109-04-6Relevant articles and documents
Deoxygenation of N-oxides with triphenylphosphine, catalyzed by dichlorodioxomolybdenum(VI)
Sanz, Roberto,Escribano, Jaime,Fernández, Yolanda,Aguado, Rafael,Pedrosa, María R.,Arnáiz, Francisco J.
, p. 1389 - 1392 (2005)
Chemoselective deoxygenation of N-oxides was carried out under mild conditions with common phosphines in the presence of dichlorodioxomolybdenum(VI) . Georg Thieme Verlag Stuttgart.
Cl3CCN/PPh3 and CBr4/PPh3: Two efficient reagent systems for the preparation of N-heteroaromatic halides
Kijrungphaiboon, Woranun,Chantarasriwong, Oraphin,Chavasiri, Wainthorn
, p. 674 - 677 (2012)
Cl3CCN/PPh3 and CBr4/PPh3 are two highly reactive reagent systems for the conversion of N-heteroaromatic hydroxy compounds into N-heteroaromatic chlorides or bromides in moderate to excellent yields under mild and acid-free conditions.
POLYORGANOMETALLIC HETEROCYCLES. 2,6-DILITHIOPYRIDINE
Newkome, George R.,Roper, Jerry M.
, p. 147 - 153 (1980)
Metal-halogen exchange between 2,6-diiodo- and 2,6-dibromopyridine and two equivalents of n-butyllithium gives 2,6-dilithiopyridine.On quenching with either carbon dioxide followed by esterification, methanol or dimethyl disulfide the dilithio compound gives a methyl 2,6-pyridinedicarboxylate, pyridine, or 2,6-dithiomethylpyridine, respectively.A convenient procedure for halogen-halogen exchange is also described.
TMSCH2Li and TMSCH2Li-LiDMAE: Efficient reagents for noncryogenic halogen-lithium exchange in bromopyridines
Doudouh, Abdelatif,Woltermann, Christopher,Gros, Philippe C.
, p. 4978 - 4980 (2007)
(Chemical Equation Presented) TMSCH2Li and TMSCH 2Li-LiDMAE have been used efficiently for bromine-lithium exchange in 2-bromo-, 3-bromo-, and 2,5-dibromopyridines under noncryogenic conditions, while low temperatures (-78 to -100°C) are always needed with n-BuLi. The aminoalkoxide LiDMAE induced a remarkable C-2 selectivity with 2,5-dibromopyridines in toluene at 0°C, which was unprecedented at such a temperature. The lithiopyridines were successfully reacted witb electrophiles also under noncryogenic conditions giving the expected adducts in good yields.
A facile halogenation of some hydroxyheterocycles using triphenylphosphine and N-halosuccinimide
Sugimoto, Osamu,Mori, Miho,Tanji, Ken-ichi
, p. 7477 - 7478 (1999)
Some hydroxyheterocycles were halogenated to give the corresponding haloheterocycles using triphenylphosphine and N-halosuccinimide. In comparison with the usual method using phosphorus oxyhalide, the haloheterocycles were easily isolated.
Steric Effects on the Structures, Reactivity, and Coordination Chemistry of Tris(2-pyridyl)aluminates
García-Rodríguez, Raúl,Wright, Dominic S.
, p. 14949 - 14957 (2015)
Introducing substituents in the 6-position of the 2-pyridyl rings of tris(pyridyl)aluminate anions, of the type [EtAl(2-py′)3]- (py′=a substituted 2-pyridyl group), has a large impact on their metal coordination characteristics. This is seen most remarkably in the desolvation of the THF solvate [EtAl(6-Me-2-py)3Li·THF] to give the monomer [EtAl(6-Me-2-py)3Li] (1), containing a pyramidal, three-coordinate Li+ cation. Similar monomeric complexes are observed for [EtAl(6-CF3-2-py)3Li] (2) and [EtAl(6-Br-2-py)3Li] (3), which contain CF3 and Br substituents (R). This steric influence can be exploited in the synthesis of a new class of terminal Al-OH complexes, as is seen in the controlled hydrolysis of 2 and 3 to give [EtAl(OH)(6-R-2-py)2]- anions, as in the dimer [EtAl(OH)(6-Br-2-py)2Li]2 (5). Attempts to deprotonate the Al-OH group of 5 using Et2Zn led only to the formation of the zincate complex [LiZn(6-Br-py)3]2 (6), while reactions of the 6-Br substituted 3 and the unsubstituted complex [EtAl(2-py)3Li] with MeOH give [EtAl(OMe)(6-Br-2-py)2Li]2 (7) and [EtAl(OMe)(2-py)2Li]2 (8), respectively, having similar dimeric arrangements to 5. The combined studies presented provide key synthetic methods for the functionalization and elaboration of tris(pyridyl)aluminate ligands.
Titanium(0) Reagents; 2. A Selective and Efficient Deoxygenation of Halogen Containing Heteroaromatic N-Oxides
Malinowski, Marek,Kaczmarek, Lukasz
, p. 1013 - 1015 (1987)
Following successful reductions of unfunctionalized heteroaromatic N-oxides by titanium(0), we applied this method to halogenated aromatic N-oxides to give the deoxygenated halogeno derivatives in 90-95percent yield.
A facile bromination of hydroxyheteroarenes
Kato, Yoshiaki,Okada, Shigemitsu,Tomimoto, Koji,Mase, Toshiaki
, p. 4849 - 4851 (2001)
Bromination of hydroxyheteroarenes using P2O5/Bu4NBr proceeds under mild conditions to afford high yields of various bromoheteroarenes. This procedure is successfully applied to large-scale syntheses of bromoheteroarenes.
Clean protocol for deoxygenation of epoxides to alkenes: Via catalytic hydrogenation using gold
Fiorio, Jhonatan L.,Rossi, Liane M.
, p. 312 - 318 (2021/01/29)
The epoxidation of olefin as a strategy to protect carbon-carbon double bonds is a well-known procedure in organic synthesis, however the reverse reaction, deprotection/deoxygenation of epoxides is much less developed, despite its potential utility for the synthesis of substituted olefins. Here, we disclose a clean protocol for the selective deprotection of epoxides, by combining commercially available organophosphorus ligands and gold nanoparticles (Au NP). Besides being successfully applied in the deoxygenation of epoxides, the discovered catalytic system also enables the selective reduction N-oxides and sulfoxides using molecular hydrogen as reductant. The Au NP catalyst combined with triethylphosphite P(OEt)3 is remarkably more reactive than solely Au NPs. The method is not only a complementary Au-catalyzed reductive reaction under mild conditions, but also an effective procedure for selective reductions of a wide range of valuable molecules that would be either synthetically inconvenient or even difficult to access by alternative synthetic protocols or by using classical transition metal catalysts. This journal is
Transition-metal-free decarboxylative halogenation of 2-picolinic acids with dihalomethane under oxygen conditions
Zhang, Xitao,Feng, Xiujuan,Zhang, Haixia,Yamamoto, Yoshinori,Bao, Ming
supporting information, p. 5565 - 5570 (2019/10/22)
A convenient and efficient method for the synthesis of 2-halogen-substituted pyridines is described. The decarboxylative halogenation of 2-picolinic acids with dihalomethane proceeded smoothly via N-chlorocarbene intermediates to afford 2-halogen-substituted pyridines in satisfactory to excellent yields under transition-metal-free conditions. This new type of decarboxylative halogenation is operationally simple and exhibits high functional-group tolerance.
