Green production and antioxidant activity study of new pyrrolo[2,1-a]isoquinolines

In current research, pyrrolo[2,1-a]isoquinoline derivative are synthesized via a new process of four component reaction of phthalaldehyde or its derivatives, primary amines, alkyl bromides, activated acetylenic compounds and potassium fluoride/Clinoptilolite nanoparticles (KF/CP NPs) under solvent-free conditions at room temperature. Also, Dielz-Alder reactions take place in the reaction of synthesized pyrrolo[2,1-a]isoquinoline derivatives, activated acetylenic compounds and triphenylphosphine in the presence of KF/CP NPs under solvent-free conditions at room temperature. As well, antioxidation property of some prepared pyrrolo[2,1-a]isoquinolines are investigated by employing of trapping diphenyl-picrylhydrazine (DPPH) radical and ability of ferric reduction experiment. Among investigated compounds, compounds 5c have good results relative to BHT and TBHQ as standard antioxidant. Our procedure has a few benefits relative to reported method such as good rate of reaction, product with high efficiency and simple removal of catalyst from mixture of reaction. In these reactions, KF/Clinoptilolite nanoparticles show a satisfactory recyclable activity.     

ZnO/Fe3O4 nanoparticles promoted green synthesis of pyrazolo pyrimidinones: Study of antioxidant activity

The preparation of pyrazolo pyrimidinone derivatives was performed by using five component reactions of phthalaldehyde, cyanomethylamine, electron deficient acetylenic compounds, isocyanate, hydrazine, and catalytic amounts of ZnO/Fe₃O₄-magnetic nanoparticles as a high performance catalyst under ultrasonic conditions at ambient temperature in aquause media at room temperature. It should be mentioned that this catalyst was prepared using Spinacia oleracea water extract. In addition, for investigation of antioxidant ability, radical trapping by DPPH and reducing power of ferric ion experiments was performed. As a result, synthesized compounds show excellent radical trapping by DPPH and good reducing ability of ferric ion. The current procedure has the benefits for instance excellent yield of reaction, green media, and easy separation of product and catalyst.     

Multicomponent reactions for the synthesis of new cyclopentadienephosphonate derivatives in water

A series of polysubstituted cyclopentadienephosphonate derivatives were synthesized via one-pot multicomponent reactions of primary amines and phosphites with activated acetylenic compounds in water as the solvent at room temperature.

Particularly valuable features of this method include high yields of products, broad substrate scope, short reaction time and a straightforward procedure.     

KF负载氧化物高效催化缺电子烯与胺类的共轭加成反应

提供了一种新型高效的催化缺电子烯与胺类的共扼加成的反应体系。首先合成了一系列负载型氟化钾固体碱,并用于催化上述反应。通过对不同载体选择考察,筛选出氟化钾负载氧化镁固体碱为最佳催化剂。在进一步的催化反应过程中发现,该催化剂对反应具有很高的催化活性,能催化该反应在短短数分钟内完成。操作简单方便,不需要任何溶剂,催化剂价格低廉,反应收率高,可重复使用,具有化学选择性,适用范围广泛等均为该催化体系的主要特征。     

KF/clinoptilolite nanoparticles as a novel catalyst for the green synthesis of chromens using three component reactions of 4‐hydroxycoumarins: Study of antioxidant activity

In this research, the green synthesis of chromen derivatives in good yields is described via three‐component reactions of 4‐hydroxycumarine, aldehydes or ketones, and methyl ketones in the presence of KF/clinoptilolite nanoparticles (KF/CP‐NPs) under solvent‐free conditions at 50°C in low time. The present methodology suggests some advantages such as low reaction time, easy and simple procedure, green method, inexpensive catalyst, high yield of product, and existence of different substrates for performing these reactions. In addition, it should be mentioned that antioxidant activity was studied for some prepared compounds, such as 4a–4d, by DPPH radical trapping and reducing potential tests of ferric ion and then comparing results with TBHQ and BHT as synthetic antioxidants. In this study, compounds 4c was shown to have moderate DPPH radical trapping, and compounds 4b and 4d displayed good reducing power of ferric ion.     

Aza-Michael addition of aliphatic or aromatic amines to α,β-unsaturated compounds catalyzed by a DBU-derived ionic liquid under solvent-free conditions

A task-specific ionic liquid, 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium acetate has been successfully used as a catalyst for aza-conjugate addition of aliphatic or aromatic amines to various electron deficient alkenes under solvent-free conditions and at room temperature. The catalyst can be reused for six times without noticeable loss of activity.     

