288389-24-2Relevant articles and documents
Practical and large-scale synthesis of rac-(3S,4aR,10aR)-6-methoxy-1-propyl-1,2,3,4,4a,5,10,10a-octahydrobenzo[g] quinoline-3-carboxylic acid methyl Ester
B?nziger, Markus,Cercus, Jacques,Stampfer, Wolfgang,Sunay, Ustun
, p. 460 - 466 (2000)
3-Substituted octahydrobenzo[g]quinolines are important intermediates for pharmaceutically active compounds. A short, efficient synthesis, which is feasible for large-scale manufacturing of rac-(3S,4aR,10aR)-6-methoxy-1-propyl-1,2,3,4,4a,5,10,10a-octahydrobenzo[g] quinoline-3-carboxylic acid methyl ester is presented. As starting materials the cheap and readily available 1,6-dimethoxynaphthalene and ethoxymethylenecyanoacetic acid ethyl ester were chosen. All atoms of the skeleton were introduced in the first step, by the reaction of 7-lithiated 1,6-dimethoxynaphthalene with ethoxymethylenecyanoacetic acid ethyl ester. Subsequent hydrogenation, followed by Birch reduction and acidic cyclization gave the 6-methoxy-2,3,4,4a,5,-10-hexahydrobenzo[g]quinoline-3-carboxylic acid·hydrochloride in high yield. The trans fusion of the two six-membered rings was established after NaBH4 reduction. After esterification, n-propylation, and kinetic protonation of an intermittantly formed trimethylsilylketene acetal, the desired product was isolated in high yield and excellent purity.
