One-pot synthesis and luminescent spectra of 3-allyl substituted quinazoline-2,4-dione derivatives as allyl capping agents

3-Nitro-N-(phenylsulphonyloxy)phthalimide (IIIa) and N-(phenylsulphonyloxy)phthalimide (IIIb) were synthesised as key intermediates in good yield. Their structures were confirmed by ¹H NMR and FTIR spectral data. The reaction of the key intermediates with allylamine produced 3-allyl-5-nitroquinazoline-2,4-(1H,3H)-dione (IVa) and 3-allylquinazoline-2,4-(1H,3H)-dione (IVb), respectively. Luminescence emission and excitation spectra of IVa and IVb are also presented.     

Reactions of 1,3-dibromopropyne with 1-aroyl-2,2-dimethylhydrazines as a new method for the synthesis of substituted 1,3,4-oxadiazinium bromides

Reactions of 1-aroyl-2,2-dimethylhydrazines with 1,3-dibromopropyne in MeOH or MeCN at 20—50 °C yield 2-aryl-6-bromomethylidene-4,4-dimethyl-5H-1,3,4-oxadiazinium bromides.     

An efficient synthesis of some new 3-bipyridinyl substituted coumarins as potent antimicrobial agents

As a part of the ongoing studies in developing new antimicrobials,a series of structurally novel 3- bipyridinyl substituted coumarin derivatives 4a-f and 5a-f were synthesized by a single-step reaction protocol under Krohnke’s reaction conditions.¹H NMR,¹³C NMR,IR and mass spectral techniques were employed for the structural elucidation of the synthesized compounds.An evaluation of antimicrobial activity showed that almost all compounds exhibited better results than the referenced drugs.Among the synthesized derivatives 4f,5a and 5d were found to be the most potent analogs.Thus they could be promising lead for novel drugs.     

Convenient synthesis of novel sulfonamide derivatives as promising anticancer agents

Novel sulfonamide derivatives have been synthesized from the readily accessible N-(4-acetylphenyl)benzenesulfonamide (1) . Condensation of 1 with phenylhydrazine in refluxing ethyl alcohol gave the corresponding phenylhydrazone 2 , which was then added to the Vilsmeier-Haack reagent (POCl₃/DMF) to give the 4-formylpyrazole derivative 3 . Fusion of 1 with thiourea in the presence of iodine at 130°C afforded the 2-aminothiazole derivative 4 . Refluxing 1 with an excess of N, N-dimethylformamide dimethyl acetal furnished the enaminone 5 . The chemical reactivity of enaminone 5 toward some nitrogen and carbon nucleophiles has been studied to obtain polyfunctionalized heteroaromatic systems bearing a sulfonamide moiety. Besides, the enaminone 5 undergoes the Gewald reaction and reacts with ethyl cyanoacetate and elemental sulfur in the presence of morpholine to yield the 2-aminothiophene derivative 18 . Moreover, the utility of 5 for the synthesis of 4-(phenylsulfonamido)benzoic acid (19) was investigated. The synthesized sulfonamides were evaluated for their in vitro cytotoxic activities against two human cell lines, MCF-7 (breast adenocarcinoma cells) and RPE-1 (normal retina pigmented epithelium cells). The results revealed that compounds 1-3 , 6-8 , 10 , 12b , 18 , 19 , and 21 have a potent cytotoxic effect on MCF-7 and less on RPE-1 cells compared to the positive control doxorubicin®.     

Stereoselective synthesis of functionalized vinyl ethers from allyl bromides activated by triethylamine

An efficient coupling reaction of allyl bromides with various alcohols as nucleophiles activated by triethylamine, leading to functionalized vinyl ethers in good yields and with full stereoselectivity.     

Indium-mediated allenylation of arylacyl bromides in a route for the synthesis of substituted furans

A three-step, single purification procedure has been developed for the concise synthesis of substituted furans from arylacyl bromides.     

An efficient green approach for the synthesis of benzothiazole-linked pyranopyrazoles as promising pharmacological agents and docking studies

Benzothiazole-tethered pyranopyrazoles derivatives were prepared via environmentally favorable conditions, which included eco-friendly catalyst, ethanol−water solvent, one-pot reaction, and atom- and step-economy procedures. Excellent yield of the products was observed. Besides, all products were screened for their antimicrobial behavior. From the biological results, it was seen that most of the compounds possessed high to moderate antimicrobial properties. Compound 6a gave prominent antimicrobial property followed by 6d , 6l , and 6n . In addition, computer-aided studies of the active compounds were also conducted. In this, selected compounds were docked into the intercalation site of DNA of the DNA−gyrase complex. From these results, the highest binding energy of −10.1 kcal/mol was for 6a against DNA−gyrase. This is the first eco-friendly synthetic method for the preparation of benzothiazole-pyranopyrazoles and the synthetic effort in this study may serve as a model for additional environmentally benign reactions. The biological results may prompt further studies related to antibiotic drugs.     

