Pot Syntheses Research Articles

Rapid one pot syntheses of magnetic Zn1-xFexS nanostructures: Enhancing properties of ZnS material for effective photocatalytic application

Here in the present work, simple, eco-friendly and economical method of synthesis has been approached known as hydrothermal synthesis that allowed easy doping of Fe ions into the ZnS host lattice. A unique approach was adopted for the first time to prepare ZnS material where thioglycolic acid (TGA) was used as a source for sulfur in addition to a reducing and capping agent. Properties of the nanostructures were explored using different techniques. The X-ray diffraction (XRD) results indicated formation of single phase hexagonal ZnS material where inclusion of Fe2+ ions into the ZnS lattice have no influence on the crystal phase of the material. Probably almost identical sizes of Zn2+ and Fe2+ ions made this possible that indicated Fe2+ ions take Zn2+ vacant sites by substitution of Zn2+ ions by Fe2+ ions. Chemical analysis (X-ray photoelectron spectroscopy) performed discovered that Zn and Fe ions were present in +2 oxidation states whereas S is in −2 state. Anisotropic growth of the nanostructures is reported where irregular shaped nanostructures of varying dimensions were formed that agglomerated as doping concentration was increased to form spherical microstructures. Inclusion of Fe ions into the host material modified magnetic behavior of the nanostructures converting diamagnetic ZnS into a ferromagnetic material. Optical properties were also influence by the doping resulting in photon absorption at different wavelengths. The band gap got reduced from 3.2 eV to 2.7 eV making the ZnS nanostructures visible light active. The nanostructures with band gap 2.7 eV exhibited good photocatalytic activity against methylene blue (MB) dye under visible light illumination degrading 94% of the dye in just 2 h. The scavenging experiments performed showed hydroxyl free radicals play an active role in mineralizing the dye. Reusability and post photocatalytic properties of the photocatalysts determined their stability and potential ability for possible commercialization.

Solvent free one pot syntheses of highly substituted propargyl ethers and propargyl amines from propargyl alcohols catalyzed by recyclable alumina-sulfuric acid

A study to develop an efficient protocol for the solvent-free synthesis of a wide variety of highly substituted propargyl ethers and amines using alumina-sulfuric acid as a recyclable heterogeneous solid acid catalyst has been presented. This mild protocol tolerates a good number of acid-sensitive moieties and can be applicable to a diverse range of alcohols and amines accommodating a variety of substitution patterns. Moreover, the entire process is highly atom-efficient leaving the most innocuous material, namely water, as the sole by-product.

One Pot Syntheses and Biological Screening of New Vanillic Acid Esters

High yielding syntheses of new esters (1a-1l) have been developed by way of facile one-pot reaction of vanillic acid (1) with a variety of 2-bromoacetophenone derivatives. Their structures were elucidated through spectroscopic data. Vanillic acid and its newly synthesized esters have been screened for antioxidant activity along with inhibition studies against the enzymes lipoxygenase and urease, respectively. The compound 1c exhibited potent antioxidant activity with an IC50 value of 44.5and#177;0.72 μ M, while 1e showed significant inhibitory potential against lipoxygenase with an IC50 value of 11.4and#177;0.22 μM. On the other hand, 1a, 1d, 1e, 1f and 1k revealed promising inhibitory activity against urease with IC50 values being 23.4and#177;0.22, 22.2and#177;0.42, 29.8and#177;0.06, 24.6and#177; 0.17 and 26.7and#177;0.13μM, respectively.

Greener route for microwave enhanced syntheses of bioactive 1,5‐benzodiazepines using heterogeneous calcium ferrite/graphene oxide nanocomposite as a novel and sustainable catalyst

AbstractIn the present paper, a novel and benign protocol for microwave enhanced one pot syntheses of 2,3‐dihydro‐1,5 benzodiazepine derivatives from substituted acetophenones, aryl‐aldehydes and o‐phenylene diamine using heterogeneous calcium ferrite/graphene oxide (CF/GO) nanocomposite has been reported. The catalyst was prepared by ultrasonication method and characterized by spectral and analytical techniques. The CF/GO nanocomposite was employed for environmentally benign synthesis of 2,3‐dihydro‐1,5 benzodiazepines. The synthesized benzodiazepine derivatives were screened for their antimicrobial activities against various bacteria and fungi. The present synthetic strategy offered several advantages such as excellent yields in short span of time, simple modus operandi, ease of isolation and purification of products, simple recovery and reusability of the catalyst. A tentative mechanism for synthesis of 2,3‐dihydro‐1,5 benzodiazepine using CF/GO nanocatalyst has also been proposed.

