The development of a knowledge base for basic active structures: an example case of dopamine agonists

Background  

Chemical compounds affecting a bioactivity can usually be classified into several groups, each of which shares a characteristic substructure. We call these substructures "basic active structures" or BASs. The extraction of BASs is challenging when the database of compounds contains a variety of skeletons. Data mining technology, associated with the work of chemists, has enabled the systematic elaboration of BASs.     

A single-step, mild, neutral, catalyst-free method for cyanohydrin synthesis

Abstract  

A wide variety of carbonyl compounds can be transformed to their corresponding cyanohydrins in a single step using a dimethyl sulfoxide (DMSO)–water system in excellent yields (75–94%). The major advantages of this system are that the reaction conditions are mild and neutral; the reaction proceeds without catalyst and gives the corresponding cyanohydrins in short time (15–120 min).     

Thiol-functionalized anthraquinones: mass spectrometry and electrochemical studies

Abstract  

In this work, the synthesis of various thiol-functionalized anthraquinone compounds is presented. The studied compounds were characterized by mass spectrometry and the main fragmentation pathways are discussed. The compounds studied formed stable self-assembled monolayers (SAMs) in the gold surface. The parameters for the reduction processes in the gold surface of the studied new anthraquinones were determined by cyclic voltamperometry tests.     

SnCl2-catalyzed three-component one-pot Mannich-type reaction: efficient synthesis of β-aminocarbonyl compounds

Abstract  

SnCl₂-catalyzed three-component one-pot Mannich reaction of acetophenone or p-chloroacetophenone with different aromatic aldehydes and aromatic amines in ethanol at ambient temperature gave the corresponding β-aminocarbonyl compounds in good to excellent yields. Four new compounds are reported for the first time.     

A one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from thioamides or thioureas and 2-chloro-1,3-dicarbonyl compounds in an ionic liquid

Abstract  

A simple one-pot synthesis of functionalized ethyl 1,3-thiazole-5-carboxylates from the reaction of 2-chloro-1,3-dicarbonyl compounds with thioureas or thioamides in the presence of 1-butyl-3-methylimidazolium trifluoromethanesulfonate is described.     

Synthesis of alkaloid-like compounds via the bridging Ritter reaction

Abstract  

Alkaloid-like compounds containing a benzo[c]azepine core structure were successfully prepared in three steps from 5H-dibenzo[a,d]cyclohepten-5-ol via the bridging Ritter reaction. Biological studies of these compounds revealed that some of them are AChE inhibitors and antimalarial agents.     

Synthesis of 6-chloroquinolines using benzyltrimethylammonium tetrachloroiodate as a selective chlorinating agent and an efficient generator of HCl

Abstract  

A simple and efficient one-pot synthesis of 6-chloroquinolines was achieved in good yields via the three-component reaction of 2-aminoaryl ketones, α-methylene carbonyl compounds, and BTMA ICl₄ in AcOH.     

Synthesis of phosphonato esters involving heterocyclic biological bases in a highly diastereoselective and chemoselective route

Abstract  

Synthesis of five phosphonato esters has been accomplished via reaction between dimethyl acetylenedicarboxylate and triphenyl phosphite in the presence of biological compounds such as theophylline, 4-hydroxypyrimidine, 2H-3,1-benzoxazine-2,4(1H)-dione, 2-chloroaniline, or 3-nitroaniline at ambient temperature. The configuration of the compounds was determined on the basis of coupling constants emerging from the Karplus equation.     

Synthesis and biological evaluation of novel piperidin-4-ol derivatives

Abstract  

A series of novel piperidin-4-ol derivatives were designed, synthesized, and evaluated for potential treatment of HIV. The compounds were obtained via an efficient synthetic route in excellent yields and have been characterized by ¹H NMR, ¹³C NMR, MS, and elemental analysis. The CCR5 antagonistic activities of the compounds have also been evaluated.     

Synthesis and biological activities of novel ethers of quinolinone linked with coumarins

Abstract  

A series of new ethers of quinolinone linked with different substituted coumarins and benzofurans were synthesized from 4-(bromomethyl)quinolinones. All newly synthesized compounds were screened for their in vitro antibacterial and antifungal activities. Most of the compounds with chloro substitution at the C-6 or C-7 position in quinolinone showed potent antibacterial and antifungal activities. In pharmacological evaluations, some of these chloroquinolinones also showed 70–77% inhibition of inflammation after 8 h, whereas the other compounds showed 51–55% inhibition. Most of the compounds showed potent analgesic activity compared to the standard and control. The structures of all newly synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, and EI-MS.     

R22(8) motifs in Aminopyrimidine sulfonate/carboxylate interactions: Crystal structures of pyrimethaminium benzenesulfonate monohydrate (2:2:1) and 2-amino-4,6-dimethylpyrimidinium sulfosalicylate dihydrate (4:2:2)

Background  

Pyrimethamine [2,4-diamino-5-(p-chlorophenyl)-6-ethylpyrimidine] is an antifolate drug used in anti-malarial chemotherapy. Pyrimidine and aminopyrimidine derivatives are biologically important compounds owing to their natural occurrence as components of nucleic acids.     

