1122-58-3Relevant academic research and scientific papers
Models for B12-conjugated radiopharmaceuticals. Cobaloxime binding to new fac-[Re(CO)3(Me2bipyridine)(amidine)]BF4 complexes having an exposed pyridyl nitrogen
Lewis, Nerissa A.,Marzilli, Patricia A.,Fronczek, Frank R.,Marzilli, Luigi G.
, p. 11096 - 11107 (2014)
New mononuclear amidine complexes, fac-[Re(CO)3(Me2bipy)(HNC(CH3)-(pyppz))]BF4 [(4,4′-Me2bipy (1), 5,5′-Me2bipy (2), and 6,6′-Me2bipy (3)] (bipy = 2,2′-bipyridine), were synthesized by treating the parent fac-[ReI(CO)3(Me2bipy)(CH3CN)]BF4complex with the C2-symmetrical amine 1-(4-pyridyl)piperazine (pyppzH). The axial amidine ligand has an exposed, highly basic pyridyl nitrogen. The reaction of complexes 1-3 with a B12model, (py)Co(DH)2Cl (DH = monoanion of dimethylglyoxime), in CH2Cl2 yielded the respective dinuclear complexes, namely, fac-[Re(CO)3(Me2bipy)(μ-(HNC(CH3)(pyppz)))Co-(DH)2Cl]BF4 [(4,4′-Me2bipy (4), 5,5′-Me2bipy (5), and 6,6′-Me2bipy (6)]. 1H NMR spectroscopic analysis of all compounds and single-crystal X-ray crystallographic data for 2, 3, 5, and 6 established that the amidine had only the E configuration in both the solid and solution states and that the pyridyl group is bound to Co in 4-6. Comparison of the NMR spectra of 1-3 with spectra of 4-6 reveals an unusually large wrong-way upfield shift for the pyridyl H2/6 signal for 4-6. The wrong-way H2/6 shift of (4-Xpy)Co(DH)2Cl (4-Xpy = 4-substituted pyridine) complexes increased with increasing basicity of the 4-Xpy derivative, a finding attributed to the influence of the magnetic anisotropy of the cobalt center on the shifts of the 1H NMR signals of the pyridyl protons closest to Co. Our method of employing a coordinate bond for conjugating the fac-[ReI(CO)3] core to a vitamin B12 model could be extended to natural B12derivatives. Because B12 compounds are known to accumulate in cancer cells, such an approach is a very attractive method for the development of 99mTc and 186/188Re radiopharmaceuticals for targeted tumor imaging and therapy. (Chemical Equation Presented).
N-Heteroarylphosphonates, Part II. Synthesis and reactions of 2- and 4- phosphonatoquinolines and related compounds
Haase, Mirko,Guì?nther, Wolfgang,Goì?rls, Helmar,Anders, Ernst
, p. 2071 - 2081 (1999)
We extend our synthetic method for the efficient preparation of dialkoxyphosphoryl- and phosphonio-disubstituted pyridines to include the preparation of other phosphonato substituted N-heterocycles. The key to the success of this method lies in the employment of cationic N- (trifluoromethylsulfonyl)heteroarylium triflates that are activated towards nucleophilic attack. The P(O)(OR)2 group can be transformed into the P(S)(OR)2 functionality. We report first attempts to substitute the P(O)(OR)2 moiety with C-nucleophiles. In addition to our synthetic results, the X-ray structures of two (dimethoxyphosphoryl)trifluoromethanesulfonyldihydro-N-heteroarenes are discussed. We also give complete carbon (13C) and phosphorus (31P)-NMR spectra of a series of 2- and 4-phosphonic ester substituted heteroaryl compounds and their dihydro analogs.
Continuous flow nucleophilic aromatic substitution with dimethylamine generated in situ by decomposition of DMF
Petersen, Trine P.,Larsen, Anders Foller,Ritzen, Andreas,Ulven, Trond
, p. 4190 - 4195 (2013)
A safe, practical, and scalable continuous flow protocol for the in situ generation of dimethylamine from DMF followed by nucleophilic aromatic substitution of a broad range of aromatic and heteroaromatic halides is reported.
Synthesis of aminopyridines via an unprecedented nucleophilic aromatic substitution of cyanopyridines
Penney, Jonathan M.
, p. 2667 - 2669 (2004)
The direct reaction of 2- and 4-cyanopyridines with lithium amides affords good yields of the corresponding aminopyridines via displacement of cyanide. Addition of CsF accelerates the reaction and can lead to significantly higher yields.
A Novel One-Pot Synthesis of N,N-Dimethylaminopyridines by Diazotization of Aminopyridines in Dimethylformamide in the Presence of Trifluoromethanesulfonic Acid
Filimonov, V. D.,Krasnokutskaya, E. A.,Potapova, M. I.,Sanzhiev, A. N.
