- Models for B12-conjugated radiopharmaceuticals. Cobaloxime binding to new fac-[Re(CO)3(Me2bipyridine)(amidine)]BF4 complexes having an exposed pyridyl nitrogen
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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).
- Lewis, Nerissa A.,Marzilli, Patricia A.,Fronczek, Frank R.,Marzilli, Luigi G.
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- N-Heteroarylphosphonates, Part II. Synthesis and reactions of 2- and 4- phosphonatoquinolines and related compounds
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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.
- Haase, Mirko,Guì?nther, Wolfgang,Goì?rls, Helmar,Anders, Ernst
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- Continuous flow nucleophilic aromatic substitution with dimethylamine generated in situ by decomposition of DMF
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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.
- Petersen, Trine P.,Larsen, Anders Foller,Ritzen, Andreas,Ulven, Trond
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- Synthesis of aminopyridines via an unprecedented nucleophilic aromatic substitution of cyanopyridines
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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.
- Penney, Jonathan M.
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- A Novel One-Pot Synthesis of N,N-Dimethylaminopyridines by Diazotization of Aminopyridines in Dimethylformamide in the Presence of Trifluoromethanesulfonic Acid
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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.
- Filimonov, V. D.,Krasnokutskaya, E. A.,Potapova, M. I.,Sanzhiev, A. N.
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- A simple synthesis of aminopyridines: Use of amides as amine source
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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.
- Kodimuthali, Arumugam,Mungara, Anitha,Prasunamba, Padala Lakshmi,Pal, Manojit
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- Mechanistic insight gained into the ligand substitution reactions of bis(o-benzosemiquinonediiminato)(triphenylphosphane)cobalt(III) - Kinetic, solvent, and volume profile studies
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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.
- Alzoubi, Basam M.,Hamza, Mohamed S. A.,Duecker-Benfer, Carlos,Van Eldik, Rudi
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- Formation of Singlet Oxygen in the Deoxygenation of Heteroarene N-Oxides by Dimethyldioxirane
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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.
- Adam, Waldemar,Briviba, Karlis,Duschek, Frank,Golsch, Dieter,Kiefer, Wolfgang,Sies, Helmut
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- Method for catalyzing N-alkylation of aminopyridine
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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.
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Paragraph 0087-0091
(2021/08/07)
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- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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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.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
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supporting information
(2022/01/04)
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- CO2-tuned highly selective reduction of formamides to the corresponding methylamines
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We herein describe an efficient, CO2-tuned and highly selective C-O bond cleavage of N-methylated formanilides. With easy-to-handle and commercially available NaBH4 as the reductant, a variety of formanilides could be turned into the desired tertiary amines in moderate to excellent yields. The role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments.
- Chao, Jianbin,Guo, Zhiqiang,Pang, Tengfei,Wei, Xuehong,Xi, Chanjuan,Yan, Leilei
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supporting information
p. 7534 - 7538
(2021/10/12)
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- Simple RuCl3-catalyzed N-Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol
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Methanol is a potential hydrogen source and C1 synthon, which finds interesting applications in both chemical synthesis and energy technologies. The effective utilization of this simple alcohol in organic synthesis is of central importance and attracts scientific interest. Herein, we report a clean and cost-competitive method with the use of methanol as both C1 synthon and H2 source for selective N-methylation of amines by employing relatively cheap RuCl3.xH2O as a ligand-free catalyst. This readily available catalyst tolerates various amines comprising electron-deficient and electron-donating groups and allows them to transform into corresponding N-methylated products in moderate to excellent yields. In addition, few marketed pharmaceutical agents (e. g., venlafaxine and imipramine) were also successfully synthesized via late-stage functionalization from readily available feedstock chemicals, highlighting synthetic value of this advanced N-methylation reaction. Using this platform, we also attempted tandem reactions with selected nitroarenes to convert them into corresponding N-methylated amines using MeOH under H2-free conditions including transfer hydrogenation of nitroarenes-to-anilines and prepared drug molecules (e. g., benzocaine and butamben) as well as key pharmaceutical intermediates. We further enable one-shot selective and green syntheses of 1-methylbenzimidazole using ortho-phenylenediamine (OPDA) and methanol as coupling partners.
- Sarki, Naina,Goyal, Vishakha,Tyagi, Nitin Kumar,Puttaswamy,Narani, Anand,Ray, Anjan,Natte, Kishore
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p. 1722 - 1729
(2021/04/19)
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- Photocatalytic Water-Splitting Coupled with Alkanol Oxidation for Selective N-alkylation Reactions over Carbon Nitride
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Photocatalytic water splitting technology (PWST) enables the direct use of water as appealing “liquid hydrogen source” for transfer hydrogenation reactions. Currently, the development of PWST-based transfer hydrogenations is still in an embryonic stage. Previous reports generally centered on the rational utilization of the in situ generated H-source (electrons) for hydrogenations, in which photogenerated holes were quenched by sacrificial reagents. Herein, the fully-utilization of the liquid H-source and holes during water splitting is presented for photo-reductive N-alkylation of nitro-aromatic compounds. In this integrate system, H-species in situ generated from water splitting were designed for nitroarenes reduction to produce amines, while alkanols were oxidized by holes for cascade alkylating of anilines as well as the generated secondary amines. More than 50 examples achieved with a broad range scope validate the universal applicability of this mild and sustainable coupling approach. The synthetic utility of this protocol was further demonstrated by the synthesis of existing pharmaceuticals via selective N-alkylation of amines. This strategy based on the sustainable water splitting technology highlights a significant and promising route for selective synthesis of valuable N-alkylated fine chemicals and pharmaceuticals from nitroarenes and amines with water and alkanols.
