Regioselective synthesis and biological evaluation of novel dispiropyrrolidine derivatives via one-pot four-component reaction

Abstract

A new series of regioselective dispiropyrrolidine analogs via efficient one-pot four-component tandem reaction has been discovered. The reaction was carried out in the presence of four common reactants and magnesium silicate nanoparticles (NPs) in ethanol under microwave irradiation. The reaction proceeds rapidly and can be completed within 60–90?min. This methodology offers several significant advantages such as high yield, mild catalyst, and easy to perform. The synthesized compound was further screened for antibacterial and antiproliferative activities. The results showed that compound 5c and 5a were potent antibacterials against Gram-positive and Gram-negative bacteria. Further, 5a showed best antiproliferative activity against tested cell lines.     

Microwave assisted synthesis and Anti-microbial activity of new Diethyl ((dialkoxyphosphoryl) (2-hydroxyphenyl) methyl) phosphoramidates

The synthesis of new α-aminophosphonates 4a-j (diethyl((dialkoxyphosphoryl)(phenyl)methyl)phosphoramidates) were achieved through a one pot simple and efficient method from the three-component condensation reaction (Kabachnik-Fields reaction) of diethyl phosphoramidate, aryl salicylaldehydes, and dialkyl phosphite by using microwave irradiation under solvent-free and catalyst-free conditions in good to excellent yields and short reaction times. The structures of the novel products were established by IR, ¹H, ¹³C & ³¹P-NMR and Mass spectroscopy. All the synthesized compounds were screened their antimicrobial activity.     

Indium-mediated mild and efficient one-pot synthesis of alkyl phenyl selenides

A mild and convenient one-pot process for synthesizing alkyl phenyl selenides is developed using indium metal. The reaction shows the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides.     

Amberlyst-15 catalyzed synthesis of alkyl/aryl/heterocyclic phosphonates

A novel and efficient procedure for the synthesis of alkyl phosphonates through one pot condensation of alkyl halide and trialkyl /aryl phosphite in the presence of Amberlyst-15 as catalyst under solvent free conditions was applied.It demonstrated several advantages such as good yields of products,simple operation,convenient separation and inexpensive catalyst.     

Synthesis and biological evaluation of newer analogues of 2,5-disubstituted 1,3,4-oxadiazole containing pyrazole moiety as antimicrobial agents

A series of 2,5-disubstituted-1,3,4-oxadiazole derivatives bearing pyrazole moiety were synthesized by reacting various substituted pyrazole-4-carboxylic acids with different hydrazides in POCl₃. All the synthesized compounds (4a–n) were characterized by IR, NMR, mass spectra and elemental analyses. Synthesized 1,3,4-oxadiazole derivatives were screened for their antibacterial activity against three different strains, namely Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, while antifungal activity was determined against three different strains Aspergillus flavus, Chrysosporium keratinophilum and Candida albicans. The investigation of antimicrobial screening revealed that compounds 4i and 4j exhibited excellent activity when compared with the standard drugs.     

Ketones in the catalytic three-component “one-pot” Kabachnik-Fields synthesis of α-amino phosphonates

Reactions of carbocyclic, heterocyclic, and steroidal ketones with benzylamine and diethyl phosphite in a catalytic three-component “one-pot” synthesis of α-amino phosphonates were studied. The activities of mono-and binuclear complexes of tetra(tert-butyl)phthalocyanines as catalysts for this process were compared. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1164–1169, July, 2006.     

Microwave mediated facile one-pot synthesis of polyarylpyrroles from but-2-ene- and but-2-yne-1,4-diones

Several pyrrole derivates with multiple aryl substituents were prepared conveniently in a one pot-reaction from but-2-ene-1,4-diones and but-2-yne-1,4-diones via hydrogenation of the carbon-carbon double bond/triple bond followed by amination-cyclization. The reaction could be performed with ammonium formate or alkyl/arylammonium formates under Pd/C in polyethylene glycol-200 (PEG-200) under microwave irradiation. Using this procedure, different aryl-substituted pyrroles were prepared. Furthermore, studies on microwave vs thermal conditions indicate faster heating under microwave conditions was responsible for rate enhancement.     