Novel efficient procedure for the conjugate addition of amines to electron deficient alkenes

The novel efficient procedure has been developed for the conjugate addition of amines to electron deficient alkenes using the novel SO₃H functionalized ionic liquid as catalyst. The results showed that the novel catalyst owned high activities for the reactions with excellent yields within several minutes. Various amines and electron deficient alkenes were successfully transformed to the corresponding products in the catalytic system. Operational simplicity, without need of any solvent, low cost of the catalyst used, room temperature, high yields, reusability, excellent chemoselectivity and wide applicability are the key features of this methodology.     

Vanadyl(IV) Acetate: An Efficient,Reusable Heterogenous Catalyst for Aza-Michael Reaction Under Solvent-Free Conditions

Vanadyl(IV) acetate [VO(OAc)₂] efficiently catalyzes the conjugate addition of aliphatic, aromatic amines to α,β-unsaturated carbonyl compounds in solvent-free media at room temperature to afford corresponding amino compounds in good to excellent yields. The catalyst can be recovered and reused for further cycles.     

Synthesis of Furanone Derivatives Using 15‐Nonacosanole Extracted from Fumaria officinalis in the Presence of KF/Clinoptilolite Nanoparticles

Synthesis of a variety of furanone derivatives is described using multicomponent reaction of 15‐nonacosanole extracted from Fumaria officinalis , electron‐deficient acetylenic compounds, and epoxides in the presence of catalytic amount of nano KF/Clinoptilolite. Aerial parts of F. officinalis were collected from Alborz Mountains (north of Iran) in September 2014. Voucher specimens (2625T) were deposited in the chemistry department of Qaemshahr University in Mazandaran‐Iran.     

ZnO-nanoparticle-promoted synthesis of polyhydroquinoline derivatives via multicomponent Hantzsch reaction

Abstract  

Zinc oxide nanoparticles are used as an effective and reusable catalyst for one-pot, four-component couplings of aldehydes, dimedone, active methylene compounds, and ammonium acetate to produce polyhydroquinoline derivatives under solvent-free conditions at room temperature. Compared with other methods, satisfactory results are obtained with high yields, short reaction times, and simplicity in the experimental procedure. The catalyst could easily be recycled and reused four times without noticeable decrease in catalytic activity.     

Novel one-pot, three-component synthesis of new 2-alkyl-5-aryl-(1H)-pyrrole-4-ol in water

New 2-alkyl-5-aryl-(1H)-pyrrole-4-ol derivatives were synthesized via three-component reaction of beta-dicarbonyl compounds with arylglyoxals in the presence of ammonium acetate in water at room temperature.     

A microwave-assisted bismuth nitrate-catalyzed unique route toward 1,4-dihydropyridines

The classical Hantzsch reaction is one of the simplest and most economical methods for the synthesis of biologically important and pharmacologically useful 1,4-dihydropyridine derivatives. Bismuth nitrate pentahydrate under microwave irradiation is proven to act as a very efficient catalyst for a one-pot, three-component synthesis of 1,4-dihydropyridines in excellent yields from diverse amines/ammonium acetate, aldehydes and 1,3-dicarbonyl compounds within 1-3 min under solvent-free conditions. The present environmentally benign procedure for the synthesis of 1,4-dihydropyridines is suitable for library synthesis and it will find application in the synthesis of potent biologically active molecules. The excellent yield and extreme rapidity of the method is due to a concurrent effect of the catalyst and microwave irradiation.     

Water-promoted highly regio- and stereoselective synthesis of α-dehydro-β-amino esters and nitriles from Baylis-Hillman acetates

The nucleophilic addition of amines to Baylis-Hillman acetates has been efficiently carried out in water at room temperature in the absence of any base, acid, or metal catalyst to produce α-dehydro-β-amino esters and nitriles. This procedure addresses a variety of aliphatic open-chain and cyclic amines and anilines. All the reactions are highly regio- and stereoselective, fast and high yielding.     

