نتایج جستجو برای: hantzsch condensation
تعداد نتایج: 32606 فیلتر نتایج به سال:
By the immobilization of bipyridinium chloride onto mesoporous MCM-41encapsulated Fe3O4 nanoparticles via a simple post-synthesis method, a totally new organic-inorganic hybrid nanocomposite was formulated. The heterogeneous hybrid nanomagnetic composite was characterized by <spa...
The polymer supported hypochlorite ion is a facile selective oxidizing agent for the oxidation of various alcohols to aldehydes and ketones. Similarly is successfully oxidizes various Hantzsch type 1,4- dihydropyridines to corresponding pyridines.
Hantzsch 1 ,4- dihy&opyridines are rapidly oxidized to the corresponding pyridine derivatives using zinc chlorochromate nonahydrate [Zn(C1CrO ) .9H O] in dichloromethane at room temperature. In addition to aromatization, no loss of the 4- substituent is observed
A continuous-flow asymmetric organocatalytic photocyclization-transfer hydrogenation cascade reaction has been developed. The new protocol allows the synthesis of tetrahydroquinolines from readily available 2-aminochalcones using a combination of photochemistry and asymmetric Brønsted acid catalysis. The photocylization and subsequent reduction was performed with catalytic amount of chiral BINO...
A novel and green approach for efficient and rapid synthesis of biologically active polyhydroquinoline derivatives via unsymmetric Hantzsch reaction using nanorods Vanadatesulfuric acid (VSA NRs) as a new and recyclable catalyst under solvent-free conditions was reported. The catalyst was characterized by FT-IR, XRD, XRF and TEM analysis. The present method offers several advantages such as sim...
In this study, novel condensed 1,4-dihydropyridines bearing cyclopentanone (1-21) or tetrahydrothiophene-1,1-dioxide ring (22-42) with various ester substituents were synthesized via a modified Hantzsch reaction and their calcium channel modulator activities were investigated on isolated rat ileum and rat thoracic aorta. The introduction of a cyclopentanone ring fused to the 1,4-dihydropyridine...
Hantzsch esters (1,4-dihydropyridine dicarboxylates) have become, in this century, very versatile reagents for enantioselective organic transformations. They can act as hydride transfer agents to reduce, regioselectively, a variety of multiple bonds, e.g., C=C and C=N, under mild reaction conditions. are excellent the dearomatization heteroaromatic substances, participate readily cascade proces...
Allylation and benzylation of p-quinones was achieved through an unusual redox chain reaction. Mechanistic studies suggest that the existence of trace hydroquinone initiates a redox chain reaction that consists of a Lewis acid catalyzed Friedel-Crafts alkylation and a subsequent redox equilibrium that regenerates hydroquinone. The electrophiles could be various allylic and benzylic esters. The ...
Dynamic kinetic Transfer hydrogenation reaction of 2-methyl-2,4-diaryl-2,3-dihydrobenzo[b][1,4]diazepines, using phosphoric acids as catalysts and Hantzsch ester as hydride source, has been studied. A 3,3'-H8-binol derived phosphoric acid has been identified the optimal chiral catalyst for this transformation, affording 1,3-diamine derivatives with up to 8/1 dr, 86% ee and 94% ee for the major ...
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