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US 10,239,857 B2Granted
Processes for the preparation of 2-thiophenecarbonyl chloride
AssigneeMonsanto Technology LLC
InventorsDaniel P. Walker, William H. Miller
Life of this patent
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Abstract
Provided herein are processes for the preparation of 2-thiophenecarbonyl chloride, which is useful, for example, in the preparation of 3,5-disubstituted-1,2,4-oxadiazoles, such as tioxazafen (3-phenyl-5-(2-thienyl)-1,2,4-oxadiazole).
Claims19
A process for preparing 2-thiophenecarbonyl chloride, the process comprising:
- reacting thiophene with chlorosulfonyl isocyanate in a reaction medium comprising an organic solvent, thereby producing (thiophene-2-carbonyl)sulfamoyl chloride,
- wherein the reaction is initiated by mixing the thiophene and the chlorosulfonyl isocyanate,
- and wherein the chlorosulfonyl isocyanate is present in molar excess relative to thiophene,
- hydrolyzing the (thiophene-2-carbonyl)sulfamoyl chloride to produce 2-thiophenecarboxylic acid, and
- chlorinating the 2-thiophenecarboxylic acid to produce 2-thiophenecarbonyl chloride.
2 more elements
A process for preparing 2-thiophenecarbonyl chloride, the process comprising:
- reacting thiophene with chlorosulfonyl isocyanate in a reaction medium comprising an organic solvent comprising dibutyl ether, thereby producing (thiophene-2-carbonyl)sulfamoyl chloride,
- hydrolyzing the (thiophene-2-carbonyl)sulfamoyl chloride to produce 2-thiophenecarboxylic acid, and
- chlorinating the 2-thiophenecarboxylic acid to produce 2-thiophenecarbonyl chloride.
A process for preparing a 3,5-disubstituted 1,2,4-oxadiazole of Formula (I) or a salt thereof,
- the process comprising adding a first liquid medium comprising thiophene dissolved in dibutyl ether to a second liquid medium comprising chlorosulfonyl isocyanate, thereby producing a third liquid medium comprising (thiophene-2-carbonyl)sulfamoyl chloride in the form of a substantially homogeneous solution or a solid suspension in a liquid organic phase comprising dibutyl ether, wherein the chlorosulfonyl isocyanate is present in the second liquid medium in molar excess relative to thiophene in the first liquid medium;
- adding at least a portion of the third liquid medium to an aqueous medium comprising a strong acid or a strong base, thereby producing a fourth liquid medium comprising 2-thiophenecarboxylic acid dissolved in an organic phase comprising dibutyl ether;
- reacting at least a portion of the 2-thiophenecarboxylic acid present in the fourth liquid medium with thionyl chloride, thereby producing a reaction medium comprising 2-thiophenecarbonyl chloride;
- and reacting at least a portion of the 2-thiophenecarbonyl chloride obtained in the fourth liquid reaction medium with an N-hydroxyamidine of Formula (II), or a tautomeric form thereof,
- wherein Ar1 is selected from the group consisting of phenyl, pyridyl, pyrazyl, oxazolyl or isoxazolyl, each of which can be optionally independently substituted with one or more substituents selected from the group consisting of halogen, CF3, CH3, OCF3, OCH3, CN and C(H)O, and Ar2 is thienyl, which can be optionally independently substituted with one or more substituents selected from the group consisting of fluorine, chlorine, CH3, and OCF3.
2 more elements
Dependencies are inferred from the claim text.