Borates are classified as critical materials, they are the main source of boron and have a variety of industrial applications. Organic trifluoroborate is stable to heat, air and humidity, and is a very convenient crystalline boric acid compound. Since it has a tetra-coordinated boronic acid structure after the substitution of fluorine, it does not exhibit Lewis acidity and is stable to oxidation conditions. In addition, it can be regarded as the protector of boronic acid and boronic acid ester, which can be converted into each other. The compound can generally exist stably in organic solvents, but will decompose in protic solvents to liberate trivalent boron, so it can be directly used as a substrate for Suzuki coupling. The difference between trifluoroborate and boric acid is that it must exist in a monomeric form, so the equivalent weight can be closely controlled.
Isoxazole is a liquid heterocyclic compound C3H3NO isomeric with oxazole and having a penetrating odor like that of pyridine. Isoxazoles belong to an important class of five-membered aromatic heterocycles containing two electronegative heteroatoms, nitrogen and oxygen, in a 1,2-relationship and three regular sp2 carbon atoms. These molecules are found to be key components in various synthetic products in daily use and also present as a pharmacophore essential for biological activity in many drugs and bioactive natural products. In addition, isoxazoles have demonstrated their ability to exhibit hydrogen bond donor/acceptor interactions with a variety of enzymes and receptors.