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US 2003/0125567 A1Published application
Process for the preparation of substituted oxazoles
AssigneeBASF SE
InventorsHarald Rust, Kirsten Burkart, Tillmann Faust, Jochem Henkelmann, Alois Kindler, Christian Knoll, Michael Becker
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Abstract
The present invention relates to a process for preparing 5-alkoxy-substituted oxazoles, in particular for preparing 4-methyl-5-alkoxy-substituted oxazoles and also a process for preparing pyridoxine derivatives.
Claims17
(amended) A process for preparing 5-alkoxy-substituted oxazoles of the formula I,
- 12
- where
- R1 is an unsubstituted or substituted C1-C6-alkyl radical and
- R2 is hydrogen or an unsubstituted or substituted C1-C6-alkyl radical,
- which comprises
- converting α-isocyanoalkanoate esters of the formula II
- 13
- in the presence of assistants at temperatures above 80° C. into the 5-alkoxy-substituted oxazoles of the formula I
- and, simultaneously with the conversion, removing the 5-alkoxy-substituted oxazoles of the formula I from the reaction mixture.
6 more elements
(amended) A process for preparing pyridoxine derivatives of the formula IX
- 14
- where
- R2 is hydrogen or an unsubstituted or substituted C1-C6-alkyl radical,
- which comprises converting amino acids of the formula III
- 15
- to amino esters of the formula IV,
- 16
- where
- R1 is an unsubstituted or substituted C1-C6-alkyl radical,
- converting the latter into formamido esters of the formula V
- 17
- converting the latter into α-isocyanoalkanoate esters of the formula II,
- 18
- converting the latter in the presence of assistants at temperatures above 80° C. to the 5-alkoxy-substituted oxazoles of the formula I
- 19
- and, simultaneously with the conversion, removing the 5-alkoxy-substituted oxazoles of the formula I from the reaction mixture,
- reacting the 5-alkoxy-substituted oxazoles of the formula I with protected diols of the formula VI,
- 20
- where
- R3 and R4 independently or R3 and R4 together are a protecting group of the hydroxyl function,
- to give the Diels-Alder adducts of the formula VII,
- 21
- and converting the latter by acid treatment and detachment of the protecting group to the pyridoxine derivatives of the formula IX.
20 more elements
Dependencies are inferred from the claim text.