- Xu, Yangsen,Zhang, Zhaofei,Qiu, Chuntian,Chen, Shaoqin,Ling, Xiang,Su, Chenliang
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p. 582 - 589
(2020/12/09)
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- Metal-Free Deoxygenation of Amine N-Oxides: Synthetic and Mechanistic Studies
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We report herein an unprecedented combination of light and P(III)/P(V) redox cycling for the efficient deoxygenation of aromatic amine N-oxides. Moreover, we discovered that a large variety of aliphatic amine N-oxides can easily be deoxygenated by using only phenylsilane. These practically simple approaches proceed well under metal-free conditions, tolerate many functionalities and are highly chemoselective. Combined experimental and computational studies enabled a deep understanding of factors controlling the reactivity of both aromatic and aliphatic amine N-oxides.
- Lecroq, William,Schleinitz, Jules,Billoue, Mallaury,Perfetto, Anna,Gaumont, Annie-Claude,Lalevée, Jacques,Ciofini, Ilaria,Grimaud, Laurence,Lakhdar, Sami
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p. 1237 - 1242
(2021/06/01)
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- Photocatalytic deoxygenation of N-O bonds with rhenium complexes: From the reduction of nitrous oxide to pyridineN-oxides
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The accumulation of nitrogen oxides in the environment calls for new pathways to interconvert the various oxidation states of nitrogen, and especially their reduction. However, the large spectrum of reduction potentials covered by nitrogen oxides makes it difficult to find general systems capable of efficiently reducing variousN-oxides. Here, photocatalysis unlocks high energy species able both to circumvent the inherent low reactivity of the greenhouse gas and oxidant N2O (E0(N2O/N2) = +1.77 Vvs.SHE), and to reduce pyridineN-oxides (E1/2(pyridineN-oxide/pyridine) = ?1.04 Vvs.SHE). The rhenium complex [Re(4,4′-tBu-bpy)(CO)3Cl] proved to be efficient in performing both reactions under ambient conditions, enabling the deoxygenation of N2O as well as synthetically relevant and functionalized pyridineN-oxides.
- Anthore-Dalion, Lucile,Cantat, Thibault,Kjellberg, Marianne,Nicolas, Emmanuel,Ohleier, Alexia,Thuéry, Pierre
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p. 10266 - 10272
(2021/08/12)
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- Boron-Containing Organic Diradicaloids: Dynamically Modulating Singlet Diradical Character by Lewis Acid-Base Coordination
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Organic diradicaloids have unique open-shell structures and properties and promising applications in organic electronics and spintronics. Incorporation of heteroatoms is an effective strategy to alter the electronic structures of organic diradicaloids. However, B-containing organic diradicaloids are very challenging due to their high reactivities, which are caused by not only diradical nature but also the B atom. In this article, we report a new kind of organic diradicaloids containing boron atoms. Our strategy is to incorporate planarized triarylboranes to antiaromatic polycyclic hydrocarbons (PHs). We synthesized two isomeric B-containing PHs composed of indenofluorene π-skeletons and two dioxa-bridged triphenylborane moieties. As proved by theoretical and experimental results, both of them have excellent ambient stability and open-shell singlet diradical structures, as well as intriguing magnetic and optoelectronic properties, such as thermally accessible triplet species, reversible multiredox ability, and narrow energy gaps. Notably, they possess sufficient Lewis acidity, which has never been observed for organic diradicaloids. In addition, they can coordinate with Lewis bases to form Lewis adducts, achieving unprecedented dynamic modulations of (anti)aromaticity and thus diradical character of organic diradicaloids.
- Dou, Chuandong,Guo, Jiaxiang,Wang, Yue,Yang, Yue
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supporting information
p. 18272 - 18279
(2021/11/12)
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- Lewis Acidic Boranes, Lewis Bases, and Equilibrium Constants: A Reliable Scaffold for a Quantitative Lewis Acidity/Basicity Scale
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A quantitative Lewis acidity/basicity scale toward boron-centered Lewis acids has been developed based on a set of 90 experimental equilibrium constants for the reactions of triarylboranes with various O-, N-, S-, and P-centered Lewis bases in dichloromethane at 20 °C. Analysis with the linear free energy relationship log KB=LAB+LBB allows equilibrium constants, KB, to be calculated for any type of borane/Lewis base combination through the sum of two descriptors, one for Lewis acidity (LAB) and one for Lewis basicity (LBB). The resulting Lewis acidity/basicity scale is independent of fixed reference acids/bases and valid for various types of trivalent boron-centered Lewis acids. It is demonstrated that the newly developed Lewis acidity/basicity scale is easily extendable through linear relationships with quantum-chemically calculated or common physical–organic descriptors and known thermodynamic data (ΔH (Formula presented.)). Furthermore, this experimental platform can be utilized for the rational development of borane-catalyzed reactions.
- Mayer, Robert J.,Hampel, Nathalie,Ofial, Armin R.
