Tag: M.W=150-200

Tran, Gael published the artcileBase-Controlled Completely Selective Linear or Branched Rhodium(I)-Catalyzed C-H ortho-Alkylation of Azines without Preactivation, Application of 3-Chloro-4-(trifluoromethyl)pyridine, the main research area is base controlled rhodium catalyzed regioselective alkylation azine acrylate acrylamide; C−H activation; homogeneous catalysis; nitrogen heterocycles; regioselectivity.

A [RhI]/bisphosphine/base catalytic system for the ortho-selective C-H alkylation of azines by acrylates and acrylamides is reported. This catalytic system features an unprecedented complete linear or branched selectivity that is solely dependent on the catalytic base that is used [e.g., 3-(trifluoromethyl)pyridine + N,N-dimethylacrylamide �linear product I when KOPiv was used as base vs. branched product II when K3PO4 was used under otherwise identical conditions]. Complete branched selectivity is even achieved for Et methacrylate, which enables the introduction of a quaternary carbon center. Excellent functional group compatibility is demonstrated for both linear and branched alkylations. The operational simplicity and broad scope of this transformation allow for rapid access to functionalized azines of direct pharmaceutical and agrochem. relevance.

Angewandte Chemie, International Edition published new progress about Alkenes Role: RCT (Reactant), RACT (Reactant or Reagent) (acrylates and acrylamides). 81565-19-7 belongs to class pyridine-derivatives, name is 3-Chloro-4-(trifluoromethyl)pyridine, and the molecular formula is C6H3ClF3N, Application of 3-Chloro-4-(trifluoromethyl)pyridine.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Nguyen, Viet D. published the artcileRapid and Chemodivergent Synthesis of N-Heterocyclic Sulfones and Sulfides: Mechanistic and Computational Details of the Persulfate-Initiated Catalysis, Quality Control of 24484-93-3, the main research area is azaheterocyclyl sulfone sulfide chemoselective preparation; persulfate initiated sulfonylation azaheterocyclyl halide sulfinate biphasic solvent; mechanism persulfate initiated sulfonylation azaheterocyclyl halide sulfinate; hydroxymethylsulfinate mediated sulfonylation reduction azaheterocyclyl halide initiated persulfate; transition state structure kinetics sulfonylation azaheterocyclyl halide sulfinate.

Aromatic nitrogen heterocyclyl halides underwent sulfonylation reactions with sodium sulfinates mediated by sodium or ammonium persulfates in biphasic aqueous/organic solvent mixtures to yield azaheterocyclyl sulfones at ambient temperature; the products can be isolated by filtration. Reaction of aromatic nitrogen heterocyclyl halides with sodium hydroxymethylsulfinate mediated by sodium persulfate yielded either sym. azaheterocyclyl sulfones or sym. azaheterocyclyl sulfides, depending on the amount (1.2 or 3-4 equiv) of sulfinate used. Study of the mechanism of persulfate-mediated sulfonylation by DFT calculations and kinetic studies indicates that persulfate reacts with sulfinates to form sulfinic acids by a nonradical mechanism which accelerates the sulfonylation, particularly in water; the sulfonylation and reduction of azaheterocycles with sodium hydroxymethylsulfinate is proposed to act through a radical mechanism. The structures of seventeen of the products were determined by X-ray crystallog.

ACS Catalysis published new progress about Aromatic nitrogen heterocycles Role: RCT (Reactant), RACT (Reactant or Reagent) (halo-). 24484-93-3 belongs to class pyridine-derivatives, name is Methyl 4-chloropicolinate, and the molecular formula is C7H6ClNO2, Quality Control of 24484-93-3.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Tayama, Eiji published the artcileBase-induced Sommelet-Hauser rearrangement of N-(pyridinylmethyl) tetraalkylammonium salts, HPLC of Formula: 24484-93-3, the main research area is acylmethyl pyridylammonium bromide Sommelete Hauser rearrangement bond activation; acyl aminomethylpyridine preparation.

