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Supplementary Information

Facile and effective approach for oxidation of boronic acids

Ravindra B. Wagh and Jayashree M. Nagarkar*

Department of Chemistry, Institute of Chemical Technology, Matunga, Mumbai – 400019, India.

E-mail: jm.nagarkar@ictmumbai.edu.in

Tel.: +91 22 33611111/2222

Table of Contents

General Experimental Page 2

Spectroscopic Data Page 3

Mass Spectra’s Page 5

1H NMR Spectra’s Page 14

References Page 21

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General Experimental

The chemicals and reagents were purchased from firms of repute in the highest purity available and used

without further purification. The reaction was monitored by TLC and GC analysis performed on Perkin

Elmer Clarus 480. GC equipped with flame-ionized detector with capillary column (Elite-1701, 30m X

0.32 X 0.25). The mass of product was confirmed by GC–MSQP 2010 instrument (Rtx-17, 30 m_25 mm

ID, film thickness 0.25μm, column flow: 2 mL min–1

, 40- 240 °C at 10 °C/ min rise). The products were

purified by column chromatography using (60-120 mesh) silica gel with pet ether and ethyl acetate as

solvent. 1H NMR spectroscopic data was recorded on a Varian Mercury plus-300 spectrometer using

CDCl3 as a solvent unless otherwise stated. Melting points of the products were determined on a Galaxy

scientific apparatus.

General procedure for the oxidation of boronic acids

A mixture of boronic acid (1 mmol), DMC (1.0 mL) was taken in 25 mL round bottom flask with

magnetic stirring bar. Then the reaction was activated by addition of 30% H2O2 (2.0 equiv.) and stirred at

room temperature for 5 h. The progress of reaction was monitored by TLC. After disappearance of

starting material, added H2O (1.0 mL) in to the reaction mixture. The reaction mixture was then further

diluted with ethyl acetate (30 mL) and subsequently washed with distilled water (5.0 mL). The resulting

organic extract was dried over anhydrous sodium sulphate. The solvent was removed under vacuum to get

crude product which was purified (if necessary) by column chromatography using silica gel with pet ether

and ethyl acetate as solvent system to obtain the pure product. The structure of the product was confirmed

by GC-MS, M.P. and 1H NMR spectroscopic techniques.

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Spectroscopic Data

Phenol (2a) – Colourless solid, Yield: 98%, MP: 41-43°C, 1H NMR (400MHz, CDCl3) δ7.28 (t, 2H),

6.96 (t, 1H), 6.87 (d, 2H), 2.75 (s, 1H), GCMS m/z, [M]+= 94.

p-cresol (2b) – Colourless solid, Yield: 98%, MP: 35-36°C, 1H NMR (400MHz, CDCl3) δ 7.04 (d, 2H),

6.79- 6.77 (m, 2H), 2.30 (s, 3H), GCMS m/z, [M]+= 107.

4-methoxyphenol (2c) – White solid, Yield: 98%, MP: 58-59°C, 1H NMR (400 MHz, CDCl3) δ 6.78-

6.75 (m, 4 H), 5.88 (s, 1H), 3.77 (s, 3H), GCMS m/z, [M]+=124.

4-(tert-butyl)phenol (2d) – White solid, Yield: 98%, MP: 97-98°C, 1H NMR (400MHz, CDCl3) δ 7.27

(d, 2H), 6.79 (d, 2H), 5.13 (s, 1H), 1.29 (s, 9H), GCMS m/z, [M]+= 150.

[1, 1'-biphenyl]-4-ol (2e) – White solid, Yield: 98%, MP: 165-166°C, 1H NMR (400MHz, DMSO) δ

7.54 (d, 2H), 7.46 (d, 2H), 7.38 (t, 2H), 7.34 (t, 1H), 6.83(d, 2H), 4.83(s, 1H), GCMS m/z, [M]+= 170.

4-chlorophenol (2f) – White solid, Yield: 97%, MP: 44-46°C, 1H NMR (400MHz, CDCl3) δ 7.18-7.15

(m, 1H), 6.76-6.74 (m, 1H), 6.23 (s, 1H) GCMS m/z, [M]+= 128.

