Methanol → Methyl 4,6-dimethoxynaphthalene-1-carboxylate

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Reaction Steps

4,6-Dimethoxy-1-naphthalenecarboxylic acid (98.5 g, 0.425 mole, described in Example 61) was added to an ice-cooled solution of SOCl2 (59.5 g, 0.5 mole) in anhydrous methanol (225 ml). The mixture was heated at reflux for 18 hr. Another portion of SOCl2 (35.5 ml) was added and the reflux was continued for another 7 hr. The mixture was extracted with diethyl ether. The ether extract was washed with water and then aqueous NaHCO3 solution, dried (Na2SO4) and concentrated to dryness. The solid residue was crystallized from methanol (720 ml) to give 64.5 g of 4,6-dimethoxy-1-naphthalenecarboxylic acid methyl ester; mp 102°-104° C.; NMR (CDCl3) δ 3.9 (s, 6H), 4.0 (s, 3H), 7.7 (m, 5H).

Provenance & Evidence