Background and overview of preparation and application of 2-methylphenylboronic acid
2-Methylbenzeneboronic acid is widely used in Suzuki cross-coupling reactions. Suzuki-Miyaura coupling reaction (SMC) is an important reaction to construct various C-C single bonds, and its main raw material is organic boronic acid compounds. Among them, 2-methylphenylboronic acid is an important aminomethylpyridine compound among organic boric acid compounds and has important application value in the fields of organic synthesis and pharmaceutical chemical industry.
Preparation and application of 2-methylphenylboronic acid
Under nitrogen protection, add magnesium (2.9 g, 1.2 times), tetrahydrofuran (20 ml) and dibromoethane (1.9 g) to a 250 ml three-necked flask with a dropping funnel; then add it to the dropping funnel Add o-methylbromobenzene (17.1 g, 0.1 mol), triisopropyl borate (28.8 g, 1.5 times) and tetrahydrofuran (50 ml) as solvents. Heat to 40°C to activate the magnesium powder, then slowly add the mixture in the dropping funnel dropwise, control the speed until the reaction temperature does not exceed 60°C, and stir the reaction until the magnesium basically disappears. Then add trimethyl borate (21.0 g, 2 times) to the dropping funnel, and heat to reflux for 6 hours. Stop heating, cool to room temperature, and hydrolyze with 5% dilute hydrochloric acid until pH<2. The THF solvent is recovered by distillation. As the solvent decreases, the product precipitates; it is cooled, filtered, and recrystallized in methanol/water to obtain o-tolueneboronic acid, 11.5 grams, with a yield of 85%. 1HNMR(CDCl3), δ(ppm):7.88(d,J＝7.3Hz,1H),7.25(m,1H),7.18-7.12(m ,2H),2.65(s,3H). 13CNMR:144.2,137.6,135.6,130.7,130.1,125.5,23.2.
Preparation and application of 2-methylphenylboronic acid
CN201410249316.4 discloses a marine heavy-duty anti-corrosion coating and a preparation method thereof. The coating is composed of the following components by weight: 5 to 15 parts by weight of mica powder, B-N coordination polyaniline/montmorillonite 10~15 parts by weight of composite conductive material, 8~15 parts by weight of talc powder, 10~15 parts by weight of quartz powder, 30~40 parts by weight of matrix resin, 0~3 parts by weight of pigment, 0.5~1.0 parts by weight of defoaming agent, dispersed 0.5~1.0 parts by weight of agent, 0.5~1.0 parts by weight of film-forming assistant and 30~40 parts by weight of solvent potassium trifluoroborate, wherein the B-N coordination polyaniline/montmorillonite composite conductive material is activated and modified by ionic surfactant Synthesis of montmorillonite, organic boronic acid, aniline monomer and dihydroxyphenol derivatives, wherein the organic boronic acid is 2-methylphenylboronic acid, 3-methylphenylboronic acid, 4-methylphenylboronic acid, 3,5 – One of dimethylbenzeneboronic acid, phenylboronic acid and 4-methoxyphenylboron; the dihydroxyphenol derivative is 3,4-dihydroxybenzoic acid methyl ester, 3,4-dihydroxybenzaldehyde and One of the ethyl 3,4-dihydroxybenzoates. The coating has excellent anti-corrosion properties.
References
[1] [Chinese invention] CN201810715935.6 Preparation method of arylboronic acid
[2] CN201410249316.4 Marine heavy-duty anti-corrosion coating and preparation method thereof
