Synthesis of Highly Functionalized Fluorinated Cispentacin Derivatives

Fluorinated highly functionalized cispentacin derivatives were synthetised starting from an unsaturated bicyclic β‐lactam through C?C bond functionalization via the dipolar cycloaddition of a nitrile oxide, isoxazoline opening, and fluorination by OH/F exchange.     

Partial Conversion of Maltose into Cyclohexane Derivatives

5,6-Unsaturated disaccharide derivative prepared from maltose via its 6-iodo derivative was treated with mercuric chloride, giving α-linked pseudodisaccharide in good yield, which contains cyclohexanone derivatives as constituents. On treatment with an acetic anhydride-pyridine mixture, the cyclohexanone constituents underwent β-elimination to be changed into a sole cyclohexenone moiety. Hydrogenation of the double bond between two carbon atoms and subsequent reductive amination of the carbonyl group gave aminocyclitol-containing pseudodisaccharides.     

Synthesis of Some Isocoumarin Derivatives

An alkaline κ-carrageenase, Cgk-K142, was found in the culture broth of a deep-sea bacterium, Pseudoalteromonas tetraodonis JAM-K142. A gene for the enzyme was cloned and expressed. Purified recombinant Cgk-K142 (rCgk-K142) showed an optimal pH of about 8.8 in glycine-NaOH buffer at 30 °C and of about 8.0 in MOPS buffer at 50 °C. The optimal temperature for the enzyme was 55 °C at pH 8.0. rCgk-K142 was unstable, but λ- and ι-carrageenans, non-degradative substrate homologs, extensively enhanced its stability. The nucleotide sequence of the gene for Cgk-K142 comprised 1,194 bp, and the deduced amino acid sequence (397 amino acids) showed a high level of similarity to the κ-carrageenase of P. carrageenovora, with 94% identity. Another gene for a κ-carrageenase-like protein was found downstream of the gene for Cgk-K142. The nucleotide sequence of that gene consisted of 966 bp (321 amino acids), and it showed the highest similarity, at 64% identity, to protein CgkB of P. carrageenovora, which has been reported as an incomplete 57-amino acid sequence.     

Determination of the Optical Isomers of Insecticidal Pyrethroids by Gas-liquid Chromatography

Determination of the optical isomers of insecticidal pyrethroids was carried out by gas-liquid chromatography. Chrysanthemic acid, which was obtained during hydrolysis of the corresponding pyrethroids, was esterifled with d- or l-2-octanol and the diastereoisomer ester derivatives were resolved on a column of Chromosorb W coated with 10% QF–1. All four isomers, d-trans, l-trans, d-cis and l-cis chrysanthemic acids, could be separated. These compounds were not isomerized during hydrolysis, esteriflcation or gasliquid chromatographic operations and their proportions were accurately determined from their peak area ratios.     

Conversion of Unprotected Amino-Link Oligonucleotides into Their Tetramethylguanidinium Derivatives

Abstract

The preparation of tetramethylguanidinium oligodeoxynucleotide (ODN) derivatives by reaction of the corresponding aminoalkyl-ODN with the uronium salts HBTU, TBTU or HATU, respectively, is described. The binding affinity of the new tetramethylguanidinium ODN derivatives was determined.     

Configurational Relationship between Substituents on Cyclopropane Ring of Pyrethroids and Their Insecticidal Toxicity

Several methyl-substituted cyclopropanecarboxylates were prepared and their steric configurations were established. The insecticidal activity against the housefly of their 5-benzyl-3-furylmethyl esters were tested. Among the substituents on cyclopropane ring, cis-methyl group to ester linkage has been found to be the most essential part for toxicity and trans-methyl and trans-isobutenyl groups greatly enhance its toxic activity.     

Microwave-Assisted Synthesis and Molecular Docking Studies of Fluorinated 1,3,4-Oxadiazole Derivatives as Antimicrobial Agent

Russian Journal of Bioorganic Chemistry - A series of phenyl-5-(2,3,5,6-tetrafluoro-phenyl)-[1,3,4]-oxadiazole were prepared from 2,3,5,6-tetrafluoro-benzoic acid hydrazide by treatment with...     

Synthesis and Insecticidal Activities of Novel 1,3,4-Thiadiazole 5-Fluorouracil Acetamides Derivatives: An RNA Interference Insecticide

A series of novel 1,3,4-thiadiazole 5-fluorouracil acetamides derivatives were designed and synthesized. Their structures were confirmed by infrared, ¹H NMR spectroscopy, and elemental analysis. The insecticidal activities against Tetranychus cinnabarinus and Aphis craccivora of these new compounds were evaluated. The bioassay tests showed that most of these title compounds possessed a good combination of stomach toxicity as well as contact toxicity against Tetranychus cinnabarinus and Aphis craccivora. In particular, the insecticidal activity of the title compound IVe against Aphis craccivora was better than the commercialized thiacloprid and was also comparable to another commercialized product, imidacloprid. The introduction of fluorines to meta and para-position of the benzene ring was essential for high bioactivity.     

