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  • Open access
  • 133 Reads
An expedient synthesis of some new Pyrazole, Pyrazolone, Hydrazone and Thiosemicarbazide.

Malonamic acid, Malonamic acid hydrazide and Malonamic acid amide was designed and synthesized from direct condensation of diethyl malonate with m-NO2 primary aromatic aniline which used as precursor for synthesis of various possible bio active molecules. We also designed and synthesized the novel non cyclic and hetero cyclic compounds from  malonamic acid hydrazide like hydrazone, thiosemicarbazide, pyrazole and pyrazolone were achieved by a single step condensation reaction in good to excellent yields.  The simple starting materials, mild conditions, easy operation, high bioactivity of hydrazone, thiosemicarbazide, pyrazole and pyrazolone derivatives, this protocol has great potential in medicinal chemistry. All synthesized compounds evaluated for their antimicrobial activity and screening results are awaited. The structure elucidation of synthesized compounds was established on the basis of IR & NMR techniques (1H-NMR) and elemental analysis.

  • Open access
  • 202 Reads
Cu2(BDC)2(BPY) as excellent catalyst in synthesis of Pyrazine derivatives

Pyrazine, which is one of the well-known and important classes of heterocyclic compounds, exhibits extraordinary biological and pharmaceutical properties. In recent years, Pyrazines have received a lot of attention because of their applications in the field of luminescent materials. We used Metal-Organic Frameworks [Cu2(BDC)2(BPY)] for synthesis of Pyrazines in good yields. Metal-organic frameworks (MOFs) consist of coordination bonds between transition-metal cations and multidentate organic linkers.

  • Open access
  • 112 Reads
Synthesis of 2-tetrazolylmethyl-tetrahydro-1H-beta-carboline methane-linked bis-heterocycles via one pot Ugi-azide / Pictet-Spengler process

A series of seven new 2-tetrazolylmethyl-tetrahydro-1H-beta-carboline methane-linked bis-heterocycles including their fluorine-containing analogs were synthesized in good to excellent yields (74-97%) via one pot Ugi-azide / Pictet-Spengler strategy under mild thermal conditions. One intermediate (Ugi-azide product) was isolated and fully characterized in order to confirm the reaction pathway. The products herein described may find application in medicinal chemistry because they are formed by two heterocyclic frameworks (1,5-disubstituted-1H-tetrazole and tetrahydro-beta-carboline), which are present in a variety of bioactive compounds and drugs. In the same context, it has been reported that fluorine atoms placed suitably into structures of bioactive compounds enhances often very interesting features like bioavailability, lipophilicity and metabolic resistance.

  • Open access
  • 90 Reads
Synthesis of 1,5-disubstituted-1H-tetrazole methane-linked bis-heterocycles via Ugi-azide

A series of twelve new 1,5-disubstituted-1H-tetrazoles were synthesized via Ugi-azide. The products were synthesized in moderate to excellent yields (50-96%). Methane-linked bis-heterocycles play a relevant role in medicinal chemistry. Tetrazole and furan heterocyclic moieties are present in many drugs. It has been well documented that both moieties could improve parameters of bioactive products such as bioavailability, lipophilicity and metabolic resistance.

  • Open access
  • 277 Reads
Synthesis of 1-tetrazolyl-1,2,3,4-tetrahydroisoquinoline bound-type bis-heterocycles via oxidative Ugi-azide reaction

A series of five novel 1-tetrazolyl-1,2,3,4-tetrahydroisoquinolines were synthesized in moderate yields (29-60%) by a two-step process. The first one involved a NH-CH2 bond oxidation of the 1,2,3,4-tetrahydroisoquinoline to give the corresponding imine using IBX as oxidant. The second step was an oxidative Ugi-azide reaction using 3,4-dihydroisoquinoline, TMSN3 and the corresponding isocyanides as starting reagents. Final bis-heterocycles may find application in medicinal chemistry because tetrazole and tetrahydroisoquinoline are present in a variety of bioactive products and drugs.