Copper(II) Oxide Nanoparticles Impregnated on Melamine‐Modified UiO‐66‐NH2 Metal–Organic Framework for C–N Cross‐Coupling Reaction and Synthesis of 2‐Substituted Benzimidazoles

A zirconium‐based metal–organic framework, UiO‐66‐NH₂, modified by melamine (Mlm) was used as a support for CuO nanoparticles (NPs). Melamine offered a platform for uniform and homogeneous distribution of NPs on the surface of the frameworks and made a strong bonding to the NPs to avoid undesirable leaching. UiO‐66‐NH₂‐Mlm/CuO NPs were used for the Buchwald–Hartwig C–N cross‐coupling reaction to synthesize arylated anilines from phenyl iodide, bromide, and chloride and primary and secondary amines in DMF at 110°C. The catalyst was also employed for the synthesis of 2‐substituted benzimidazole derivatives from various aromatic aldehydes and o‐phenylenediamine in the absence of an oxidant in EtOH at room temperature. The catalyst was recyclable and reusable for several times and exhibited good stability (examined by BET, XRD, and SEM–EDX) in reaction conditions.     

The one-pot process for the preparation of <Emphasis Type="Italic">N</Emphasis>-monoalkyl aromatic amines from nitroarene derivatives

A series of N-monoalkyl aromatic amines are synthesized in high yields from corresponding nitroarene derivatives, aldehydes, and ammonium formate in the presence of Pd/C as a catalyst through one-pot operations at room temperature. Both the conversion and selectivity of the process are above 80%. Optimum reaction conditions are investigated, and it is found that the optimum molar ratio of nitroarene derivatives to ammonium formate and the optimum weight ratio of nitroarene derivatives to Pd/C are 1/4 and 1/0.10, respectively. These experiments provide a novel access for N-monoalkyl aromatic amines with advantages of simplicity, high selectivity, and environmental benignity.     

Catalyst-free green synthesis and study of antioxidant activity of new pyrazole derivatives

In this research, a novel procedure for the synthesis of pyrazole derivatives in excellent yields was studied using catalyst-free multicomponent reaction of isoquinoline, activated acetylenic compounds, alkyl bromides, triphenylphosphine and hydrazine in water under ultrasonic irradiation at room temperature. The advantages of this procedure than to reported methods are short time of reaction, high yields of product, easy separation of product, clean mixture of reaction and green media for performing reaction. In addition, because of having pyrazole and isoquinoline core in the synthesized compounds, in this research, antioxidant activity of some synthesized compounds was investigated.     

Fluorodensitometric determination of compounds containing primary amino groups with o-phthalaldehyde after separation by HPTLC

Summary The applicability to TLC of the o-phthalaldehydereaction with compounds containing primary amino groups is demonstrated. o-Phthalaldehydehyde rapidly forms fluorescent derivatives with primary amines in the presence of mercaptoethanol at room temperature. The reaction is carried out as a dipping procedure and is applied to the quantitative determination of some sympaticomimetics, central stimulants and hallucinogens in the picomole range.     

Hydrated ferric sulfate catalyzed synthesis of 5,6-unsubstituted 1,4-dihydropyridines using three-component reaction

A wide variety of 5,6-unsubstituted 1,4-dihydropyridines derivatives (4a–q) were synthesized through a one-pot three-component reaction from α,β-unsaturated aldehydes, amines, and 1,3-diketones at room temperature using hydrated ferric sulfate as a Lewis acid catalyst. The key features of the present protocol are mild and simple reaction procedure, good to excellent yields, and use of inexpensive, recyclable, and environmentally benign catalyst.     

Synthesis of Spiro Pyrrolobenzothiazole Derivatives via a Three‐Component Reaction

A novel three‐component reaction involving 2‐methylbenzothiazole or 2,5‐dimethylbenzothiazole, acetylenic esters and 1,3‐dicarbonyl compounds such as (1,3‐dimethylbarbituric acid or 1,3‐indanedione) leading to the synthesis of spiro pyrrolobenzothiazole derivatives. The reactions proceeded smoothly at room temperature without using any catalyst. This method is very useful to functionalize benzothiazole derivatives in a one‐pot operation. The structures of the synthesized compounds have been characterized by spectral studies.     

Synthesis of pyrido[2,3-e]pyrrolo[1,2-a]pyrazine derivatives via tandem iminium cyclization and smiles rearrangement

The tandem iminium cyclization and Smiles rearrangement of pyridinyloxyacetaldehyde 1 and a primary amine generated a novel pyrido[2,3-e]pyrrolo[1,2-a]pyrazine scaffold. TFA was discovered to be an efficient catalyst in the reactions with aromatic amines, whereas TiCl4 was found to be superior in the case of aliphatic amines. This methodology proved to be efficient in the preparation of a library of diversified pyrido[2,3-e]pyrrolo[1,2-a]pyrazine derivatives.