4-bromophenol (2g) – Light yellow solid, Yield: 98%, MP: 56-57°C, 1H NMR (400MHz, CDCl3) δ 7.32-

7.24 (m, 2H), 6.72-6.69 (m, 2H), 5.29 (s, 1H), GCMS m/z, [M]+= 172.

4-flurophenol (2h) – White solid, Yield: 98%, MP: 46-47°C, 1H NMR (400MHz, CDCl3) δ 6.91-6.87 (t,

2H), 6.77-6.74 (m, 2H), 4.14 (s, 1H), GCMS m/z, [M]+= 112.

4-(trifluoromethyl)phenol (2i) – Yellow solid, Yield: 98%, MP: 46-47°C, 1H NMR (400MHz, DMSO) δ

7.49 (d, 2H), 6.91 (d, 2H), 5.27 (s, 1H), GCMS m/z, [M]+= 162.

4-nitrophenol (2j) – Light yellow solid, Yield: 97%, MP: 113-114°C, 1H NMR (400MHz, DMSO) δ 8.08

(d, 2H), 7.87 (d, 2H), 3.02 (s, 1H), GCMS m/z, [M]+= 139.

4-hydroxybenzaldehyde (2k) –White solid, Yield: 97%, MP: 114-116°C, 1H NMR (400 MHz, DMSO) δ

9.74 (s, 1H), 7.73 (d, 2H), 6.88 (d, 2H), 6.36 (s, 1H), GCMS m/z, [M]+=121.

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naphthalen-1-ol (2l) – Light brown solid, Yield: 98%, MP: 95-96°C, 1H NMR (400MHz, CDCl3) δ 8.18

(m, 1H), 7.81 (m, 1H), 7.50-7.46 (m, 2H), 7.44 (d, 1H), 7.30 (t, 1H), 6.81 (d, 1H), 5.49 (s, 1H),GCMS

m/z, [M]+= 144.

naphthalen-2-ol (2m) – White solid, Yield: 98%, MP: 121-122 °C, 1H NMR (400MHz, CDCl3) δ 7.79 (t,

2H), 7.68 (d, 1H), 7.42 (m, 1H), 7.32 (m, 1H), 7.14 (m, 1H), 7.10 (m, 1H), 5.04 (s, 1H), GCMS m/z,

[M]+= 144.

Pyridin-3-ol (2n) – Light Yellow Solid, Yield: 90%, MP: 125-127 °C, 1H NMR (400 MHz, CDCl3) δ

8.25 (d, 1H), 8.07 – 8.05 (m, 1H),7.42 – 7.28 (m, 2H), GCMS m/z, [M]+= 95.

Cyclohexanol (2o)1

– Colourless liquid, Yield: 91%, 1H NMR (400 MHz, CDCl3) δ 3.62 (m,1H), 1.99-

1.82 (m, 2H), 1.80-1.62 (m, 2H), 1.53 (m, 1H), 1.32-1.18 (m, 5H), GCMS m/z, [M]+= 100.

Heptan-1-ol (2p)2

– Colourless liquid, Yield: 85%, 1H NMR (400 MHz, CDCl3) δ3.65-3.62 (m, 2H),

1.58-1.53 (m, 2H), 1.36-1.28 (m, 8H), 0.90-0.86 (t, 3H), GCMS m/z, [M]+= 115.

Butan-2-ol (2q) – Colourless liquid, Yield: 84%, GCMS m/z, [M]+= 73.

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Mass Spectra’s

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1H NMR Spectra’s

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References

1 Maegawa, T.; Akashi, A.; Yaguchi, K.; Iwasaki, Y.; Shigetsura, M.; Monguchi, Y.; Sajiki,

H. Chem. Eur. J., 2009, 15, 6953-6963.

2 Jia, Z.; Zhou, F.; Liu, M.; Li, X.; Chan, A. S. C.; Li, C-J. Angew. Chem. Int. Ed., 2013, 52

11871-11874.