New domino‐reaction for the synthesis of N4‐(5‐aryl‐1,3‐oxathiol‐2‐yliden)‐2‐phenylquinazolin‐4‐amines and 4‐[4‐aryl‐5‐(2‐phenylquinazolin‐4‐yl)‐1,3‐thiazol‐2‐yl]morpholine

The model morpholine‐1‐carbothioic acid (2‐phenyl‐3H‐quinazolin‐4‐ylidene) amide (1) reacts with phenacyl bromides to afford N⁴‐(5‐aryl‐1,3‐oxathiol‐2‐yliden)‐2‐phenylquinazolin‐4‐amines (4) or N⁴‐(4,5‐diphenyl‐1,3‐oxathiol‐2‐yliden)‐2‐phenyl‐4‐aminoquinazoline ( 5 ) by a thermodynamically controlled reversible reaction favoring the enolate intermediate, while the 4‐[4‐aryl‐5‐(2‐phenylquinazolin‐4‐yl)‐1,3‐thiazol‐2‐yl]morpholine ( 8 ) was produced by a kinetically controlled reaction favoring the C‐anion intermediate. ¹H nmr, ¹³C nmr, ir, mass spectroscopy and x‐ray identified compounds ( 4 ), ( 5 ) and ( 8 ).     

Synthesis of some new 1‐acyl‐5‐aryl‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐4,5‐dihydro‐1H‐pyrazole

Some new compounds (E)‐3‐aryl‐1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐prop‐2‐en‐1‐ones 5a–e were prepared by 1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐ethanone and various aromatic aldehydes. Then one pot reaction was happened by compounds 5a–e with hydrazine hydrate in acetic acid or propionic acid, respectively, to give the title compounds 1acyl‐5‐aryl‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐4,5‐dihydro‐1H‐pyrazoles 6a–i . All structures were established by MS, IR, CHN, ¹H‐NMR and ¹³C‐NMR spectral data. J. Heterocyclic Chem., (2012).     

Two novel organic–inorganic hybrid materials from tetrachloridometallate(II) salts and 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium

Two organic–inorganic hybrid compounds have been prepared by the combination of the 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium cation with perhalometallate anions to give 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridocobaltate(II), (C₁₂H₁₂N₂)[CoCl₄], (I), and 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridozincate(II), (C₁₂H₁₂N₂)[ZnCl₄], (II). The compounds have been structurally characterized by single‐crystal X‐ray diffraction analysis, showing the formation of a three‐dimensional network through X—H...Cl_nM⁻ (X = C, N⁺; n = 1, 2; M = Co^II, Zn^II) hydrogen‐bonding interactions and π–π stacking interactions. The title compounds were also characterized by FT–IR spectroscopy and thermogravimetric analysis (TGA).     

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 and antimicrobial activity of 2‐substituted‐2,3‐dihydro‐5‐propoxy‐1H‐1,3,2‐benzodiazaphosphole 2‐Oxides

Several 2‐alkylcarbamato/thiocarbamato/aryloxy/trichloromethyl‐2,3‐dihydro‐5‐propoxy‐1H‐1,3,2‐benzodiazaphosphole 2‐oxides ( 4 and 6 ) were synthesised by reacting 4‐propoxy‐o‐phenylenediamine ( 1 ) with various N‐dichlorophosphinyl carbamates ( 3 ), aryl phosphorodichloridates ( 5a‐f ) and trichloromethyl phosphonic dichloride ( 5g ) in the presence of triethylamine at 45‐65 °C. Their ir, ¹H, ¹³C, ³¹P nmr and mass spectral data are discussed. The compounds were screened for antifungal activity against Curvularia lunata and Aspergillus niger and for antibacterial activity against Bacillus subtilis and Escherichia coli. Most of these compounds exhibited moderate activity in the assays.     

