An Efficient Synthesis of Pyrazolyl‐1,2,3‐thiadiazoles via Hurd–Mori Reaction

An efficient synthetic strategy has been developed for the synthesis of pyrazolyl‐1,2,3‐thiadiazoles via Hurd–Mori cyclization reaction. The reaction of various pyrazolyl‐phenylethanones with semicarbazide hydrochloride in the presence of sodium acetate/methanol gave the corresponding semicarbazones ( 3a – i ). These semicarbazones were further reacted with thionyl chloride via the Hurd–Mori cyclization conditions to accomplish the title products ( 4a – i ). The present protocol favored for the formation of both pyrazolyl semicarbazone derivatives and pyrazolyl‐1,2,3‐thiadiazole derivatives by forming C─S, N─S, and C═N bonds in excellent yields with variety of substrates. The final compounds were characterized by analytical and spectral studies.     

TFAA/H3PO4‐Mediated C‐2 Acylation of Thiophene: A Direct Synthesis of Known and Novel Thiophene Derivatives of Pharmacological Interest

A number of aliphatic and aromatic carboxylic acids were reacted with thiophene in the presence of trifluoroacetic anhydride and H₃PO₄ to give a variety of acylated thiophenes in good to excellent yields. The methodology was used to prepare known nonsteroidal anti‐inflammatory drug‐based novel compounds of potential pharmacological significances. Molecular modeling studies were carried out by using nonsteroidal anti‐inflammatory drug‐based thiophene derivatives to assess their cyclooxygenase inhibiting potential in silico. On the basis of docking studies followed by subsequent in vitro assay, indomethacin‐based thiophene derivative was identified as a novel cyclooxygenase‐2 inhibitor with balanced selectivity.     

Stereoselective Synthesis of 1,2,3‐Triazolooxazine and Fused 1,2,3‐Triazolo‐δ‐Lactone Derivatives

The stereoselective synthesis of 1,2,3‐triazolooxazine and fused 1,2,3‐triazolo‐δ‐lactone by applying chemoenzymatic methods is described. trans‐2‐Azidocyclohexanol was successfully resolved by Novozyme 435 with an ee value of 99%. Installation of the alkyne moiety on the enantiomerically enriched azidoalcohol by O‐alkylation, followed by intramolecular azide? alkyne [3+2] cycloaddition resulted in the desired 1,2,3‐triazolooxazine derivative. Enantiomerically pure azidocyclohexanol was also subjected to the Huisgen 1,3‐dipolar cycloaddition reaction with dimethylacetylene dicarboxylate, followed by intramolecular cyclization of the corresponding cycloadduct, to furnish a fused 1,2,3‐triazolo‐δ‐lactone.     

Synthesis of Novel Substituted 2‐Lactosylthiothieno[2,3‐d]pyrimidin‐4(3H)‐one Derivatives

The title compounds substituted 2‐lactosylthiothieno[2,3‐d]pyrimidin‐4‐ones 6 were synthesized by the glycosyl reaction and alcoholysis reaction of substituted 2‐thioxo‐thieno[2,3‐d]pyrimidin‐4‐ones 4 ,which is formed by the base catalytic and acetic acidify reaction of amino esters 2 with alkyl or arylisothiocyanates and hepta‐O‐acetyl‐lactosyl bromide in good yields. All of the compounds were confirmed by NMR, ESI‐MS, and elemental analysis.     

Synthesis of 2(5H)‐Furanone Derivatives with Bis‐1,2,3‐triazole Structure

A series of new chiral 2(5H)‐furanone derivatives containing bis‐1,2,3‐triazole moiety were designed and synthesized from (5S)‐5‐alkoxy‐3,4‐dihalo‐2(5H)‐furanones 1 , dicarboxyl amino acids 2 , propargyl bromide, and organic azides 5 under mild conditions via the sequential three steps, including asymmetric Michael addition‐elimination, substitution and no‐ligand click reaction. Twelve new intermediates, including N‐[5‐alkoxy‐2(5H)‐furanonyl] dicarboxyl amino acids 3 and their corresponding propargyl esters 4 , and twelve target molecules 6 were characterized by FTIR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The influences of different synthetic conditions and substrates in each step were investigated. The research provides a new method and idea for the synthesis of 2(5H)‐furanone compounds with polyheterocyclic structure due to the diversities of four basic unit molecules.     