, p. 1023 - 1028 (2020)
Abstract: Diazotization of aminopyridines in the presence of trifluoromethanesulfonic acid gives the corresponding pyridinyl trifluoromethanesulfonates instead of expected diazonium salts. Pyridinyl trifluoromethanesulfonates can be converted to N,N-dimethylaminopyridines on heating in dimethylformamide via replacement of the trifluoromethanesulfonyloxy group. The reaction is accelerated under microwave irradiation. A novel one-pot procedure has been proposed for the synthesis of 2- and 4-(dimethylamino)pyridines from commercially available aminopyridines. The procedure provides high yields of the target products, and it can be regarded as an alternative to the known methods of synthesis of N,N-dimethylpyridin-4-amine (DMAP) widely used as base catalyst in organic synthesis.
A simple synthesis of aminopyridines: Use of amides as amine source
Kodimuthali, Arumugam,Mungara, Anitha,Prasunamba, Padala Lakshmi,Pal, Manojit
, p. 1439 - 1445 (2010)
A transition metal/microwave irradiation (or base) free synthesis of aminopyridines has been accomplished via C-N bond forming reaction between chloropyridine and a variety of simple amides under refuxing conditions.
Mechanistic insight gained into the ligand substitution reactions of bis(o-benzosemiquinonediiminato)(triphenylphosphane)cobalt(III) - Kinetic, solvent, and volume profile studies
Alzoubi, Basam M.,Hamza, Mohamed S. A.,Duecker-Benfer, Carlos,Van Eldik, Rudi
, p. 2972 - 2978 (2003)
The ligand substitution reactions of bis(o-benzosemiquinone-diiminato)(triphenylphosphane)cobalt(III), [Co III(s-BQDI)2-(Ph3P)]+, were studied with imidazole (Imid) and 4-dimethyl-aminopyridine (4-Me2Npy) as entering nucleophiles in MeOH and CH3CN as solvents (S). The complex [CoIII(s-BQDI)2(Ph3P)S]+ undergoes dissociation of the solvent to form a five-coordinate intermediate, [Co III(s-BQDI)2(Ph3P)]+, which binds the entering nucleophile in a rate-determining step through a six-coordinate transition state, [CoIII(s-BQDI)2(Ph3P)L] +, followed by the release of triphenylphosphane to form [Co III(s-BQDI)2L]+. From the temperature and pressure dependence of the substitution of triphenylphosphane by imidazole, the activation parameters for the forward and reverse reactions of [Co III(s-BQDI)2(Ph3P)]+ with imidazole in MeOH were found to be ΔH? = 58±2 and 43.4±0.5 kJ·mol-1, ΔS? = -116±6 and -73±2 J·K-1·mo-1, and ΔV? = -10.6±0.1 and -8.7±0.3 cm3·mo-1, respectively. In CH3CN, however, ΔH?, ΔS?, and ΔV? for the forward reaction were found to be 50±3 kJ·mol-1, -111±9 J·mol-1· K-1, and -12.9±0.3 cm3·mol-1, respectively. The activation parameters for the reaction between [Co III(s-BQDI)2(Ph3P)]+ and 4-dimethylaminopyridine in MeOH for the forward and reverse reactions were found to be ΔH? = 76±2 and 47.9±0.4 kJ·mol-1, ΔS? = -51±7 and -64±2 J·K-1·mo-1, and ΔV? = -10.5±0,3 and -11.1±0.2 cm3·mo-1, respectively. From these reported rate and activation parameters, the substitution of triphenylphosphane by imidazole and 4-dimethylaminopyridine follows an associative mechanism. The ligand substitution reactions of [Co III(s-BQDI)2(Ph3P)]+ in CH 3CN were found to be faster than those in MeOH, which is attributed to the potential for hydrogen bond formation with the entering nucleophile in the case of MeOH as solvent. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Formation of Singlet Oxygen in the Deoxygenation of Heteroarene N-Oxides by Dimethyldioxirane
Adam, Waldemar,Briviba, Karlis,Duschek, Frank,Golsch, Dieter,Kiefer, Wolfgang,Sies, Helmut
, p. 1831 - 1832 (1995)
4-Dimethylaminopyridine-N-oxide 2 and 2',3',5'-triacetyladenosine-N1-oxide 4 are partially deoxygenated by dimethyldioxirane (DMD) to the corresponding amines 1 and 3; the formation of singlet oxygen suggests a polar rather than a radical mechanism, in which we propose SN2 attack of the N-oxide on the dioxirane peroxide bond.
Method for catalyzing N-alkylation of aminopyridine
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Paragraph 0087-0091, (2021/08/07)
The invention discloses a method for catalyzing N-alkylation of aminopyridine. The method comprises the step of reacting an aminopyridine compound with an alkylation raw material in the presence of a heterogeneous catalyst to obtain an N-alkylated aminopyridine compound. The alkylation reaction has high activity and selectivity, is simple to operate and low in catalyst price, does not need other reaction steps, is beneficial to large-scale industrial production, and compared with previous reports, does not need to use a large amount of noble metals, can be continuously carried out, and does not use other expensive organic raw materials or reducing agents in the process. Generation of a large amount of organic waste liquid and solid waste is avoided, and collection operation of process products is simple.
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information, (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
