| 摘要 |
<p>In the preparation of 3,4-dialkoxy- or 3,4-alkylenedioxy-thiophenes (I) or (II) by decarboxylation of the corresponding 3,4-dialkoxy- or 3,4-alkylene-dioxo-2,5-thiophene-dicarboxylic acids (III) or (IV), (i) decarboxylation is carried out in a solvent or diluent with a higher boiling point than (I) or (II), which is not an aromatic amine; and (ii) the end product is separated from this solvent or diluent by distillation. In the preparation of 3,4-dialkoxy- or 3,4-alkylenedioxy-thiophenes of formula (I) or (II) by decarboxylation of the corresponding 3,4-dialkoxy- or 3,4-alkylene-dioxo-2,5-thiophene-dicarboxylic acids of formula (III) or (IV): (i) decarboxylation is carried out in a solvent or diluent with a higher boiling point than (I) or (II), which is not an aromatic amine; and (ii) the end product is separated from this solvent or diluent by distillation. R<1>, R<2> = linear or branched 1-15 carbon (C) alkyl; X = optionally substituted -(CH2)n-; n = 1-12.</p> |
