36995-48-9

Upstream product

• 30004-39-8 1-(4-Methylbenzyl)pyridiniumchlorid 
• 872-85-5 pyridine-4-carbaldehyde 
• 106-38-7 para-bromotoluene 
• 100-48-1 pyridine-4-carbonitrile 
• 99-94-5 p-Toluic acid 
• 108-89-4 picoline 
• 89980-67-6 p-methylbenzylmagnesium bromide 
• 63755-30-6 N-ethoxycarbonylpyridinium chloride 
• 104-82-5 4-Methylbenzyl chloride 
• 110-86-1 pyridine 
• 80891-12-9 diisopropyl-1-ethoxycarbonyl-1,4-dihydropyridine-4-phosphonate 
• 882525-07-7 4-(diisopropoxy-phosphoryl)-4-(hydroxy-p-tolyl-methyl)-4H-pyridine-1-carboxylic acid ethyl ester 
• 87732-42-1 1,4-Dihydro-1-(4-methoxybenzoyl)-4-(4-methylbenzyliden)pyridin 
• 33974-28-6 α-(4-methylphenyl)-4-pyridinemethanol 

Downstream Products

• 87732-44-3 1-phenyl-2-(pyridin-4-yl)-2-(p-tolyl)ethan-1-one 
• 14548-30-2 (4-methylphenyl)(pyridin-4-yl)methanone 
• 87732-45-4 1-(4-Methoxyphenyl)-2-(4-pyridyl)-2-(p-tolyl)-1-ethanon 
• 141685-99-6 1-Methyl-4-(4-methyl-benzyl)-1,2,3,6-tetrahydro-pyridine 
• 87732-42-1 1,4-Dihydro-1-(4-methoxybenzoyl)-4-(4-methylbenzyliden)pyridin 
• 87755-69-9 1-Benzoyl-1,4-dihydro-4-(4-methylbenzyliden)pyridin 

Relevant academic research and scientific papers

A facile synthesis of 4-benzylpyridines by regiospecific addition of substituted benzylic Griganard reagents to pyridinium salts

Substituted 4-benzylpyridines are prepared by regiospecific γ-addition of substituted benzylic Grinard reagents to pyridinium salts in fairly good yields.

Metal-Free Heterogeneous Semiconductor for Visible-Light Photocatalytic Decarboxylation of Carboxylic Acids

A suitable protocol for the photocatalytic decarboxylation of carboxylic acids was developed with metal-free ceramic boron carbon nitrides (BCN). With visible light irradiation, BCN oxidize carboxylic acids to give carbon-centered radicals, which were trapped by hydrogen atom donors or employed in the construction of the carbon-carbon bond. In this system, both (hetero)aromatic and aliphatic acids proceed the decarboxylation smoothly, and C-H, C-D, and C-C bonds are formed in moderate to high yields (35 examples, yield up to 93%). Control experiments support a radical process, and isotopic experiments show that methanol is employed as the hydrogen atom donor. Recycle tests and gram-scale reaction elucidate the practicability of the heterogeneous ceramic BCN photoredox system. It provides an alternative to homogeneous catalysts in the valuable carbon radical intermediates formation. Moreover, the metal-free system is also applicable to late-stage functionalization of anti-inflammatory drugs, such as naproxen and ibuprofen, which enrich the chemical toolbox.

Metal-Free Halogen(I) Catalysts for the Oxidation of Aryl(heteroaryl)methanes to Ketones or Esters: Selectivity Control by Halogen Bonding

Metal-free halogen(I) catalysts were used for the selective oxidation of aryl(heteroaryl)methanes [C(sp3)?H] to ketones [C(sp2)=O] or esters [C(sp3)?O]. The synthesis of ketones was performed with a catalytic amount of NBS in DMSO solvent. Experimental studies and density functional theory (DFT) calculations supported the formation of halogen bonding (XB) between the heteroarene and N-bromosuccinimide, which enabled imine–enamine tautomerism of the substrates. No additional activator was required for this crucial step. Isotope-labeling and other supporting experiments suggested that a Kornblum-type oxidation with DMSO and aerobic oxygenation with molecular oxygen took place simultaneously. A background XB-assisted electron transfer between the heteroarenes and halogen(I) catalysts was responsible for the formation of heterobenzylic radicals and, thus, the aerobic oxygenation. For selective acyloxylation (ester formation), a catalytic amount of iodine was employed with tert-butyl hydroperoxide in aliphatic carboxylic acid solvent. Several control reactions, spectroscopic studies, and Time-Dependent Density Functional Theory (TD–DFT) calculations established the presence of acetyl hypoiodite as an active halogen(I) species in the acetoxylation process. With the help of a selectivity study, for the first time we report that the strength of the XB interaction and the frontier orbital mixing between the substrates and acyl hypoiodites determined the extent of the background electron-transfer process and, thus, the selectivity of the reaction.