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supporting information
p. 4070 - 4080
(2021/01/29)
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- Preparation method of substituted pyridine
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The invention discloses a preparation method of substituted pyridine. The method is implemented in a jet loop reactor based on a Venturi effect. First nitrogen displacement is performed, then, acrylicacid and 4-cyanopyridine raw materials are sequentially added through a material feeding opening; an outer circulating pump is started at 70 to 110 DEG C for high-speed spraying and mixing; a hydrogen chloride raw material is slowly added into the jet loop reactor through a gas raw material feeding hole; spraying and mixing are performed through a spraying type mixer, and full reaction among materials is realized; and the like. According to the method, a novel jet loop reactor based on the Venturi effect is adopted; a traditional stirred tank reactor is replaced; according to the reactor, themass transfer among various reaction species in the reactor is greatly promoted, so that the reaction can be dynamically controlled, and when reaction raw materials are sprayed and pushed forwards under the action of the pump, strong suction force can be generated to automatically suck gas-phase reaction materials in the reaction kettle, so that an excellent mass transfer effect is obtained in violent turbulent flow.
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Paragraph 0028-0058
(2020/07/13)
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- Novel method for preparing efficient acylation catalyst material
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The invention discloses a novel method for preparing an efficient acylation catalyst material. The method comprises the following steps: in an external circulation spray type reactor, removing oxygenand charging nitrogen for replacement protection; then, sequentially adding acrylic acid and 4-cyanopyridine as raw materials; starting an external circulating pump at a temperature of 70-110 DEG C for high-speed circulating spraying; controlling a temperature to be 70 to 110 DEG C, slowly adding a hydrogen chloride raw material into the external circulation spray type reactor through a gas raw material feeding hole, mixing the hydrogen chloride raw material with liquid drops from a nozzle to realize sufficient mass transfer and reaction between materials; etc. According to the invention, theunique external circulation spray type reactor is adopted to replace a traditional stirred tank reactor, the recovery rate of acrylic acid is greater than 95%, the yield of 4-dimethylaminopyridine interms of 4-cyanopyridine is greater than 98%, and the content of 4-dimethylaminopyridine is greater than 99%.
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Paragraph 0028-0061
(2020/08/06)
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- Novel method for preparing 4-dimethylaminopyridine
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The invention discloses a novel method for preparing 4-dimethylaminopyridine, which comprises the following steps: adding an acrylic acid raw material, a concentrated hydrochloric acid raw material and hydroquinone into a reaction kettle, heating, stirring, and reacting for 2-4 hours while stirring at 80-100 DEG C; at the temperature of 80 to 100 DEG C, slowly adding a 4-cyanopyridine raw material; wherein the feeding time is 1-2 hours; after feeding, continuously reacting for 1-2hours, and performing decompressed distillation for recycling the excessive hydrochloric acid; according to a reaction mechanism and a reaction kinetics principle, firstly, an acrylic acid raw material and a cheap hydrochloric acid raw material are subjected to a reaction, so that the phenomenon that the reactionprobability of acrylic acid is reduced after hydrochloric acid and 4-cyanopyridine are directly salified is avoided. According to the preparation method, acrylic acid is fully activated, so that acrylic acid and 4-cyanopyridine can be subjected to a full group protection reaction. Meanwhile, hydroquinone is added as a polymerization inhibitor of acrylic acid, so that other side reactions are avoided at high temperature.
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Paragraph 0028-0060
(2020/07/13)
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- Two-State Reactivity in Iron-Catalyzed Alkene Isomerization Confers σ-Base Resistance
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A low-coordinate, high spin (S = 3/2) organometallic iron(I) complex is a catalyst for the isomerization of alkenes. A combination of experimental and computational mechanistic studies supports a mechanism in which alkene isomerization occurs by the allyl mechanism. Importantly, while substrate binding occurs on the S = 3/2 surface, oxidative addition to an η1-allyl intermediate only occurs on the S = 1/2 surface. Since this spin state change is only possible when the alkene substrate is bound, the catalyst has high immunity to typical σ-base poisons due to the antibonding interactions of the high spin state.
- Lutz, Sean A.,Hickey, Anne K.,Gao, Yafei,Chen, Chun-Hsing,Smith, Jeremy M.
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supporting information
p. 15527 - 15535
(2020/10/20)
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- Method for efficiently preparing 4-dimethylaminopyridine
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The invention relates to the technical field of organic synthesis, in particular to a method for efficiently preparing 4-dimethylaminopyridine. The method for efficiently preparing 4-dimethylaminopyridine comprises the following steps: mixing 4-cyanopyridine, acrylamide and concentrated hydrochloric acid, keeping the temperature at 50-60 DEG C for 4-8 hours, then mixing with dimethylamine, stirring at 30-50 DEG C for 1-3 hours, directly adding an alkaline solution, and refluxing at 85-95 DEG C for 0.5-1.5 hours to obtain 4-dimethylaminopyridine. According to the method for efficiently preparing 4-dimethylaminopyridine, the reaction time is greatly shortened, and the yield is greatly increased.
