Pyridine → 3-Butyl-6-(3,5-di-tert-butyl-4-hydroxybenzamido)-phthalide

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Reaction Steps

2.50 g (10 mmol) of 3,5-di-tert-butyl-4-hydroxy-benzoic acid are heated with 2.5 ml of thionyl chloride under reflux for 30 minutes. The reaction mixture is evaporated in vacuo and the residue is mixed with petroleum ether to remove the excess of thionyl chloride. 2.05 g (10 mmol) of compound obtained in Example 4 are mixed with 8.6 g of dry pyridine and dried ether. To this suspension there is added, dropwise, the ethereal solution of acyl chloride prepared above; the reaction mixture is refluxed for 30 minutes. The solvents are removed in vacuo. The residue is washed with water and dried. The title compound is crystallised from ethyl acetate.

Provenance & Evidence