Novel Carbon–Carbon Bond Formation between N‐Methyl‐3‐phenyl‐3‐hydroxypropylamine and Cresols Catalyzed by p‐Toluenesulphonic Acid

The p‐toluenesulphonic acid–catalyzed reaction between appropriate cresols and N‐methyl‐3‐phenyl‐3‐hydroxypropylamine in refluxing toluene resulted in the formation of o‐substituted phenol derivatives by an aromatic nucleophilic substitution reaction.     

Synthesis,spectral analysis,and <Emphasis Type="Italic">in vitro</Emphasis> microbiological evaluation of ethyl 7,9-diaryl-1, 4-diazaspiro[4.5]dec-9-ene-6- carboxylates as a new class of antibacterial and antifungal agents

A series of novel ethyl 7,9-diaryl-1,4-diazaspiro[4.5]dec-9-ene-6-carboxylates was synthesized by the reaction of ethyl 4,6-diaryl-2-oxocyclohex-3-ene-1-carboxylates with ethylenediamine in the presence of p-toluenesulfonic acid without a solvent under focused microwave irradiation. The title compounds were screened for their antimicrobial activities against a spectrum of clinically isolated microorganisms.     

New environmentally-friendly solvent-free synthesis of imines using calcium oxide under microwave irradiation

Condensation of structurally diverse aldehydes including heterocyclic aldehydes, like furfural, with various amines in the presence of calcium oxide affording the corresponding imines in solvent-free conditions in good to excellent yields under microwave irradiation is described. A comparative study has been done under thermal conditions. The synergy between dry media and microwave irradiation in this reaction is evaluated by condensing less electrophilic aldehydes with poorly nucleophilic amines. The main advantages of this environmentally friendly protocol are the use of the non-toxic and inexpensive reagent calcium oxide and the considerable rate enhancement in comparison with a thermal reaction.     

Solvent-free one-pot synthesis,characterization, antibacterial and antifungal activities of novel spiropiperidinyl-1,2,4-triazolidine-3-thiones

A novel approach towards the synthesis of spiropiperidinyl 1,2,4-triazolidine-3-thiones was proposed, exploiting microwave activation coupled with solvent-free reaction conditions. In search for new leads towards potent antimicrobial agents, we tested all the synthesized compounds for their in vitro antibacterial activity against Bacillus subtilis and Micrococcus luteus and antifungal activity against Aspergillus niger, Candida albicans, Candida-6, and Candida-51. Two of the compounds exerted strong in vitro antibacterial activity against B. subtilis and M. luteus, and all the synthesized compounds were potent against the tested fungal strains.     

Spectral characterization of novel <Emphasis Type="Italic">bis</Emphasis> heterocycles comprising both piperidine and thiohydantoin nuclei

Abstract  

A series of bis heterocycles comprising both piperidine and thiohydantoin nuclei namely 3-(3-alkyl-2,6-diarylpiperin-4-ylidene)-2-thioxoimidazolidin-4-ones is synthesized and characterized by melting point, elemental analysis, MS, FT–IR, one-dimensional NMR (¹H, D₂O exchanged ¹H and ¹³C), two-dimensional HOMOCOSY, and NOESY spectroscopic data.     

Synthesis and characterization of 4,6-diaryl-4,5-dihydro-2H-indazol-3-ols and 4,6-diaryl-2-phenyl-4,5-dihydro-2H-indazol-3-ols — a new series of fused indazole derivatives

A novel class of 4,6-diaryl-4,5-dihydro-2H-indazol-3-ols and 4,6-diaryl-2-phenyl-4,5-dihydro-2H-indazol-3-ols is synthesized and characterized by melting point, elemental analysis, MS, FT-IR, ¹H and ¹³C NMR, D₂O exchanged ¹H NMR, and two-dimensional HSQC spectra. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1183–1188, August, 2008.     

Environmentally safe one-pot solvent-free synthesis of 6-aryl-1,2,4,5-tetrazinane-3-thiones(ones) catalyzed by NaHSO4-SiO2

One-pot condensation of thiourea (urea), diverse aromatic aldehydes, and ammonium acetate in the presence of repeatedly usable heterogeneous catalyst NaHSO₄-SiO₂ in the absence of solvent under the microwave irradiation proceeds faster and with better yields of 6-aryl-1,2,4,5-tetrazinane-3-thiones(ones) that under common heating. Compounds synthesized exist as a rule as two isomers distinguished by the position of the phenyl ring: It is located in the major isomer nearly in the equatorial position, in the minor one, close to axial position.