The base-induced Sommelet-Hauser (S-H) rearrangement of various types of N-(pyridinylmethyl) tetraalkylammonium salts to produce N,N-dialkyl-α-pyridinylamino acid esters were investigated. For example, a treatment of N-(2-pyridinylmethyl) glycine tert-Bu ester-derived tetraalkylammonium salt with 1.2 equiv of potassium tert-butoxide in THF at -40°C gave the corresponding S-H product, I [R = Obut; R1 = R2 = Me; R3= H] in 93% yield. Method was an efficient C-H functionalization of pyridines under simple and mild conditions.

Tetrahedron published new progress about Aralkyl halides Role: RCT (Reactant), RACT (Reactant or Reagent). 24484-93-3 belongs to class pyridine-derivatives, name is Methyl 4-chloropicolinate, and the molecular formula is C7H6ClNO2, HPLC of Formula: 24484-93-3.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Trawny, Daniel published the artcileModular syntheses of star-shaped pyridine, bipyridine, and terpyridine derivatives by employing Sonogashira reactions, Application of Ethyl 6-chloropicolinate, the main research area is pyridine preparation; trialkyne pyridine Sonogashira reaction; bipyridine preparation; bromo bipyridine trialkyne Sonogashira reaction; terpyridine preparation; nonaflate terpyridine trialkyne Sonogashira reaction.

A simple and flexible synthesis for a series C3-sym. core units of star-shaped pyridine e.g., I, bipyridine e.g., II and terpyridine derivatives e.g., III by employing a Sonogashira reaction in the crucial final step was described. A star-shaped dodecafluorinated compound I was also prepared in a straightforward fashion. A simple procedure for the preparation of partially silylated 1,3,5-triethynylbenzene derivatives was presented, which provides an approach to C2-sym. star-shaped compounds that have only one terpyridine and two terphenyl units as ‘dummy’ ligands. The absorption and emission spectra of the fully conjugated C3-sym. pyridine derivatives were systematically investigated, and fairly large Stokes shifts were observed

European Journal of Organic Chemistry published new progress about Pyridines Role: PRP (Properties), RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 21190-89-6 belongs to class pyridine-derivatives, name is Ethyl 6-chloropicolinate, and the molecular formula is C8H8ClNO2, Application of Ethyl 6-chloropicolinate.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Negi, Shigeto published the artcileSynthesis of (2R)-1-(4-chloro-2-pyridyl)-2-(2-pyridyl)ethylamine. A selective oxime reduction and crystallization-induced asymmetric transformation, COA of Formula: C7H6ClNO2, the main research area is pyridylethylamine preparation stereoselective crystallization; ethylamine chloropyridyl pyridyl preparation; oxime selective reduction.

Reduction of 1-(4-chloro-2-pyridyl)-2-(2-pyridyl)ethanone oxime using Zn in CF3CO2H gave the corresponding racemic pyridylethylamine I in excellent yield without reductive removal of the Cl atom. A subsequent diastereomeric crystallization of I with an optically active cis-cyclohexanecarboxylic acid derivative in the presence of a catalytic amount of 3,5-dichlorosalicylaldehyde gave the desired (R)-amine in 42% yield via a crystallization-induced asym. transformation.

Synthesis published new progress about Reduction, chemoselective. 24484-93-3 belongs to class pyridine-derivatives, name is Methyl 4-chloropicolinate, and the molecular formula is C7H6ClNO2, COA of Formula: C7H6ClNO2.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Schlosser, Manfred published the artcileThe reactivity of 2-fluoro- and 2-chloropyridines toward sodium ethoxide: Factors governing the rates of nucleophilic (het)aromatic substitutions, Related Products of pyridine-derivatives, the main research area is reactivity fluoropyridine chloropyridine sodium ethoxide nucleophilic aromatic heteroaromatic substitution.

