Removal of fluorine from and introduction of fluorine into polyhalopyridines: an exercise in nucleophilic hetarenic substitution
Starting from six industrially available fluorinated pyridines, an expedient access to all three tetrafluoropyridines, all six trifluoropyridines, and the five non-com. difluoropyridines was developed. The methods employed for the selective removal of fluorine from polyfluoropyridines were the redn. by metals or complex hydrides and the site-selective replacement by hydrazine followed by dehydrogenation-dediazotation or dehydrochlorination-dediazotation. To introduce an extra fluorine atom, a suitable precursor was metalated and chlorinated before being subjected to a chlorine/fluorine displacement process. [on SciFinder (R)]
WOS:000227662900022
2005
11
6
1903
1910
CAN 142:447087 27-16 Heterocyclic Compounds (One Hetero Atom) Institute of Chemical Sciences and Engineering,Ecole Polytechnique Federale,Lausanne,Switz. Journal 0947-6539 written in English. 372-47-4 (3-Fluoropyridine); 372-48-5 (2-Fluoropyridine); 700-16-3 (Pentafluoropyridine); 1735-84-8 (3-Chloro-2,4,5,6-tetrafluoropyridine); 1737-93-5 (3,5-Dichloro-2,4,6-trifluoropyridine); 2879-42-7 Role: RCT (Reactant), RACT (Reactant or reagent) (removal of fluorine from and introduction of fluorine into polyhalopyridines via nucleophilic hetarenic substitution); 1480-64-4P (2-Fluoro-3-chloropyridine); 1513-66-2P (2,3-Difluoropyridine); 2546-56-7P (4-Chloro-3-fluoropyridine); 2875-18-5P (2,3,5,6-Tetrafluoropyridine); 3512-13-8P (2,3,4,6-Tetrafluoropyridine); 3512-17-2P (2,4,6-Trifluoropyridine); 3512-18-3P; 71902-33-5P (3,5-Difluoropyridine); 76469-41-5P (2,3,5-Trifluoropyridine); 84477-04-3P; 89402-43-7P (3-Chloro-5,6-difluoropyridine); 248255-70-1P; 259675-77-9P; 514797-99-0P (3-Fluoro-5-chloropyridine); 837364-95-1P; 837364-96-2P; 849937-92-4P; 851178-96-6P; 851178-97-7P (4-Chloro-3,5-difluoropyridine); 851178-98-8P (3-Chloro-4,5-difluoropyridine); 851178-99-9P (4-Chloro-2,3-difluoropyridine); 851179-00-5P (3-Chloro-2,5-difluoropyridine); 851179-01-6P (3-Chloro-2,4-difluoropyridine); 851179-02-7P (3-Fluoro-4,5-dichloropyridine); 851179-03-8P (2-Fluoro-3,4-dichloropyridine); 851179-04-9P; 851179-05-0P; 851179-06-1P; 851179-07-2P; 851179-08-3P; 851179-09-4P; 874907-81-0P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (removal of fluorine from and introduction of fluorine into polyhalopyridines via nucleophilic hetarenic substitution); 3512-16-1P (2,3,4,5-Tetrafluoropyridine); 34941-90-7P (2,4-Difluoropyridine); 67815-54-7P (3,4,5-Trifluoropyridine); 82878-63-5P (3,4-Difluoropyridine); 84476-99-3P (2,5-Difluoropyridine); 837365-04-5P Role: SPN (Synthetic preparation), PREP (Preparation) (removal of fluorine from and introduction of fluorine into polyhalopyridines via nucleophilic hetarenic substitution)
REVIEWED
EPFL