Synthesis and Liquid Crystalline Properties of 3‐Substituted Pentane‐2,4‐dione, Pyrazole and Isoxazole Derivatives

Abstract

The γ-substituted β-diketonate 2,4-dioxo-3-pentyl 4-[4-(n-octyloxy)cinnamoyl]oxybenzoate 1 and its pyrazole and isoxazole derivatives (2 and 3 respectively) have been synthesized and characterized by the spectroscopic methods and elemental analysis. The mesogenic properties of these compounds have been studied by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). A monotropic nematic mesophase was observed for the β-diketonate 1, in contrast, the pyrazole 2 displays an enantiotropic smectic A and isoxazole 3 exhibits an enantiotropic nematic mesophase. The relationship between the structure and liquid crystalline properties has also been discussed.

Vitamin B1‐Catalyzed Multicomponent Reaction for Efficient Synthesis of an Isoxazolone Compound by Using Ultrasound in a Water and Its Selective Identification of Metal Ions

“…The other solvents and reagents used were supplied by Tianjin Fuyu Fine Chemical Co. Ltd. All melting points were determined on a XT-4 melting point apparatus and were uncorrected. 1 H NMR spectra were measured using a Bruker AVANCE-500 NMR spectrometer and with TMS as an internal standard. HR-MS were a US Agilent 1290-micrOTOF Q II spectrometer.…”

“…Isoxazole scaffolds, bearing both oxygen and nitrogen atoms, are important heterocyclic compounds with a wide variety of applications in liquid crystalline materials, [1] organic synthesis, [2] light‐conversion molecular devices, [3] filter dyes in photographic films, [4] and optical storage and nonlinear optical research [5] . Several substituted isoxazoles have been reported to have a wide range of biological properties, such as anti‐obesity, [6] analgesic, [7] anti‐inflammatory, [8] anti‐tumor [9] and anti‐bacterial [10] activity.…”

Sulfonated Graphene‐Oxide as Metal‐Free Efficient Carbocatalyst for the Synthesis of 3‐Methyl‐4‐(hetero)arylmethylene isoxazole‐5(4H)‐ones and Substituted Pyrazole

“…Substituted isoxazoles display beneficial biological properties such as antitumor, antifungal, cytotoxic, anti‐inflammatory, antibacterial and anti‐HIV activities . Furthermore, compounds belonging to this class have been employed as versatile building blocks of a variety of natural products, synthetic drug molecules, [8(a,b)] fungicides and insecticides . In particular, isoxazoles are privileged scaffolds in various organic synthesis, liquid crystalline material, optical storage as well as nonlinear optical research and filter dyes in photographic films [12(a–d)] (Figure ).…”

Synthesis and characterization of nanocrystalline hydroxyapatite and its catalytic behavior towards synthesis of 3,4‐disubstituted isoxazole‐5(4H)‐ones in water

“…Isoxazole and its derivatives have several biological, pharmacological and chemical properties, and some of them have been activated in agrochemical compounds. For example, it can be argued that there is a skeleton of isoxazole in the merocyanine dyes for optical recording, non‐linear optical research and some liquid crystalline materials . It also has biological properties, for example anti‐obesity, anti‐inflammatory, antifungal, anticancer, antitumor and antibacterial…”