  • Open access
  • 95 Reads
Ultrasound mediated synthesis of ecofriendly zinc chalcogenates in "on water conditions"

Nucleophilic Selenium is a convenient strategy for the functionalization of organic substrates having electrophilic character. Among all the methods developed for their preparation, the reduction of the corresponding diselenides represents the most versatile procedure. Using these protocols selenolates were usually prepared in situ using atom expensive reducing agents such as NaBH4, LiAlH4, or metals (Na, Li) or metal hydride (NaH). We recently reported that zinc can be efficiently used to reduce Se-halogen bond affording bench stable regents such as PhSeZnCl that showed a strong rate acceleration in “on water” conditions for a number of reactions: alkyl, aryl, vinyl and acyl substitutions, ring-opening reactions of epoxides and aziridines and Michael type addition.  We report now the use of Ultrasound irradiation for the oxidative insertion of zinc into Se-Se bond and the formation of the nucleophilic reagent PhSeZnSePh  as a green strategy to avoid the use of useless halogen and increase the atom economy of the selenenylating species. 

  • Open access
  • 105 Reads
Chemoselective Protection of hydroxyl and amine functional groups catalysed by MOFs

     The Friedel–Crafts reactions are a set of reactions developed to attach substituents to an aromatic ring. There are two main types of Friedel–Crafts reactions: Alkylation and Acylation reactions. The acylation of alcohols, phenols, amines and aromatic compounds with using acetic anhydride, acyl chloride and acetic acid is one of the most important reactions in organic synthesis. Particularly, chemo-selectivity and the curious reactivity preferences of functional groups in chain reactions, like protection of alcohols and amines has received much attention [1]. Recently, different heterogeneous catalysts have been employed to catalyst this reaction [2].

     In this work, we used Metal Organic Frameworks (MOFs) as heterogeneous catalyst for protection reactions of hydroxyl and amine functional groups. MOFs are porous crystalline materials in which metal ions are joined by organic linkers.

     Cu-MOF, Ni-MOF, Co-MOF were separately utilized as efficient and green catalysts for the protection of alcohols and amines with suppliers source of acethyl (Benzyl alcohol/acetic anhydride) to afford protected compounds. Products were obtained in excellent yields within short times under microwave irradiation. The catalyst was recovered without significant decrease in its catalytic activity.

  • Open access
  • 205 Reads
New multicomponent approach for the synthesis of coumarin derivatives by using environmental-friendly core/shell nanocatalyst

In this work, a three-component reaction of salicylaldehyde, diethylmalonate and phenylhydrazine in the presence of Fe3O4@SiO2@NH2 as a core/shell nanocatalyst in EtOH was used to form a novel series of coumarin derivatives. This catalytic protocol was simply carried out in high yields and short reaction times. The remarkable magnetic properties of this nanocomposite provide easy separation of the catalyst from the reaction mixture without considerable loss of activity.

  • Open access
  • 92 Reads
Synthesis and biological activity of 2-phenylbenzofuran derivatives as butyrylcholinerase inhibitors

Alzheimer disease (AD) is an irreversible and progressive brain disorder characterized by progressive memory loss and a wide range of cognitive impairments. An accepted strategy towards its treatment is to restore the levels of acetylcholine by inhibiting cholinesterase enzymes, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). BChE activity progressively increases in patients with AD, while AChE activity remains unchanged or declines, with changes that become more and more pronounced during the disease course. Therefore, compounds that selectively interact with BChE might have a relevant role in treatment of patients with advanced AD.

Benzofuran scaffold has drawn considerable attention over the last few years due to its profound physiological and chemotherapeutic properties. In our recent study, a series of 2-phenylbezonfurans compounds were synthesized and their inhibition activity towards both the enzymes were investigated. These compounds showed no inhibition toward AChE while inhibited BChE with different efficiencies. In addition to biological assays, molecular dynamics simulations allowed highlighting the molecular basis of the selective BChE inhibition by the benzofuran scaffold.

Based on these previous results, in the current work we have designed new 2-benzofurans derivatives in order to increase the strength of enzyme inhibition. We have used the Wittig reaction as a key step of a good methodology for the efficient and general synthesis of a selected series of 2-phenylbenzofurans. For all the compounds of the series, the IC50 values were determined.

In this scenario, our findings could be extended to design and develop new potentially therapeutic molecules, especially useful in neurodegenerative diseases.

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