Synthesis of organic phosphines and phosphine oxides from elemental phosphorus and phosphine in the presence of strong bases

Data on the reactions of elemental phosphorus and phosphine with electrophilic reagents are described systematically and analyzed. These reactions occur in the presence of strong bases and yield primary, secondary, and tertiary phosphines and phosphine oxides. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1695–1702, September, 1998.     

Metal-free reduction of tertiary phosphine oxides with Hantzsch ester简

The （COCl）2/Hantzsch ester is found to be an effective system for the metal-free reduction of tertiary phosphine oxides. The reaction proceeds under mild conditions, and is applicable to triarylphosphine oxides and alkyldiarylphosphine oxides to produce the corresponding tertiary phosphines in good to excellent yields. This new finding provides a practical, convenient and metal-free method for the reduction of tertiary phosphine oxides to tertiary phosphines, and shows potential application in organic synthesis.     

Thermal rearrangement of bis(hydroxymethyl)phosphines as a way to P-chiral phosphine oxides

Bis(hydroxymethyl)(2-pyridyl)- and bis(hydroxymethyl)-[(2-pyridyl)ethyl]phosphines on heating to 180 °C undergorearrangement leading to racemic P-chiral tertiary P-methyl-P-(hydroxymethyl)-containing phosphine oxides. The spontaneous self-resolution of these enantiomer mixtures during the crystallization was demonstrated.     

Microwave-Assisted Synthesis of P-Heterocycles*

Abstract

The direct esterification, thioesterification and amidation of cyclic phosphinic acids, such as 1-hydroxy-3-phospholene 1-oxides, 1-hydroxy-phospholane 1-oxides and a 1-hydroxy-1,2,3,4,5,6-hexahydrophosphinine 1-oxide, which do not take place on conventional heating, were carried out under MW conditions in excess of the alcohol, thioalcohol and amine, respectively. The cyclic phosphinates were also prepared by MW-assisted alkylating esterification of the corresponding phosphinic acids in solid–liquid phase. Using alkyl halides of normal reactivity, the application of a phase transfer catalyst was also beneficial. In addition, MW-assisted Diels–Alder reactions, so-called inverse Wittig-type reactions furnishing β-oxophosphoranes, a few kinds of phospha-Michael additions leading to precursors of bidentate P-ligands, and a few Kabachnik–Fields condensations affording α-aminophosphonates and α-aminophosphine oxides are discussed.     

Silver-catalyzed 2-isocyanobiaryls insertion/cyclization with phosphine oxides: synthesis of 6-phosphorylated phenanthridines

A silver-catalyzed 2-isocyanobiaryls insertion/cyclization with phosphine oxides was described for the construction of the 6-phosphorylated phenanthridines through radical addition of in situ formed P-centered radical to 2-isocyanobiphenyls and homolytic aromatic substitution process. The reactions could proceed smoothly to give the desired 6-phosphorylated phenanthridines promoted by AgOAc (20 mol %) with PhI(OAc)₂ (3.0 equiv).     

Benson group additivity values of phosphines and phosphine oxides: Fast and accurate computational thermochemistry of organophosphorus species

Composite quantum chemical methods W1X-1 and CBS-QB3 are used to calculate the gas phase standard enthalpy of formation, entropy, and heat capacity of 38 phosphines and phosphine oxides for which reliable experimental thermochemical information is limited or simply nonexistent. For alkyl phosphines and phosphine oxides, the W1X-1, and CBS-QB3 results are mutually consistent and in excellent agreement with available G3X values and empirical data. In the case of aryl-substituted species, different computational methods show more variation, with G3X enthalpies being furthest from experimental values. The calculated thermochemical data are subsequently used to determine Benson group additivity contributions for 24 Benson groups and group pairs involving phosphorus, thereby allowing fast and accurate estimations of thermochemical data of many organophosphorus compounds of any complexity. Such data are indispensable, for example, in chemical process design or estimating potential hazards of new chemical compounds. © 2018 Wiley Periodicals, Inc.     

