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Search for "milling" in Full Text gives 96 result(s) in Beilstein Journal of Organic Chemistry.
Synthetic accesses to biguanide compounds
Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82
- . screened various conditions for the addition of TMG to different alkyl- and arylcarbodiimides [80]. In particular, the authors compared different approaches such as classical thermic conditions, microwave irradiation with or without Y(OTf)3, high-speed vibrational milling using stainless steel balls, high
Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues
Beilstein J. Org. Chem. 2021, 17, 977–982, doi:10.3762/bjoc.17.79
- nitrochromenobenzofuropyridine 21 was achieved after treatment of 16 with nitrostyrene in the presence of DABCO applying our previously reported ball milling procedure [40]. The synthesis of 22 was performed using the Perkin reaction [41]. The reaction of 16 with propionic anhydride and the corresponding sodium salt in the
Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate
Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211
- reactants throughout the solid mixture under ball-milling conditions. A weak association of bulky substrates and/or their corresponding products with the CD cavities under ball-milling conditions improved the mobility of the partners in the solid state. The reaction reactivity and selectivity were then
- constituting the reaction mixture on the reactivity for the synthesis of β-CDMts under ball-milling conditions. Additionally, in the presence of a base such as KOH, we show that the chemoselectivity of the reaction is significantly altered in favor of the β-CD product mono-substituted on the primary face, thus
- different milling times. As can be seen from Figure 1, the powder particles experience comminution and decrease in size over time and after grinding for 10 min, β-CD displays microsized particles (Figure 1c). Longer grinding times led to particles with sizes below 300 nm in diameter (Figure 1d and Figure 1e
Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors
Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202
The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY
Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188
- phenylboronic acid (PBA)-functionalized boron dipyrromethene (BODIPY) applying the ball milling approach. The ball milling formation of boron esters between PBA BODIPY and dextran proved to be more efficient in terms of reaction time, amount of reactants, and labelling degree compared to the corresponding
- biocompatibility while remaining fluorescent. Keywords: ball milling; boronic ester; dextran; bodipy; nanoparticles; Introduction In the last few decades, mechanochemistry has gathered a great deal of attention and a lot of efforts have been focused on its use in organic synthesis, catalysis, biotransformation
- evident with the development of atomized ball milling technologies, which allow for a better reproducibility and control of reaction parameters over traditional mortar or pestle [4][6]. Mechanochemical syntheses are not just a means for cleaner, safer, higher yielding, and more sustainable chemical
One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?
Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143
- cellulose and a glucose content between 40.1% and 46.5%. The biomass feedstock was crushed by a simple ball milling procedure without further treatment. The one-pot conversion of Japanese cedar was carried out by combining Pt/C or Ru/C with 4 wt % of metal and Amberlyst 70 catalysts in a batch reactor of
Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers
Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127
- aprotic liquids (e.g., N,N-dimethylformamide or dimethyl sulfoxide), which affect the final result, especially for potential biomedical applications. This article describes a new, green synthetic pathway through mechanochemistry, in particular via ball milling and using 1,1-carbonyldiimidazole as the
- , and rhodamine B) and the still reactive imidazoyl carbonyl group of the NS. Keywords: β-cyclodextrin; ball-milling; crosslinking; green chemistry; mechanochemistry; nanosponges; Introduction The research in the fields of nanomedicine and nanotechnology has nowadays become predominant
- drive and control chemical reactions, for example, using grinding or milling to transfer energy to chemical bonds [11]. Mechanochemical transformations are well established in inorganic chemistry and they are easily transferable to an industrial scale [12][13]. Mechanochemistry in organic chemistry
Activated carbon as catalyst support: precursors, preparation, modification and characterization
Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104
- impurities [30]. Drying at ≈100 °C for a defined time removes the free moisture in the material, which could affect the carbonization step [81]. A defined and standardized starting material size of the raw materials is also essential for the activated carbon production process and is obtained by milling and
Six-fold C–H borylation of hexa-peri-hexabenzocoronene
Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37