Design and synthesis of some novel pyridothienopyrimidine derivatives and their biological evaluation as antimicrobial and anticancer agents targeting EGFR enzyme

A new series of pyridothienopyrimidine derivatives was designed and evaluated as antimicrobial and anticancer agents. The target compounds were synthesized starting with 3-aminothieno[2,3-b]pyridine-2-carboxamide derivative 1 which underwent cyclocondensation reaction with aromatic aldehydes to give the key intermediates 2a,b. By further treatment of 2a,b with various reagents, the target 2,4-disubstituted-pyrido[3′,2′:4,5]thieno[2,3-d]pyrimidines 3a,b–11a,b were obtained. To evaluate the antimicrobial activity of the new compounds, they were tested against five bacterial and five fungal strains. Compounds 6c, 8b, 9a and 9b revealed the most significant antimicrobial activity against the tested microorganisms with MIC values range (4–16 μg/mL). Also, compounds 2a,b–11a,b were screened for their in vitro cytotoxic activity against HepG-2 and MCF-7 cancer cell lines compared with doxorubicin and cisplatin as references drugs. Moreover, compounds (2b, 4a, 6a, 7b, 7c and 9a) which exhibited the most potent anticancer activity, were further subjected to EGFR^WT enzyme inhibition assay utilizing erlotinib as a standard drug. The compounds 6a, 7b, 7c and 9a which showed the most promising suppression effects were also evaluated as inhibitors against the mutant forms EGFR^L858R and EGFR^T790M. The 4-aminopyrazolone analogue 9a showed superior anticancer activity against both HepG-2 and MCF-7 cell lines (IC50 = 1.27, 10.80 μM, respectively) and more potent enzymatic inhibition activity against EGFR^WT and its mutant forms EGFR^L858R and EGFR^T790M than that obtained by erlotinib (IC₅₀ = 0.021, 0.053, 0.081 µM, respectively, IC_50erlotinib; 0.027, 0.069, 0.550 µM, respectively). Finally, the molecular docking study showed good binding patterns of the most active compounds with the prospective target EGFR^WT.     

Synthesis,spectral characterization,and biological evaluation of imidazole‐substituted pyridine‐2‐amine and benzo‐substituted imidazole‐2‐amine

A series of new imidazole‐substituted pyridine‐2‐amine and benzo‐substituted imidazol‐2‐amine 3 – 12 were synthesized by treating various amines 1(a – d) with alkyl/aryl isothiocyanate 2(a‐c) at 60–90°C in isopropyl alcohol without using any catalyst with high yields. The structures of all the newly synthesized compounds were characterized using IR, NMR (¹H, ¹³C), mass, and elemental analyses. All the newly synthesized compounds were screened for their in vitro antioxidant and antimicrobial activities to understand their biological potency. All the title compounds exhibited good antioxidant and antimicrobial activities in vitro when compared to the standard drugs.     

Efficient synthesis and biological evaluation of bis dispiro imidazolidines through 1,3-dipolar cycloaddition reaction

A highly efficient and milder protocol for the synthesis of dispiro imidazolidines in good yields through 1,3-dipolar cycloaddition of in situ-generated azomethine ylide from different di/tri ketones and secondary amino acids with bisimine has been developed. The structure of all newly synthesized compounds was established by analytical and spectral data. Furthermore, the synthesized compounds were screened for antimicrobial activity by agar well-diffusion method. Some of the synthesized compounds showed appreciable antibacterial activity.     

Efficient synthesis and biological evaluation of 4-arylcoumarin derivatives

Two bioactive natural 4-arylcoumarins,5,7,4’-trimethoxy-4-phenylcoumarin(1a),5,7-dimethoxy-4-phenylcoumarin(1b) and five closely related derivatives 1c-g were synthesized.In vitro evaluation with a catechol subunit for antioxidant and antimicrobial activity,these compounds using standard methods showed that compounds 1d,1f displayed promise radical scavenging activity and 1f was found to be the most active one against Bacillus dysenteriae.     

An efficient one-pot three-component synthesis and antimicrobial evaluation of tetra substituted thiophene derivatives

A convenient one-pot three-component method for the preparation of tetra-substituted thiophene derivatives has been developed. Reaction of acetyl acetone 1, phenyl isothiocynate 2 and 2-chloromethyl derivatives 3a–3c in the presence of potassium carbonate afforded the target compounds, namely ethyl2-(4-acetyl-3-methyl-5-(phenylamino)thiophen-2-yl)-2-oxoacetate derivatives 4a–4e, ethyl 3-(4-acetyl-3-methyl-5-(phenylamino)thiophen-2-yl)-3-oxopropanoate derivatives 4f–4i, di((4-acetyl-3-methyl-5-phenylamino)thiophen-2-yl)ketone derivatives 4j–4n in reasonable overall yields. The synthesized compounds were screened for antimicrobial activity. The detailed synthesis, spectroscopic data and antimicrobial activities of synthesized compounds were reported.     

