Study on the Structure of Supramolecular Inclusion Complex of β-Cyclodextrin with Retinoic Acid

Inclusion compound of retinoic acid with (-cyclodextrin was prepared by coprecipitating method, the structure of resulting product was studied by elemental analysis, differential scanning caloriemetry(DSC) analysis, FT-IR spectroscopy and X-ray diffractometry, and the formed supramolecule self-assembles in aqueous solution according to molar ratio 2:1 of host-guest.

Toxicological studies for some agricultural waste extracts on mosquito larvae and experimental animals

Objective:To evaluate some agricultural waste extracts as insecticide and their effects on enzyme activities in liver and kidney of male mice.Methods:The insecticidal activity of five tested compounds(one crude extract and 4 waste compounds) was bioassay against the 3rd instars of the Culex pipiens(Cx.pipiens) larvae in the laboratory.The LC_(50) values of eucalyptol,apricot kernel.Rice bran,corn,black liquor and white liquor are 91.45.1166.1,1203.3.21449.65.4025.78 and 6343.18 ppm,respectively.Selection of the compounds for the subsequent studies was not only dependent on LC_(50) values but also on the persistence of these wastes products on large scale.Results:White and black liquor did not produce any gross effect at 200 mg/Kg body weight.No apparent toxic symptoms were observed in tested animals during the whole period of the experimenl which run out for 14 days.No statistically significance was observed in the enzyme choliuesterase activity,the activities of liver enzymes and kidney function in treated mice with black and while liquors.While,no and slighl inhibition was observed after the 2weeks ol treatment period with deltamethrin and lenilrothion reached to about 24%in plasma cholinesterase enzyme activity.Significantly increase in the activities ol liver enzymes and kidney function in treated mice with deltamethrin and fenitrothion.Conclusions:Black liquor can be used efficiently In control Cx.pipiens larvae under laboratory condition.Environmental problem caused by rice straw can be solved by converting the waste material to beneficial natural selective insecticide.

An altemative synthetic approach towards erythrinan and homoerythrinan alkaloids by tandem semipinacol/intramolecular Schmidt reaction

An alternative construction of A-B-D ring-system of erythrinan and homoerythrinan alkaloids by TiCl4-mediated tandem semipinacol/intramolecular Schmidt reaction of α-siloxyepoxyazide was addressed and the unusual epoxidation stereoselectivity was observed in preparation of the substrate once again.

Removal of Cu(II),Pb(II),Mg(II),and Fe(II) by Adsorption onto Alginate/Nanocellulose Beads as Bio-Sorbent

Alginate blended with cellulose nanocrystals(CNC),cellulose nanofibers(CNF),and tri-carboxylate cellulose nanofibers(TPC-CNF)prepared and encapsulated in the form of microcapsules(bio-polymeric beads).The cellulosic nanomaterials that used in this study were investigated as nanomaterials for wastewater treatment applications.Batch experiments were performed to study the removal of copper,lead,magnesium,and iron from aqueous solutions by the prepared beads.The effects of the sorbent dosage and the modified polymers on the removing efficiency of the metal cations were examined.Atomic absorption was used to measure the metal ions concentrations.The modified bio-polymeric beads(Alg-CNF,Alg-CNC,and Alg-TPC-CNF)exhibited high-efficiency towards removing of the metal cations;Cu^(2+),Pb^(2+),Mg^(2+),and Fe^(2+).The Alg-TPC-CNF composite was exhibited excellent removing efficiency which around 95%for Pb,92%for Cu,43%for Fe and 54%for Mg.These outcomes affirm that the utilization of nanomaterials giving higher adsorption capacities contrasted with similar material in its micro or macrostructure form.

Studies on the Synthesis of Morphinan Alkaloid:Preparation of the Key Allylic Silyl Ether Precursor

A convergent strategy to the key allylic silyl ether precursor 4 in our synthetic efforts toward morphinan alkaloid is presented. The vital step is the selective 1,2-addition of the organocerium agent of 6 to ketene 5.

The Rearrangement of 2-Benzothiazolylthioacetyl Hydrazide in Synthesis of s-Triazolo[3,4-b]benzothiazole-3-thiol

The rearrangement reaction of 2-benzothiazolylthioacetyl hydrazide 1 with potassium hydroxide and carbon disulfide in ethanol to produce s-triazolo[3, 4-b]benzothiazole-3-thiol 3 was described. 3 also can be obtained from 2-benzothiazolylhydazine 2 and the two methods for getting 3 were compared. Mannich reaction of compounds 3 was reported too.

