1); melting point 179–181 °C.

Results

The crystal structure crystallizes in the monoclinic system with the P-1 space group. The asymmetric unit contains one molecule. The crystal structure exhibits three types of intermolecular hydrogen bonds: Cl–H···N, N–H···Cl, and C–H···N. The N–H···Cl hydrogen bonds connect the molecules in the crystal and form a chain-like network along the [110] direction. This indicates that the chlorine atom of the molecule and the inversion center link the quinazoline molecules together. In addition, π···π interactions between the molecules contribute to the formation of a three-dimensional structure. The crystal structure was further analyzed using Hirshfeld surface analysis.

Conclusion

In this study, we examined not only the synthesis and structure of 3-Butylquinazolin-4(3H)-one hydrochloride, but also its Hirshfeld surface. Biological tests of the synthesized 3-Butylquinazolin-4(3H)-one hydrochloride confirmed its insecticidal activity.