Finkelstein Reaction Research Articles

Miniature spectrometer based on graded bandgap perovskite filter

Abstract Miniature spectrometer is powerful tool for scientific research and industrial inspection. Here, we report the fabrication of graded perovskite filters with tunable bandgap and their application in constructing miniature spectrometer. The graded perovskite filters were fabricated using a Finkelstein reaction between in-situ formed halogen ion with a preformed MAPbX3 film. The graded bandgap of perovskite films can be well tunned from 400 to 750 nm by controlling the volume ratio between 5,5-dimethyl-1-pyrroline N-oxide and benzyl chloride(bromide). By combining a deep residual network, graded bandgap perovskite film and commercial CMOS sensor chip, a miniature spectrometer is demonstrated, achieving an accurate spectrum reconstruction (PSNR = 40.749) with monochromatic spectral resolution of 1.31 nm.

Total synthesis of natural product trichophycin-I

Concise total synthesis of chlorovinylidene containing natural product Trichophycin-I has been achieved in 11 steps with an overall yield 8.5%. The key steps involved in the synthesis are Pinnick oxidation, Evan’s methylation, vinylic Finkelstein reaction and Brown allylation.

Synthesis of Seven Indolizine-Derived Pentathiepines: Strong Electronic Structure Response to Nitro Substitution in Position C-9.

Seven new 1,2,3,4,5-pentathiepino[6,7-a]indolizines were synthesized in which the pentathiepine moieties bear an indolizine backbone that is derivatized from C-H to F-, Cl-, Br-, I-, NO2-, and CH3-substitutions, respectively, in a meta position relative to the aza group on the pyridine moiety. Their preparation took place via two common steps: (i) a Sonogashira coupling between (4-substituted) 2-bromo- or 2-chloropyridines and propynyl 3,3-diethylacetal, and (ii) a ring closing reaction mediated by a molybdenum oxo-bistetrasulfido complex and elemental sulfur. The latter simultaneously facilitates the 1,2,3,4,5-pentathiepino chain/ring- and indolizine ring-formations. The fluoro derivative was addressed with 2-bromo-5-aminopyridine as the starting material via a Sandmeyer reaction. The iodo derivative was obtained from 5-bromo-2-alkynylpiridine using a metal-assisted variation of the Finkelstein reaction. The requirement to explore different reaction conditions and the varied respective yields of the final products are discussed. The influence of the distinct substitutions on the pyridine moieties, their electronic structures, and respective chemical properties was investigated through a set of spectroscopic/analytical characterizations. Intriguingly, in all cases, the nitro-substituted derivative exhibited a distinct behavior compared to the six other investigated derivatives, which was also addressed computationally. All seven new pentathiepines were crystallized, and their respective molecular structures were determined using single crystal X-ray diffraction. These structures are compared and discussed as are their respective packing patterns.

Facile preparation of azido functionalized polyvinyl chloride (PVC) nanofiber (NF) membrane for various applications

Polyvinyl chloride (PVC) nanofiber (NF) membrane functionalized with azido groups (Az-PVC NF) was prepared using various techniques with the aim of enhancing azide substitution of chlorine in the PVC backbone. Azidation strategies that were investigated include: (1) catalyst-assisted azidation in organic solvent, (2) phase transfer catalyzed azidation in aqueous media, (3) phase transfer catalyzed azidation in aqueous media using pre-iodinated membrane, and (4) phase transfer catalyzed azidation in aqueous media of electrospun pre-iodinated PVC granules prepared via Finkelstein reaction. Results showed that azidation was greatly enhanced when PVC NF membrane or PVC powder underwent pre-iodination prior to azidation. As far as it is known, this is the first time that preparation techniques for azidized PVC NF membrane in aqueous media that involve halogen exchange have been studied. Hence, the optimized conditions for the preparation of azidized PVC NF membranes and the resulting membrane properties are hereby reported. Furthermore, the utility of Az-PVC NF in the development of water treatment technologies was demonstrated with successful grafting of cucurbiturils via nitrene insertion.

Synthesis of Bridged Tetrazoles with Promising Properties and Potential Applications by a One-Step Finkelstein Reaction.