Synthesis and Characterization of 11‐Amino‐3‐methoxy‐8‐substituted‐12‐aryl‐8,9‐dihydro‐7H‐chromeno[2,3‐b]quinolin‐10(12H)‐one Derivatives

A series of 2‐amino‐7‐methoxy‐4‐aryl‐4H‐chromene‐3‐carbonitrile compounds 2 were obtained by condensation of 3‐methoxyphenol with β‐dicyanostyrenes 1 in absolute ethanol containing piperidine. The intermediate enamines 3 were prepared by compounds 2 with 5‐substituted‐1,3‐cyclohexanedione using p‐toluenesuflonic acid (TsOH) as catalyst. The title compounds 11‐amino‐3‐methoxy‐8‐substituted‐12‐aryl‐8,9‐dihydro‐7H‐chromeno[2,3‐b]quinolin‐10(12H)‐one 4 were synthesized by cyclization of the intermediate enamines 3 in THF with K₂CO₃ /Cu₂Cl₂ as catalyst. The structures of all compounds were characterized by elemental analysis, IR, MS, and ¹H NMR spectra. The crystal structure of compound 4i was determined by single‐crystal X‐ray diffraction analysis.     

Green approach for the synthesis of 3‐methyl‐1‐phenyl‐4‐((2‐phenyl‐1H‐indol 3‐yl)methylene)‐1H‐pyrazole‐5(4H)‐ones and their DNA Cleavage,antioxidant, and antimicrobial activities

3‐Methyl‐1‐phenyl‐4‐((2‐phenyl‐1H‐indol‐3‐yl)methylene)‐1H‐pyrazol‐5(4H)‐ones (5a‐i) was prepared by the condensation reaction of different 3‐formyl‐2‐phenylindole derivatives (2a‐i) and 3‐methyl‐1‐phenyl‐2‐pyrazoline‐5‐one in quantitative yield by applying various green synthetic methods as grinding, microwave irradiation using different catalysts under solvent‐free mild reaction conditions with high product yields. The structures of the synthesized compounds were characterized on the basis of elemental analysis, infrared, ¹HNMR, ¹³C NMR, and mass spectral data. The synthesized compounds were screened for free radical scavenging, antimicrobial, and DNA cleavage activities. Most of the tested compounds belonging to the 3‐methyl‐1‐phenyl‐4‐((2‐phenyl‐1H‐indol‐3‐yl)methylene)‐1H‐pyrazol‐5(4H)‐ones series exhibited promising activities.     

Synthesis and Herbicidal Activity of Novel N‐(2‐Fluoro‐5(3‐methyl‐2,6‐dioxo‐4‐(trifluoromethyl)‐2,3‐dihydro‐pyrimidin‐1(6H)‐yl)phenyl)‐2‐phenoxyacetamide Derivatives

Thirteen novel N‐(2‐fluoro‐5‐(3‐methyl‐2,6‐dioxo‐4‐(trifluoromethyl)‐2,3‐dihydropyrimidin‐1(6H)‐yl)phenyl)‐2‐phenoxy)acetamides were designed and synthesized utilizing 4‐fluoro‐aniline and ethyl 3‐amino‐4,4,4‐trifluoro‐but‐2‐enoate as starting materials. The chemical structures of all compounds were confirmed by ¹H NMR, IR, mass spectrum and elemental analyses. Subsequently, the herbicidal activities of the as‐prepared compounds were evaluated in the greenhouse. Bioassay results indicated that most of compounds had better herbicidal activities against dicotyledonous weeds. Among all the tested compounds, compounds 4a – 4i showed good herbicidal activities at both pre‐emergence and post‐emergence treatment against two or three kinds of dicotyledonous weeds, such as Abutilon theophrasti Medic, Amaranthus ascendens L, and Chenopodium album L at the dosage of 75 g ai/ha.     

Synthesis of 4-(4-Methylsulfonylphenyl)-3-phenyl-2(3H)-thiazole Thione Derivatives as New Potential COX-2 Inhibitors

Synthesis of novel 4-（4-methylsulfonylphenyl）-3-phenyl-2（3H）-thiazole thione derivatives with functionalized diarylheterocycle pharmacophore as potential COX-2 inhibitors was described. The title compounds were synthesized by cyclocondensation of corresponding dithiocarbamate and 2-bromo-1-（4-methylsulfonylphenyl）ethanone, followed by dehydration with H2SO4. All of the target compounds were characterized by ^1H NMR, IR and mass spectral data.     

