cas 1513-66-2, 2,3-Difluoropyridine | Articles data

Articles about 1513-66-2Total 9 be found

Article title
Article abstract
Author
Journal number and time
Download

Tetramethylammonium Fluoride Alcohol Adducts for SNAr Fluorination
Nucleophilic aromatic fluorination (SNAr) is among the most common methods for the formation of C(sp2)-F bonds. Despite many recent advances, a long-standing limitation of these transformations is the requirement for rigorously dry, aprotic conditions to maintain the nucleophilicity of fluoride and suppress the generation of side products. This report addresses this challenge by leveraging tetramethylammonium fluoride alcohol adducts (Me4NF·ROH) as fluoride sources for SNAr fluorination. Through systematic tuning of the alcohol substituent (R), tetramethylammonium fluoride tert-amyl alcohol (Me4NF·t-AmylOH) was identified as an inexpensive, practical, and bench-stable reagent for SNAr fluorination under mild and convenient conditions (80 °C in DMSO, without the requirement for drying of reagents or solvent). A substrate scope of more than 50 (hetero) aryl halides and nitroarene electrophiles is demonstrated.
Bland, Douglas C.,Lee, So Jeong,Morales-Colón, Mariá T.,Sanford, Melanie S.,Scott, Peter J. H.,See, Yi Yang
supporting information
p. 4493 - 4498
(2021/06/28)

C-H FLUORINATION OF HETEROCYCLES WITH SILVER (II) FLUORIDE
The present invention provides compositions and methods for the selective C-H fluorination of nitrogen-containing heteroarenes with AgF2, which has previously been considered too reactive for practical, selective C-H fluorination. Fluorinated heteroarenes are prevalent in numerous pharmaceuticals, agrochemicals and materials. However, the reactions used to introduce fluorine into these molecules require pre-functionalized substrates or the use of F2 gas. The present invention provides a mild and general method for the C-H fluorination of nitrogen-containing heteroarene compounds to 2-fluoro-heteroarenes with commercially available AgF2. In various embodiments, these reactions occur at ambient temperature within one hour and occur with exclusive selectivity for fluorination at the 2-position. Exemplary reaction conditions are effective for fluorinating diazine heteroarenes to form a single fluorinated isomer.
-
Paragraph 00123

(2015/02/19)

Selective C-H fluorination of pyridines and diazines inspired by a classic amination reaction
Fluorinated heterocycles are prevalent in pharmaceuticals, agrochemicals, and materials. However, reactions that incorporate fluorine into heteroarenes are limited in scope and can be hazardous. We present a broadly applicable and safe method for the site-selective fluorination of a single carbon-hydrogen bond in pyridines and diazines using commercially available silver(II) fluoride. The reactions occur at ambient temperature within 1 hour with exclusive selectivity for fluorination adjacent to nitrogen. The mild conditions allow access to fluorinated derivatives of medicinally important compounds, as well as a range of 2-substituted pyridines prepared by subsequent nucleophilic displacement of fluoride. Mechanistic studies demonstrate that the pathway of a classic pyridine amination can be adapted for selective fluorination of a broad range of nitrogen heterocycles.
Fier, Patrick S.,Hartwig, John F.
p. 956 - 960
(2013/12/04)

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 (2-4), all six trifluoropyridines (5-10), and the five non-commercial difluoropyridines (11-14 and 16) was developed. The methods employed for the selective removal of fluorine from polyfluoropyridines were the reduction 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.
Bobbio, Carla,Rausis, Thierry,Schlosser, Manfred
p. 1903 - 1910
(2007/10/03)

