Process for the preparation of 3, 4-alkylenedioxythiophene-2,5-dicarboxylic acid derivatives
US6528662B2 · kind B2 · utility
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5Claims
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Key dates
| Filing date | Jun 8, 2001 |
| Grant date | Mar 4, 2003 |
| Priority date | — |
| Expiry date | Jun 8, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D495/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for the preparation of 3,4-alkylenedioxythiophene-2,5- dicarboxylic acid derivatives selected from the group consisting of compounds of the general formulae IV and V: comprising carrying out at least 2 steps in accordance with formula scheme 1 without isolation of intermediates, wherein R1, R2, R3 and R4 are identical or different and are a linear or branched, optionally substituted alkyl radical having 1 to 20 carbon atoms, A is lithium, sodium or potassium, and Hal is fluorine, chlorine, bromine or iodine, wherein the formula scheme 1 comprises:
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