| 摘要 |
<p>Chlorinated hydroquinone dimethyl ethers of formula (where R is H or Cl) are prepd. by mixing the corresp. p-benzoquinone tetramethyl ketal of formula (II) with a soln. of excess HCl in an aprotic solvent at -50 to +50 pref. -20 to +20 degrees C and then isolating the product. Pref. (II) is dissolving in the same solvent as the HCl before, mixing. The solvent is pref. an ether, esp. Et2O or dioxane, or benzene. Cpds. (I) are known intermediates for dyestuffs, pharmaceuticals and pesticides. Prepn. is in one step and polychloro by-products are avoided. Initial purity of 90-98% achievable. Process is technically simple. The starting cpd. (II) is also easy to prepare e.g. anodic oxidation of anisole or hydroquinone dimethyl ether in methanol/KOH.</p> |