Ultrasound‐Mediated Synthesis of Novel 1,2,3‐Triazole‐Based Pyrazole and Pyrimidine Derivatives as Antimicrobial Agents

In the development of novel antimicrobial agents, we synthesized novel 1,2,3‐triazole‐based pyrazole and pyrimidine derivatives 6 ( a–f ) and 7 ( a–f ) by ultrasound‐assisted method. The synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR, MS, and elemental analysis. All compounds were assessed in vitro for their efficacy as antimicrobial agents against four bacteria (Staphylococcus aureus , Bacillus subtilis , Escherichia coli , and Pseudomonas aeruginosa ) and two fungi (Candida albicans and Aspergillus niger ). In particular, compounds 6a , 6e , 7a , 7c , and 7e exhibited highly potent antimicrobial activity.     

Synthesis and Anticancer Evaluation of Some Novel Quinazolin‐4(3H)‐one Derivatives

A new series of quinazolinone derivatives bearing pyridine, pyrimidine, pyrazole, or pyran moieties were synthesized for the purpose of anticancer cell line evaluation. Synthesis of these derivatives was achieved by the reaction of the ketone 2 with the appropriate aldehydes in the presence of either ethylcyanoacetate or malononitrile and ammonium acetate in one‐pot reaction. Chalcones 6 reacted also with hydrazine hydrate to give the corresponding pyrazolines 7 and reacted with urea or thiourea to give the 2‐oxopyrimidines or the 2‐thioxopyrimidines 8 , respectively. Evaluation of some representative examples of the newly synthesized compounds against cancer cell lines showed promising activity as anticancer agents.     

Two new soluble iron–oxo complexes: [Fe2(μ‐O)(μ‐O2CCF3)2(O2CCF3)2(C10H8N2)2] and [Fe4(μ3‐O)2(μ‐O2CCF3)6(O2CCF3)2(C10H8N2)2]·CF3CO2H

Two new iron–oxo clusters, viz. di‐μ‐tri­fluoro­acetato‐μ‐oxo‐bis­[(2,2′‐bi­pyridine‐κ²N,N′)(tri­fluoro­acetato‐κO)­iron(III)], [Fe₂O(CF₃CO₂)₄(C₁₀H₈N₂)₂], and bis(2,2′‐bi­pyridine)­di‐μ₃‐oxo‐hexa‐μ‐tri­fluoro­acetato‐bis­(tri­fluoro­acetato)­tetrairon(III) tri­fluoro­acetic acid solvate, [Fe₄O₂(CF₃CO₂)₈(C₁₀H₈N₂)₂]·CF₃CO₂H, contain dinuclear and tetranuclear Fe^III cores, respectively. The Fe^III atoms are in distorted octahedral environments in both compounds and are linked by oxide and tri­fluoro­acetate ions. The tri­fluoro­acetate ions are either bridging (bidentate) or coordinated to the Fe^III atoms via one O atom only. The fluorinated peripheries enhance the solubility of these compounds. Formal charges for all the Fe centers were assigned by summing valences of the chemical bonds to the Fe^III atom.     

Synthesis of 2‐Amino 3‐Substituted Quinazolin‐4(3H)‐one Derivatives via Iodine‐Mediated Guanidinylation of Pbf‐Activated Thiourea

2‐Amino 3‐substituted‐quinazolin‐4(3H)‐one derivatives were synthesized from Pbf‐isothiocyanate and methyl anthranilate. The construction of the guanidine‐containing quinazolinone heterocyclic skeleton was achieved using Pbf‐activated thiourea treated with primary amines via iodine‐mediated guanidinylation. The desired compounds were obtained after Pbf cleavage by trifluoroacetic acid.     

