4-(but-2-ynyloxy)benzoic acid synthesis

Yield:362705-53-1 100%

Reaction Conditions:

Stage #1: methyl 4-(but-2-yn-1-yloxy)benzoatewith water;sodium hydroxide in tetrahydrofuran at 45; for 23 h;Reflux;
Stage #2: with hydrogenchloride in tetrahydrofuran;water;ethyl acetate; pH=6;

Steps:

1.1-4

26 ml (262 mmol) of an aqueous solution of sodium hydroxide having a concentration of 10N are added to a solution of 13.4 g (65.7 mmol) of methyl 4-but-2- ynyloxybenzoate diluted in 200 ml of tetrahydrofuran and 25 ml of water. The reaction medium is stirred at reflux for 5 h then at 45°C for 18 h. The reaction medium is hydrolysed, diluted with ethyl acetate then brought to pH = 6 using an aqueous solution of hydrochloric acid having a concentration of IN. The product is extracted with ethyl acetate. The organic phase is washed with water then with a saturated aqueous solution of sodium chloride, dried over magnesium sulphate, filtered and concentrated.12.5 g (100%) of 4-but-2-ynyloxybenzoic acid are obtained in the form of a white solid.

References:

WO2011/33010,2011,A1 Location in patent:Page/Page column 27-28