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Paragraph 0023; 0030-0038
(2020/09/09)
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- Preparation method of pyridine derivative (by machine translation)
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To the method, piperidine-4-one hydrochloride is used as a raw material, and a series of pyridine derivatives are obtained through halogenation reaction and elimination reaction. The reaction is eliminated by reacting piperidine-4-one hydrochloride with a specific amount of the 3,5 - halogenating agent in a halogenation 3, 3, 5 - reaction with a halogen-3, 3, 5, 5 - based reaction, followed by reaction with a pyridine derivative of a hydroxyl group, an amino group 4 - or a dimethylamino group, respectively, by eliminating the reaction with a different kind of basic agent. The method is simple and convenient to operate, mild in condition, short in technological process, low in waste water yield, environment-friendly, low in cost and beneficial to green industrial production of the pyridine derivative. (by machine translation)
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Paragraph 0083-0086; 0123-0125
(2019/12/02)
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- Commercial Pd/C-Catalyzed N-Methylation of Nitroarenes and Amines Using Methanol as Both C1 and H2 Source
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Herein, we report commercially available carbon-supported-palladium (Pd/C)-catalyzed N-methylation of nitroarenes and amines using MeOH as both a C1 and a H2 source. This transformation proceeds with high atom-economy and in an environmentally friendly way via borrowing hydrogen mechanism. A total of >30 structurally diverse N-methylamines, including bioactive compounds, were selectively synthesized with isolated yields of up to 95%. Furthermore, selective N-methylation and deuteration of nimesulide, a nonsteroidal anti-inflammatory drug, were realized through the late-stage functionalization.
- Goyal, Vishakha,Gahtori, Jyoti,Narani, Anand,Gupta, Piyush,Bordoloi, Ankur,Natte, Kishore
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p. 15389 - 15398
(2019/12/04)
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- Ring-Opening Polymerization of Cyclic Phosphonates: Access to Inorganic Polymers with a PV-O Main Chain
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We describe a new class of inorganic polymeric materials featuring a main chain consisting of PV-O bonds and aryl side groups, which was obtained with >70 repeat units by ring-opening polymerization of cyclic phosphonates. This monomer-polymer system was found to be dynamic in solution enabling selective depolymerization under dilute conditions, which can be tuned by varying the substituents. The polymers show high thermal stability to weight loss and can be easily fabricated into self-standing thin films. Structural characterizations of the cyclic 6-and 12-membered ring precursors are also described.
- Arz, Marius I.,Annibale, Vincent T.,Kelly, Nicole L.,Hanna, John V.,Manners, Ian
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supporting information
p. 2894 - 2899
(2019/03/05)
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- Amination of Aromatic Halides and Exploration of the Reactivity Sequence of Aromatic Halides
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A base-promoted amination of aromatic halides has been developed using a limited amount of dimethylformamide (DMF) or amine as an amino source. Various aryl halides, including F, Cl, Br, and I, have been successfully aminated in good to excellent yields. Although the amination of aromatic halides with amines or DMF is usually considered as an aromatic nucleophilic substitution (SNAr) process, and the reactivity of an aromatic halide is F > Cl > Br > I, the reactivity of aromatic halides in this system was found to be I > Br a‰ F > Cl. This protocol also showed a good regioselectivity for multihalogenated aromatics. This protocol is valuable for industrial application due to the simplicity of operation, the unrestricted availability of amino sources and aromatic halides, transition metal-free conditions, no requirement for solvent, and scalability.
- Yang, Chu,Zhang, Feng,Deng, Guo-Jun,Gong, Hang
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p. 181 - 190
(2019/01/10)
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- Efficient Chemoselective Reduction of N-Oxides and Sulfoxides Using a Carbon-Supported Molybdenum-Dioxo Catalyst and Alcohol
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The chemoselective reduction of a wide range of N-oxides and sulfoxides with alcohols is achieved using a carbon-supported dioxo-molybdenum (Mo@C) catalyst. Of the 10 alcohols screened, benzyl alcohol exhibits the highest reduction efficiency. A variety of N-oxide and both aromatic and aliphatic sulfoxide substrates bearing halogens as well as additional reducible functionalities are efficiently and chemoselectively reduced with benzyl alcohol. Chemoselective N-oxide reduction is effected even in the presence of potentially competing sulfoxide moieties. In addition, the Mo@C catalyst is air- and moisture-stable, and is easily separated from the reaction mixture and then re-subjected to reaction conditions over multiple cycles without significant reactivity or selectivity degradation. The high stability and recyclability of the catalyst, paired with its low toxicity and use of earth-abundant elements makes it an environmentally friendly catalytic system.
- Li, Jiaqi,Liu, Shengsi,Lohr, Tracy L.,Marks, Tobin J.
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p. 4139 - 4146
(2019/05/27)
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- A mild and efficient H2O2 oxygenation of N-heteroaromatic compounds to the amine N-oxides and KI deoxygenation back to the tertiary amine with hexaphenyloxodiphosphonium triflate
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A mild and efficient method for the oxidation of N-heteroaromatic compounds to the corresponding N-oxides using H2O2 in the presence of hexaphenyloxodiphosphnium triflate (Hendrickson reagent) in EtOH at room temperature was reported. This methodology presented relatively fast and selective reactions to afford the N-oxides in good yields. The reverse reactions, deoxygenation reactions, were also carried out under the same reaction conditions by KI to produce the tertiary amines.