The relative displacement rates of the halide substituent from 2-fluoro- and 2-chloropyridines by EtONa in EtOH at +25° were assessed by competition kinetics. The 2-fluoropyridine reacts 320 times faster than the chloro analog. A CF3 group increases the reactivity more than single halogen atoms do, whatever the element, and the latter are superior to Me3Si groups. Substituents accommodated at the 4-position operate through their inductive effect, whereas at the 3-position, this action may be attenuated by steric hindrance. Almost all 5-substituents enhance the rate of the nucleophilic substitution occurring at the 2-position. The sole exception concerns the F-atom at the 5-position which retards the reaction, presumably by lone-pair/lone-pair repulsion with the neg. charge building up at the central C-atom of the intermediate Meisenheimer complex. The substituent effects are additive. Therefore, by using the increments derived from the present work, the rates of future reactions should be predictable with fair accuracy.

Helvetica Chimica Acta published new progress about Ethoxylation kinetics. 42144-78-5 belongs to class pyridine-derivatives, name is 2-Chloro-6-ethoxypyridine, and the molecular formula is C7H8ClNO, Related Products of pyridine-derivatives.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Schlosser, Manfred published the artcileThe reactivity of 2-fluoro- and 2-chloropyridines toward sodium ethoxide: Factors governing the rates of nucleophilic (het)aromatic substitutions, Related Products of pyridine-derivatives, the main research area is reactivity fluoropyridine chloropyridine sodium ethoxide nucleophilic aromatic heteroaromatic substitution.

The relative displacement rates of the halide substituent from 2-fluoro- and 2-chloropyridines by EtONa in EtOH at +25° were assessed by competition kinetics. The 2-fluoropyridine reacts 320 times faster than the chloro analog. A CF3 group increases the reactivity more than single halogen atoms do, whatever the element, and the latter are superior to Me3Si groups. Substituents accommodated at the 4-position operate through their inductive effect, whereas at the 3-position, this action may be attenuated by steric hindrance. Almost all 5-substituents enhance the rate of the nucleophilic substitution occurring at the 2-position. The sole exception concerns the F-atom at the 5-position which retards the reaction, presumably by lone-pair/lone-pair repulsion with the neg. charge building up at the central C-atom of the intermediate Meisenheimer complex. The substituent effects are additive. Therefore, by using the increments derived from the present work, the rates of future reactions should be predictable with fair accuracy.

Helvetica Chimica Acta published new progress about Ethoxylation kinetics. 42144-78-5 belongs to class pyridine-derivatives, name is 2-Chloro-6-ethoxypyridine, and the molecular formula is C7H8ClNO, Related Products of pyridine-derivatives.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Byun, Seunghwan published the artcileFluoro-imidazopyridinylidene Ruthenium Catalysts for Cross Metathesis with Ethylene, Synthetic Route of 24484-93-3, the main research area is fluoro imidazopyridinylidene ruthenium preparation catalyst alkene metathesis ethylene; crystal structure fluoro imidazopyridinylidene ruthenium preparation catalyst ethenolysis iridium; mol structure fluoro imidazopyridinylidene ruthenium preparation catalyst ethenolysis iridium; imidazopyridinylidene fluoro NHC preparation frontier MO ruthenium selenium iridium.

Ru metathesis catalysts bearing fluorinated imidazo[1,5-a]pyridin-3-ylidene carbenes (F-ImPy) were developed for ethenolysis (cross metathesis with ethylene) of Me oleate. X-ray crystal structure anal. shows Ru-F interaction, and this F substitution appears to be pivotal to have stable ImPy-Ru precatalysts. Ligand structure was varied for high catalyst activity and cross metathesis selectivity in ethenolysis reaction. F-ImPy-Ru catalysts showed high selectivity in ethenolysis of Me oleate and thermal robustness under an ethylene atm.

Organometallics published new progress about Carbene complexes, N-heterocyclic, transition metal complexes Role: CAT (Catalyst Use), PRP (Properties), RCT (Reactant), SPN (Synthetic Preparation), USES (Uses), RACT (Reactant or Reagent), PREP (Preparation). 24484-93-3 belongs to class pyridine-derivatives, name is Methyl 4-chloropicolinate, and the molecular formula is C7H6ClNO2, Synthetic Route of 24484-93-3.