A novel synthesis for new substituted imidazoles

The addition of dimethyl acethylendicarboxylate (DMAD) to thiosemicarbazone and guanylhydrazone of aldehydes afforded compoundes which were characterized to be new substituted imidazoles. Their structures were determined by ¹H NMR, IR, mass spectra and elemental analyses.     

A new general synthesis of functionally substituted pyrazolo[1,5-a]pyrimidines

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Several convenient methods for the synthesis of 2-amido substituted furans

Several new methods for the synthesis of differently substituted 2-amidofurans are described. The thermolysis of furan-2-carbonyl azide results in a Curtius rearrangement and the resulting furanyl isocyanate was trapped with various organometallic reagents. A second method consists of a C-N cross-coupling reaction of a bromo-substituted furan with various amides, carbamates, and lactams. The CuI-catalyzed cross-coupling reaction between furanyl bromides and amides furnished 2- and 3-substituted amidofurans in 45-95% yield. The third protocol used involves the reaction of cyclic carbinol amides with triflic anhydride. The reaction proceeds under very mild conditions to provide alpha-(trifluoromethyl)sulfonamido-substituted furans in high yield. The resulting iminium ion derived from the reaction of the hydroxy pyrrolidinone with Tf(2)O undergoes a facile ring opening as a consequence of the adjacent hydroxyl group to produce an imino triflate intermediate. Subsequent cyclization of this highly electrophilic imine with the oxygen atom of the adjacent carbonyl group leads to an imino dihydrofuran that reacts further with another equivalent of Tf(2)O to give the observed product.     

3-Naphthylindoles as new promising candidate antioxidant,antibacterial, and antibiofilm agents

Research on Chemical Intermediates - Indole derivatives have attracted significant attention in organic synthesis and bioactivity research owing to their substantial biological activity. In the...     

Efficient methods for the synthesis of 2-hydroxyphenazine based on the Pd-catalyzed N-arylation of aryl bromides

[reaction: see text] Substituted diphenylamines can be synthesized by Pd(0)-catalyzed N-arylation using o-nitroanilines and nitro-substituted aryl bromides for a substrate. Cyclization of the diphenylamines by various methods, including the intramolecular Pd(0)-catalyzed N-arylation, produces 2-methoxyphenazine which can easily be deprotected to give 2-hydroxyphenazine. This phenazine is required to synthesize methanophenazine, a novel redoxactive cofactor isolated from methanogenic archaea.     

Low-toxicity complexes with nitrogen-containing ligands as promising new agents for treatment and prevention of free radical states

A method for synthesis of complexes with 1,5-pentamethylenetetrazole ligand was proposed. These compounds hold promise for antioxidant treatment of so-called “free radical” diseases of different geneses, including those caused by unfavorable environmental factors. The antioxidant activity of the complexes synthesized was tested by two independent methods: by assessing the ability to inhibit lipid peroxidation and by measuring the SOD-like activity.     

An effective green and ecofriendly catalyst for synthesis of bis(indolyl)methanes as promising antimicrobial agents

An effective and suitable meglumine‐catalyzed high‐yielding process was considered and engaged for the synthesis of new bis(indolyl)methanes at ambient temperature under aqueous conditions. The catalytic reaction proceeds very smoothly. Clean reaction, ease of product isolation/purification, easily available reactant and ecofriendly reaction conditions are the notable advantages of the present methodology. All the title compounds were characterized by IR, 1H, ¹³C NMR, and mass spectra. All the synthesized compounds were tested for antimicrobial activity, and the results indicated that most of the synthesized compounds exhibited excellent activity against the tested microorganisms. In this new series, compound 3l , having nitro substituent on the aromatic ring, showed exceptional potent inhibitory activity against Pseudomonas aeruginosa and Penicillium chrysogenum.     

1,2,4-Thiadiazoles as promising multifunctional agents for treatment of neurodegenerative diseases

Detailed studies of properties of new 3-substituted 5-anilino-1,2,4-thiadiazoles containing different substituents at position 3 of the thiadiazole ring were carried out, in particular, their esterase profile and antioxidant properties. It was found that the presence in the molecule of 2-aminopropyl fragment determines an efficient and selective inhibition of butyrylcholinesterase as compared to acetylcholinesterase and carboxylesterase, with radical-scavenging activity being weak. The compounds containing a 2-aminopropenyl fragment possess a high radicalscavenging activity, weakly inhibit cholinesterases, and exhibit anticarboxylesterase activity. A wide spectrum of activity of 3-substituted 5-anilino-1,2,4-thiadiazoles as inhibitors of cholinesterases and highly efficient scavengers of free radicals gives a basis for the optimization of structure and development in this series of original agents for therapy of neurodegenerative diseases.     

Cyclic sulfamidates as vehicles for the synthesis of substituted lactams

[reaction: see text] A structurally diverse series of mono- and disubstituted 1,2- and 1,3-cyclic sulfamidates react with stabilized enolates, including malonate and phosphonoacetate variants, to provide, after lactamization, substituted and alpha-functionalized pyrrolidinone and piperidinone derivatives.