Atropisomers of pyridazinone derivatives as herbicides
AssigneeFMC Corporation
InventorsThomas Paul Selby, John Robbins Debergh, Thomas Martin Stevenson, Stephen Frederick Mccann
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Abstract
The present disclosure provides atropisomers of pyridazinone derivatives of a compound of Formula 1a and Formula 1b, N-oxides or salts thereof, wherein R1, R2, R3, R4 and R5 are defined in the disclosure. Also disclosed is a composition containing a compound of Formula 1a or 1b, and methods for controlling undesired vegetation comprising contacting the undesired vegetation or its environment with an effective amount of a compound of Formula 1a or 1b or a composition thereof. Also disclosed are methods for preparing a compound of Formula I.
Claims10
An optically active compound selected from atropisomers of Formula 1a and Formula 1b:
- wherein
- R1 is Cl or CH3,
- R2 is CH3 or difluoromethoxy;
- R3 is CH3 or H;
- R4 is H;
- and
- R5 is H or —(C═O)CH2CH3;
- and
- wherein
- the atropisomer of Formula 1a or 1b, has a plus (+) optical rotation value and is present in excess of its corresponding enantiomer.
A process for preparing a compound of Formula 1a or 1b
- wherein
- R1 is Cl or CH3;
- R2 is CH3 or difluoromethoxy;
- R3 is CH3 or H;
- R4 is H;
- and
- R5 is H or —(C═O)CH2CH3;
- the process comprising:
- 1) loading a racemic mixture of a compound of Formula 1 comprising the atropisomers of Formulae 1a and 1b onto a chiral supported supercritical fluid chromatography column and eluting with a mobile phase which comprises carbon dioxide;
- 2) isolating two separate fractions with different retention times;
- one containing an atropisomer with a positive optical rotation value [α]1 (+);
- and one atropisomer with a negative optical rotation value [α]1 (−).
Dependencies are inferred from the claim text.