Acetyl chloride → Methyl 5-acetyl-2,4-dihydroxybenzoate

Participants

Reaction Steps

The toluene solution from Step 1 was cooled in an ice bath under N2 and triflic acid (9.44 L) added slowly over 3 h. On stirring a fine white solid was formed which dissolved on warming to RT over 20 h and then stirring at RT for 37 h to give a yellow solution. To the solution was added acetyl chloride (726 mL) and the solution stirred at RT for a further 1 h. This solution was cannulated into a stirred cooled (0° C.) solution of EtOAc (217.8 L) and NaOAc.3H2O (14.52 Kg) dissolved in water (145 L). The organic phase was washed with saturated brine (twice, 72.6 L), and was evaporated to 5.5 Kg. Toluene:Isopropanol (2:3) was added and the crystalline solid removed by filtration and dried to give 12.6 Kg (61% over 2 steps), mp 124-126° C.

Provenance & Evidence