5231-96-9Relevant articles and documents
Copper Catalyzed Oxidative C-C Bond Cleavage of 1,2-Diketones: A Divergent Approach to 1,8-Naphthalimides, Biphenyl-2,2′-dicarboxamides, and N-Heterocyclic Amides
Sakhare, Priyanka R.,Subramanian, Parthasarathi,Kaliappan, Krishna P.
, p. 2112 - 2125 (2019/02/14)
We report here a simple and efficient copper catalyzed oxidative C-C bond cleavage of stable aromatic cyclic-fused and acyclic 1,2-diketones to deliver amides and imides in high yields. This newly developed protocol provides an excellent tool to transform structurally different 1,2-diketones into different products under the same reaction conditions. The key synthetic features of this methodology are the formation of 1,8-naphthalimides and biphenyl-2,2′-dicarboxamide motifs in high yields. The fluorescent studies of 1,8-naphthalimide derivatives were also carried out in order to show the potential application of these scaffolds.
2-Aminopyridines as an α-Bromination Shuttle in a Transition Metal-Free One-Pot Synthesis of Imidazo[1,2-a]pyridines
Roslan, Irwan Iskandar,Ng, Kian-Hong,Chuah, Gaik-Khuan,Jaenicke, Stephan
supporting information, p. 364 - 369 (2016/04/26)
A wide range of imidazo[1,2-a]pyridines are accessible from cheap and readily available 2-aminopyridines and 1,3-dicarbonyl compounds using a unique CBrCl3/2-aminopyridine system for bromination at the α-carbon. 2-Aminopyridine is not only the substrate but also acts as a bromination shuttle, transferring the bromine atom from CBrCl3 to the α-carbon of the 1,3-dicarbonyl. The reaction mechanism involves a series of reversible steps, including an addition reaction with cyclic transition state, to form a bromo-hemiaminal intermediate. Isolated yields of up to 97% were obtained under mild conditions and at short reaction times in this transition metal-free, one-pot synthesis.
A novel three-component reaction of N-fluoropyridinium salts: A facile approach to imidazo[1,2-a]pyridines
Kiselyov, Alexander S.
, p. 4487 - 4490 (2007/10/03)
The reaction of N-fluoropyridinium triflate with isonitriles in acetonitrile and propionitrile in the presence of NaBH(OAc)3 led to the formation of the corresponding imidazo[1,2-a]pyridines in 44-73% yields. The proposed reaction mechanism involves the intermediate formation of a highly reactive carbene species and apparent reduction of the pyridinium intermediate with NaBH(OAc)3 to yield the targeted heterocycles.
Novel base-initiated reactions of N-substituted pyridinium salts
Umemoto, Teruo,Tomizawa, Ginjiro,Hachisuka, Hitoharu,Kitano, Masakatsu
, p. 161 - 168 (2007/10/03)
Reaction of N-fluoropyridinium triflate with a base in dichloromethane gave 2-chloropyridine as the major product along with 2-pyridyl triflate and 2-fluoropyridine, regardless of the nature of the base. This base-initiated reaction was also shown to take place similarly in other halogenated alkanes, ethers, a nitrile, aromatics, a ketone, vinyl ethers, alcohols and trimethylsilyl acetate as solvents to give pyridine derivatives substituted with a solvent molecule (s) at the 2-position. N-(Trifluoromethanesulfonyloxy)-and (benzenesulfonyloxy) pyridinium salts were found to undergo the same base-initiated reaction. These reactions may be explained by a postulated singlet carbene (canonical formula 11b) produced through proton abstraction of N-substituted pyridinium salts. A similar carbene reaction may thus likely occur in the thermal decomposition of thiatriazole 10. Ab initio MO calculations revealed the structure and properties of the labile deprotonated N-fluoropyridinium cation and supported the carbene intermediate reaction mechanism rather than a pyridynium or pyridyl cation mechanism. Quarroz's reports on the reactions of picolinic acid N-oxide and the reported reactions of pyridines with F2, CH3COOF or CsSO4F in solvents may be explained by this carbene mechanism.
Carboxamidation of pyridines by the system of elemental fluorine- carbonitrile-water: A useful alternative to the chichibabin amination
Kiselyov,Strekowski
, p. 2387 - 2392 (2007/10/02)
The title reaction with pyridine, 4-methylpyridine, 3-methylpyridine, 3- bromopyridine, nicotinonitrile, and quinoline yields 2-carboxamido derivatives regioselectively. Isoquinoline is amidated at position 1.
BASE-INITIATED REACTIONS OF N-FLUOROPYRIDINIUM SALTS; A NOVEL CYCLIC CARBENE PROPOSED AS A REACTIVE SPECIES
Unemoto, Teruo,Tomizawa, Ginjiro
, p. 2705 - 2708 (2007/10/02)
A new type of base-initiated reactions of pyridinium salts was found and a novel cyclic carbene was proposed as the reactive species.
