Yield:871571-19-6 96.95 %Chromat.

Reaction Conditions:

with hydrogen bromide;dihydrogen peroxide in water at 10 - 25; for 8 h;Inert atmosphere;

Steps:

20.2 Example 20 2. Step of Bromination of Guaiacol Mesylate

A 40% aqueous solution of hydrobromic acid (31 g, 0.15 mol) is added to the guaiacol mesylate (28 g, 0.14 mol) obtained after distillation. The resulting mixture is stirred under an inert nitrogen atmosphere and then a 30% aqueous solution of hydrogen peroxide (17 g, 0.15 mol) is added slowly, while the temperature is held below 25° C. Following this addition, the mixture is stirred at 10° C. for 8 h. At this stage, the reaction mixture contains 96.95% of guaiacol 5-bromomesylate (percentage calculated by area % obtained by gas chromatography coupled with mass spectrometry). A 20% solution of sodium hydrogen sulphite, NaHSO₃ (10 ml) is added and the reaction is tested with an iodine starch paper to verify that there is no longer any oxidizing agent present.

References:

US2013/66097,2013,A1 Location in patent:Paragraph 0276; 0277; 0278; 0279; 0280