Synthesis and antibacterial activity of novel series of 2‐(p‐tolyloxy)‐3‐(5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazol‐2‐yl)quinoline

A new series of 2‐(p‐tolyloxy)‐3‐(5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazol‐2‐yl)quinoline were synthesized from oxidative cyclization of N′‐((2‐(p‐tolyloxy)quinoline‐3‐yl)methylene)isonicotinohydrazide in DMSO/I₂ at reflux condition for 3–4 h. The structures of the new compounds were confirmed by elemental analyses as well as IR, ¹H‐NMR, and mass spectral data. All the synthesized compounds were screened for their antibacterial activities against various bacterial strains. Several of these compounds showed potential antibacterial activity. J. Heterocyclic Chem., (2011).     

Synthesis of New (Pyrazol‐3‐yl)‐1,3,4‐oxadiazole Derivatives by Unexpected Aromatization During Oxidative Cyclization of 4,5‐Dihydro‐1H‐pyrazole‐3‐carbohydrazones and Their Biological Activities

A series of novel 2‐(4‐(4‐chlorophenyl)‐1H‐pyrazol‐3‐yl)‐5‐(Aryl)‐1,3,4‐oxadiazoles were synthesized by unexpected aromatization during oxidative cyclization of 4‐(4‐chlorophenyl)‐4,5‐dihydro‐1H‐pyrazole‐3‐carbohydrazones using chloramine‐T as an oxidant. The hydrazones were derived from 4‐(4‐chlorophenyl)‐4,5‐dihydro‐1H‐pyrazole‐3‐carbohydrazide and various substituted aldehydes. The structure of the synthesized compounds was confirmed by FTIR, ¹H NMR, ¹³C NMR, and mass spectral data. The synthesized compounds were evaluated for their antitubercular and antioxidant activities. All the compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h and 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h showed good antitubercular activity against Mycobacterium tuberculosis (minimum inhibitory concentration = 25 µg/mL for 4f and 4g , 50–100 µg/mL for the rest). However, all the compounds exhibited poor antioxidant activity against 1,1‐diphenyl‐2‐picryl‐hydrazil free radical.     

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.     

Microwave Induced Synthesis of 3‐Aryl‐6‐(6‐/8‐substituted 4‐chloroquinoline‐3‐yl) ‐ s ‐triazolo [3,4‐b] −1,3,4‐thiadiazoles

The condensation of 4‐amino‐3‐aryl‐5‐mercapto‐1, 2, 4‐triazoles (1a‐f) with 6‐/8‐substituted 1,4‐dihydro‐4‐oxo‐quinoline‐3‐carboxylic adds (2a‐d) in the presence of phosphorus oxychloride on refluxng or under microwave irradiation gave twenty four novel 3‐aryl‐6‐ (6‐/8‐substituted 4‐chloroquinoline‐3‐yl)‐s‐triazolo[3,4‐b]‐1, 3,4‐thiadiazoles (4a‐x), Considerable increase in the reaction rate has been observed with improved yields under microwave irradiation. The structures of the compounds synthesized were determined by elemental analyses, IR, ¹H NMR and MS spectra. Their spectral properties and the reaction mechanism were also discussed. The preliminary biological test showed that some of compounds bad moderate antibacterial activities.     