Catalyst Free Synthesis of Pyridine-2,6-bis(2-bromo-propane-1,3-dione) and Pyrdine-2,6-bis(<i>N</i>-arylthiazoline-2-thiones)

We have described herein a catalyst-free preparation method of pyridine-2,6-bis(N-alkylthiazoline-2-thiones) (4a-i) by the reaction of primary amines, CS2, and pyridine-2,6-bis(2-bromo-1,3- dicarbonyl) derivatives (2a-c) in water. Also, we have described a catalyst free, green chemistry protocols to monobromination of pyridine-2,6-bis(2-bromo-1,3-dicarbonyl) derivatives with high yield, using NBS as a brominating agent, that led to eco-friendly isolation and purification proce-dures. Furthermore, we have studied the reactivity of pyridine-2,6-bis(2-bromo-1-methyl-pro- pane-1,3-dione) (2a) towards thiourea to afford 2,6-bis(5-benzoyl-2-aminothiazol-4-yl)pyridine (9).

Synthesis of 2- [ (4-Hydroxylcarbomylphenyl) -methylamino ] - N- ( 2- aminophenyl ) acetamide

Early studies revealed that the hybrid polar/apolar compound N, N′-hexamethylene bisacetaamide (HMBA) was a very effective inducer of differentiation in a transformed cell lines. [1] The use of this polar/apolar compound to induce murine erythroleukemia cells (MELC) to undergo erythoid differentiation with suppression of oncogenicity has proved a useful model to study inducer-mediated differentiation of transformed cell. [2] To search more effective inducers, we utilized the computer to design a new target compound. Herein, we reported the synthesis of title compound.……

Highly Enantioselective Phenylacetylene Addition to Benzaldehyde Catalyzed by Chiral Tridentate Ligand

Development of new or improved methods for the asymmetric preparation of chiral propargylic alcohols has gained considerable significance during the past years because they are useful building blocks for the synthesis of many biologically active compounds and natural products.[1] A series of chiral tridentate ligands were conveniently synthesized from amino acids with good yields (Scheme 1).[2] A preliminary study of the enantioselective alkynylation of benzaldehyde catalyzed by this chiral tridentate ligand was carried out and up to 83% ee of chiral propargyl alcohols was obtained (Table 1 ). A further investigation of the tridentate ligand is currently underway.……

Peptide Deravatives as New Chiral Ligands for Enantioselective Phenylacetylene Addition to Aldehydes

The asymmetric addition of alkynylzinc to aldehydes is an important method of synthesizing chiral propargyl alcohols, which are important precursors to many chiral organic compounds. Recently, many significant chiral ligands in this area have been disclosed.[1] Use of a short peptide as a catalyst would allow expansion beyond the (still uncharted) repertoire of single amino acids, while conserving the advantages of a small molecule catalyst. To the best of our knowledge,no results of peptide derivatives as chiral ligands in this reaction has been disclosed to date.[2] Herein, we report the initial results of peptide derivatives, which have been used directly as a chiral ligand in this reaction (Scheme 1).……

A TOTAL SYNTHESIS OF[5',5'-BIS(VALINE)]ACTINOMYCIN D

A new analogue of A M D, [5',5'-bis(valine)]actinomycin D was synthesized

Strategies for constructing seven-membered rings:Applications in natural product synthesis

The seven-membered ring motifs are found in bioactive pharmaceuticals and a wide range of natural products,including alkaloids and terpenoids,which hold significant importance in synthetic chemistry and has garnered considerable attention from both academia and industry.Despite the challenges faced in the past decade,the total synthesis of natural products incorporating the non-aromatic cycloheptane skeletons remains a compelling pursuit.Recently,numerous elegant strategies for constructing the sevenmembered ring system have been successfully developed.This review focuses on the recent advancements in this field from 2017 to April 2023,highlighting key transformations utilized to construct the non-aromatic cycloheptane core structures and serves as a valuable guide for synthetic chemists engaged in the total synthesis of natural products containing seven-membered ring motifs.