Microwave-assisted synthesis of benzoxazinediones under solvent-free conditions

Benzoxazinediones exhibit potential as versatile synthons in the synthesis of wide variety of heterocyclic compounds with biological activity. In this work, an efficient and eco-friendly one-step synthesis of benzoxazine-2,4-diones from phthalic anhydrides derivatives and trimethylsilyl azide using the microwave technique was developed and compared with conventional heating. Microwave irradiation plays a critical role in driving the reaction and providing access to products and/or regioisomers not available from conventional heating. Thus, the regioselectivity of the reaction may be modulated by the irradiation time. Depending on the method employed the benzoxazinediones were isolated with yields in the range of 30–90%.     

Microwave-assisted green synthesis of 1, 3-benzodioxole derivatives

Abstract

2-Phenyl-substituted 1,3-benzodioxole derivatives were synthesized by microwave irradiation by reacting catechol with benzoic acid derivatives in the presence of polyphosphoric acid as a catalyst which acts as a solvent and also as a cyclizing agent. This synthesis has various advantages over other catalytic conventional synthesis because it saves time, increases yield, and is a simple, economical, and effective synthesis. Moreover, this is also an excellent green chemistry approach as it does not require additional toxic solvents or harmful chemicals, and overall it reduced energy utilization than the other methods of synthesis.

     

Hydrolysis of tetrafluorosilane under neutral conditions: A quantum chemical study

A density functional quantum chemical study of the first step of SiF₄ hydrolysis under neutral conditions in the presence of one or two H₂O molecules was carried out. The reaction is endothermic and can follow three different pathways that involve the formation of penta-coordinated (pathway A) and hexacoordinated (pathways B and C) intermediates and transition states as the key steps. Pathway B is the most energetically favorable. All three pathways of the hydrolysis reaction lead to a product with formal retention of the configuration of substituents at the silicon atom. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 749–753, May, 2006.     

Ultrasound mediated green synthesis of rhodanine derivatives: Synthesis,chemical behavior,and antibacterial activity

A variety of rhodanine derivatives were synthesized via a three-component reaction of carbon disulfide, amines, and dialkyl acetylenedicarboxylate in polyethylene glycol under conventional stirring or ultrasound irradiation. The sonochemical-assisted procedure provides an improved and accelerated conversion when compared to the conventional reaction, with increased rate of reaction and quality of product obtained. The product formed, 2a, could be readily converted to bis-rhodanine under microwave conditions. Moreover, the pyranothiazoles 9a,b were prepared from the corresponding rhodanines 2a,b and malononitrile. Fifteen compounds were screened for their antibacterial activities against nine human, animal and plant pathogenic Gram-positive and Gram-negative bacteria using the agar well diffusion method. Out of these derivatives, compounds 2g and 2h were the most effective against all tested bacteria.     

A review on multi-component green synthesis of N-containing heterocycles using mixed oxides as heterogeneous catalysts

The use of mixed oxides is a well-appreciated approach in the fields of material science and synthesis, due to remarkable tunable surface properties such as acidic and basic characteristics, oxidation/reduction capabilities, and high agility of lattice oxygen, which makes them ideal choices as heterogeneous catalysts. The activity of the mixed oxides broadly relies on the nature of support and active material used and on the preparation method, calcination temperatures. Wide range of techniques for preparation of mixed oxide materials are adoptable, viz. sol-gel, co-precipitation, wet impregnation, microwave irradiation and hydrothermal methods. Use of mixed oxides as solid catalysts have gained popularity in many valued organic transformations, via alkylation, oxidation, condensation, dehydration, dehydrogenation, cycloaddition and isomerization. Application of mixed oxides in the area of green organic synthesis is a valuable strategy, which contributed significantly to the design of many novel heterocyclic scaffolds. The chemistry of N-heterocycle scaffolds, which generally possess five and six membered rings, is an interesting area for both synthetic and medicinal chemistry research constituting over 60% organics used in various arenas. The position and number of nitrogen atoms in the rings, distinguish them as pyrroles, pyrazoles, imidazoles, triazoles, pyridines and pyramidines classes. In this review, we focus on the scope, importance and versatile applications of mixed metal oxides and their synergetic effects as heterogeneous catalysts in the synthesis of variety of N-heterocyclic derivatives. The scientific aspects of the mixed oxides as catalytic active materials to design efficient synthetic protocols for the organic transformations is also discussed.     

