| 摘要 |
<p>The prepn. of pyrogallol (I), or its salts, comprises reacting halo cpds. (II), or their salts, with an alkoxide ROM to give the ether (III), or its salts, which is then subjected to dealkylation and elimination of R1 = H. A and C = Br or I; and B = OR2; or one of A and B = Br or I, the other and C = OR2. A1 and C1 = R and B1 = R2, or one of A1 and B1 = R, the other and C1 = R2. R= 1-4C alkyl. R1 = H, 10C sec. or tert. alkyl, COOH or 2-5C alkoxycarbonyl. R2 = H or 1-4C alkyl. M = alkali metal. (I) is used as photographic developer, in dyeing of wool and leather; in analysis of heavy metals and as an intermediate, e.g., for the insecticide 2,2-dimethyl-1,3-benzodioxol-4-yl methyl carbamate. The process gives high yields of pure prod. without relying on scare starting matls. of vegetable origin. Pref. first stage is in presence of a Cu salt catalyst and dealkylation and R1 removal is done with aq. HBr. 2,6-dibromo-4-t.-butylphenol was converted in 77% yield to the 2,6-dimethoxy cpd. with Na methoxide and CuI, and this refluxed with 48% HBr to give an 83% yield of (I).</p> |
