| 摘要 |
Process for the preparation of 2-aryl-3-hydroxy-4-hydro-1,2-arylopyrans (2-aryl-3-hydroxy-3,4-dihydro-2H-1-arenopyrans) of formula D: <IMAGE> in which P and Q are mono- or polynuclear aromatic radicals, which can carry substituents and contain hetero atoms, by demethylation of a 2-aryl-3-methoxy-4-hydro-1,2-arylopyran (2-aryl-3-methoxy-3,4-dihydro-2H-1-arenopyran) of formula C <IMAGE> by reaction with a trimethylsilyl halide. There are thus obtained, in particular, 2-phenyl-4-hydro-1,2-benzopyran (2-phenyl-3,4-dihydro-2H-1-benzopyran) derivatives of formula: <IMAGE> in which R' and R'' can be H or the OCH3 group, it also being possible for R' to represent the OH group or the -O-C-R4R5(CH2)n-COOR2 radical, R2 having one of the following meanings: hydrogen or alkali metal or alkaline-earth metal atom, alkyl radical preferably having from 1 to 6 carbon atoms or phenyl radical, or cation of an organic base. It is possible to obtain water-soluble salts from these derivatives by reacting them with an alkyl haloacetate in the presence of a base, then hydrolysis of the esters thus formed to acids and, finally, reaction with an inorganic or organic base.
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