Experimental and theoretical studies on the structure and spectroscopic properties of Co(III) and Co(II) complexes with 2-aminopyrimidine

We report preparation and characterization of two mononuclear cobalt(III) and cobalt(II) complexes: HL[CoIII(L)2(NCS)4]·2H2O (1) and [CoII(L)2(NCS)2(H2O)2]·2H2O (2), where L=2-aminopyrimidine. The most essential feature was isolation in one pot syntheses cobalt(III) complex(1), from the system containing zerovalent cobalt, 2-aminopyrimidine and NH4NCS. Crystal structures and infrared (IR, FIR) of both isolated complexes have been analyzed and discussed. The spectra were interpreted on the basis of theoretical (DFT) calculations and Potential Energy Distribution (PED) analysis. Both experimental and theoretical methods provided the results of reasonable compatibility. The thermal behavior of the isolated complexes has been also investigated by TG and DTG techniques.

MgO Nanoparticles: an Efficient, Green and Reusable Catalyst for the One- pot Syntheses of 2,6-Dicyanoanilines and 1,3-Diarylpropyl Malononitriles under Different Conditions

This work described one pot syntheses of polysubstituted 2,6- dicyanoaniline and 2-(3-Oxo-1,3-diarylpropyl) malononitrile derivatives in the presence of MgO nanoparticles (NPs) under grinding conditions and microwave irradiation, respectively. The simple experimental procedure includes shorter reaction times, higher yields, lower cost and environmental friendliness. Other remarkable features are reusability of catalyst, MgO NPs can be reused at least five times without any obvious change in its catalytic activity.

ChemInform Abstract: Diels—Alder Reaction of 1,3‐Diarylbenzo[c]furans with Thiophene S,S‐Dioxide/Indenone Derivatives: A Facile Preparation of Substituted Dibenzothiophene S,S‐Dioxides and Fluorenones.

AbstractOne pot syntheses of substituted dibenzothiophene S,S‐dioxides and fluorenones are successfully achieved by Diels—Alder reaction of benzo[c]furans with thiophene S,S‐dioxides and indenones, respectively.

Modelling and optimisation of the one-pot, multi-enzymatic synthesis of chiral amino-alcohols based on microscale kinetic parameter determination

Advances in synthetic biology are facilitating the de novo design of complex, multi-step enzymatic conversions for industrial organic synthesis. This work describes the integration of multi-step enzymatic pathway construction with enzyme kinetics and bioreactor modelling, in order to optimise the synthesis of chiral amino-alcohols using engineered Escherichia coli transketolases (TK) and the Chromobacterium violaceum transaminase (TAm). The specific target products were (2S,3S)-2-aminopentane-1,3-diol (APD) and (2S,3R)-2-amino-1,3,4-butanetriol (ABT). Kinetic models and parameters for each of the enzymatic steps were first obtained using automated microwell experiments. These identified the TK-catalysed conversions as being up to 25 times faster than the subsequent TAm conversions and inhibition of TAm by the amino-donor used, (S)-(−)-α-methylbenzylamine (MBA), as limiting the overall conversion yields. In order to better ‘match’ the relative rates of the two enzymes an E. coli expression system, based on two compatible plasmids, was constructed to produce both enzymes in a single host. By control of induction time and temperature it was possible to produce six times more recombinant TAm than TK to help balance the reaction rates. To overcome MBA inhibition and an unfavourable reaction equilibrium, fed-batch addition of the amino-donor was introduced as well as the use of isopropylamine as an alternate amino-donor. Adopting these strategies, and using the kinetic models to optimise feeding strategies, the one pot syntheses of APD and ABT were successfully scaled-up to preparative scales. Excellent agreement was found between the kinetic profiles and yields predicted and those achieved experimentally at the larger scale. In this case the integration of these multi-disciplinary approaches enabled us to achieve up to a 6 fold greater yield using concentrations an order of magnitude higher than in previous preparative scale batch bioconversions carried out sequentially.

Diels-Alder reaction of 1,3-diarylbenzo[c]furans with thiophene S,S-dioxide/indenone derivatives: a facile preparation of substituted dibenzothiophene S,S-dioxides and fluorenones.

One pot syntheses of substituted dibenzothiophene S,S-dioxides and fluorenones were successfully achieved by Diels-Alder reaction of benzo[c]furans with thiophene S,S-dioxides and indenones, respectively. Photophysical properties of representative seven- and nine-membered dibenzothiophene S,S-dioxide acenes were also reported.