Detail review on chemical,physical and green synthesis,classification, characterizations and applications of nanoparticles

ABSTRACT

Nanotechnology is an emerging field of science. The base of nanotechnology is nanoparticles. The size of nanoparticles ranges from 1 to 100?nm. The nanoparticles are classified into different classes such as inorganic nanoparticles, organic nanoparticles, ceramic nanoparticles and carbon base nanoparticles. The inorganic nanoparticles are further classified into metal nanoparticles and metal oxide nanoparticles.similarly carbon base nanoparticles classified into Fullerene, Carbon nanotubes, Graphene, Carbon nanofiber and carbon black Nanoparticles are also classified on the basis of dimension such as one dimension nanoparticles, two-dimension nanoparticles and three-dimension nanoparticles. The nanoparticles are synthesized by using two approaches like top-down approach and bottom-up approach. In this review chemical, physical and green synthesis of nanoparticles is reported. The synthesized nanoparticles are synthesized using different qualitative and quantitative techniques. The Qualitative techniques include Fourier Transform Infrared Spectroscopy (FT-IR), UV-Vis spectrophotometry, Scanning electron microscope (SEM), X.ray diffraction (XRD) and Atomic Force Microscopy (AFM). The Quantitative techniques include Transmission Electron Microscopy (TEM), Annular Dark-Field Imaging (HAADF) and Intracranial pressure (ICP). The nanoparticles have different application which is reported in this review.     

A practical and green approach towards synthesis of new N-sulfonylimines under ultrasound irradiation

An efficient protocol was developed for the synthesis of N-sulfonylimines under environment friendly conditions. Ultrasonic energy was employed to obtain the desired products in excellent yields with high purity under solvent- and catalyst-free conditions. The synthesis of new N-sulfonylimines was accomplished from various N-sulfonamides and benzaldehyde.

The structures of the synthesized compounds are confirmed by elemental analysis as well as by ¹H, ¹³C NMR spectral data, IR and MS.     

Environment-friendly and solvent-free synthesis of symmetrical bis-imines under microwave irradiation

Abstract

A short library of symmetrical bis-imines has been constructed efficiently from the reaction between dialdehydes and mono amines or diamines and mono aldehydes under microwave irradiation catalyzed by p-toluenesulphonic acid. The methodology is associated with shorter reaction time, good yields and simple workup.     

Pure green chemical approach for synthesis of Ag2O nanoparticles

In this study, a green chemistry method is reported for the synthesis of Ag₂O nanoparticles with the utilization of starch molecules as a stabilizing agent. In particular, by simply adjusting the concentration of starch in the reaction media, the structure of A₂O nanoparticles can be engineered in disc and faceted shapes, which has been analyzed by transmission electron microscopy, UV-Vis spectroscopy, and X-ray diffraction technique. In addition, antibacterial activity of the prepared Ag₂O nanoparticles had been evaluated against food poisoning and pathogenic bacteria.     

Efficient and green synthesis of 4H-pyrans and 4H-pyrano[2,3-c] pyrazoles catalyzed by task-specific ionic liquid [bmim]OH under solvent-free conditions

Abstract

A facile and convenient procedure for the synthesis of 4H-pyrans from aldehydes, malononitrile, and ethyl acetoacetate/acetylacetone and also synthesis of 4H-pyrano[2,3-c]pyrazoles from three-component condensation of aldehydes, malononitrile, and pyrazolone or four-component condensation of aldehydes, malononitrile, ethyl acetoacetate, and hydrazine monohydrate using [bmim]OH as task-specific ionic liquid has been described. The protocol proves to be efficient and environmentally benign in terms of high yields, low reaction times, ease of recovery, and reusability of reaction medium.

     

Aiding the self-assembly of supramolecular polyoxometalates under hydrothermal conditions to give precursors of complex functional oxides

In?situ Raman spectroscopy allows insight into molecular processes under hydrothermal conditions during synthesis of complex nanostructured MoVTeNb oxides (see picture: Nb?yellow, Mo?blue, V/Mo?pale blue, Te?red). Based on the knowledge acquired, the synthesis can be more efficiently directed towards the desired product with improved functionality.