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem

Moustani, Chrysavgi published the artcileNovel aqueous-phase hydrogenation reaction of the key biorefinery platform chemical levulinic acid into γ-valerolactone employing highly active, selective and stable water-soluble ruthenium catalysts modified with nitrogen-containing ligands, Related Products of pyridine-derivatives, the publication is Applied Catalysis, B: Environmental (2018), 82-92, database is CAplus.

High catalytic activities (TO = 000 ^-1) have been achieved by novel water-soluble ruthenium catalysts modified with nitrogen-containing ligands such as the bathophenanthrolinedisulfonic acid disodium salt (BPhDS) in the hydrogenation reaction of the renewable polar platform chem. levulinic acid (LA) which possesses a central relevance in the development of biorefineries of the future in a sustainable way to produce with essentially quant. selectivity of 99.9 mol% γ-valerolactone (GVL) in aqueous media. The apparent activation energy of the Ru/BPhDS catalyst was calculated and amounts a relative low value of 53.3 J/mol when one considers that in the LA hydrogenation reaction this catalyst reduces a less reactive keto group into alc. functionality. A recycling experiment of the Ru/BPhDS catalyst by extraction after addition of di-Et ether has shown that the catalyst is stable without loss of activity and selectivity in a consecutive run.

Applied Catalysis, B: Environmental published new progress about 636-73-7. 636-73-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Sulfonic acid, name is Pyridine-3-sulfonic acid, and the molecular formula is C5H5NO3S, Related Products of pyridine-derivatives.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem

Lee, Hon Cheung published the artcileStructural determinants of nicotinic acid adenine dinucleotide phosphate important for its calcium-mobilizing activity, Name: Pyridine-3-sulfonic acid, the publication is Journal of Biological Chemistry (1997), 272(33), 20378-20383, database is CAplus and MEDLINE.

Nicotinic acid adenine dinucleotide phosphate (NAADP) mobilizes Ca²⁺ through a mechanism totally independent of cyclic ADP-ribose or inositol trisphosphate. The structural determinants important for its Ca²⁺ release activity were investigated using a series of analogs. It is shown that changing the 3-carboxyl group of the nicotinic acid (NA) moiety in NAADP to either an uncharged carbinol or from the 3-position to the 4-position of the pyridine ring totally eliminates the Ca²⁺ release activity. Conversion of the 3-carboxyl to other neg. charged groups, either 3-sulfonate, 3-acetate, or 3-quinoline carboxylate, retains the Ca²⁺ release activity, although their half-maximal effective concentrations (EC₅₀) are 100-200-fold higher. Changing the 6-amino group of the adenine to a hydroxyl group results in more than a 1000-fold decrease in the Ca²⁺ release activity. Conversion of the 2′-phosphate to 2′,3′-cyclic phosphate or 3′-phosphate likewise increases the EC₅₀ by about 5- and 20-fold, resp. Similar to NAADP, all of the active analogs can also desensitize the Ca²⁺ release mechanism at subthreshold concentrations, suggesting that this novel property is intrinsic to the release mechanism. The series of analogs used was produced by using ADP-ribosyl cyclase to catalyze the exchange of the nicotinamide group of various analogs of NADP with various analogs of NA. An important determinant in NA that is crucial to the base exchange reaction was shown to be the 2-position of the pyridine ring. Neither pyridine-2-carboxylate nor 2-methyl-NA support the exchange reaction. The neg. charge and the position of the 3-carboxyl group ware nonessential since both pyridine-3-carbinol and pyridine-4-carboxylate support the base exchange reaction. In addition to the information on the structure-activity relationships of NAADP and NA, this study also demonstrates the utility of the base exchange reaction as a general approach for synthesizing NAADP analogs.

Journal of Biological Chemistry published new progress about 636-73-7. 636-73-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Sulfonic acid, name is Pyridine-3-sulfonic acid, and the molecular formula is C5H5NO3S, Name: Pyridine-3-sulfonic acid.

Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem