Anhydrous CeCl3 Research Articles

Electrophotocatalytic Si–H Activation Governed by Polarity-Matching Effects

Electrophotocatalytic Si–H Activation Governed by Polarity-Matching Effects

Synthesis and Characterization of the Cerium(III) UV‐Emitting 2D‐Coordination Polymer 2∞[Ce2Cl6(4, 4′‐bipyridine)4]·py

Abstract The 2D‐coordination polymer 2∞[Ce2Cl6(bipy)4]·py (bipy = 4, 4′‐bipyridine) shows a 5d‐4f centered emission in the soft UV‐B region. It was synthesized via the reaction of anhydrous CeCl3 and 4, 4′‐bipyridine in pyridine under solvothermal conditions. The two‐dimensional sheet structure consisting of 4, 4′‐bipyridine coordinated Ce2Cl6 dimers closes the gap between the known lanthanum 3∞[La2Cl6(bipy)5]·4bipy framework and the 2D networks of the formula 2∞[Ln2Cl6(bipy)3]·2bipy from praseodymium on. They differ in the number of coordinating bipy linkers, which decreases along La > Ce > Pr, with the remarkable observation that lanthanum, cerium, and praseodymium exhibit different network constitutions. The structure of 2∞[Ce2Cl6(bipy)4]·py exhibits a cem topology constituted of double strands, which are diagonally linked by 4, 4′‐bipyridine forming trapezoid cavities in‐between the strands. The cavities contain intercalated pyridine molecules.

Efficient Synthesis of α-Ferrocenyl Tertiary Alcohols Via CeCl3-Promoted Addition of Grignard Reagents to Large Hindered Ketones

The addition of Grignard reagents to highly hindered acylferrocenes in the presence of anhydrous CeCl3 at room temperature provided the corresponding α-ferrocenyl tertiary alcohols FcC(OH)R1R2 (R1 = Ph or Fc, R2 = Me, Et, iPr, nBu, Ph; Fc = C5H4FeC5H5) in moderate to high yields. Optimum conditions and factors affecting the reaction were investigated.

Regio- and stereoselective synthesis of (Z)-2-Arylsulfanyl allylic alcohols using anhydrous CeCl3 as catalyst under solvent free conditions

Anhydrous CeCl3 was successfully employed as catalyst for the synthesis of (Z)-2-Arylsulfanyl allylic alcohols from propargylic alcohols and thiols under solvent free conditions. The products were obtained in good to excellent yields.

A novel and efficient method for N-acylation of sulfonamides and carbamates: Their biological evaluation towards anti Malassezia activity

BackgroundThe N-acylation of sulfonamides and carbamates with acid anhydrides in the presence of Lewis catalysis has been described. The N-acylation of various sulfonamides and carbamates with carboxylic acid anhydrides were effectively promoted by catalytic amount of CeCl3 under solvent-free conditions to produce the corresponding N-acyl products in good to excellent yields. The synthesized compounds were tested for their antifungal activity. MethodsTo a mixture of sulfonamide and anhydride, and anhydrous CeCl3 was added and the reaction was stirred for the given time. After completion of the reaction, the reaction mixture was diluted with dichloromethane and washed with water and brine solution. The combined organic layers were dried over Na2SO4 and evaporated in vacuum. The crude compound was purified by column chromatography to afford the corresponding N-acylated product. ResultsSynthesized compounds were screened for their antifungal activity against two virulent organisms Malassezia furfur and Malassezia pachydermatis. The compounds were tested in different concentrations ranging from 200 uM to 1 uM and taking their growth observations at OD 600 nm at different time intervals. The growth in the treated wells was compared with the growth in the untreated wells. Ketoconazole was used as control, among the compounds screened 2a, 2i and 4a showed activity than the standard antifungal drug i.e. Ketoconazole. ConclusionSynthesized compounds were evaluated for their antifungal activity and three compounds 2a, 2i, and 4a showed very good activity against both the organisms, for the first time N-acyl sulfonamides and carbamates classes were evaluated as potential anti-Malassezia agents.

ChemInform Abstract: Anhydrous CeCl3‐Catalyzed C3‐Selective Propargylation of Indoles with Tertiary Alcohols.

Anhydrous CeCl3 was successfully used as catalyst for the synthesis of several 3-propargyl indoles in good yields through the reaction of indole with propargyl alcohols in nitromethane.

ChemInform Abstract: Cerium(III) Chloride Mediated Addition of Grignard Reagents to Nitroalkanes: Synthesis of N,N-Disubstituted Hydroxylamines.

Reaction of nitroalkanes with Grignard reagents, in the presence of anhydrous CeCl3 in tetrahydrofuran at –78 °C, affords N,N-disubstituted hydroxylamines in fair to good yields, depending on the nature of the reagent used.

The use of anhydrous CeCl3 as a catalyst for the synthesis of 3-sulfenyl indoles

Abstract Anhydrous CeCl3 was successfully used as a catalyst for the synthesis of several 3-sulfenyl indoles in good to excellent yields through the reaction of indole with N-(alkylthio) and N-(arylthio)phthalimides in DMF.

The use of anhydrous CeCl3 as a recyclable and selective catalyst for the acetalization of aldehydes and ketones

An efficient, clean, chemoselective and solvent-free method for the synthesis of ketone and aldehyde dimethyl acetals was developed using trimethyl orthoformate and commercially available anhydrous CeCl3 as a recyclable catalyst. The method is general and affords the protected carbonyl compounds in good yields and under mild conditions, including aryl and alkyl ketones and activated aldehydes. The catalyst could be utilised directly for 3 cycles, without significant loss of activity.