Investigation of Some Functionalization Reactions of 4‐Benzoyl‐5‐phenyl‐1‐(4‐methoxyphenyl)‐1H‐pyrazole‐3‐carbonyl Chloride and Their Antimicrobial Activity

The 1H‐pyrazole‐3‐carboxylic acid 1 was converted via reactions of its acid chloride 3 with various asymmetrical disubstituted urea and alcohol derivatives into the corresponding novel 4‐benzoyl‐N‐(N′,N′‐dialkylcarbamyl)‐1‐(4‐methoxyphenyl)‐5‐phenyl‐1H‐pyrazole‐3‐carboxamide 4a , b and alkyl 4‐benzoyl‐1‐(4‐methoxyphenyl)‐5‐phenyl‐1H‐pyrazole‐3‐carboxylate 7a‐c , respectively, in good yields (57%‐78%). Friedel‐Crafts reactions of 3 with aromatic compouns for 15 min.‐2 h led to the formation of the 4‐3‐diaroyl‐1‐(4‐hydroxyphenyl)‐5‐phenyl‐1H‐pyrazoles 9a‐c , 4‐benzoyl‐1‐(4‐methoxyphenyl)‐3‐aroyl‐5‐phenyl‐1H‐pyrazoles 10a , b and than from the acylation reactions of 9a‐c were obtained the 3,4‐diaroyl‐1‐(4‐acyloxyphenyl)‐5‐phenyl‐1H‐pyrazoles 13a‐d . The structures of all new synthesized compounds were established by NMR experiments such as ¹H, and ¹³C, as well as 2D COSY and IR spectroscopic data, and elemental analyses. All the compounds were evaluated for their antimicrobial activities (agar diffusion method) against eight bacteria and two yeasts.     

The Synthesis of 1,4‐Bis[N‐(4/6‐Substituted Benzothiazole‐2‐yl)‐N′‐Glycosylguanidino]Benzenes

The starting material O‐protected glycosyl isothiocyanate ( 1?3 ) was refluxed with 1,4‐diaminobenzene in CHCl₃ under nitrogen atmosphere to give 1,4‐bis(N‐glycosyl)thioureidobenzene ( 4?6 ). Then 1,4‐bis[N‐(4/6‐substituted benzothiazole‐2‐yl)‐N′‐glycosylguanidino]benzenes ( 8a?8e , 9a?9e , 10a?10e ) were obtained in good yield by reaction of compounds ( 4?6 ) with 2‐amino‐4/6‐benzothizoles ( 7a?7e ) and HgCl₂ in the presence of TEA in DMF. The structures of all 18 new compounds were confirmed by IR, ¹H NMR, LC‐MS and elemental analysis. The bioactivity of anti‐HIV‐1 protease (HIV‐1 PR) and against angiotensin converting enzyme (ACE) have been evaluated.     

Synthesis of Analogues of Indole Alkaloids from Sea Sponges – Aplysinopsins by the Reaction of Amines with (4Z)‐4‐[(1H‐indol‐3‐yl)‐methylene]‐1,3‐oxazol‐5(4H)‐ones

A new two‐step approach toward the synthesis of aplysinopsin analogues 5‐(1‐R‐1H‐indol‐3‐ylmethylene)‐2‐aryl‐3,5‐dihydroimidazol‐4‐ones consisting in obtaining and reaction of 4‐(1‐R‐1H‐indol‐3‐ylmethilene)‐2‐Ar‐4H‐oxazol‐5‐ones with amines was developed. The configuration of starting compounds and final products was determined by ¹³С and ¹H‐nmr spectroscopy.     

New Approaches to the Synthesis of 4‐(2‐Aminophenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ones and 3‐Ureidoindoles and a Study of Their Interconversion

3‐Alkyl/aryl‐3‐ureido‐1H,3H‐quinoline‐2,4‐diones ( 2 ) and 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones ( 3 ) react in boiling concentrated HCl to give 5‐alkyl/aryl‐4‐(2‐aminophenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ones ( 6 ). The same compounds were prepared by the same procedure from 2‐alkyl/aryl‐3‐ureido‐1H‐indoles ( 4 ), which were obtained from the reaction of 3‐alkyl/aryl‐3‐aminoquinoline‐2,4(1H,3H)‐diones ( 1 ) with 1,3‐diphenylurea or by the transformation of 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones ( 3 ) and 5‐alkyl/aryl‐4‐(2‐aminophenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ones ( 6 ) in boiling AcOH. The latter were converted into 1,3‐bis[2‐(2‐oxo‐2,3‐dihydro‐1H‐imidazol‐4‐yl)phenyl]ureas ( 5 ) by treatment with triphosgene. All compounds were characterized by ¹H‐ and ¹³C‐NMR and IR spectroscopy, as well as atmospheric pressure chemical‐ionisation mass spectra.     