Numerous nitramine bridged compounds which show promising combinations of properties have already been identified in the area of energetic materials. In this work, four new nitrazapropane bridged tetrazoles, as well as four new trinitrazaheptane tetrazoles and three oxapropane bridged tetrazoles were synthesized and fully characterized. These new compounds can all be synthesized by a simple, one-step synthesis using Finkelstein conditions. All of these new energetic materials were characterized using NMR spectroscopy, single crystal X-ray diffraction, vibrational analysis and elemental analysis. The thermal behaviour of these compounds was studied by differential thermal analysis (DTA) and partly by thermogravimetric analysis (TGA). The BAM standard method was used to determine the sensitivities towards impact (IS) and friction (FS). The enthalpies of formation were calculated at the CBS-4M level, and the energetic performances were calculated using the EXPLO5 (V6.06.01) computer code. The properties of the new compounds were compared to each other as well as to the known energetic material RDX. Moreover, the iron(II) and copper(II) perchlorate complexes with 1,3-bis-1,1-tetrazolylnitrazapropane as ligand were prepared and investigated.

An Asymmetric Aromatic Finkelstein Reaction: A Platform for Remote Diarylmethane Desymmetrization.

A first-of-its-kind enantioselective aromatic Finkelstein reaction is disclosed for the remote desymmetrization of diarylmethanes. The reaction operates through a copper-catalyzed C-I bond-forming event, and high levels of enantioselectivity are achieved through the deployment of a tailored guanidinylated peptide ligand. Strategic use of transition-metal-mediated reactions enables the chemoselective modification of the aryl iodide products; thus, the synthesis of a diverse set of otherwise difficult-to-access diarylmethanes with excellent levels of selectivity is realized from a common intermediate. A mixed experimental/computational analysis of steric parameters and substrate conformations identifies the importance of remote conformational effects as a key to achieving high enantioselectivity in this desymmetrization reaction.

Construction of α-Halogenated Boronic Esters via Visible Light-Induced C-H Bromination.

α-Halogenated boronic esters are versatile building blocks that can be diversified into a wide variety of polyfunctionalized molecules. However, their synthetic potential has been hampered by limited preparation methods. Herein, we report a visible light-induced C-H bromination reaction of readily available benzyl boronic esters. This method features high yields, mild conditions, simple operation, and good functional group tolerance. The analogous chlorides and iodides can be accessed via Finkelstein reaction. Synthesis of halogenated geminal diborons has also been demonstrated.

Synthesis of Diastereomeric 8‐Fluoro‐ABC‐Steroid Building Blocks

AbstractAn eight‐step linear sequence for the preparation of two diastereomers of an 8‐fluoro‐ABC‐steroid building block was developed. Key step was an intramolecular Diels–Alder reaction of an intermediate o‐quinodimethane formed from a benzocyclobutene substituted with a 5‐fluorohex‐5‐en‐4‐one chain. This side chain was prepared from 6‐chlorohex‐1‐ene by bromofluorination, elimination of HBr, Finkelstein reaction and alkylation of a literature‐known benzocyclobutene derivative with the thus‐formed 6‐iodo‐2‐fluorohex‐1‐ene. Allylic oxidation of side chain's fluorovinyl moiety to an α‐fluoro‐α,β‐unsaturated ketone completed the preparation of the precursor for the [4+2]‐cycloaddition.

Synthesis of (Hetero)aryl/Alkenyl Iodides via Ni-Catalyzed Finkelstein Reaction from Bromides or Chlorides

Synthesis of (Hetero)aryl/Alkenyl Iodides via Ni-Catalyzed Finkelstein Reaction from Bromides or Chlorides

Improved method for the obtaining DTTA-appended 2,2’-bipyridine ligands for lanthanide cations

The composition of the reaction mixture after DTTA tert-butyl ester alkylation with 6'-halomethyl-5-phenyl-2,2'-bipyridines was studied. In addition to the target product, DTTA-appended 2,2’-bipyridine, the corresponding 6'-hydroxymethyl-substituted 2,2’-bipyridine and (5'-phenyl-[2,2'-bipyridin]-6-yl)methyl formate were isolated as by-products in some cases. Finally, an improved procedure for the DTTA tert-butyl ester alkylation with 6'-halomethyl-5-phenyl-2,2'-bipyridines by using Finkelstein reaction was developed.

