Tempo → 4-(Benzyloxy)-2,5-dimethylbenzaldehyde

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Reaction Steps

A mixture of 11.0 g (46 mmol) of 2,5-dimethyl-4-(phenylmethoxy)benzenemethanol (Example I), 0.4 g (0.05×46=2.3 mmol) of TEMPO (tetramethyl-1-piperidinyloxy, free radical) (Aldrich) and 0.2 g (2.3 mmol) of cuprous chloride in 150 mL of dimethylformamide is stirred vigorously under an atmosphere of oxygen (maintained by a balloon) at ambient temperature for 18 hours overnight. The heterogeneous mixture is (dark green) filtered through a pad of celite, washed with diethyl ether and the solvents are removed on a rotary evaporator. The residue is dissolved in diethyl ether and the solution is washed with 2×50 mL of 2N hydrochloric acid solution, brine, dried (magnesium sulfate) and evaporated leaving 10.7 g of a yellow viscous residue. Distillation of the product through a short path apparatus affords 10.3 g of a pale yellow distillate, bp 156°-8° C./0.50 (175°-180° C.) on standing the product crystallizes; mp 48°-49° C.

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