- Khodaei, Mohammad Mehdi,Alizadeh, Abdolhamid,Hezarkhani, Hadis Afshar
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p. 1843 - 1849
(2018/07/06)
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- Synthesis and structural, photophysical, electrochemical redox and axial ligation properties of highly electron deficient perchlorometalloporphyrins and selective CN- sensing by Co(ii) complexes
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A straightforward synthetic route has been adopted to synthesize highly nonplanar electron deficient perchlorometallo-porphyrins. Herein, we report the synthesis and characterization of MTPP(NO2)Cl7 where M = CoII, NiII, CuII and ZnII. Further, we examined their optical and electrochemical redox properties and the results are compared with MTPPCl8. MTPP(NO2)Cl7 exhibited red-shifted (～10-15 nm) absorption spectra relative to MTPPCl8 due to the strong electron withdrawing nature of the nitro group. Mixed β-substitution alters the electrochemical redox properties to such an extent that an appreciable increase in the anodic shift in reduction potential (200-300 mV) is observed for MTPP(NO2)Cl7 relative to MTPPCl8 whereas only a minimal shift (15-50 mV) in the oxidation potential is observed. Nonplanarity of the macrocyclic core was investigated by single crystal X-ray analysis and DFT calculations. A higher ΔCβ (0.706 ?) for 1d as compared to 2d (0.642 ?) undoubtedly signifies nonplanarity induced by the nitro group. To substantiate the effect of mixed substitution, we performed axial ligation studies of Zn(ii) complexes with nitrogenous bases and basic anions and found higher log:β2 values as well as a linear relation between log:β2 and pKa as compared to perbromoporphyrins. Highly electron deficient β-substituted Co(ii) porphyrins (1a and 2a) were utilized as novel sensors for selective rapid visual detection of CN- ions.
- Chaudhri, Nivedita,Butcher, Ray J.,Sankar, Muniappan
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p. 8190 - 8199
(2018/05/24)
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- Structures, Lewis Acidities, Electrophilicities, and Protecting Group Abilities of Phenylfluorenylium and Tritylium Ions
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The isolation, characterization, and the first X-ray structures of a fluorenylium ion and its Lewis adducts with nitrogen- and phosphorus-centered Lewis bases are reported. Kinetics of the reactions of a series of fluorenylium ions with reference π-, σ-, and n-nucleophiles of various sizes and nucleophilicities allowed the interplay between electronic and structural parameters on the electrophilicities of these planarized tertiary carbenium ions to be elucidated. Structure–reactivity correlations and extensive comparisons of their reactivities with those of di- and triarylcarbenium ions are described. Quantitative determination of the electrofugalities of fluorenylium ions revealed to which extent they are complementing tritylium ions as protecting groups and how their tuning is possible. Determination of the equilibrium constants of the Lewis adducts formation between pyridines of calibrated Lewis basicities and phenylfluorenylium and tritylium ions allowed the determination of their Lewis acidities and to showcase the potential of these carbon-centered Lewis acids in catalysis.
- Follet, Elsa,Mayer, Peter,Berionni, Guillaume
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supporting information
p. 623 - 630
(2017/01/18)
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- Deoxygenation of tertiary amine N-oxides under metal free condition using phenylboronic acid
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A simple and efficient method for the deoxygenation of amine N-oxides to corresponding amines is reported using the green and economical reagent phenylboronic acid. Deoxygenation of N,N-dialkylaniline N-oxides, trialkylamine N-oxides and pyridine N-oxides were achieved in good to excellent yields. The reduction susceptible functional groups such as ketone, amide, ester and nitro groups are well tolerated with phenylboronic acid during the deoxygenation process even at high temperature. In addition, an indirect method for identification and quantification of tert-amine N-oxide is demonstrated using UV–Vis spectrometry which may be useful for drug metabolism studies.
- Gupta, Surabhi,Sureshbabu, Popuri,Singh, Adesh Kumar,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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supporting information
p. 909 - 913
(2017/02/15)
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- Metal-Free Reduction of Phosphine Oxides, Sulfoxides, and N-Oxides with Hydrosilanes using a Borinic Acid Precatalyst
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The general reduction of phosphine oxides, sulfoxides, and amine N-oxides was achieved by combining bis(2-chlorophenyl)borinic acid with phenylsilane. The reaction was shown to tolerate a wide range of substrates and could be performed under mild conditions, with only 2.5 mol % of the easily synthesized catalyst. Mechanistic investigations pointed to a key borohydride as the real catalyst and at bis(2-chlorophenyl)borinic acid as a precatalyst.
- Chardon, Aurélien,Maubert, Orianne,Rouden, Jacques,Blanchet, Jér?me
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p. 4460 - 4464
(2017/11/22)
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- Room-temperature copper-catalyzed arylation of dimethylamine and methylamine in neat water
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The first room-temperature copper-catalyzed arylations of dimethylamine and methylamine in neat water have been developed. Using a combination of CuI and 6,7-dihydroquinolin-8(5 H)-one oxime as catalyst, dimethylamine is arylated with various aryl halides to give the corresponding products in good to excellent yields. Further, this catalysis enables the selective arylation of methylamine to afford the high yields of monoarylated methylamines as the sole products.
- Wang, Deping,Kuang, Daizhi,Zhang, Fuxing,Yang, Chunlin,Zhu, Xiaoming
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supporting information
p. 714 - 718
(2015/03/18)
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- (METH)ACRYLATE COMPOUND, OPTICAL COMPOSITION, MOLDED ARTICLE, AND OPTICAL ELEMENT
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An optical element including a molded article is provided, the molded article being prepared by molding a polymer prepared by polymerizing a (meth)acrylate compound represented at least by the following general formula (1): wherein a and b are each an integer of 1 or 2; X and Y are each —S— or —O—; R1 and R2 are each an alkyl group having 1 or 2 carbon atoms or a hydrogen atom; and Z1 and Z2 are each an alkyl group having 1 or 2 carbon atoms, having a substituent and represented by the following general formula (2): wherein m is selected from 0 and 1; W is a hydrogen atom or a methyl group; and V is selected from substituents represented by the following: *—O—CnH2n—O—**; *—S—CnH2n—S—**; and *—S—CnH2n—O—**, wherein * represents a bond with an alkyl group; ** represents a bond with a (meth)acryloyl group; n is selected from 2, 3 and 4; and at least one hydrogen atom of —CnH2n— is replaced by a methyl group.
