Allyl bromide → 2-Formyl-3-hydroxy-5-methoxy-6-methylbenzoic acid allyl ester

Beteiligte Stoffe

Reaktionsschritte

To a solution of 42.0 g of (RS)-3,4-dihydroxy-6-methoxy-7-methyl-1,3-dihydro-isobenzofuran-1-one in 11 of N,N-dimethylformamide were added 23.0 g of 1,1,3,3-tetramethylguanidine. The solution was stirred for 30 min and then, 48.4 g of allyl bromide were added and stirring was continued for 3 h. The mixture was evaporated in vacuo and the residue was dissolved in 0.7 l of ethyl acetate. The solution was washed with brine, dried over sodium sulfate, and the solvent was evaporated in vacuo. The solid residue was crystallized from tert-butyl methyl ether to give 37.3 g of 2-formyl-3-hydroxy-5-methoxy-6-methylbenzoic acid allyl ester as white crystals of m.p. 73°-74° C.

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