NITROGENOUS FUSED?RING COMPOUND HAVING PYRAZOLYL GROUP AS SUBSTITUENT AND MEDICINAL COMPOSITION THEREOF
The present invention provides a compound having an excellent inhibitory action on activation of STAT6 and a pharmaceutical composition thereof. Inparticular, it provides a compound represented by the following formula (I), a salt thereof or a hydrate of them. In the formula, X represents a nitrogen-containing condensed aromatic heterocyclic group such as imidazo[1,2-a]pyridine, benzimidazole, quinazoline, quinoline, or 2,1-benzisoxazole and has (R4)n as substituent groups; Y represents a C3-8 cycloalkyl group, C4-8 cycloalkenyl group, 5- to 14-membered non-aromatic heterocyclic group, C6-14 aromatic hydrocarbon cyclic group or 5- to 14-membered aromatic heterocyclic group; n in (R4)n is 0, 1, 2 or 3, and Z groups independently represent (1) hydrogen atom, (2) amino group, (3) halogen atom, (4) hydroxyl group, (5) nitro group, (6) cyano group, (7) azido group, (8) formyl group, (9) hydroxyamino group, (10) sulfamoyl group, (11) guanodino group, (12) oxo group, (13) C2-6 alkenyl group, (14) C1-6 alkoxy group, (15) C1-6 alkylhydroxyamino group, (16) halogenated C1-6 alkyl group, (17) halogenated C2-6 alkenyl group, (18) (i) C3-7cycloalkyl group, (ii) C3-7cycloalkenyl group, (iii) 5- to 14-membered non-aromatic heterocyclic group, each of which may have one or more substituent groups Q, or (19) formula -M1-M2-M3, R1 represents (1) hydrogen atom, (2) halogen atom, (3) hydroxyl group, (4) nitro group, (5) cyano group, (6) halogenated C1-6 alkyl group, (7) C2-6 alkyl group substituted with a hydroxyl or cyano group, (8) C2-6 alkenyl group, or (9) formula -L1-L2-L3, and R2 represents a hydrogen atom or a protecting group; and R3 represents a hydrogen atom, halogen atom, cyano group, amino group, C1-4 alkyl group or halogenated C1-4 alkyl group.
-
Page 133

(2008/06/13)

Selective safened herbicidal composition
Mixtures of a herbicidally effective amount of a pyridylsulfonylurea of formula I, STR1 wherein R, R1, R2 and A are as defined in claim 1, and of a herbicide-antagonistically effective amount of a sulfamoylphenylurea of formula II, STR2 wherein R7 to R11 and A2 are as defined in claim 1, are very suitable for controlling weeds in crops of useful plants, especially maize and sugar cane.
-
(2008/06/13)

Process for the preparation of aromatic fluoro compounds
The invention relates to a process for the preparation of aromatic fluoro compounds of the formula I in which Ar is phenyl, naphthyl or pyridyl, R1, R2 and R3 independently of one another are hydrogen, halide, (C1 -C4)-alkyl, phenyl, NR2, OR, CN, COH or COR, where R is hydrogen or (C1 -C6)-alkyl, and n=1, 2, 3, 4 or 5, which comprises reacting aromatic fluoro compounds of the formula II in which Ar, R1, R2, R3 and n have the abovementioned meaning, each X is a chlorine or bromine atom and m=1, 2, 3, 4 or 5, with hydrogen in the presence of a palladium catalyst, a water-insoluble amine which also does not form water-soluble hydrohalides, and if desired an inert solvent.
-
(2008/06/13)

FLUORINATIONS WITH POTASSIUM TETRAFLUOROCOBALTATE(III) PART VII. FURTHER INVESTIGATIONS ON THE FLUORINATION OF PYRIDINE
The product from the fluorination of pyridine by KCoF4 at ca. 220 deg C contains eleven fluoropyridines, two fluoro-2-azahex-enes, three azahexadienes, and two fluoro-N-methylpyrrolidines, besides an azacyclohexa-1,3-diene.Four products were isolated from fluorination of pyridine by CoF3 at ca. 150 deg C, a 2-azahexene, two N-methylpyrrolidines, and 4H-nonafluoropiperidine.
Coe, Paul L.,Holton, Andrew G.,Tatlow, John Colin
p. 171 - 190
(2007/10/02)

FLUORINATIONS WITH COMPLEX METAL FLUORIDES. PART 6. FLUORINATION OF PYRIDINE AND RELATED COMPOUNDS WITH CAESIUM TETRAFLUOROCOBALTATE(III)
Pyridine has been fluorinated over caesium tetrafluorocobaltate(III) (CsCo(III)F4) at 300-400 deg C to give a mixture of undecafluoro-N-methyl-pyrrolidine, bis(trifluoromethyl)amine, pentafluoropyridine and several polyfluoropyridines; the product composition depend to some extent on the geometry of the reactor.The fluorinations of pentafluoropyridine, piperidine and undecafluoropiperidine were also investigated.
Plevey, Raymond G.,Rendell, Richard W.,Tatlow, John Colin
p. 159 - 170
(2007/10/02)