81334-60-3Relevant academic research and scientific papers
Process for the preparation of 2-(imidazolin-2-yl)-3-pyridine- and -3-quinolinecarboxylic acids
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, (2008/06/13)
There is disclosed a process for the preparation of 2-(imidazolin-2-yl)-3-pyridine and -3-quinolinecarboxylic acids of formula STR1 wherein R1 is hydrogen or C1 -C4 alkyl, R2 is hydrogen, halogen, C1 -C4 alkyl, C1 -C4 hydroxyalkyl, C1 -C4 alkoxy, phenyl or phenyl-C1 -C4 alkyl, or phenyl or phenyl-C1 -C4 -alkyl, each substituted by one C1 -C4 alkyl, C1 -C4 alkoxy or halogen, R3 is hydrogen, C1 -C4 alkyl, phenyl, phenyl-C1 -C4 -alkyl, or phenyl or phenyl-C1 -C4 -alkyl, each substituted by one C1 -C4 alkyl, C1 -C4 alkoxy or halogen, R2 and R3 together are 1,3-butadienylene which can be substituted by halogen, C1 -C4 alkyl, C1 -C4 alkoxy, C1 -C4 haloalkyl, C1 -C4 alkylsulfonyl, nitro, cyano, phenyl, phenoxy, or phenyl or phenoxy, each substituted by one C1 -C4 alkyl, C1 -C4 alkoxy or halogen, and R4 and R5 are each independently of the other C1 -C4 alkyl. In this process, the 2-(imidazolin-2-yl)-3-pyridine- and -3-quinolinecarboxylic acids of the above formula are obtained by reacting a 2,3-pyridine- or 2,3-quinolinedidicarboxylic acid ester of formula STR2 wherein R1, and R2 and R3 are as defined above and R6 is C1 -C8 alkyl, phenyl or C1 -C4 phenylalkyl with a 2-aminoalkanecarboxamide of formula STR3 wherein R4 and R5 are as defined above, in an inert solvent and in the presence of a strong base, direct to a salt of a 2-(imidazolin-2-yl)-3-pyridine- or -3-quinolinecarboxylic acid of the above formula, from which the free 2-(imidazolin-2-yl)-3-pyridine- or -3-quinolinecarboxylic acids of the above formula are obtained by converting said salt into an aqueous solution and adding an acid. The 2-(imidazolin-2-yl)-3-pyridine- and -3-quinolinecarboxylic acids of the above formula have herbicidal properties and can be used for controlling undesired plant growth.