Synthesis and Insecticidal Activity of Some New Optically Active Phenylphosphonothiolates and Thionates

The four sesquiterpenes shizukanolide (1), dehydro-shizukanolide (2), glechomanolid (3) and isofuranodiene (4) were isolated from Chloranthus japonicus Sieb. (Hitori-shizuka in Japanese, Chloranthaceae). Their absolute structures have been established on the basis of their physical and chemical properties. Dehydro-shizukanolide showed moderate antifungal activity.     

Synthesis and Anti‐HIV Activity of Guanine Modified Fluorinated Acyclic Nucleoside Phosphonate Derivatives

The preparation of an unprecedented series of nucleobase modified 3‐fluoro‐2‐(phosphonomethoxy)propyl (FPMP) acyclic nucleosides in both their (R) and (S) enantiomerically pure forms is described. The synthesis focuses on a Mitsunobu alkylation reaction to construct the C?N(9) bond between a chiral fluorinated side‐chain residue and 6‐ or 7‐modified guanine analogs. Prodrugs of FPMP‐7‐deazaguanine were also synthesized by derivatization of the corresponding phosphonic acid functionality with (bis)diamyl aspartate amidate groups, leading to moderate activity against human immunodeficiency virus type 1 (HIV‐1).     

Design,Synthesis, and Insecticidal Activities of Novel N-Pyridylpyrazole Amide Derivatives Containing a Maleimide

To discover ‘me-better’ insecticidal active molecules targeting ryanodine receptors (RyRs), a series of novel N-pyridylpyrazole amide derivatives containing a maleimide were designed and synthesized in accordance with the prior investigations of our group. Preliminary bioassay findings indicated some compounds containing a maleimide exhibited good larvicidal activities against lepidopteran pests at a concentration of 500 mg L⁻¹. Compound 9 j showed 60 % larvicidal activities against M. Separata at 50 mg L⁻¹. Compound 9 b exhibited 40 % larvicidal activities against P. xylostella at 50 mg L⁻¹. Molecular docking study indicated that H-bonds, π–π interaction and cation-π interaction made for the binding of compounds 9 b , 9 j with P. Xylostella RyR. These results indicated that compounds 9 b and 9 j could be developed as novel and promising insecticidal leads.     

Design and Synthesis of Pyridine and Thiazole Derivatives as Eco-friendly Insecticidal to Control Olive Pests

Treatment of p-tosyloxybenzaldehyde ( 1 ) with ethyl cyanoacetate afforded ethyl 2-cyano-3-(4-{[(4-methylphenyl)sulfonyl]oxy}phenyl)acrylate ( 2 ) which reacted with some active methylene derivatives under microwave irradiation in presence of ammonium acetate yielded pyridine derivatives 3 – 7 . On the other hand, when treatment of compound 1 with thiosemicarbazide gave 4-tosyloxybenzylidenethiosemicarbazone ( 8 ), which allowed to react with some active methylene compounds, such as: ethyl bromoacetate, chloroacetonitrile or phenacyl bromide derivatives gave thiazole derivatives 9 – 13 . The structure of all products were confirmed by elemental and spectroscopic analyses such as IR, ¹H-NMR, ¹³CNMR and mass spectra. The advanced of this method are short reaction time (3–7 min), excellent yield, pure products, and low-cost processing. In the final category, the toxicological characteristics of all compounds were tested towards Saissetia oleae (Olivier, 1791) (Hemiptera: Coccidae). With respect to the LC₅₀ values. It has been found that compound 3 possesses the highest insecticidal bioefficacy compared with other products, with values of 0.502 and 1.009 ppm, for nymphs and adults female, respectively. This study paves the way towards discovering new materials for potential use as insecticidal active agents.     

Synthesis and Anticancer Activity Evaluation of Some Thienopyrimidine Derivatives

Russian Journal of Bioorganic Chemistry - The current study focused on effective and straightforward routes for preparing a new series of thieno[2,3-d]pyrimidine derivatives in addition to their...     

Studies on Organophosphorus Pesticides Synthesis of Some Sulphanilamide Derivatives

Several N¹-aryl-N⁴(O, O-diethylthiophosphoryl) sulphanilamides and N¹-aiyl-N⁴-(N, N-diarylthiophosphoramidic) sulphanilamides have been prepared with a view to study their pesticidal properties. Six such compounds have been tested against two species of fungi.     

