An eco-friendly N-sulfonylation of amines using stable and reusable Zn-Al-hydrotalcite solid base catalyst under ultrasound irradiation

Ultrasound-Assisted 1,3-Dipolar Cycloadditions Reaction Utilizing Ni-Mg-Fe LDH: A Green and Sustainable Perspective

Ultrasound-assisted synthesis of novel pyrazoles using Ni-Mg-Fe LDH as a catalyst in cyclopentyl methyl ether (CPME) is introduced. Different LDHs were tested as a catalyst for the synthesis of pyrazoles via a 1,3-dipolar cycloaddition reaction. Among them, Ni-Mg-Fe LDH was the superior catalyst for this reaction. This protocol offered high yields, a short reaction time, and a green solvent, and with the reuse of this catalyst six times with the same activity, it could be regarded as an ecofriendly, greener process. The NiMgFe LDH catalyst with the smallest particle size (29 nm) and largest surface area showed its superior efficacy for the 1,3 dipolar cycloaddition rection and can be successfully used in up to six catalytic cycles with little loss of catalytic activity. A plausible mechanism for this reaction over the Ni-Mg-Fe LDH is proposed.

Explorative Sonophotocatalytic Study of C-H Arylation Reaction of Pyrazoles Utilizing a Novel Sonophotoreactor for Green and Sustainable Organic Synthesis

The development of a mild, general, and green method for the C-H arylation of pyrazoles with relatively unreactive aryl halides is an ongoing challenge in organic synthesis. We describe herein a novel sonophotoreactor based on an ultrasonic cleaning bath and blue LED light (visible light) that induce copper-catalyzed monoarylation for pharmacologically relevant pyrazoles. The hybrid effect of ultrasonic irradiation and blue LED is discussed to interpret the observed synergistic action. A broad array of pyrazoles coupled with iodobenzene avoids expensive palladium metal or salts, and certain designed substrates were attained. Only comparatively inexpensive copper(I)iodide and 1,10-phenanthroline were used all together as the catalyst. The presented technique is a greener way to create C-H arylation of pyrazoles. It significantly reduces the amount of energy needed.

Ultrasonic-Assisted Michael Addition of Arylhalide to Activated Olefins Utilizing Nanosized CoMgAl-Layered Double Hydroxide Catalysts

An efficient cobalt-based layered double hydroxide (LDH)-catalyzed Michael addition of an aryl halide compound onto activated olefin as a Michael acceptor is described. The synthesized catalytic materials were characterized using different techniques to investigate their physicochemical, morphological, and textural properties. The partial isomorphic substitution of magnesium by cobalt ions in the cationic sheets of the layered double hydroxide (CoMgAl-LDH) appears to be an appropriate catalyst to cause this reaction. This technique enables compound synthesis resulting from the 1,4-addition in good to excellent yields. Moreover, ultrasound was found to have beneficial effect on this reaction due to the cavitation phenomenon.

Design, synthesis of novel Triazolones and bis-Triazolones derivatives under ultrasound irradiation and evaluation as potent angiotensin converting enzyme (ACE) inhibitors

The condensation of several primary amines and diamines with various N¹-ethoxycarbonyles N¹-tosylhydrazonates (1a-b), triazolones (2) and bis-triazolone (3) resulted in ethanol under ultrasound irradiation. Compared with the conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields. The newly synthesized compounds were evaluated for angiotensin I-converting enzyme (ACE) inhibition. The results were compared to Captopril as a reference drug. Compounds 3b, 2h, 3a, 2d, and 2f showed not only inhibition activity with IC₅₀ values of 0.162, 0.253, 0.253, 0.281 and 0.382 µM, respectively, but also minimal toxicity. The docking of chemical compounds in the ACE active site showed possible inhibitory effect of all compounds on the catalytic activity of the enzyme, which would satisfactorily explain the anti-hypertensive effect of these compounds.

Sonochemical synthesis of novel pyrano[3,4-e][1,3]oxazines: A green protocol

The atom-efficient and green protocol for formation of pyrano[3,4-e][1,3]oxazines utilizing dimethyl carbonate under ultrasound irradiation in a presence of KF/basic alumina was reported. We provide a novel series of pyrano[3,4-e][1,3]oxazine derivatives interesting for biological screening tests. In general, it was found that ultrasound irradiations enable the reactions to occur which could not be carried out under silent conditions. These remarkable effects appeared in sonicated reactions can be reasonably interpreted in terms of acoustic cavitation phenomenon. Structures of the products were established on analytical and spectral data. This protocol offers several advantages attain many principles of green chemistry including, save energy, atom economy, clean reactions, inexpensive green reagent and use catalysts rather than stoichiometric reagents.

N-Sulfonylation of amines, imides, amides and anilides using p-TsCl in presence of atomized sodium in EtOH-THF under sonic condition

A simple, facile and an efficient procedure for the N-sulfonylation of amines, imides, amides and anilides using p-TsCl in the presence of atomized sodium in a mixture of EtOH-THF under sonic condition is developed. The method is rapid, mild and inexpensive; yields are high and the reactions go to completion within 2-8 min.

