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ChemicalBook CAS DataBase List 2,6-difluoro-4-methylbenzoic acid
1201597-23-0

2,6-difluoro-4-methylbenzoic acid synthesis

4synthesis methods
-

Yield: 53%

Reaction Conditions:

Stage #1:2,6-difluoro-4-methylbenzaldehyde with sodium hydroxide;silver(l) oxide in water for 1.5 h;
Stage #2: with hydrogenchloride in water; pH=2

Steps:

C
Silver oxide (43.8 g, 0.189mol) was placed in a flask along with water (20OmL) and sodium hydroxide (33.7g, 0.842mol). To it was added 2,6-difluoro-4-methylbenzaldehyde (29.23 g, 0.187mol) in small portions over a 30min period. After a vigorous exothermic reaction, the color of the reaction mixture changed from black to gray. The resulting thick suspension was stirred for 1 hr and then filtered through a Buchner funnel. The filtrate was acidified to pH 2 with concentrated HCl to give a suspension. The precipitate was collected by suction filtration, dissolved in ether, dried over anhydrous Na2SO4, filtered and concentrated to give white solid (17.0 g, 53%). 1H-NMR (500MHz, d6-DMSO): 613.7 ( br.s, 1H ), 7.02 ( d, 2H, J=9.3 Hz), 2.32 ( s, 3H ).

References:

MERCK SHARP &;DOHME CORP.;KOYAMA, Hiroo;SAHOO, Soumya, P.;YANG, Ginger Xu-Qiang;MILLER, Daniel, J. WO2010/129208, 2010, A1 Location in patent:Page/Page column 32-33