Microwave-assisted and scandium triflate catalyzed synthesis of tetrahydrobenzo[<Emphasis Type="Italic">a</Emphasis>]xanthen-11-ones

Abstract  

Synthesis of 12-aryl-8,9,10,12-tetrahydro-benzo[a]xanthen-11-ones was achieved by one-pot condensation of β-naphthol, substituted benzaldehydes, and 1,3-dicarbonyl compounds catalyzed by Sc(OTf)₃ under microwave irradiation in excellent isolated yields. The catalyst was recycled up to four cycles with no appreciable loss in catalytic activity. The compounds were evaluated for Src kinase activity and anticancer activity.     

NMR and molecular modelling studies on the interaction of fluconazole with β-cyclodextrin

Background  

Fluconazole (FLZ) is a synthetic, bistriazole antifungal agent, effective in treating superficial and systemic infections caused by Candida species. Major challenges in formulating this drug for clinical applications include solubility enhancement and improving stability in biological systems. Cyclodextrins (CDs) are chiral, truncated cone shaped macrocyles, and can easily encapsulate fluconazole inside their hydrophobic cavity. NMR spectroscopy has been recognized as an important tool for the interaction study of cyclodextrin and pharmaceutical compounds in solution state.     

Electrochemical pyridination of hydroquinone in aqueous solution

Abstract  

Electrochemical oxidation of hydroquinone was studied in the presence of pyridine and 4-methylpyridine as nucleophiles in aqueous solution. The results indicate the participation of electrochemically generated p-benzoquinone in Michael addition reaction with pyridine and 4-methylpyridine, converting it to pyridinated compounds.     

A one-pot synthesis of N-alkylthiazoline-2-thiones from CS2, primary amines, and 2-chloro-1,3-dicarbonyl compounds in water

Abstract  

A simple synthesis of N-alkylthiazoline-2-thiones by reaction of primary amines, carbon disulfide, and 2-chloro-1,3-dicarbonyl compounds in water is described. Proceeding without catalyst under one-pot conditions in high yields and with broad scope, this method high synthetic utility.     

Synthesis and pharmacological activity of some synthesized polyazacyclopenta[a]naphthalenes and pyrazolo[3,4-b]pyridines using 2-amino-6-methyl-4-phenylnicotinonitrile as synthon

Abstract  

A series of pyridines, pyrimidines, and their derivatives were synthesized using 2-amino-6-methyl-4-phenylnicotinonitrile as starting material. Thirteen new heterocyclics containing a pyridine ring were thus prepared. Pharmacological screening showed that many of these compounds have good anti-inflammatory and analgesic activity comparable with those of diclofenac potassium and valdecoxib as reference drugs. Assignment of the structures of the new compounds was based on chemical and spectroscopic evidence. Synthesis, spectroscopic data, and pharmacological properties of the compounds are reported in detail.     

Efficient synthesis of methyl 4-chloro-6-fluoro-3-formyl-2H-chromene-2-carboxylate and its derivatives

Abstract  

Methyl 4-chloro-6-fluoro-3-formyl-2H-chromene-2-carboxylate was synthesized conveniently using Vilsmeier reagent. A series of new 2H-chromenes was prepared in high yields by introducing a corresponding β-halovinylaldehyde into condensation and cyclization reactions with active methylene compounds.     

Synthesis and biological activity of novel 4- and 6-(1-alkyl/aryl-1H-benzimidazol-2-yl)benzene-1,3-diols

Abstract  

A one-pot synthesis of new biologically active 4- and 6-(1-alkyl/aryl-1H-benzimidazol-2-yl)benzene-1,3-diols has been developed. The compounds were obtained by the reaction of aryl-modified sulfinylbis[(2,4-dihydroxyphenyl)methanethione] with N-substituted benzene-1,2-diamines. Elemental analysis, IR, ¹H NMR, ¹³C NMR, and mass spectral data were used to elucidate their structures. The developed method offers short reaction times, easy and quick isolation of the products, and good yields. The antiproliferative properties of the synthesized compounds were investigated against a panel of human cancer cell lines. Some of the tested compounds showed significant cytotoxic activity.     

Synthetic utility of bifunctional thiophene derivatives and antimicrobial evaluation of the newly synthesized agents

Abstract  

The key intermediate ethyl 2-amino-5-benzoyl-4-methylthiophene-3-carboxylate was prepared by a Gewald reaction starting from benzoylacetone, sulfur, and ethyl cyanoacetate in the presence of diethylamine. This intermediate reacted with various reagents to afford different fused and polyfunctional substituted thiophenes. Antimicrobial screening of the synthesized compounds exhibited promising antimicrobial activities.     

Determining the chemical activity of hydrophobic organic compounds in soil using polymer coated vials

Background  

In soils contaminated by hydrophobic organic compounds, the concentrations are less indicative of potential exposure and distribution than are the associated chemical activities, fugacities and freely dissolved concentrations. The latter can be measured by diffusive sampling into thin layers of polymer, as in, for example, solid phase micro-extraction. Such measurements require equilibrium partitioning of analytes into the polymer while ensuring that the sample is not depleted. We introduce the validation of these requirements based on parallel sampling into polymer layers of different thicknesses.