103999-77-5Relevant articles and documents
Creating structural manifolds from a common precursor: Basicity gradient-driven isomerization of halopyridines
Schlosser, Manfred,Bobbio, Carla
, p. 4174 - 4180 (2007/10/03)
5-Chloro-2,3-difluoropyridine, an intermediate in the manufacturing process of an industrial pesticide, can be hydrolyzed to 5-chloro-3-fluoro-2H-pyridinone and the latter converted into 2,5-dichloro-3-fluoropyridine (1a), 2-bromo-5-chloro-3-fluoropyridine (1b), 5-chloro-3-fluoro-2-iodopyridine (1c) and 3-chloro-5-fluoropyridine (1d). Consecutive treatment of these four substrates with lithium diisopropylamide and carbon dioxide or lithium diisopropylamide and iodine affords the corresponding 4-pyridinecarboxylic acids 2 and 4-iodopyridines 3, respectively. Amide-promoted deprotonation of such 4-iodopyridines 3 triggers an isomerization in which lithium and iodine change places. The resulting species can be trapped with carbon dioxide to give the acids 5a-c or neutralized to give the halopyridines 4a-c. The iodopyridines 4a and 4b can be converted into the acids 6a and 6b, the latter product leading also to the congeners 6c and 6d. The diiodopyridine 4c provides an entry to the halopyridine 4d, which at the same time may act as the precursor to the acid 5d, the acid 7 or the bisacid 8. Finally, the acid 9 is accessible from either one of the 5-chloro-3-fluoro-2-halopyridines 1b and 1c. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002).
FLUORINATED HETEROCYCLES: TARGETS IN THE SEARCH FOR BIOACTIVE COMPOUNDS AND TOOLS FOR THEIR PREPARATION
Differding, E.,Frick, W.,Lang, R. W.,Martin, P.,Schmit, C.,et al.
, p. 647 - 671 (2007/10/02)
To strategies for the preparation and use of fluorinated heterocycles are discussed: 1.)the building block approach being used mainly for the preparation of target heterocycles with fluorinated substituents, and 2.)the direct fluorination approach in which fluorinated heterocycles are used as tools for the preparation of bioactive compounds.Strategies presented in the building block approach include electrophilic reactions of building blocks derived from trifluoroacetic acid (1), as well as the use of building blocks obtained from trichlorotrifluoroethane (2) and chlorodifluoro acetic acid (3) through organometallic reactions.The preparation and use of N-fluoro sultams 62 and 66 are shown in the direct fluorination approach.Both strategies can be successfully used n the synthesis of bioactive compounds of pharmaceutical and agrochemical interest.
2-(4-(5-chloro-3-fluoropyridin-2-yloxy)phenoxy)-propionic acid-propynyl ester with herbicidal activity
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, (2008/06/13)
There is described the 2-[4-(5-chloro-3-fluoropyridin-2-yloxy)-phenoxy]-propionic acid propynyl ester and its (R)-enantiomer of formula I STR1 These compounds are suitable for selectively controlling weeds in crops of cultivated plants, or for reducing the growth of grasses.