4-Carboxylphenylboronic acid pinacol ester

white crystalline powder

General procedure: tert-Butyl nitrite (155 mg, 1.1 mmol) wasadded drop wise to a mixture of bis(pinacolato)diborane (127 mg, 0.5 mmol), 4-anisidine (61 mg, 0.5 mmol) and eosin Y (0.01 mmol) in acetonitrile (3 mL).The resulting mixture was stirred at room temperature under irradiation withblue LED for 2 h (TLC). This mixture after being diluted with ethyl acetate(5 mL) was ltered through celite and the ltrate was extracted with ethylacetate (3 10 mL). The extract was washed with brine, dried over anhydrousNa 2 SO 4 , and evaporated to leave the crude product which was puried bycolumn chromatography over silica gel with hexane–ethyl acetate (98:2) aseluent to furnish pure 2-(4-methoxyphenyl)-4, 4, 5, 5-tetramethyl-1, 3, 2-dioxaborolane as a light yellow viscous liquid (3d, 208 mg, 88percent); IR (neat)2978, 2933, 2839, 2526, 2050, 1950, 1911, 1724, 1605, 1570 cm1;1H NMR(500 MHz, CDCl 3 ) d 1.33 (s, 12H), 7.82 (s, 3H), 6.89 (d, J = 8.0 Hz, 2H), 7.75 (d, J = 8.0 Hz, 2H);13C NMR (125 MHz, CDCl 3 ) d 24.9 (4C), 55.2, 83.6 (2C), 113.4(2C), 136.6 (2C), 162.3. The spectroscopic data is in full agreement with thosereported for an authentic sample.14This procedure was followed for all thereactions listed in Table 2. All of these products (3a, 143b, 143c, 16a3d, 143e, 143f, 8a3g, 143h, 143i, 143j, 8a3k, 8a3l, 8a3m, 143n, 8c3o, 16b) are known compounds, and their spectroscopic data are in agreement with those previously reported.4-Carboxyphenylboronic acid (10.0 g, 60.3 mmol) was suspended in 100 mL of toluene and pinnacol added (7.1 g, 60.3 mmol). The reaction was heated to reflux with a Dean-Stark trap attached. The reaction became homogenous upon heating. After 2 h reflux the reaction was allowed to stand overnight and white needles were collected by filtration, rinsed with toluene, and vacuum dried to 4-(4, 4, 5, 5-tetramethyl-[1, 3, 2]dioxaborolan-2-yl)-benzoic acid 12.2 g (81percent). MS (FD MS): M=248. Analysis calculated for C13H17BO4: C, 62.94; H, 6.91 Found: C, 62.71; H, 6.91.4-Carboxyphenylboronic acid (10.0 g, 60.3 mmol) was suspended in 100 mL of toluene and pinnacol added (7.1 g, 60.3 mmol). The reaction was heated to reflux with a Dean-Stark trap attached. The reaction became homogenous upon heating. After 2 h reflux the reaction was allowed to stand overnight and white needles were collected by filtration and rinsed with toluene. The title compound was vacuum dried to 12.2 g (81percent).[0153] Mass Spectrum (FD MS): M=248. Analysis calculated for C13H17BO4: percent C, 62.94; percent H, 6.91; Found: percent C, 62.71; percent H, 6.91.

Molecular Weight:248.08
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:2
Exact Mass:248.1219892
Monoisotopic Mass:248.1219892
Topological Polar Surface Area:55.8
Heavy Atom Count:18
Complexity:316
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes