Synthesis of Some 3‐(4‐Aryl‐benzofuro[3,2‐b]pyridin‐2‐yl)coumarins and Their Antimicrobial Screening

The synthesis of some 3‐(4‐aryl‐benzofuro[3,2‐b]pyridin‐2‐yl)coumarins 3a–r has been carried out by the reaction of 3‐coumarinoyl methyl pyridinium salts 1a–c with 2‐arylidene aurones 2a–f in the presence of ammonium acetate and acetic acid under Kröhnke's reaction conditions. All the synthesized compounds were characterized by analytical and spectral data. They have been screened for their antibacterial activity against Escherichia coli (ATCC 25922) as Gram‐negative bacteria, Bacillus subtillis (ATCC 1633) as Gram‐positive bacteria and antifungal activity against Aspergillus niger (ATCC 9029).     

Novel Approach for Rapid and Efficient Synthesis of 2‐(3‐(4‐Aryl)‐1‐isonicotinoyl‐4,5‐dihydro‐1H‐pyrazol‐4‐yl)‐3‐phenylthiazolidin‐4‐one Derivatives and Screened Their Antimicrobial Activity

A series of compounds, viz. 2‐(3‐(4‐aryl)‐1‐isonicotinoyl‐4,5‐dihydro‐1H‐pyrazol‐4‐yl)‐3‐phenylthiazolidin‐4‐one 4 ( a – n ), have been synthesized by reaction of 3 ( a – n ) with thioglycolic acid in the presence of zinc chloride. Compounds 3 ( a – n ) have been synthesized by amination of formylated pyrazoles 2 ( A – B ), which were synthesized by formylation of 1 ( A – B ) by Vilsmeier–Haack reagent (POCl₃/DMF). Compounds 1 ( A – B ) were synthesized by condensation of hydrazide and substituted acetophenones under conventional method and microwave irradiation method. These compounds were identified on the basis of melting point range, Rf values, infrared, ¹H NMR, and mass spectral analysis. These compounds were evaluated for their in vitro antimicrobial activity, and their minimum inhibitory concentration was determined. Among them, compound 4b and compound 4l possess appreciable antimicrobial and antifungal activities. Antibacterial activity results showed that compounds containing electron‐withdrawing groups were more active than compounds containing electron‐releasing groups.     

A “One Pot,” Environmentally Friendly,Multicomponent Synthesis of 2‐Amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines and Their Antimicrobial Activity

A series of multifunctional 2‐amino‐5‐cyano‐4‐[(2‐aryl)‐1H‐indol‐3‐yl]‐6‐hydroxypyrimidines ( 4a , 4b , 4c , 4d , 4e , 4f ) was synthesized by multicomponent reaction of 3‐formylindole ( 1 ), cyanoethylacetate ( 2 ), and guanidine hydrochloride ( 3 ) with NaOH by using green chemical techniques, viz. microwave irradiation and grindstone technology. The same reactants when refluxed in ethanol also gave titled compounds ( 4a , 4b , 4c , 4d , 4e , 4f ). Compared with conventional procedure, the reaction can be carried out under milder conditions, requiring a shorter reaction time and giving higher yields following the green chemistry methodology. All the synthesized compounds have been characterized on the basis of elemental analyses and spectral data (IR, ¹H NMR, ¹³C NMR, and mass). All synthesized compounds were also evaluated for their antimicrobial activity against nine pathogenic bacteria, antifungal activity against Rhizopus stolonifer, Aspergillus flavus, and Fusarium oxysporum and antibacterial activity against Escherichia coli and Pseudomonas aeruginosa at different concentrations. Most of the compounds showed mild to moderate activity.     

Synthesis,Characterization, and Biological Evaluation of Novel 3‐(4‐Chlorophenyl)‐2‐(substituted)quinazolin‐4(3H)‐one Derivatives as Multi‐target Anti‐inflammatory Agents

A novel class of 3‐(4‐chlorophenyl)‐2‐(substituted)quinazolin‐4(3H)‐one derivatives were synthesized, and the structure of synthesized compounds was characterized by IR, ¹H NMR, and mass spectroscopy. The newly synthesized compounds ( 4a–g and 6a–g ) were tested for their in vitro cyclooxygenase (COX) inhibition activity. The compounds have inhibitory profile against both COX‐1 and COX‐2, and some of the compounds are found to be selective against COX‐2. The compound 6g showed distinct inhibitory activity on COXs. The synthesized compounds were evaluated for their potential anti‐inflammatory activity as inhibitors of the proinflammatory cytokines IL‐6. Compounds 4d – g showed the highest level of inhibition among all the tested compounds. Thus, our data suggested that these compounds may represent a new class of potent anti‐inflammatory agents.     

One‐step synthesis of aminopyrimidines from 5‐Oxo‐4H‐benzopyrans

Novel 4‐amino‐6‐aryl‐2‐phenylpyrimidine‐5‐carbonitriles have been prepared in one step procedure from the readily available 4‐aryl‐2‐amino‐3‐cyano‐5,6,7,8‐tetrahydro‐7,7‐dimethyl‐5‐oxo‐4H‐benzopyrans. The mass spectroscopy study under EI conditions shows molecular peaks with high intensity corresponding to the loss of benzonitrile from the C2 position of the pyrimidine ring. Semiempirical (AMI and PM3) and ab initio HF/6–31G* calculations reveal a favored distorted geometry where the three rings are not in the same plane.     

Synthesis of 5‐methyl‐4‐oxo‐2‐(coumarin‐3‐yl)‐N‐aryl‐3,4‐dihydrothieno[2,3‐d]‐pyrimidine‐6‐carboxamides

Possible approaches to synthesis of 5‐methyl‐4‐oxo‐2‐(coumarin‐3‐yl)‐N‐aryl‐3,4‐dihydrothieno[2,3‐d]pyrimidine‐6‐carboxamides 4 have been discussed. It is shown that the preferable approach is cyclization of 2‐iminocoumarin‐3‐carboxamides 1 , utilizing 5‐amino‐3‐methyl‐N²‐arylthiophene‐2,4‐dicarboxamides 2 as binucleophilic reagents. The proposed procedure allowed us to easily obtain 4 in two stages, using common reagents. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:341–346, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20303     

First synthesis of 2‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[h]chromen‐2‐yl)‐1‐naphthol and 3‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[g]chromen‐2‐yl)‐2‐naphthol from 1‐ and 2‐naphthol derivatives

Two new structurally isomeric, 2‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[h]chromen‐2‐yl)‐1‐naphthol ( 1 ) and 3‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[g]chromen‐2‐yl)‐2‐naphthol ( 3 ) have been synthesized from 2‐acetyl‐1‐naphthol and ethyl‐3‐hydroxy‐2‐naphthoate, respectively, involving Grignard reaction, dehydration of the corresponding tertiary alcohols, and hetero Diels–Alder dimerization. The two benzochromenes ( 1 and 3 ) have been fully characterized by IR, NMR, and HRESIMS data. Their structures are further supported by crystallography of their corresponding acetates ( 2 and 4 ). J. Heterocyclic Chem., (2011).     

Design,Synthesis, Characterization,and Antimicrobial Evaluation of Novel 2‐(3, 5‐di methoxy‐4‐((1‐aryl‐1H‐1, 2, 3‐triazole‐4‐yl) methoxy) phenyl) benzo[d]thiazoles

A series of 12 new 2‐(3, 5‐dimethoxy‐4‐((1‐Aryl‐4H‐1, 2, 3‐triazol‐4‐yl) methoxy) phenyl) benzo[d]thiazoles have been synthesized from the reaction of 4‐hydroxy‐3, 5‐dimethoxybenzaldehyde, o‐amino thiophenol, propargyl bromide, and different substituted aromatic azides using “click chemistry”. The structures of these compounds were established on the basis of Fourier Transform infrared, ¹H NMR, ¹³C–NMR, and mass spectral analysis. Compounds ( 6a–l ) were screened for in vitro antimicrobial activity.     

Protic Ionic Liquid Promoted One Pot Synthesis of 2‐amino‐4‐(phenyl)‐7‐methyl‐5‐oxo‐4H,5H‐pyrano[4,3‐b]pyran‐3‐carbonitrile Derivatives in Water and Their Antimycobacterial Activity

One pot three component reaction of 4‐hydroxy‐6‐methylpyran‐2‐one, 3‐methoxy benzaldehyde, and malononitrile in water using protic ionic liquid as a catalyst at room temperature afforded pyrano[4,3‐b]pyran derivatives. Protic ionic liquid has been proved to be an efficient and mild catalyst for the synthesis of pyrano[4,3‐b]pyran scaffolds due to their highly polar nature. The notable aspects of protic ionic liquid are easy availability, improved reaction rates, high product yields, simple workup procedure, recyclability, and reusability. Molecules docking studies have been performed on enzyme enoyl‐ACP‐reductase from Mycobacterium tuberculosis. The molecular docking simulation indicated plausible π‐alkyl and alkyl‐alkyl interactions between the amino acids and scaffolds. The synthesized derivatives have been evaluated for their in vitro antituberculotic activity against M. tuberculosis H₃₇RV strain using Microplate Alamar Blue Assay method. Together, biological activity data and docking data showed that the tested scaffolds exhibited excellent antituberculotic activity.     

Insecticidal Evaluation and [4+2] Aza‐Diels‐Alder Synthesis of 3,7‐Diaryl‐6,7‐dihydro‐5H‐6‐substituted Thiazolo[3,2‐a]pyrimidin‐5‐ones Under Coupled Ultrasonic Irradiation and PTC

A series of 3,7‐diaryl‐6,7‐dihydro‐5H‐6‐substituted‐thiazolo[3,2‐a]pyrimidin‐5‐ones ( 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j ) were synthesized by the [4+2] cycloaddition reaction of 2‐arylideneamino‐4‐arylthiazoles (2a–j) with in situ generated monosubstituted ketenes under PTC conditions coupled with ultrasonication in good to excellent yields. All the synthesized compounds were characterized on the basis of their spectral (IR, PMR, and Mass) and analytical data. The synthesized compounds were also screened for their insecticidal activity against Helicoverpa armigera and some of them showed promising activity.     

Two hydrazones derived from 1‐aryl‐3‐(p‐substituted phenyl)prop‐2‐en‐1‐one: synthesis,crystal structure,Hirshfeld surface analysis and in vitro biological properties

Two chalcones were synthesized by the aldolic condensation of enolizable aromatic ketones with substituted benzaldehydes under Claisen–Schmidt reaction conditions and then treated with 2,4‐dinitrophenylhydrazine to yield their corresponding hydrazones. The two (E,Z)‐2,4‐dinitrophenylhydrazone structures, namely (Z)‐1‐(2,4‐dinitrophenyl)‐2‐[(E)‐3‐(4‐methylphenyl)‐1‐phenylallylidene]hydrazine, C₂₂H₁₈N₄O₄, ( H1 ), and (Z)‐1‐[(E)‐3‐(4‐chlorophenyl)‐1‐(naphthalen‐1‐yl)allylidene]‐2‐(2,4‐dinitrophenyl)hydrazine, C₂₅H₁₇ClN₄O₄, ( H2 ), were isolated by recrystallization and characterized by FT–IR, UV–Vis, single‐crystal and powder X‐ray diffraction methods. The UV–Vis spectra of the hydrazones have been studied in two organic solvents of different polarity. It was found that ( H2 ) has a molar extinction coefficient larger than 40000. Single‐crystal X‐ray diffraction analysis reveals that the molecular zigzag chains of ( H1 ) and ( H2 ) are interconnected through noncovalent contacts. A quantitative analysis of the intermolecular interactions in the crystal structures has been performed using Hirshfeld surface analysis. All the synthesized chalcones and hydrazones were evaluated for their antibacterial and antioxidant activities. Results indicate that the studied compounds show significant activity against Gram negative Escherichia coli strain and the chalcone 3‐(4‐methylphenyl)‐1‐phenylprop‐2‐en‐1‐one, ( C1 ), was the most effective. In addition, only hydrazone ( H1 ) displayed a moderate DPPH (2,2‐diphenyl‐1‐picryl hydrazyl) scavenging efficiency.     

New Route to Stabilize Ruthenium Nanoparticles with Non‐Isolable Chiral N‐Heterocyclic Carbenes

Ru nanoparticles (RuNPs) stabilized by non‐isolable chiral N‐heterocyclic carbenes (NHCs), namely SIDPhNp ((4S,5S)‐1,3‐di(naphthalen‐1‐yl)‐4,5‐diphenylimidazolidine) and SIPhOH ((S)‐3‐((1S,2R)‐2‐hydroxy‐1,2‐diphenylethyl)‐1‐((R)‐2‐hydroxy‐1,2‐diphenylethyl)‐4,5‐dihydro‐3H‐imidazoline), have been synthesized through a new procedure that does not require isolation of the free carbenes. The obtained RuNPs have been characterized by state‐of‐the‐art techniques and their surface chemistry has been investigated by FTIR and solid‐state MAS NMR upon the coordination of CO, which indicated the presence of free and reactive Ru sites. Their catalytic activity has been tested in various hydrogenation reactions involving competition between different sites, whereby interesting differences in selectivity were observed, but no enantioselectivity.     

Synthesis,NMR spectra and X‐ray data of chloro and dichloro derivatives of 3‐hydroxy‐2‐phenylquinolin‐4(1H)‐ones and their cytostatic activity

As known, some derivatives of quinolin‐4(1H)‐one possess interesting biological properties. The biological and cytostactic activity of 2‐substituted 3‐hydroxyquinolin‐4(1H)‐ones has not been reported yet. In this paper the synthesis of a series of chloro and dichloro 2‐phenyl‐3‐hydroxyquinolin‐4(1H)‐ones and their characterization by NMR spectra and X‐ray data is described. Their cytostatic properties have been evaluated and the results are reported.     

Synthesis,Characterization, and Anti‐inflammatory Activity of Novel Isoxazolyl‐4‐(2‐oxo‐2,3‐dihydro‐1H‐3‐indolyl)pyrrole‐3‐carboxylates

A series of novel isoxazolyl‐4‐(2‐oxo‐2,3‐dihydro‐1H‐3‐indolyl)pyrrole‐3‐carboxylates ( 17a – i) were synthesized by a three‐component reaction of 4‐amino‐3‐methyl‐5‐styrylisoxazole 14 , β‐keto ester 15 , and 3‐phenacylideneoxindole 16 , in the presence of CAN catalyst in ethanol. The structures of the synthesized compounds have been established on the basis of spectral and analytical data. The title compounds 17a – i were evaluated for their anti‐inflammatory activity. Compounds 17b and 17c exhibited potent anti‐inflammatory activity as that of standard drug.     

Synthesis and antimicrobial activity of N‐substituted N′‐[6‐methyl‐2‐oxido‐1,3,2‐dioxaphosphinino(5,4‐b)pyridine‐2‐yl]ureas

N‐Substituted N′‐[6‐methyl‐2‐oxido‐1,3,2‐dioxaphosphinino(5,4,‐b)pyridine‐2‐yl]ureas have been accomplished by condensation of equimolar quantities of chlorides of various carbamidophosphoric acids ( 3 ) with 3‐hydroxyl‐6‐methyl‐2‐pyridinemethanol (lutidine diol) ( 4 ) in the presence of triethylamine in dry toluene–tetrahydrofuran (1:1) mixture at 45–50°C. Their structures were established by elemental analyses, IR, ¹H NMR, ¹³C NMR, and ³¹P NMR spectral data. Their antifungal and antibacterial activity is also evaluated. Most of these compounds exhibited moderate antimicrobial activity in the assays. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:509–512, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10181     

An Exceedingly Mild,Green Synthesis of Substituted N‐3‐diaryl‐1,8‐naphthyridin‐2‐amine Derivatives and Their Antimicrobial Activity

An exceedingly and highly efficient procedure has been described for the synthesis of substituted N‐3‐diaryl‐1,8‐naphthyridin‐2‐amines by the reaction of 2‐chloro‐3‐aryl‐1,8‐naphthyridines with various anilines in the presence of N‐methyl‐2‐pyrrolidone and K₂CO₃ under thermal green solvent‐free conditions. The significant features of this green reaction include very good yields in purity, simple experimental, short reaction time, easy workability, and avoidance of toxic solvents. All synthesized compounds have been evaluated for their antibacterial activity.     

Synthesis and spectroscopic studies of optically active n‐acetyl butenoates and n‐acetyl‐2‐alkyl‐pyrrolin‐4‐ones

The synthesis of a series of optically active N‐acetyl butenoates 3–5 is described using a facile methodology. These butenoates undergo cyclization to the corresponding N‐acetyl‐2‐alkyl‐pyrrolin‐4‐ones 6,7 retaining their stereochemical integrity. The structure of the newly synthesized compounds has been elucidated through ¹H‐¹³C NMR, IR spectroscopy and their enantiomeric excesses have been measured by chiral HPLC analysis.     

Synthesis and antimicrobial activity of novel 2‐(aryl)‐3‐[5‐(2‐oxo‐2H‐3‐chromenyl)‐1,3‐oxazol‐2‐yl]‐1,3‐thiazolan‐4‐ones

A series of novel 2‐(aryl)‐3‐[5‐(2‐oxo‐2H‐3‐chromenyl)‐1,3‐oxazol‐2‐yl]‐1,3‐thiazolan‐4‐ones 4a , 4b , 4c , 4e , 4f , 4g , 4h , 4i , 4j have been synthesized and assayed for their antibacterial activity against Gram‐positive bacteria viz. Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538p), Micrococcus luteus (IFC 12708), and Gram‐negative bacteria viz. Proteus vulgaris (ATCC 3851), Salmonella typhimurium (ATCC 14028), Escherichia coli (ATCC 25922), and also antifungal activity against Candida albicans (ATCC 10231), Aspergillus fumigatus (HIC 6094), Trichophyton rubrum (IFO 9185), and Trichophyton mentagrophytes (IFO 40996). Among the screened compounds, 4d , 4e , 4f , 4g , and 4j exhibited potent inhibitory activity compared with the standard drug at the tested concentrations. The results reveal that, the presence of difluorophenyl in 4f and pipernyl ring in 4j at 2‐position of thiazolidine‐4‐one ring show significant inhibitory activity. The other compounds also showed appreciable activity against the test bacteria and fungi and emerged as potential molecules for further development. J. Heterocyclic Chem., 2011.     

Synthesis and Biological Evaluation of Some New N1‐[4‐(4‐Chlorophenylsulfonyl)benzoyl]‐N 4‐(aryl)‐thiosemicarbazides and Products of Their Cyclization

In the present study, new 1,2,4‐triazoles, 1,3,4‐thiadiazoles, and acylthiosemicarbaz‐ides derived from 4‐(4‐chlorophenylsulfonyl)benzoic acid hydrazide were synthesized and screened for their antimicrobial and analgesic activities. Acylthiosemicarbazides 2–4 were synthesized by a reaction of 4‐(4‐chlorophenyl‐sulfonyl)benzoic acid hydrazide 1 with different arylisothiocyanates.4,5‐Disubstituted‐2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐thiones 5–7 and 2,5‐disubstituted‐1,3,4‐thiadiazoles 8–10 were obtained by dehydrative cyclization of corresponding acylthiosemicarbazide derivatives 2–4 in basic media (8% aqueous sodium hydroxide) and in acidic media (sulfuric acid or phosphorous oxychloride), respectively. The structures of the newly synthesized compounds have been confirmed on the basis of elemental analysis and spectral studies (IR, ¹H NMR, ¹³C NMR, MS). Their antimicrobial activities against some bacteria and yeasts were investigated. The analgesic activity of all compounds was performed with two pharmacological tests: the writhing test induced with acetic acid and hot‐plate test. The results showed that triazole 7 had the best antimicrobial activity against Bacillus cereus. In the chemical stimulus test, triazoles 6 and 7 were the most active compounds whereas in the hot‐plate test thiadiazoles 9 and 10 exhibited the highest analgesic activity.     

Synthesis and Anticancer and Antiviral Activities of New 2‐Pyrazoline‐Substituted 4‐Thiazolidinones

2‐(4,5‐Dihydropyrazol‐1‐yl)‐thiazol‐4‐ones ( 2–5 ) have been synthesized starting from 3‐phenyl‐5‐aryl‐1‐thiocarbamoyl‐2‐pyrazolines via [2+3]‐cyclization with 2‐bromopropionic acid, maleic anhydride, N‐arylmaleimides, and aroylacrylic acids. The in vitro anticancer activity of 2a , 3a , 4a , 5b , and 5c were tested by the National Cancer Institute. Compounds 4a , 5b , and 5c demonstrated selective inhibition of leukemia cell lines growth at a single concentration (10^?5 M). The screening of antiviral activity for a broad panel of viruses revealed that N‐(4‐methoxyphenyl)‐2‐{2‐[5‐(4‐methoxyphenyl)‐3‐phenyl‐4,5‐dihydropyrazol‐1‐yl]‐4‐oxo‐4,5‐dihydrothiazol‐5‐yl}‐acetamide 4a was highly active against Tacaribe TRVL 11 573 virus strain (EC₅₀ = 0.71 μg/mL, selectivity index = 130).