Synthesis and Antimalarial Activity of Some New 1,2-Dioxolane Derivatives

The synthesis of 1,2-dioxolane derivatives in two different acetophenone series, as simplified models of natural coumarins is described. 2-Acetyl-3-acetoxy-4-(3-hydroperoxy-3-methylbut-1-enyl)phenyl acetate and 2-acetyl-5-acetoxy-4-(3-hydroperoxy-3-methylbut-1-enyl) phenyl acetate synthons are used as precursors to these structures. In vitro antimalarial activity of the 1,2-dioxolane derivatives has been investigated.     

Fluorinated Carbaacyclonucleosides: Synthesis and Evaluation of Antiviral Activity

Abstract

Two series of fluoroacyclic nucleosides were synthesised by condensation of nucleic acid bases with substituted fluoropentanes. 1-(5′-Fluoro-4′-hydroxypentyl)-cytosine showed a modest activity against cytomegalovirus (MIC₅₀: 12–15 μg/ml). All the other compounds were inactive against all the viruses tested.     

Deoxyribonolactone Lesion in DNA: Synthesis of Fluorinated Analogues

Abstract

Mono- and difluorinated derivatives of 2-deoxyribonolactone were synthesized using diastereoselective Reformatski reaction as a key step.     

Design,Synthesis, and Insecticidal Activities of Novel meta-Diamide Compounds Containing Ethyl Acetate and Their Derivatives

In this study, a series of meta-diamide compounds containing ethyl acetate group and their derivatives were designed and synthesized. Their insecticidal activities against Plutella xylostella, Spodoptera frugiperda and Alfalfa sprouts were evaluated. Preliminary bioassays showed that some of the title compounds exhibited excellent insecticidal activities. Especially compound ethyl N-(3-((2-bromo-4-(perfluoropropan-2-yl)-6-(trifluoromethyl)phenyl)carbamoyl)-2-fluorophenyl)-N-(4-cyanobenzoyl)glycinate and ethyl N-(3-((2-bromo-4-(perfluoropropan-2-yl)-6-(trifluoromethyl)phenyl)carbamoyl)-2-fluorophenyl)-N-(6-fluoronicotinoyl)glycinate showed 100 % mortality at 0.1 mg/L against Plutella xylostella and Spodoptera frugiperda, same to broflanilide. Their LC₅₀ against Plutella xylostella is 0.286 mg/L and 0.0218 mg/L, respectively. Moreover, compound ethyl N-(3-((2-bromo-4-(perfluoropropan-2-yl)-6-(trifluoromethyl)phenyl)carbamoyl)-2-fluorophenyl)-N-(6-fluoronicotinoyl)glycinate displayed faster control efficacy than broflanilide at 0.1 mg/L. The results indicated that meta-diamide compounds containing ethyl acetate group could be developed as novel and promising insecticides.     

Design,Synthesis, Insecticidal Activities and Molecular Docking of Sulfonamide Derivatives Containing Propargyloxy or Pyridine Groups

The discovery of new highly active molecules from natural products is a common method to create new pesticides. Celangulin V targeting Mythimna separate (M. separate) midgut V-ATPase H subunit, has received considerable attention for its excellent insecticidal activity and unique mechanism of action. Therefore, combined with our preliminary work, thirty-seven sulfonamide derivatives bearing propargyloxy or pyridine groups were systematically synthesized to search for insecticidal candidate compounds with low cost and high efficiency on the H subunit of V-ATPase. Bioactive results showed that compounds A2-A4 and A6-A7 exhibited a better bioactivity with median effective concentration (LC₅₀) values (2.78, 3.11, 3.34, 3.54 and 2.48 mg/mL, respectively) against third-instar larvae of M. separate than Celangulin V (LC₅₀=18.1 mg/mL). Additionally, molecular docking experiments indicated that these molecules may act on the H subunit of V-ATPase. Based on the above results, these compounds provide new ideas for the discovery of insecticides.     

Synthesis and Reactions of Some Glycosylamine Derivatives of 6-Azauracil Nucleosides

Abstract

Reaction of the silylated 6-azauracil (2) with 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-D-glucose (3) gave 1-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-ß-D-glucopyranosyl)-6-azauracil (4), which gave the free nucleoside 5 on deblocking. Acetalation of 5 gave the monoacetal 6 which was oxidized into the ketone 7. Reduction of 7 gave the allo-nucleoside 9 which on hydrolysis afforded the free nucleoside 10. Alternatively, compound 10 was obtained from mesylation of 6 to give 8 followed by subsequent acetolysis and hydrolysis.