Synthesis and Herbicidal Activities of 3‐(4‐Chloro‐2‐fluoro‐5‐substituted phenyl)benzo[d][1,2,3]triazin‐4(3H)‐one Derivatives

A series of 3‐phenyl benzo[d][1,2,3]triazin‐4(3H)‐one derivatives were synthesized through the condensation of phenol E and alkyl (alkenyl, alkynyl) chlorides (bromides, iodide) or alkyl chloroacetates or N‐alkyl chloroacetamides using K₂CO₃ as the acid acceptor in N,N‐dimethylformamide. Phenol E was prepared from starting material, 5‐amino‐2‐chloro‐4‐fluorophenyl ethyl carbonate, in four steps involving in amidation, reduction, diazotization, and deprotecting‐group reaction. The herbicidal activities of the title compounds were tested against two dicotyledonous plants and two monocotyledonous plants, in which some of them exhibited high herbicidal activities against two dicotyledonous plants in preemergence and postemergence treatments. Moreover, when the dosage was decreased to 180 and 90 g/ha, compounds F1 , F8 , and F9 showed highly selective inhibitory activities against amaranth pigweed, alfalfa, asteraceae, field sowthistle, morning glory, purslane, and velvetleaf in postemergence treatment but had no herbicidal efficacy on rape except F1 , suggesting that it be possible to find a kind of herbicides to inhibit dicotyledonous weeds in the field of dicotyledonous crops with the same genus as aforementioned weeds.     

Catalytic CO Oxidation by O2 Mediated by Noble‐Metal‐Free Cluster Anions Cu2VO3–5−

Catalytic CO oxidation by molecular O₂ is an important model reaction in both the condensed phase and gas‐phase studies. Available gas‐phase studies indicate that noble metal is indispensable in catalytic CO oxidation by O₂ under thermal collision conditions. Herein, we identified the first example of noble‐metal‐free heteronuclear oxide cluster catalysts, the copper–vanadium bimetallic oxide clusters Cu₂VO_3–5^? for CO oxidation by O₂. The reactions were characterized by mass spectrometry, photoelectron spectroscopy, and density functional calculations. The dynamic nature of the Cu?Cu unit in terms of the electron storage and release is the driving force to promote CO oxidation and O₂ activation during the catalysis.     

Synthesis of Some Quinazoline‐2(1H),4(3H)‐dione Derivatives

Several quinazoline‐2(1H),4(3H)‐dione derivatives were synthesized from pyrimidine‐2(1H),4(3H)‐dione derivative.     

Synthesis and Cytotoxicity Evaluation of Novel Andrographolide‐1,2,3‐Triazole Derivatives

A series of new andrographolide‐1,2,3‐triazole derivatives, 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , were synthesized from a natural bioactive labdane type diterpenoid, andrographolide. All the derivatives were screened against human cancer cell lines MCF7, MDA‐MB‐231, COLO205, HepG2, K562, Hela, and HEK293 to evaluate their cytotoxic activity. All the compounds showed anticancer activity selectively against K562 cell line, with IC₅₀ values ranging from 8.00 to 17.11 µM, and are inactive against the rest of the cell lines. Compounds 3c and 3d showed significant cytotoxicity among the synthesized derivatives. The in silico docking studies revealed compounds 3b and 3d with high binding affinity against the cancer target, transient receptor potential vanilloid 1.     

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.     

