Total Synthesis of Methyl O-Methyl-11-Desoxycarnosate

Abstract

<p> Synthetic methods for the preparation of 2,7-dimethoxy-1-naphthoic acid are presented. The selective reduction of this acid with sodium in liquid ammonia to give 1,4-dihydronaphthoic acid is described.</p> <p> The selective Birch reduction of 2,7-dimethoxynaphthalene to 1,4-dihydro-2,7-dimethoxynaphthalene has been accomplished. 2,7-Dimethoxy-3- isopropylnaphthalene was converted to 3-keto-12-methoxy-10-carbomethoxy-13-isopropylperhydrophenanthra-4,8,11,13-tetraene via, 1,2,3,4-tertrahydro-7-methoxy-6-isopropyl-1-carbomethoxynaphthalen-2-one. The transformation of 3-keto-12-methoxy-10-carbomethoxy-13-isopropylperhydrophenanthra-4,8,11,13- tetraene to methyl O-methyl-11-desoxycarnosate via methylation, thioketalisation, desulphurisation and hydrogenation is also described.</p>