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Page/Page column
(2015/07/02)
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- QUINAZOLINE-2,4-DIONE DERIVATIVES
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The invention relates to antibacterial compounds of formula (I), wherein R1 is H, halogen, (C1-C3)alkyl or (C1-C3)alkoxy; R2 is H, halogen, (C1-C3)alkyl, (C1-C3)alkoxy or pyrrolidin-1-yl; R3 is H, halogen, (C1-C3)alkyl, (C1-C3)alkoxy, vinyl or 2-methoxycarbonyvinyl or R2 and R3 together with the two carbon atoms which bear them form a phenyl ring; R4 is H, halogen, (C1-C3)alkyl or (C1-C3)alkoxy; and R5 is H, (C1-C3)alkyl or cyclopropyl, or R4 and R5 form together a —CH2CH2CH2— group; A is the divalent group —CH2—, —CH2CH2—, #—CH(OH)CH2—*, #—CH2N(R6)—* and —CH2NHCH2—, wherein # indicates the point of attachment to the optionally substituted (quinazoline-2,4-dione-3-yl)methyl residue and * represents the point of attachment to the substituted (oxazolidinon-4-yl)methyl residue; R6 is H or acetyl; Y is CH or N; and Q is O or S; and salts of such compounds.
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- Acid-base responsive switching between 3+1 and 2+2 platinum complexes
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We report that the acid-base induced changes to a cyclometallated platinum complex can be used to drive the exchange of accompanying ligands with different denticities.
- Sooksawat, Dhassida,Pike, Sarah J.,Slawin, Alexandra M.Z.,Lusby, Paul J.
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supporting information
p. 11077 - 11079
(2013/11/19)
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- Activation of rhenium(I) toward substitution in fac -[Re(N,O′ -Bid)(CO)3(HOCH3)] by Schiff-base bidentate ligands (N,O′ -Bid)
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A series of fac-[Re(N,O′-Bid)(CO)3(L)] (N,O′-Bid = monoanionic bidentate Schiff-base ligands with N,O donor atoms; L = neutral monodentate ligand) has been synthesized, and the methanol substitution reactions have been investigated. The complexes were characterized by NMR, IR, and UV-vis spectroscopy. X-ray crystal structures of the compounds fac-[Re(Sal-mTol)(CO)3(HOCH3)], fac-[Re(Sal-pTol)(CO) 3(HOCH3)], fac-[Re(Sal-Ph)(CO)3(HOCH 3)], and fac-[Re(Sal-Ph)(CO)3(Py)] (Sal-mTol = 2-(m-tolyliminomethyl)phenolato; Sal-pTol = 2-(p-tolyliminomethyl)phenolato; Sal-Ph = 2-(phenyliminomethyl)phenolato; Py = pyridine) are reported. Significant activation for the methanol substitution is induced by the use of the N,O bidentate ligand as manifested by the second order rate constants, with limiting kinetics being observed for the first time. Rate constants (25 C) (k1 or k3) and activation parameters (ΔH ka, kJ mol-1; ΔS ka, J K-1 mol-1) from Eyring plots for entering nucleophiles as indicated are as follows: fac-[Re(Sal-mTol)(CO)3(HOCH3)] 3-chloropyridine: (k 1) 2.33 ± 0.01 M-1 s-1; 85.1 ± 0.6, 48 ± 2; fac-[Re(Sal-mTol)(CO)3(HOCH3)] pyridine: (k1) 1.29 ± 0.02 M-1 s-1; 92 ± 2, 66 ± 7; fac-[Re(Sal-mTol)(CO)3(HOCH3)] 4-picoline: (k1) 1.27 ± 0.05 M-1 s-1; 88 ± 2, 53 ± 6; (k3) 3.9 ± 0.03 s-1; 78 ± 8, 30 ± 27; (kf) 1.7 ± 0.02 M-1 s-1; 86 ± 2, 49 ± 6; fac-[Re(Sal-mTol)(CO) 3(HOCH3)] DMAP (k3) 1.15 ± 0.02 s -1; 88 ± 2, 52 ± 7. An interchange dissociative mechanism is proposed.
- Brink, Alice,Visser, Hendrik G.,Roodt, Andreas
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supporting information
p. 8950 - 8961
(2013/09/02)
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- Reversible addition of the Si-H bond of phenylsilane to the Sc=N bond of a scandium terminal imido complex
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The facile and reversible addition of the Si-H bond of phenylsilane to the Sc=N bond of the scandium terminal imido complex [LSc=NDIPP(DMAP)] (1; L = [MeC(N(DIPP))CHC(Me)(NCH2CH2NMe)]-, DIPP = 2,6-iPr2C6H3) is reported. The reaction gives the scandium anilido hydride [LSc(H)(N(DIPP)(SiH2Ph))] (2), and a labeling experiment shows a rapid σ-bond metathesis between Sc-H of the formed scandium anilido hydride and Si-H of phenylsilane during the reaction. 2 was trapped by an insertion reaction with diphenylcarbodiimide, giving the stable scandium anilido amidinate [LSc(N(DIPP)(SiH 2Ph))(κ2(N,N′)-PhNCHNPh)] (3). Furthermore, the scandium terminal imido complex can efficiently catalyze the hydrosilylation of N-benzylidenepropan-1-amine. The reaction was completed within 2 h at 50 C with 5 mol % of catalyst loading and highly selectively produced the monoaminosilane.
