148493-37-2Relevant articles and documents
Deprotonation of chloropyridines using lithium magnesates
Awad, Ha?an,Mongin, Florence,Trécourt, Fran?ois,Quéguiner, Guy,Marsais, Francis
, p. 7873 - 7877 (2004)
Chloropyridines are deprotonated using lithium magnesates. 4-Chloropyridine was deprotonated on treatment with 1/3 equiv of the highly coordinated magnesate Bu3(TMP)MgLi2 in THF at -10°C, as evidenced by trapping with I2. The use of Bu(TMP)2MgLi in Et 2O allowed the reaction of 2-chloropyridine, giving the 3-functionalized derivative as the main product. Mixtures of 3- and 4-functionalized derivatives were obtained when 2,6-dichloropyridine was involved in the reaction. Performing the reaction on 3-chloropyridine with lithium magnesates in THF, either the 4,4′-dimer or the 4-iodo derivative was formed after quenching by I2, the former using 1/3 equiv of Bu2(TMP)MgLi and the latter using 1 equiv of (TMP)3MgLi. Similar results were observed with 3,5-dichloropyridine, 2,5-dichloropyridine and 3-chloro-2-fluoropyridine. 1,2-Migration of the lithium arylmagnesate formed by deprotonation was proposed to justify the dimers formation.
Intermolecular contacts in the crystal structures of specifically varied halogen and protonic group substituted azines
Hübscher, J?rg,Seichter, Wilhelm,Weber, Edwin
, p. 3026 - 3036 (2017/07/10)
A series of azines featuring differently halogen and protic group substituted pyridine, pyrimidine and pyridazine compounds have been synthesized and studied in terms of their crystal structures in order to develop a better understanding of the links between structural conditions and molecular packing behavior. Complemented by the structure results of related compounds known from the literature, intermolecular contact relationships connected to the present substance types were found, having potential use in future crystal engineering of similar compounds. This primarily involves the formation of N?I contacts aside from specific halogen?halogen and hydrogen bond type interactions.
Deprotonative metalation of chloro- and bromopyridines using amido-based bimetallic species and regioselectivity-computed CH acidity relationships
Snegaroff, Katia,Nguyen, Tan Tai,Marquise, Nada,Halauko, Yury S.,Harford, Philip J.,Roisnel, Thierry,Matulis, Vadim E.,Ivashkevich, Oleg A.,Chevallier, Floris,Wheatley, Andrew E. H.,Gros, Philippe C.,Mongin, Florence
experimental part, p. 13284 - 13297 (2012/02/03)
A series of chloro- and bromopyridines have been deprotometalated by using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. Whereas lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase and as a solution in THF by using the DFT B3LYP method.
Concise total synthesis of the thiazolyl peptide antibiotic GE2270 A
Delgado, Oscar,Martin Mueller,Bach, Thorsten
supporting information; experimental part, p. 2322 - 2339 (2009/04/10)
The potent antibiotic thiazolylpeptide GE2270 A was synthesized starting from N-tert-butyloxycarbonyl protected valine in a longest linear sequence of 20 steps and with an overall yield of 4.8 %. Key strategy was the assembly of the 2,3,6-trisubstituted p
Regiochemically flexible substitutions of di-, tri-, and tetrahalopyridines: The trialkylsilyl trick
Schlosser, Manfred,Bobbio, Carla,Rausis, Thierry
, p. 2494 - 2502 (2007/10/03)
(Chemical Equation Presented) 2,4-Difluoropyridine, 2,4-dichloropyridine, 2,4,6-trifluoropyridine, 2,4,6-trichloropyridine and 2,3,4,6-tetrafluoropyridine react with standard nucleophiles exclusively at the 4-position under halogen displacement. However, the regioselectivity can be completely reversed if a trialkylsilyl group is introduced in the 5-position of the 2,4-dihalopyridines or in the 3-position of the 2,4,6-trihalopyridines or 2,3,4,6-tetrahalopyridine. Then only the halogen most remote from the bulky silyl unit (at the 2-position in the case of the 2,4-halopyridines, at the 6-position with the other substrates) gets involved in the exchange process. After removal of the silyl protective group the nucleophile is invariably found to occupy the nitrogen-neighboring position.
Strategies for the selective functionalization of dichloropyridines at various sites
Marzi, Elena,Bigi, Anna,Schlosser, Manfred
, p. 1371 - 1376 (2007/10/03)
Whereas 2,3-dichloropyridine and 2,5-dichloro-4-(lithiooxy)-pyridine undergo deprotonation exclusively at the 4- and 2-positions, respectively, optional site selectivity can be implemented with 2,5- and 3,4-dichloropyridine (which are attacked, depending on the choice of the reagents, at either the 4- or 6- and either the 2- and 5-positions, respectively). Upon treatment with lithium diisopropylamide, 2,4-dichloro-3-iodopyridine, 3,5-dichloro-4-bromopyridine and 2,6-dichloro-3-iodopyridine afford 5-, 2- and 4-lithiated intermediates, but the latter isomerize instantaneously to species in which lithium and iodine have swapped places, the driving force being the low basicity of C-Li bonds when flanked by two neighboring halogens.
A short entry into the pyrido[2,3-b] indole ring system. Synthesis of the tetracyclic segment of the marine antitumor agents: Grossularines-1 and -2
Achab, Said,Guyot, Michele,Potier, Pierre
, p. 2127 - 2130 (2007/10/02)
A new method for the synthesis of substituted pyrido[2,3-b] indoles (α-carbolines) (14, 27-31), featuring Pd-catalyzed cross coupling between pyridine and aniline derivatives and subsequent intramolecular cylization, has been developed. This method provid