Synthesis and Characterization of New Thebaine Derivatives as Potential Opioid Agonists and Antagonists: 2‐[N‐(1H‐Tetrazol‐5‐yl)‐6,14‐endo‐etheno‐6,7,8,14‐tetrahydrothebaine‐7α‐yl]‐5‐phenyl‐1,3,4‐oxadiazoles

In this study, we report the synthesis a series of novel 2‐[N‐(1H‐tetrazol‐5‐yl)‐6,14‐endo‐etheno‐6,7,8,14‐tetrahydrothebaine‐7α‐yl]‐5‐phenyl‐1,3,4‐oxadiazole derivatives ( 7a – e ) which have potential opioid antagonist and agonist. The substitution reaction of 6,14‐endo‐ethenotetrahydrothebaine‐7α‐carbohydrazide with corresponding benzoyl chlorides gave diacylhydrazine compounds 4a – e in good yields. The treatment of compounds 4a – e with POCl₃ caused the conversion of side‐chain of compounds 5a – e into 1,3,4‐oxadiazole ring at C(7) position; thus, compounds 5a – e were obtained. Subsequently, cyanamides ( 6a – e ) were prepared from compounds 5a – e and then compounds 7a – e were synthesized by the azidation of 6a – e with NaN₃. The structures of the compounds were established on the basis of their IR, ¹H NMR, ¹³C APT, 2D‐NMR (COSY, NOESY, HMQC, HMBC) and high‐resolution mass spectral data.     

Synthesis of 2‐(sulfamoylphenyl)‐4′‐(iminoaryl/hetroaryl)‐4‐(4′′‐hydroxyphenyl)‐thiazoles and their O‐glucosides

In continuation of our work, we synthesized 2‐(sulfamoylphenyl)‐4′‐amino‐4‐(4″‐hydroxyphenyl)‐thiazole ( 3a ), which were reacted with various (aryl/hetroaryl) aldehyde to form 2‐(sulfamoylphenyl)‐4′‐(iminoaryl/hetroaryl)‐4‐(4″‐hydroxyphenyl)‐thiazoles ( 4a , 4b , 4c , 4d , 4e , 4f ). Glucosylation of compounds ( 4a , 4b , 4c , 4d , 4e , 4f ) have been done by using acetobromoglucose as a glucosyl donor to afford 2‐(sulfamoylphenyl)‐4′‐(iminoaryl/hetroaryl)‐4‐(2,3,4,6‐tetra‐O‐acetyl‐4″‐O‐β‐D ‐glucosidoxyphenyl)‐thiazoles ( 5a , 5b , 5c , 5d , 5e , 5f ), further on deacetylation to produce 2‐(sulfamoylphenyl)‐4′‐(iminoaryl/hetroaryl)‐4‐(4″‐O‐β‐D ‐glucosidoxyphenyl)‐thiazoles ( 6a , 6b , 6c , 6d , 6e , 6f ). The compounds are confirmed by FTIR, ¹H‐NMR, ¹³C‐NMR, and ES‐Mass spectral analysis. J. Heterocyclic Chem., (2011).     

Synthesis ofN1‐3‐{(4‐Substituted aryl‐3‐chloro‐2‐oxo‐azetidine)‐iminocarbamyl}‐propyl‐6‐nitroindazole Derivatives and Their Biological Significance

Synthesis ofN¹‐3‐{(4‐substitute daryl‐3‐chloro‐2‐oxo‐azetidine)‐iminocarbamyl}‐propyl‐6‐nitroindazole 4a – 4s was conducted by a conventional method. All the compounds were synthesized and characterized by IR, ¹H NMR, ¹³C NMR, FAB‐Mass techniques and chemical methods. All the final synthesized compounds were evaluated for their antimicrobial activity and antitubercular activity with MIC values against some selected microorganisms.