Synthesis and Biological Activity of Novel Diphenyl N- Substituted Carbamimidoylphosphoramidate Derivatives

Abstract

An efficient synthesis of a series of novel diphenyl N-substituted carbamimidoyl phosphoramidate derivatives was accomplished in two steps. Diphenyl phosphorochloridate (1) was reacted with cyanamide (2) in the presence of 1,4–dimethylpiperazine as a base in THF at 50–55 °C to form an intermediate, diphenyl cyanophosphoramidate (3). Subsequently 3 was reacted with various aromatic/heterocyclic amines (4) in the presence of 1,4–dimethyl piperazine as a base at 55–60 °C to form the corresponding title compounds 5(a-k). The title compounds were tested for antiviral activity against Tobacco mosaic virus (TMV) in vitro, antibacterial and antifungal activities at two different concentrations of 50 and 100 μg/mL. The title compounds exhibited good antiviral and antimicrobial activities when compared to the standards.     

Design,synthesis and herbicidal activity of novel cyclic phosphonates with diaryl ethers containing pyrimidine

Abstract

Thirteen novel cyclic phosphates were rationally designed and synthesized by introducing diary ethers containing pyrimidine. All the target compounds were characterized by ¹H, ¹³C, ³¹P NMR and HRMS. The test of herbicidal activity indicated that most of the compounds showed good herbicidal activities against Amaranthus retroflexus. The compounds IA-2 (1-(5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)propyl-2-((4,6-dimethoxypyrimidin-2-yl)oxy)benzoate) and IA-3 ((5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)(phenyl)methyl-2-((4,6-dimethoxypyrimidin-2-yl)oxy)benzoate) exhibited remarkable post-emergency herbicidal activity against the tested monocotyledonous weed at the dosage of 112.5?g ai/ha.     

Coordination polymers of glutaraldehyde with glycine metal complexes: synthesis,spectral characterization,and their biological evaluation

Glycine metal complexes were prepared by the reaction of glycine with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) in 1?:?2 molar ratio. Thereafter their condensation polymerization was done with glutaraldehyde to obtain polymer metal complexes. All the synthesized polymer metal complexes were characterized by elemental analysis, FT-IR, ¹H-NMR, and UV-Vis spectrometry, magnetic susceptibility, and thermogravimetric studies. The analytical data of all the polymers agreed with 1?:?1 molar ratio of metal complex to glutaraldehyde and magnetic moment data suggest that PGG–Mn(II), PGG–Co(II), PGG–Ni(II), and PGG–Cu(II) have an octahedral geometry around the metal atom, whereas the tetrahedral geometry was proposed for PGG–Zn(II) polymer. The PGG–Mn(II) and PGG–Cu(II) showed octahedral geometry. Thermal behavior of the polymer metal complexes was obtained at a heating rate of 10°C?min^?1 under nitrogen atmosphere from 0°C to 800°C. The antimicrobial activities of synthesized polymers were investigated against Streptococcus aureus, Escherichia coli, Bacillus sphaericus, Salmonella sp. (Bacteria), Fusarium oryzae, Candida albicans, and Aspergillus niger (Yeast).     

Indium-mediated cleavage of diphenyl diselenide and diphenyl disulfide: efficient one-pot synthesis of unsymmetrical diorganyl selenides, sulfides, and selenoesters

A convenient and efficient method was developed for the synthesis of alkyl phenyl selenides, sulfides, and selenoesters in one-pot reaction by using indium metal. The reaction showed the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides. For the reaction of primary and secondary alkyl iodides and bromides, the yields of selenides were improved by the addition of a catalytic amount of iodine.     

2-(Benzo[d]thiazol-2-yl) phenyl-4-nitrophenyl alkyl/aryl substituted phosphoramidates: Synthesis,characterization and antimicrobial activity evaluation

A series of new 2-(benzo[d]thiazol-2-yl) phenyl-4-nitrophenyl alkyl/aryl substituted phosphoramidate derivatives (7a-j) of biological interest are synthesized in two steps via an in situ process without the isolation of the intermediate. 2-(Benzo[d]thiazol-2-yl) phenol (3) was treated with 4-nitrophenyl phosphorodichloridate(4) to obtain the monochloro intermediate, 2-(benzo[d]thiazol-2-yl)phenyl (4-nitrophenyl) phosphorochloridate(5). It was subsequently reacted with various amines, 6(a-j) to afford the desired title products. IR, NMR (¹H, ¹³C and ³¹P), mass spectral and elemental analysis are used to characterize the structures of the newly synthesized compounds. The antibacterial and antifungal activities are determined by the growth of inhibition of bacteria and fungi of the title compounds at two concentrations, 50 and 100 µg/mL, and minimum inhibitory concentrations to the active compounds. The compounds 7e, 7f and 7j exhibited promising inhibition activity against bacterial strains and 7c, 7e and 7i against A. niger and C. albicans and MIC values are in the range of 10.0–15.0 µg/mL.