Synthesis of 1,8-Naphthyridine Derivatives under Ultrasound Irradiation and Cytotoxic Activity against HepG2 Cell Lines

Novel pyrazole derivatives3a,b,5, 1,3,4-oxadiazole6, 1,3,4-thiadiazole8, and 1,2,4-triazole9a–cincorporated into 1,8-naphthyridine have been synthesized using the versatile synthon 2-(2,7-dimethyl-1,8-naphthyridin-4-yloxy) acetohydrazide1. An improvement in rates and yields was observed when the reactions were carried out under ultrasonic irradiation compared with the classical synthesis. The newly synthesized compounds were evaluated for HepG2 cell growth inhibition. The results obtained revealed that the tested compounds possess inhibitory effect on the growth of HepG2 liver cancer cells. The results were compared to doxorubicin (DOX) as a reference drug (IC50 : 0.04 μM). Compounds9bshowed the highest inhibition activity against HepG2 cell line (IC50 : 0.048 μM) among all tested compounds.

A simple and eco-sustainable method for the sulfonylation of amines under microwave-assisted solvent-free conditions

A new environmentally benign, simple, and efficient protocol for the sulfonylation of amines using microwave irradiation under solvent- & catalyst-free conditions is reported. The corresponding sulfonamides were obtained in excellent yields within short reaction times.

Ultrasound-promoted green approach for the synthesis of sulfonamides using natural, stable and reusable Natrolite nanozeolite catalyst at room temperature

Natural Natrolite nanozeolite has been investigated as an efficient and reusable catalyst for the N-sulfonylation of amines under ultrasound irradiation at room temperature. Compared with traditional methods, the significant advantages for method are green solvent, milder and cleaner conditions, higher purity and yields, shorter reaction time, easier work-up procedure and the lower generation of waste or pollutions. The catalyst can be recovered and reused several times without significant loss of its catalytic activity.

Divergent reaction pathways for one-pot, three-component synthesis of novel 4H-pyrano[3,2-h]quinolines under ultrasound irradiation

The present paper deal with the multi-component condensation of 8-hydroxy quinoline, aromatic aldehydes, and sulfone derivatives catalyzed by p-toluenesulfonic acid for the synthesis of a series of 4H-pyrano[3,2-h]quinoline derivatives in ethanol under ultrasonic irradiations. We provide a series of quinoline derivatives containing sulfone moiety interesting for biological screening tests. The reactions were carried out under both conventional and ultrasonic irradiation conditions. In general, improvement in rates and yields were observed when reactions were carried out under sonication compared with classical silent conditions. Also, also, sonochemical reaction give different reaction pathway other than silent reaction. These remarkable effects appeared in sonicated reactions can be reasonably interpreted in terms of acoustic cavitation phenomenon. Structures of the products were established on analytical and spectral data.

Ultrasonic irradiation assisted efficient regioselective synthesis of CF3-containing pyrazoles catalyzed by Cu(OTf)2/Et3N

Background

Most of the known approaches to the synthesis of CF₃-containing organic compounds suffer from serious drawbacks. For example the starting materials required for these methods are rather difficult to obtain, or they are fairly toxic and inconvenient to work with and methods for direct fluorination and trifluoromethylation do not always allow the introduction of the CF₃-group at the required position of a molecule.

Results

An efficient and attractive regioselective synthesis of a series of novel pyrazoles containing the trifluromethyl moiety was achieved using Cu(OTf)₂/Et₃N as an efficient catalytic system under ultrasonic irradiation.

Conclusions

Cu(OTf)₂/Et₃N catalyst showed a great advantage over all the investigated catalysts, and the ultrasonic irradiation method offered high yields of pyrazoles in short reaction time compared with classical conditions. gHMBC spectra of the product were used to rationalize the observed regioselectivity.

Comparative Studies on Conventional and Ultrasound-Assisted Synthesis of Novel Homoallylic Alcohol Derivatives Linked to Sulfonyl Dibenzene Moiety in Aqueous Media

Novel homoallylic alcohols incorporating sulfone moieties were synthesized by the treatment of different carbonyl compounds with allylic bromides in aqueous mediaviasonochemical Barbier-type reaction conditions. Sulfonation ofα-bromoketones with sodium benzenesulfinate in presence of CuI/2,6-lutidine rapidly gaveβ-keto-sulfones in good yields. In general, ultrasound irradiation offered the advantages of high yields, short reaction times, and simplicity compared to the conventional methods. The structures of all the compounds were confirmed by analytical and spectral data.

Ultrasound promoted synthesis of some novel fused pyrans

Novel fused pyrans were synthesized from the reaction of the tetrahydropyran-4-one with arylidine malononitriles. Different fused pyran derivatives were obtained from the mentioned reaction depending on type of catalyst used and type of energy used. Reactions were carried out under silent and ultrasonic conditions. In general, it was found that sometimes ultrasound irradiations change the reaction path in comparing with silent condition. In addition to improvement in reaction times, the products were obtained in high yields and their structures were determined by elemental analyses, spectral data.

Ultrasound assisted one-pot, three-components synthesis of pyrimido[1,2-a]benzimidazoles and pyrazolo[3,4-b]pyridines: A new access via phenylsulfone synthon

A simple, facile, efficient and three-components procedure for the synthesis of pyrimido[1,2-a]benzimidazoles and pyrazolo[3,4-b]pyridines utilizing phenylsulfone synthon, under ultrasonic irradiation was developed.