Synthesis of 4-benzylpyridines via Pd-catalyzed CH3-arylation of 4-picoline

A highly efficient synthesis of 4-benzylpyridines was developed via Pd-catalyzed C(sp3)-H arylation between 4-picoline and aryl halides. It was found that the best yields were achieved with a simple Pd(PPh3)4 catalyst and Cs2CO3 as the base. Compared with the known methods, our reaction does not require the use of a strong organometallic reagent as the base.

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

The methylene group of various substituted 2- and 4-benzylpyridines, benzyldiazines and benzyl(iso)quinolines was successfully oxidized to the corresponding benzylic ketones using a copper or iron catalyst and molecular oxygen as the stoichiometric oxidant. Application of the protocol in API synthesis is exemplified by the alternative synthesis of a precursor to the antimalarial drug Mefloquine. The oxidation method can also be used to prepare metabolites of APIs which is illustrated for the natural product papaverine. ICP-MS analysis of the purified reaction products revealed that the base metal impurity was well below the regulatory limit.

Regioselective synthesis of 4-alkylpyridines from pyridine and aldehydes via dipole reversal process of 1,4-dihydropyridine phosphonate

4-Alkylation of pyridine has been accomplished by the reaction of ylides, derivated from 1,4-dihydropyridine phosphonate via phosphonioalkoxycarbonylation of pyridine with aldehydes and subsequent elimination of diisopropyl phosphate followed by aromatization with potassium tert-butoxide.

Flexible N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine analogues: Synthesis and monoamine oxidase catalyzed bioactivation

Eighteen analogues of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were synthesized and evaluated as substrates of monoamine oxidase. In general, the flexible analogues, characterized by the presence of a methylene (or ethylene) bridge between the aryl/heteroaryl and tetrahydropyridyl moieties, were better substrates of the enzyme than the conformationally restricted MPTP. It is suggested that the increased oxidative activity of these flexible analogues reflects enhanced binding due to the ability of the C-4-aryl/heteroaryl substituent to gain access to a hydrophobic pocket within the substrate binding site.

Therapeutically useful 1-phenyl-2-piperidinoalkanol derivatives

Compounds of the formula: STR1 wherein R1 is hydrogen, halogen, trifluoromethyl, alkyl, hydroxyl, alkyoxy, benzyloxy, alkanoyloxy, or benzoyloxy, or when R2 is hydroxyl or methoxy in the 4-position and R3 is hydrogen, R1 may also represent hydroxymethyl carbamoyl or alkoxycarbonyl, R2 is hydrogen, halogen, alkyl, hydroxyl, or alkoxy, R3 is hydrogen or alkyl, R4 is alkyl (in which case the compounds are (±)-erythro) or when R3 represents hydrogen, R4 may also be hydrogen, and R5 is hydrogen, halogen, alkyl, alkoxy, or three methoxy groups in the 3-, 4- and 5-positions and pharmaceutically acceptable acid addition salts thereof, with the exclusion of compounds wherein: (a) one of R1 and R2 is in the 4-position and is hydroxyl, alkoxy or benzyloxy, the other is in the 3-position and is hydrogen, hydroxyl, alkoxy or benzyloxy, and R3 and R5 are hydrogen and wherein: (b) R1 is in the 4-position and is halogen, R4 is methyl and R2, R3 and R5 are hydrogen, are useful as medicaments.

1-Acyl-4-alkylidene-1,4-dihydropyridines, 7. Activation with Boron Trifluoride: Intermolecular Acyl Group Transfer and Formation of 1-(4-Pyridyl)-2-alkanones

1-Acyl-4-alkylidene-1,4-dihydropyridines 5, representatives of the thermally stable enamides, can be activated by means of boron trifluoride 6, so the ketones 7 result from attack of 6 on 5 (intermolecular acyl group transfer).The mechanism of this reaction, which has not previously been observed for enamides, is strongly suggested to be as follows: 5 and 6 form first the adduct 21, which attacks 5 with formation of 27.Special examples of 5 (11 and 12) are found to be reactive enough that the ketone 7h or the sulfone 15 can be obtained from their isolable precursors (14 and 13) without Lewis-acid activation. 13 is particularly noteworthy: being the precursor of the salt 16, which is generated in situ, it serves as an extremely effective tosylating agent.Even tertiary alcohols are attackted by 16.