Water → 2,4-dipropylresorcinol

Participants

Reaction Conditions

Reaction Steps

The crude solid trifluoroacetophenone from Step 1 (11.54 kg) is dissolved in 48 L of ethanol and is charged into a 100 L round-bottom flask. Water (8L) is then added. Hydroxylamine hydrochloride (NH2OH.HCl, 11.05 kg) is added to the stirred mixture, followed by the addition of NaHCO3 (13.36 kg). The heterogeneous solution is stirred at 60° C. overnight. The reaction is complete within 24 hours by LC assay. Work-up consists of the addition of 40L of water and 25L of toluene, followed by transfer to an extractor. The flask is rinsed with an additional 25L of toluene, which is also transferred to the extractor. The layers are separated, and the organic layer is extracted with one washing of 60L of 1N NaOH. The layers are separated, and the NaOH layer is neutralized with 12N HCL to pH=6.1. The aqueous layer is then extracted with 60L of toluene. The layers are separated and the aqueous layer is extracted a second time with toluene. The combined organic layers are washed with 4L of water. The organic layer is concentrated to a crude solid which can be used in the next step without further purification. Alternatively, the product can be crystallized from a toluene/heptane mixture. The product is predominantly the E oxime (shown in the equation above) rather than the Z oxime and is obtained in 85% yield from 2,4-dipropylresorcinol.

Provenance & Evidence