3,6-dichlorosalicylic acid compounds and related synthetic processes
AssigneeMonsanto Technology LLC
InventorsTerri L. Boehm, Mangesh Bore, Jeffery N. Carroll, G. Davis Harris, Jr., Matthew D. McReynolds, Justin R. Struble, Daniel P. Walker
Life of this patent
Estimating the term…
Abstract
The present disclosure relates, in general, to 5-halo-3,6-dichlorosalicylic acid compounds, 5-halo-3,6-dichlorosalicyaldehyde compounds, processes for preparing 5-halo-3,6-dichlorosalicylic acid compounds, processes for preparing 5-halo-3,6-dichlorosalicyaldehyde compounds, processes for preparing 3,6-dichlorosalicylic acid compounds, and processes that employ such compounds as intermediates in the preparation of the herbicide dicamba.
Claims18
A process for the preparation of a compound corresponding in structure to Formula (III):
- or a salt thereof, the process comprising:
- contacting a compound corresponding in structure to Formula (II):
- or a salt thereof, with a chlorinating agent in an acidic reaction medium to provide the compound or salt of Formula (III);
- wherein R1 is hydrogen or C1-6-alkyl;
- R2 is hydrogen or C1-6-alkyl;
- and
- the compound or salt of Formula (II) is contacted with about 2.0 to about 8.0 active chlorine equivalents of the chlorinating agent.
A process for the preparation of a compound corresponding in structure to Formula (III):
- or a salt thereof, the process comprising:
- contacting a compound corresponding in structure to Formula (I):
- or a salt thereof, with a brominating agent in an acidic reaction medium comprising sulfuric acid to provide the compound corresponding in structure to Formula (II):
- or a salt thereof;
- contacting the compound or salt of Formula (II) with a first chlorinating agent without first isolating the compound or salt of Formula (II) from the acidic reaction medium to provide a compound corresponding in structure to Formula (VI):
- or a salt thereof;
- and
- contacting the compound or salt of Formula (VI) with a second chlorinating agent to provide the compound or salt of Formula (III);
- wherein:
- R1 is hydrogen or C1-6-alkyl;
- R2 is hydrogen or C1-6-alkyl;
- and
- the first chlorinating agent and the second chlorinating agent can be the same or different.
A process for the preparation of a compound corresponding in structure to Formula (V):
- or a salt thereof, the process comprising:
- contacting a compound corresponding in structure to Formula (VII):
- or a salt thereof, with a chlorinating agent to provide a compound corresponding in structure to Formula (VIII):
- or a salt thereof;
- contacting the compound or salt of Formula (VIII) with a chlorinating agent to provide a compound corresponding in structure to Formula (IX):
- or a salt thereof;
- contacting the compound or salt of Formula (IX) with a debrominating agent to provide a compound corresponding in structure to Formula (X):
- or a salt thereof, contacting the compound or salt of Formula (X) with an oxidizing agent to provide a compound corresponding in structure to Formula (IV-1):
- or a salt thereof;
- and converting the compound or salt of Formula (IV-1) to the compound or salt of Formula (V);
- wherein R1 is hydrogen or C1-6-alkyl.
Dependencies are inferred from the claim text.