Alkali metal ion binding using cyclic polyketones.

Cyclic oligoketones composed of 3,3-dimethylpentane-2,4-diones showed crown ether-like alkali metal ion binding behavior with association constants up to 1.7 × 104 M-1 in chloroform/acetonitrile (v/v, 9/1). The binding properties have been used for catalysis in the Finkelstein reaction in a low-polarity solvent. Furthermore, novel ion-binding hosts were generated by terminal functionalization of linear polyketones.

Synthesis and Reactivity of 3,5-Diiodo-BODIPYs via a Concerted, Double Aromatic Finkelstein Reaction.

3,5-Diiodo-8-aryl-BODIPYs are prepared from the corresponding 3,5-dichloro- and 3,5-dibromo- congeners via a double aromatic Finkelstein reaction with NaI in refluxing propionitrile, in yields from 51 to 100%. Rate enhancement is observed for 3,5-dibromo-BODIPYs (ArBr > ArCl) suggesting a concerted SNAr mechanism for this transformation. Thus formed 3,5-diiodo-BODIPYs are examined as coupling partners in Migita-Kosugi-Stille, Mizoroki-Heck, Sonogashira, and Suzuki-Miyaura reactions, providing routes toward complex BODIPY architectures.

Finkelstein Reaction in Non-polar Organic Solvents: A Streamlined Synthesis of Organic Iodides

Finkelstein Reaction in Non-polar Organic Solvents: A Streamlined Synthesis of Organic Iodides

The SN2 reaction and its relationship with the Walden inversion, the Finkelstein and Menshutkin reactions together with theoretical calculations for the Finkelstein reaction

This communication gives an overview of the relationships between four reactions that although related were not always perceived as such: SN2, Walden, Finkelstein, and Menshutkin. Binary interactions (SN2 & Walden, SN2 & Menshutkin, SN2 & Finkelstein, Walden & Menshutkin, Walden & Finkelstein, Menshutkin & Finkelstein) were reported. Carbon, silicon, nitrogen, and phosphorus as central atoms and fluorides, chlorides, bromides, and iodides as lateral atoms were considered. Theoretical calculations provide Gibbs free energies that were analyzed with linear models to obtain the halide contributions. The M06-2x DFT computational method and the 6-311++G(d,p) basis set have been used for all atoms except for iodine where the effective core potential def2-TZVP basis set was used. Concerning the central atom pairs, carbon/silicon vs. nitrogen/phosphorus, we reported here for the first time that the effect of valence expansion was known for Si but not for P. Concerning the lateral halogen atoms, some empirical models including the interaction between F and I as entering and leaving groups explain the Gibbs free energies.

Polypeptide-based batteries toward sustainable and cyclic manufacturing

Polypeptide-based batteries toward sustainable and cyclic manufacturing

Nondestructive and Controllable Anion Exchange of Halide Perovskite Films through Finkelstein Reaction

Anion exchange of halide perovskite has been successfully demonstrated as an effective route to modulate its optoelectronic properties; however, it generally suffers from the issues of morphology d...

Rational Design, Synthesis, Characterization and Evaluation of Iodinated 4,4'-Bipyridines as New Transthyretin Fibrillogenesis Inhibitors.

The 3,3′,5,5′-tetrachloro-2-iodo-4,4′-bipyridine structure is proposed as a novel chemical scaffold for the design of new transthyretin (TTR) fibrillogenesis inhibitors. In the frame of a proof-of-principle exploration, four chiral 3,3′,5,5′-tetrachloro-2-iodo-2′-substituted-4,4′- bipyridines were rationally designed and prepared from a simple trihalopyridine in three steps, including a Cu-catalysed Finkelstein reaction to introduce iodine atoms on the heteroaromatic scaffold, and a Pd-catalysed coupling reaction to install the 2′-substituent. The corresponding racemates, along with other five chiral 4,4′-bipyridines containing halogens as substituents, were enantioseparated by high-performance liquid chromatography in order to obtain pure enantiomer pairs. All stereoisomers were tested against the amyloid fibril formation (FF) of wild type (WT)-TTR and two mutant variants, V30M and Y78F, in acid mediated aggregation experiments. Among the 4,4′-bipyridine derivatives, interesting inhibition activity was obtained for both enantiomers of the 3,3′,5,5′-tetrachloro-2′-(4-hydroxyphenyl)-2-iodo-4,4′-bipyridine. In silico docking studies were carried out in order to explore possible binding modes of the 4,4′-bipyridine derivatives into the TTR. The gained results point out the importance of the right combination of H-bond sites and the presence of iodine as halogen-bond donor. Both experimental and theoretical evidences pave the way for the utilization of the iodinated 4,4′-bipyridine core as template to design new promising inhibitors of TTR amyloidogenesis.