Preparation,Spectroscopic Properties,and Crystal Structures of Fe2(CO)6(μ‐CO)(μ‐CF2)2, Fe2(CO)6(μ‐CO)2(μ‐CF2), and Fe2(CO)6(μ‐CF2)(PPh3)2 – Theoretical Studies of Methylenic vs. Carbonyl Bridges in Diiron Complexes

The reaction of Na₂[Fe(CO)₄] with Br₂CF₂ in n‐pentane generates a mixture of the compounds (CO)₃Fe(μ‐CO)_3–n(μ‐CF₂)_nFe(CO)₃ ( 2 , n = 2; 3 , n = 1) in low yields with 3 as the main product. 3 is obtained free from 2 by reacting Br₂CF₂ with Na₂[Fe₂(CO)₈]. The non‐isolable monomeric complex (CO)₄Fe=CF₂ ( 1 ) can probably considered as the precursor for 2 . 3 reacts with PPh₃ with replacement of two CO ligands to form Fe₂(CO)₆(μ‐CF₂)(PPh₃)₂ ( 4 ). The complexes 2 – 4 were characterized by single crystal X‐ray diffraction. While the structure of 2 is strictly similar to that of Fe₂(CO)₉, the structure of 3 can better be described as a resulting from superposition of the two enantiomers 3 a and 3 b with two semibridging CO groups. Quantum chemical DFT calculations for the series (CO)₃Fe(μCO)_3–n(μ‐CF₂)_nFe(CO)₃ (n = 0, 1, 2, 3) as well as for the corresponding (μ‐CH₂) derivatives indicate that the progressively larger σ donor and π acceptor properties for the bridging ligands, in the order CO < CF₂ < CH₂, favor a stronger Fe–Fe bond.     

Synthesis and In Vitro Antibacterial Activities of Novel 2‐Aryl‐3‐(phenylamino)‐2,3‐dihydroquinazolin‐4(1H)‐one Derivatives

An efficient synthesis of novel 2‐aryl‐3‐(phenylamino)‐2,3‐dihydroquinazolin‐4(1H)‐one derivatives using KAl(SO₄)₂.12H₂O (Alum) as a catalyst from an aldehyde and 2‐amino‐N‐phenylbenzohydrazine in ethanol is described. All synthesized derivatives were screened for anti‐bacterial activity. Some compounds exhibited promising anti‐bacterial activity with reference to standard antibiotics.     

An Enolate‐Mediated Organocatalytic Azide–Ketone [3+2]‐Cycloaddition Reaction: Regioselective High‐Yielding Synthesis of Fully Decorated 1,2,3‐Triazoles

An enolate‐mediated organocatalytic azide–ketone [3+2]‐cycloaddition (OrgAKC) reaction of a variety of enolizable arylacetones and deoxybenzoins with aryl azides was developed for the synthesis of fully decorated 1,4‐diaryl‐5‐methyl(alkyl)‐1,2,3‐triazoles in excellent yields with high regioselectivity at 25 °C for 0.5–6 h. This reaction has an excellent outcome with reference to reaction rate, yield, regioselectivity, operation simplicity, and availability of substrates and catalyst. This reaction has advantages over the previously known metal‐mediated reactions.     

An Efficient Protocol for the Synthesis of Novel 1,2,3‐Triazole Substituted 4H‐Chromene Derivatives

A facile and an efficient protocol has been developed for the synthesis of novel 1,2,3‐triazole substituted 4H‐chromene derivatives 4 in single pot by multicomponent reaction of 1,3‐cyclohexanedione, malononitrile and 1‐substituted 1,2,3‐triazole‐5‐aldehyde using potassium carbonate as catalyst.     

Structure cristalline de (NH4)2PO3H,H2O: Stereochimie de l'Ion PO3H2− et ses relations avec PO3F2− et SO32−

(NH₄)₂PO₃H, H₂O crystallizes in the monoclinic system, space group P2₁/c, with a = 6.322(1) Å, b = 8.323(1) Å, c = 12.676(1) Å, β = 98.84(1) and Z = 4. The structure was refined to R = 0.022 based on 853 independent X-Rays intensities. Improved dimensions of the tetrahedral PO₃H^2? ion have been obtained: P?H = 1.34(2) and P?O = 1.514(2) Å. The geometry of this ion is compared with that of PO₃F^2? and SO₃^2? ions and we find a decrease of the volume: V_F? > V_H+ > V_{lone pair}.