A novel synthesis of Rhein (2), the active metabolite of the anti-osteoarthritic drug Diacetyl Rhein (1) has been achieved. Key steps include stereospecific olefination of aldehyde 21 with novel phosphonate 28 and the cyclisation of acid 31 to produce anthracene 32.
Synthesis of Hydroxy-7<i>H</i>-benzo[<i>c</i>]fluoren-7-ones
作者:Paulo J. Coelho、Maria A. Salvador、M. Manuel Oliveira、Luis M. Carvalho
DOI:10.1055/s-2004-822890
日期:——
An efficient synthesis of 2-, 3- and 4-hydroxy-7H-benzo[c]fluoren-7-ones, useful intermediates for the synthesis of photochromic naphthopyrans, is described. The synthetic approach involves the use of oxazolines as activating groups for aromatic nucleophilicsubstitution and starts with readily available dimethoxynaphthaldehydes.