Total Synthesis of Conulothiazole A.

An efficient total synthesis of the chlorinated thiazole-containing natural product conulothiazole A is reported. Key features of this synthesis include a novel rhodium-catalyzed enantioselective hydrogenation of a 2-enamido-thiazole and a vinylic Finkelstein reaction that could be implemented at all stages of the synthesis to install the chlorinated alkene.

An enzymatic Finkelstein reaction: fluorinase catalyses direct halogen exchange.

The fluorinase enzyme from Streptomyces cattleya is shown to catalyse a direct displacement of bromide and iodide by fluoride ion from 5'-bromodeoxyadenosine (5'-BrDA) and 5'-iododeoxyadenosine (5'-IDA) respectively to form 5'-fluorodeoxyadenosine (5'-FDA) in the absence of l-methionine (l-Met) or S-adenosyl-l-methionine (SAM). 5'-BrDA is the most efficient substrate for this enzyme catalysed Finkelstein reaction.

PO-437 Ultrasound-triggered delivery of halogenated pyruvate analogues to breast cancer cells

Introduction Targeting the altered cancer metabolism has opened new therapeutic opportunities. Upregulation of the expression of the monocarboxylate transporter 1 (MCT1) has been shown in various cancers, including breast tumours. MCT1 is responsible for the transport of lactate and pyruvate. Lactate/pyruvate analogues, such as 3-bromopyruvate, have been shown to be toxic to cells overexpressing MCT1. However, in order to successfully treat the tumour, the therapeutic must be shielded from the immune system, target the tumour and penetrate it. To overcome these challenges we have encapsulated lactate/pyruvate analogues inside ultrasound labile liposomes. These will protect the therapeutic and extend its circulation time, enabling delivery and triggered release at the tumour site using externally applied ultrasound, whereas MCT1 expression offers selective uptake of the compounds. Material and methods Western blotting was used to identify cell lines with high and low expression of MCT1. Cell viability after treatment was tested with an MTT assay. Chromatography techniques were used to measure encapsulation efficiency into the liposomes. A novel iodinated lactate analogue, 3-iodolactate (3IL), was synthesised via Finkelstein reaction and characterised by NMR spectroscopy and mass spectrometry. Ultrasound-labile liposomes were synthesised by dispersion of a lyophilised lipid film (DOPE, cholesterol and DSPC-PEG(2000) in 65:25:10 molar ratio) in an aqueous solution of the compound, followed by extrusion and size exclusion chromatography. Results and discussions Breast cancer cell lines with low, intermediate and high expression of MCT1 have been identified (MDA-MB-231, MDA-MB-468 and BT20, respectively). 3 BP toxicity correlated with MCT1 expression. BT20 had an LD50 of 87.10±0.03 µM, while MDA-MB-231, were 90% viable even up to concentrations of 300 µM 3 BP. Toxicity is reversed with MCT1 inhibition. 3IL has been synthesised and purified. Ultrasound labile liposomes with an average hydrodynamic diameter of 120 nm have been synthesised and encapsulation of 3 BP has been confirmed and tested with cells with and without ultrasound. Conclusion Cell toxicity of halogenated lactate/pyruvate analogues has been confirmed. A novel iodinated analogue has been synthesised. These molecules have been encapsulated within ultrasound labile liposomes. A novel drug delivery system has been engineered for the delivery of metabolic inhibitors targeting the lactate/pyruvate transporter (MCT1) for targeted cancer therapy.