- Chu, Jiaxiang,Lu, Erli,Chen, Yaofeng,Leng, Xuebing
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p. 1137 - 1140
(2013/05/21)
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- Quantitative evaluation of the stability of gem -diaurated species in reactions with nucleophiles
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The reactivity of diaurated species toward nucleophiles was investigated. The reaction yields vinyl gold species and is described as simple SN2 ligand exchange at gold. Using suitably strong nucleophiles, equilibrium constants were determined to measure the stability of various diaurated species. On the basis of these equilibrium constants the influence of ligand and the nature of vinyl cores on the stability were analyzed. These results have direct implication for gold catalysis: it was demonstrated that vinyl gold intermediates bind the catalytic LAu+ species generally stronger than an alkyne (the substrate) by a factor of 106-109. This demonstrates that the formation of diaurated species from vinyl gold intermediates is thermodynamically favored in a catalytic reaction.
- Zhdanko, Alexander,Maier, Martin E.
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supporting information
p. 2000 - 2006
(2013/05/08)
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- COELENTERAZINE ANALOGUES AND COELENTERAMIDE ANALOGUES
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Coelenterazine analogues with different luminescence properties from conventional ones and coelenteramide analogues with different fluorescence properties from conventional ones have been desired. The invention provides coelenterazine analogues modified at the 8-position of coelenterazine and coelenteramide analogues modified at the 2- or 3-position of coelenteramide.
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- Nucleophilicities and carbon basicities of DBU and DBN
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The nucleophilicity and Lewis basicity of DBU and DBN toward C sp2 centers have been measured: nucleophilicities increase in the series DMAP DBU DBN DABCO while Lewis basicities are DABCO DMAP DBU DBN. The Royal Society of Chemistry
- Baidya,Mayr, Herbert
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p. 1792 - 1794
(2008/12/22)
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- The effect of substitution on the utility of piperidines and octahydroindoles for reversible hydrogen storage
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Substituted piperidines and octahydroindoles are compared in terms of their usability as reversible organic hydrogen storage liquids for hydrogen-powered fuel cells. Theoretical Gaussian calculations indicate which structural features are likely to lower the enthalpy of dehydrogenation. Experimental results show that attaching electron donating or conjugated substituents to the piperidine ring greatly increases the rate of catalytic dehydrogenation, with the greatest rates being observed with 4-aminopiperidine and piperidine-4-carboxamide. Undesired side reactions were observed with some compounds such as alkyl transfer reactions during the dehydrogenation of 4-dimethylaminopiperidine, C-O and C-N cleavage reactions during hydrogenation and/or subsequent dehydrogenation of 4-alkoxy and 4-amino indoles, and disproportionation during the hydrogenation of 4-aminopyridine. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Cui, Yi,Kwok, Samantha,Bucholtz, Andrew,Davis, Boyd,Whitney, Ralph A.,Jessop, Philip G.
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p. 1027 - 1037
(2008/12/20)
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- Displacement of neutral nitrogen donors by chloride in AuCl3(am) (am = pyridines and amines): Kinetics and DFT calculations show the effects of basicity and π-acceptor ability
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The kinetics of the process AuCl3(am) + Cl- → AuCl4- + am (am = sp2 N-donor isosteric pyridines with different π systems and sp3 amines; they cover a wide range of basicity) have been studied in methanol at 25°C. The reactions obey the usual two-term rate law observed in substitutions on square-planar complexes. The second-order rate constants, k2, are very sensitive to the nature of the leaving group, and plots of log k2 against the pKa of the conjugate acids are linear, with the same slope, -0.68, for both normal pyridines and pyridines with a more extended π system, such as 4-cyanopyridine, isonicotinic acid, methyl isonicotinate and 4-acetylpyridine. The reactivity of the considered N-donors is different and follows the order sp3 N-donors > normal pyridines > π-extended pyridines. This result, with the support of ground-state DFT calculations on the AuCl3(am) derivatives, is explained on the basis of an Au-N bond enforcement due to an increased π-back-donation contribution. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Pitteri, Bruno,Bortoluzzi, Marco
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p. 4456 - 4461
(2008/03/12)
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- Nucleophilicities and carbon basicities of pyridines
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Rate and equilibrium constants for the reactions of pyridines with donor-substituted benzhydrylium ions have been determined spectrophotometrically. The correlation equation log k(20°C) = s(N+E). in which s and N are nucleophile-specific parameters and E is an electrophile-specific parameter, has been used to determine the nucleophilicity parameters of various pyridines in CH2Cl2 and aqueous solution and to compare them with N of other nucleophiles. It is found that the nucleophilic organocatalyst 4-(dimethylamino)pyridine (DMAP) and tertiary phosphanes have comparable nucleophilicities and carbon basicities despite widely differing Bronsted basicities. For that reason, these reactivity parameters are suggested as guidelines for the development of novel organocatalysts. The Marcus equation is employed for the determination of the intrinsic barriers of these reactions.