Zeolite Synthesis under Insertion of Silica Rich Filtration Residues from Industrial Wastewater Reconditioning

Zeolite synthesis was studied using two silica rich filtration residues (FR 1 and FR 2) as Si-source and sodium aluminate in a direct synthesis at 60°C at strong alkaline conditions (8 M - 16 M NaOH). In addition to these one-pot syntheses, a two-step process was investigated. Here, an alkaline digestion of FR at 60°C was followed by gel precipitation with sodium aluminate and gel crystallization under usual conditions of 80°C - 90°C. The results show that the substitution of chemical reagent sodium silicate by a waste material like FR as Si-source is possible but requires fine tuning of the reaction conditions as zeolite crystallization is a process under kinetic control. The solubility behaviour and impurities of the inserted filtration residues strongly influenced the course of reaction. Thus zeolites like hydrosodalite or intermediate zeolite between cancrinite and sodalite, or zeolite NaA or Z-21 in cocrystallization with hydrosodalite could be observed in the one pot syntheses already in a short time interval between 1 - 4 h depending on the alkalinity. The two step process yield to zeolites NaA and NaX in very good quality. The reaction process of FR in both reaction methods was characterized by chemical analyses, X-ray powder diffraction, Fourier transform infrared spectroscopy as well as scanning electron microscopy. Surface area and water content of selected products were further characterized by the BET-method and by thermogravimetry. Summing up the results, we can show that zeolite formation from filtration residues is possible by several reaction procedures as model cases for a re-use of industrial waste materials. Beside the importance for environmental protection, the reactions are of interest for zeolite chemistry as the re-use of FR is possible under economically conditions of low energy consumption at 60°C and short reaction periods.

Heck-type coupling of intramolecularly-generated thiopalladacycles with alkenes: One pot syntheses of 3-alkenylbenzo[b]thiophenes

A method for stoichiometric functionalization of benzothiophene is developed by Heck-type coupling of alkenes with intramolecularly-generated thiopalladacycles obtained from palladium salts and ortho-thioanisole-substituted propargyl imines. The synthetic strategy for preparing structurally diverse 3-alkenylbenzo[b]thiophene is also extended to 3-alkenylbenzo[b]selenophenes.

End-Quenching of TiCl4-Catalyzed Quasiliving Polyisobutylene with Alkoxybenzenes for Direct Chain End Functionalization

Alkoxybenzenes were used to end-quench TiCl4-catalyzed quasiliving isobutylene polymerizations initiated from 2-chloro-2,2,4-trimethylpentane or 5-tert-butyl-1,3-di(1-chloro-1-methylethyl)benzene at −70 °C in 40/60 (v/v) hexane/methyl chloride. The alkoxybenzene/chain end molar ratios were in the range 2.5−4. Effective alkoxybenzene quenchers included those with simple alkyl groups, such as anisole and isopropoxybenzene, haloalkyl tethers, such as (3-bromopropoxy)benzene and (2-chloroethoxy)benzene, and even those with hydroxyl and amine functionality, such as 4-phenoxy-1-butanol and 6-phenoxyhexylamine. Alkylation was generally quantitative and occurred exclusively in the para position; multiple alkylations on the same alkoxybenzene were not observed. The alkylation reactions were tolerant of temperatures ranging from −70 to −30 °C and were unimpeded by the presence of endo- or exo-olefin termini. In situ cleavage of the ether linkage of anisole and isopropoxybenzene termini allowed single pot syntheses of phenol-terminated polyisobutylenes.

ChemInform Abstract: Bicycloannulation Leading to the Tricyclo(4.4.0.01,5)decane Framework and Its Congeners.

Reactions of the kinetic enolates of 1-acetylcyclohexenes with α-bromo-α,β-unsaturated esters afford 5-methoxycarbonyltricyclo[4.4.0.01,5]decan-2-ones in one pot syntheses via successive Michael–Michael-substitution reactions.

Microwave assisted one pot synthesis of 7-substituted 2-(2-oxo-2H-chromen-3-yl)acetic acids as precursors of new anti-tumour compounds

AbstractPerkin condensation with subsequent intramolecular lactonisation as one pot syntheses of 2-(2-oxo-2H-chromen-3-yl)acetic acids VIIa-Xa has been studied. The required acids VIIa-Xa were prepared as precursors of recently discovered compounds possessing antineoplastic activities. Syntheses of VIIa-Xa were carried out using para substituted 2-hydroxybenzaldehydes II-VI, succinic acid anhydride, sodium succinate under thermal or microwave conditions. Significant shortening of the reaction time under microwave irradiation was observed (18–50 min instead of 1.5–5 h of heating). Microwave assisted reactions proceeded more smoothly to give higher yield of the required products VIIa-Xa (31–61 %) compared to those under classical thermal conditions e.g. 21.8 % for IXa (Hurenkamp et al., 2007). Seven reaction by-products were isolated and determined as 2H,2′H-3,3′-bichromene-2,2′-diones VIIb-Xb and (E)-3-(2-hydroxystyryl)-2H-chromen-2-ones VIIc-IXc.

