Formaldehyde → 6-Methoxy-3,4-dihydro-1H-2-benzopyran-1-one

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Reaction Steps

A 1.6M solution of n-butyllithium in hexane (145.9 mL) was added dropwise at −78° C. to a solution of diisopropylamine (33.5 mL) in dry THF (190 mL). Then the reaction mixture was warmed to room temperature for 5 min, and then cooled again to −78° C., and a solution of 4-methoxy-2-methylbenzoic acid in dry THF (210 mL) was added dropwise. After stirring at this temperature for 10 min, paraformaldehyde (7 g) was added. Then the reaction mixture was allowed to return to room temperature and it was stirred at this temperature for 4 h. Water was added to the reaction mixture, then the THF was removed in vacuum and then the aqueous phase was extracted with diethyl ether. The aqueous phase was acidified with conc. HCl, the precipitate obtained was filtered off and washed with water several times. In this way the product was obtained with molecular weight 178.06 (C10H10O3); MS (ESI): 179 (M+H+).

Provenance & Evidence