- Brotzel, Frank,Kempf, Bernhard,Singer, Thomas,Zipse, Hendrik,Mayr, Herbert
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p. 336 - 345
(2007/10/03)
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- DABCO and DMAP - Why are they different in organocatalysis?
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(Chemical Equation Presented) What makes a good organocatalyst? DABCO (1,4-diazabicyclo[2.2.2]octane) is a thousandfold better nucleophile (k →) and at the same time a million times better leaving group (k←) than DMAP (4-(dimethylamino)pyridine). This apparent contradiction is resolved by consideration of the intrinsic reaction barriers.
- Baidya, Mahiuddin,Kobayashi, Shinjiro,Brotzel, Frank,Schmidhammer, Uli,Riedle, Eberhard,Mayr, Herbert
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p. 6176 - 6179
(2008/04/05)
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- Process for producing 4-dimethyl amino pyridine (4-DMAP)
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An improved process for producing 4-dimethyl amino pyridine is provided. The process comprises quaternizing pyridine with a suitable quaternizing agent in the presence of organic solvent, isolating the resulting salt and aminating the salt, N-[4-pyridyl] pyridinium chloride hydrochloride, with N,N-dimethyl formamide. The resultant reaction mass is hydrolysed in the presence of a base, extracted with an aromatic solvent and distilled under vacuum to produce 4-dimethyl amino pyridine.
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- Process for producing 4-dimethyl amino pyridine (4-DMAP)
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An improved process for producing 4-dimethyl amino pyridine is provided. The process comprises quaternizing pyridine with a suitable quaternizing agent in the presence of organic solvent, isolating the resulting salt and aminating the salt, N- [4-pyridyl] pyridinium chloride hydrochloride, with N, N-dimethyl formamide. The resultant reaction mass is hydrolysed in the presence of a base, extracted with a suitable organic solvent and distilled under vacuum to produce 4-dimethyl amino pyridine.
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Page column 5
(2008/06/13)
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- Convenient dimethylamino amination in heterocycles and aromatics with dimethylformamide
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A convenient dimethylamino amination of various heterocyclic and aromatic compounds having activated chloro group has been carried out in good yields using dimethyl formamide (DMF).
- Agarwal, Anu,Chauhan, Prem M. S.
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p. 2925 - 2930
(2007/10/03)
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- Interconversion of MeReO(dithiolate)(NC5H4-X) and MeReO(dithiolate)(PAr3) complexes: The equilibrium constants follow the Hammett equation but the rate constants do not
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Equilibration occurs among the species MeReO(dithiolate)Py, MeReO(dithiolate)(PZ3), Py, and PZ3 where the chelating dithiolate ligand is 1,2-ethanedithiol (edt) or 1,3-propanedithiol (pdt), Py stands for NC5H4-4-X and PZ3 for both P(C 6H4-4-Y)3 and P(alkyl)n(Ph) 3-n. Equilibrium constants in the pdt series were evaluated directly; values of K generally favor phosphane coordination and range from 4.8 × 10-2 (X = NMe2, Y = Cl) to 3.2 × 10 4 (X = CN, Y = OMe). The values of K are well correlated by the Hammett equation with ρXK = 2.7(3) and ρ YK = -2.0(3). Kinetic data were determined with the stopped-flow method for 65 reactions of the edt and pdt complexes, and resolved into forward and reverse components by use of the equilibrium constants. Values of kfor, deviate markedly from Hammett behavior, especially along any series with a given X substituent, where plots of log kfor against 3σY take on a V-shaped appearance. This pattern has been interpreted in terms of a two step mechanism for ligand substitution reactions of these complexes. The rate constants for those phosphanes that are the better Lewis bases are governed by Re-P bond formation. The rate constants for those phosphanes that are weaker Lewis bases, on the other hand, are governed by the second step in which an initial ψ-octahedral complex rotates towards a transition state that is an approximate trigonal prism. In so doing, the prior Re-P interaction is weakened, which gives rise to an increase in log kfor with σY.
- Shan, Xiaopeng,Espenson, James H.
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p. 3612 - 3616
(2007/10/03)
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- The Rate and Equilibrium Constants for N-, O-Acyl Transfer
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Reactions with dimethylcarbamoyl group transfer from N-acylpyridinium salts to pyridine N-oxides and from N-acyloxypyridinium salts to pyridines in acetonirile solutions were studied. Their rate and equilibrium constants and activation parameters were determined. The reactions were shown to be one-step and to follow the SN2 mechanism. Equations relating the rate and equilibrium parameters of the N-O and O-N acyl transfer reactions to the basicity of the nucleophile and outgoing group were obtained.
- Rybachenko,Chotii,Kovalenko,Shreder
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p. 1695 - 1698
(2007/10/03)
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- Supernucleophilic 4-substituted-pyridine catalysts, and processes useful for preparing same
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A process of preparing 4-substituted pyridine compounds via pyridine betaine compounds.
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Page column 15
(2010/01/31)
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- Processes and intermediates useful to make antifolates
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The present invention concerns intermediates, and processes directed to and from those intermediates, to a series of pyrimidine derivatives of formula (V), which are intermediates to useful antifolate compounds or are themselves useful antifolate compounds.
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