On the one pot syntheses of chromeno[4,3-b]pyridine-3-carboxylate and chromeno[3,4-c]pyridine-3-carboxylate and dihydropyridines

Substituted chromenos, dihydropyridines and pyridines have been important in the syntheses of compounds having interesting pharmacological properties. Therefore, we found of interest to synthesize chromenopyridines and chromenodihydropyridines (i.e., fused chromeno and dihydropyridine or pyridine rings) to further study their biological activity. Here, we propose one-pot syntheses for substituted ethyl-2,4-dimethyl-5-oxo-5H-chromeno[4,3-b]pyridine-3-carboxylates, ethyl-2,4-dimethyl-5-oxo-5H-chromeno[3,4-c]pyridine-3-carboxylates and their respective 1,4-dihydropyridines based on a modified Hantzsch pyridine synthesis using 2-hydroxyaryl aldehydes, with electron withdrawing and electron donating groups on the phenyl ring, as starting reactants. Sixteen compounds were synthesized by the described method and fully characterized. An average yield of 37% was obtained for the different derivatives.

Reatividade do [Fe(CO)2(eta2-CS2)(PPh 3)2] frente a compostos de Cu(I): síntese de espécies binucleares heterometálicas contendo CS2 em ponte entre Fe(0) e Cu(I)

Este trabalho contempla a síntese e caracterização espectroscópica de dois compostos carbonílicos heterometálicos do tipo [Fe(CO)3(m-CS2)(PPh3 )(CuX)], X = Cl, ClO4. Os dados provenientes da espectroscopia no infravermelho e de RMN de 31P{¹H} foram conclusivos quanto à proposição da geometria octaédrica distorcida ao redor do átomo de ferro (0), como também sobre a natureza bimetálica de ambos compostos. Estes dados esclareceram o modo de coordenação dos grupos carbonilos, da trifenilfosfina (PPh3), bem como a disposição do ligante dissulfeto de carbono em ponte entre os átomos de Fe (0) e Cu (I).

Syntheses of Novel Derivatives of 2‐Acetylfuro[2,3‐a]carbazoles, Benzo[1,2‐b]‐1,4‐thiazepino[2,3‐a]carbazoles and 1‐Acetyloxycarbazole‐2‐carbaldehydes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Investigação por espectroscopia Mössbauer de compostos de ferro(0) contendo dissulfeto de carbono

Neste trabalho são apresentados resultados proveniente da aplicação da Espectroscopia Mössbauer na investigação de compostos carbonilferro contendo o ligante CS2, [Fe(CO)2(h²-CS2 )(PPh3)2] e [Fe(CO)2(h²-CS2) {P(OPh)3}2]. Nas sínteses dessas espécies, a utilização de TMNO (trimetilaminóxido) como agente descarbonilante mostrou-se bastante eficiente, superando aquelas descritas na literatura que requerem inclusive preparação de compostos precursores. Os resultados de espectroscopia Mössbauer, juntamente com dados no IV e de RMN de 31P, foram conclusivos na proposição da geometria octaédrica distorcida ao redor do átomo de ferro para ambos os compostos investigados.

Diastereoselective synthesis of cis-fused pyrano and furanobenzopyrans catalyzed by indium trichloride or triphenyl phosphonium perchlorate

Indium trichloride (InCl3) and triphenyl phosphonium perchlorate (TPP) are found to be effective catalysts for the cyclization of o-hydroxyaldimines with 3,4-dihydro-2H-pyran and 2,3-dihydrofuran at ambient temperature to afford novel pyrano and furanobenzopyran derivatives in excellent yields with high diastereoselectivity. One pot syntheses of pyrano and furanobenzopyrans from o-hydroxybenzaldehyde, aromatic amines and an enol ether under identical conditions is reported for the first time. Similarly, o-hydroxyaldimine reacted with ethyl vinyl ether to give 2-ethoxy-4-N-aryl aminobenzopyran in good yields.

Low-valent titanium induced one pot syntheses of imidazolidines

Under the action of a low-valent titanium reagent, imidazolidine derivatives were synthesized from imines and triethyl orthoformate in moderate yields. NMR spectroscopy was used to assign the configuration of the products.