Scalable Synthesis of the VEGF-R2 Kinase Inhibitor JNJ-17029259 Using Ultrasound-Mediated Addition of MeLi−CeCl3 to a Nitrile

The preparation of the selective VEGF-R2 kinase inhibitor 10 (JNJ-17029259) is described in which the key precursor, 4-(5-isoxazolyl)benzonitrile, undergoes clean transformation to the corresponding cumylamine derivative with CeCl(3)-MeLi in THF. This high-yielding cerium mediated transformation is robust, reproducible, and readily scalable based on a requirement for the anhydrous CeCl(3) to be milled and subjected to ultrasound treatment prior to addition of methyllithium.

Tert‐Butyl Ethers: Renaissance of an Alcohol Protecting Group. Facile Cleavage with Cerium(III) Chloride/Sodium Iodide

AbstractThe tert‐butoxy derivative is one of the most underused alcohol protecting groups. After having developed an easy and useful protocol for its introduction, we offer here a simple procedure for its removal by treatment with anhydrous CeCl3 and NaI in CH3CN. The procedure led to the successful cleavage of aliphatic and aromatic tert‐butyl ethers and was compatible with various other functionalities and protecting groups present in the molecule.

Synthesis and crystal structure of the first cerium sandwich complex of a carborane ligand system

The reaction of closo- exo-Li(TMEDA)-1-Li(TMEDA)-2,3-(SiMe 3) 2-2,3-C 2B 4H 4 ( 1) and anhydrous CeCl 3, in a molar ratio of 2:1, in dry benzene at 0 °C produced a novel Ce(III) bent-sandwich complex, [Li(TMEDA) 2][1-Cl-1-( μ-Cl)-2,2 ′,3,3 ′-(SiMe 3) 4-5,6-[( μ-H) 2Li(TMEDA)]-4,4 ′,5 ′-[( μ-H) 3Li(TMEDA)]-1,1 ′- commo-Ce(2,3-C 2B 4H 4) 2] ( 2), as an orange crystalline solid in 91% yield, thus establishing a pattern of reactivity in the formation of lanthanacarboranes.

Synthesis of Ultrafine Ceria Powders by Mechanochemical Processing

The synthesis of ultrafine cerium dioxide (CeO2) powders via mechanochemical reaction and subsequent calcination was studied. Anhydrous CeCl3 and NaOH powders, along with NaCl diluent, were mechanically milled. A solid‐state displacement reaction—CeCl3+ 3NaOH → Ce(OH)3+ 3NaCl—was induced during milling in a steady‐state manner. Calcination of the as‐milled powder in air at 500°C resulted in the formation of CeO2 nanoparticles in the NaCl matrix. A simple washing process to remove the NaCl yielded CeO2 particles ∼10 nm in size. The particle size was controlled in the range of ∼10–500 nm by changing the calcination temperature.

Cerium(III) chloride promoted addition of organometallic reagents to (−)-menthone—preparation of chiral neomenthyl derivatives

The activation of (−)-menthone with anhydrous CeCl3 led to high yielding additions of different organometallic reagents. Products of exclusively equatorial-addition of the reagents were obtained; only PhMgBr yielded additionally ca. 5% of the axial-addition product.

Efficient Syntheses of Secondary and Tertiary 2-Aryl- and 2-Heteroaryl-allyl Alcohols

Reactions of α-aryl-, α-heteroaryl-, and α-heteroatom-substituted masked alkenyllithiums with aldehydes and ketones provide a general method for the synthesis of allylic alcohols substituted with an aryl or heteroaryl in the β position and aryl, heteroaryl or alkyl substituents in the α position via a [1,4]-C→O silicon rearrangement. In the case of reactions with enolizable aldehydes and ketones, anhydrous CeCl3 was used as an additive. High diastereoselectivities are observed for allyl alcohols produced from α-substituted aldehydes.

The Presence of Water in the Common CeCl3/RLi Alkylation System

Dehydration of CeCl3(H2O)7 following standard procedures for making the commonly-used CeCl3/RLi reagent forms a material containing water and not anhydrous CeCl3. Heating CeCl3(H2O)7 at 150 °C and 0.03 Torr for 12 h forms a material which has an elemental composition of [CeCl3(H2O)]n, contains water by Karl Fischer analysis, reacts with MeLi to form methane, and crystallizes from THF as [Ce(μ-Cl)3(THF)(H2O)]n in space group P1 with a = 6.691(2) A, b = 7.433(2) A, c = 10.092(2) A, α = 84.46(2)°, β = 76.72(2)°, γ = 74.76(3)°, V = 471.0(2) A3, ρcalcd = 2.37 g/cm3, and Z = 2 at T = 158 K. [Ce(μ-Cl)3(THF)(H2O)]n crystallizes in a layered structure in which eight-coordinate cerium atoms are ligated to terminal water and THF ligands and six bridging chlorides in a distorted square antiprismatic geometry. The THF ligands extend above and below the layers which contain the water molecules. Reactions of “CeCl3/RLi” must take into account the presence of 1 equiv of water.

Cerium(III) Amide Enolate. Addition to Aldehydes and Ketones

Abstract The cerium(III) amide enolates, prepared in situ from the corresponding lithium enolates and anhydrous CeCl3, were found to undergo facile additions to ketones and aldehydes. Yields of the adducts are superior to those obtained using the lithium enolates.

Cerium(III) chloride mediated addition of Grignard reagents to nitroalkanes: synthesis of N,N-disubstituted hydroxylamines

Reaction of nitroalkanes with Grignard reagents, in the presence of anhydrous CeCl3 in tetrahydrofuran at –78 °C, affords N,N-disubstituted hydroxylamines in fair to good yields, depending on the nature of the reagent used.