Manganese dioxide(MnO_(2))/Fullerene-C_(60)-Modified Electrodes for the Voltammetric Determination of Rifaximin

Rifaximin(RFX)is a broad-spectrum oral antibiotic with bactericidal actions against Gram-negative and Gram-positive bacteria.In the present work,a sensitive voltammetric assay for the RFX in pharmaceutical formulations is designed using nanostructured working electrodes.Surface functionalization with manganese dioxide(MnO_(2))/fullerene-C_(60) nanocomposite exhibited the highest electrochemical responses with a sharp oxidation peak at about 336 mV that was obtained using the differential pulse voltammetry(DPV).The cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)were applied,while the electrode matrix composition including types of nanomaterials,electroanalytical parameters,and pH eff ect were optimized.To that end,using the DPV,high sensitivity was obtained from the linear calibration curve ranged from 0.8 to 31.5μg·mL^(-1) with the correlation coe fficient of 0.99,limit of detection of 0.76μg·mL^(-1) and limit of quantification of 2.31μg·mL^(-1) .Accordingly,the designed approach is off ering a potential applicability towards the RFX determination in pharmaceutical preparations and its quality control.

A Facile Approach to Synthesis of the Di-O-methyl Ethers of （-）-Agatharesinol, （-）-Sugiresinol, （＋）-Nyasol and （＋）-Tetrahydronyasol

The facile enantioselective synthesis of the di-O-methyl ethers of （-）-agatharesinol （1b）, （-）-sugiresionl （2b）, （＋）-nyasol （3b） and （＋）-tetrahydronyasol （4） were achieved in high yield. The absolute configuration of （＋）-3a was confirmed via first total synthesis of （＋）-3b and （＋）-4.

Enzyme-like C-H Oxidation of Glucosides Promoted by Visible Light

To match nature’s prowess at using enzymes to make desired motifs in a regioselective fashion,we explore the use of visible light for the selective oxidation of the hydroxyl group to afford the corresponding ketosaccharide.This highly admirable approach offers several advantages over the enzymatic approach in terms of yields and the scope of substrates.Herein,we report the development of a simple visiblelight-promoted selective oxidation of unprotected glucosides that allows for inexpensive access to valuable keto-saccharide building blocks.The method is employed on a variety of different natural and artificial glucosides,is operationally simple and scalable,and can be used to access keto-saccharides rapidly and inexpensively.

Enantioselective Addition of Phenylacetylene to Ketones Catalyzed by Titanium（IV） Complexes of N-Sulfonylated β-Amino Alcohols

The easily prepared and recoverable chiral N-sulfonylated fl-amino alcohol 2 in combination with Ti（OPr-i）4 was found to be an effective chiral catalyst for the enantioselective addition of alkynylzinc to ketones, which gave the useful products, i.e. chiral tertiary propargyl alcohols, with the ee up to 92%.

A Novel Strategy for the Key Fully Substituted Cyclopentenedione Moiety of Madindolines via AIEt3-promoted Tandem Reductive Rearrangement of α-Hydroxy Epoxides

The fully substituted cyclopentenedione core of madindoline A （1） and B （2） as potent and selective inhibitor of IL-6 has been synthesized efficiently. The quaternary carbon center C-2＇ was constructed on the basis of a newly developed AIEt3-promoted tandem reductive rearrangement of α-hydroxy epoxides.

Stereodivergent synthesis of C-glycosamino acids via Pd/Cu dual catalysis

Herein,we reported the stereodivergent synthesis of C-glycosamino acids via Pd/Cu dual catalysis and found a suitable system to resolve many challenges,such as the tolerance towards the density of functional groups,the variability of the anomeric position,the compatibility of appropriate catalyst combinations,the regioselectivity of nucleophiles,and the match/mismatch problems between chiral substrates and chiral ligand-metal complexes.The method enables the efficient preparation of a series of unnatural C-glycosamino acid skeletons bearing two contiguous stereogenic centers in good yields with excellent diastereoselectivity.From this crucial precursor,various C-glycosamino acid derivatives have been achieved diversely.The readily prepared C-glycosamino acid hybrids will meet the growing demands for the development of new molecular entities for discovering new drugs and materials.This stereodivergent synthesis of C-glycosamino acids will further accelerate the study of their structural features,mode of action,and potential biological applications in the near future.

A Dipolar Cyclization/Fragmentation Strategy for the Catalytic Asymmetric Synthesis of Chiral Eight-Membered Lactams

Medium-sized nitrogen heterocycles,including eightmembered lactams,are important in synthetic and pharmaceutical chemistry because of their presence in a variety of natural products and drug molecules.Previous attempts at synthesis using a direct headto-tail cyclization strategy suffered from competitive self-cyclization and oligomerization of dipolar species.Herein,we propose an alternative strategy.

Mechanism of reduction of benzylidenemalono-nitrile by l-benzyl-1,4-dihydronicotinamide

The reduction of benzylidenemalononitrile by 1-benzyl-1,4-dihydronicotinamide undergoes via a one-step hydride transfer mechanism rather than a multistep mechanism involving initial electron transfer.