- permeation chromatography (GPC) was performed with a JAI LaboACE LC-5060 instrument equipped with JAIGEL-2H columns using chloroform as an eluent. Retsch MM400, zirconia milling jars and zirconia balls were used for pulverizing at 30 Hz and 60 min. The high-resolution mass spectrum (HRMS) was obtained from a
Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst
Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16
- ]. Noël and co-workers reported the C3–H olefination of indoles using Pd(OAc)2 as a catalyst and molecular oxygen as the oxidant under continuous flow conditions [29]. Jia et al. reported the synthesis of 3-alkenylindoles using Pd(OAc)2 as the catalyst and MnO2 as the oxidant under ball milling conditions
Current understanding and biotechnological application of the bacterial diterpene synthase CotB2
Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228
- with residual organic waste streams, such as milling or forestry waste. Additionally, the heterologous terpene production minimizes waste generation as the targeted production of a single compound reduces extraction and purification steps [24][25]. Additionally, heterologous production enables protein
Halide metathesis in overdrive: mechanochemical synthesis of a heterometallic group 1 allyl complex
Beilstein J. Org. Chem. 2019, 15, 1856–1863, doi:10.3762/bjoc.15.181
- ]∞, enable an otherwise unfavorable halide metathesis to proceed with mechanochemical assistance. From this result, we demonstrate that ball milling and unexpected solid-state effects can permit seemingly unfavored reactions to occur. Keywords: caesium; entropy; intermolecular forces; mechanochemistry
- , which promotes reactions through grinding or milling with no, or minimal, use of solvents, has been used in conjunction with halide metathesis to form organometallic compounds of the transition metals [3][4][5][6][7] and both s- [8][9] and p-block [10][11] main group elements. The extent to which the
Nanopatterns of arylene–alkynylene squares on graphite: self-sorting and intercalation
Beilstein J. Org. Chem. 2019, 15, 1848–1855, doi:10.3762/bjoc.15.180
- -down method, with examples such as focused ion beam milling and subsequent oxygen etching [6], one bottom-up way for the formation of (supported) nanoporous systems is based on the physisorption of molecular species [7]. Non-covalently bound (e.g., hydrogen-bonded) [8][9] nanoporous systems can be
Metal-free mechanochemical oxidations in Ertalyte® jars
Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172
- on a mechanochemical activation [28]. In comparison to solution-based techniques, ball-milling procedures provide an ideal solution for overcoming many of the drawbacks described above, due to the simplicity of use, shorter reaction times, large-scale production, low cost and sustainability of this
- methodology [28][29][30][31][32][33][34][35][36][37][38][39]. In addition, impact forces, that are generated by ball-milling media involve a very minimal fraction of reactive material mimicking the ideal behavior/trend of highly diluted reactive systems. This peculiar aspect of mechanochemical reactions
- grinding mixture [51]. Two different mechanisms have been postulated for similar reactions in homogeneous phase: one occurs under acidic conditions, while the other works better in a basic medium through a cyclic dipolar mechanism (Scheme 2) [52][53]. On the contrary, under ball-milling conditions, it is
Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions
Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145
- chemistry. The restricted mobility of solid-state components further reduces the aforementioned side-reactions and enhances the utilization in the CD substitution. Although many side reactions are suppressed in ball milling, they cannot be completely eliminated when alkaline hydroxides are used to activate
- practically constant at around room temperature (rt) during stirring. Freshly dried CDs were generally used in ball-milling reactions to minimise the hydrolysis of propylene oxide, but we also tested CD-hydrates. Unlike in the solution method, HEBM experiments provide for relatively poor opportunities to
- the reaction [39]. The well-sealed jar is able to keep all the epoxides inside over the total milling time and, despite the necessity to have a considerable amount of propylene oxide in the vapour phase, the reagent also remains in the reaction vessel. In order to minimise the destruction of the
Mechanochemical Friedel–Crafts acylations
Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130
- friendly, solvent-free mechanochemical reaction conditions of this industrially important reaction were developed. Reaction parameters such as FC catalyst, time, ratio of reagents and milling support were studied to establish the optimal reaction conditions. The scope of the reaction was explored by
- employment of different aromatic hydrocarbons in conjunction with anhydrides and acylation reagents. It was shown that certain FC-reactive aromatics could be effectively functionalized by FC acylations carried out under ball-milling conditions without the presence of a solvent. The reaction mechanism was
- studied by in situ Raman and ex situ IR spectroscopy. Keywords: ball milling; Friedel–Crafts reaction; mechanochemistry; Introduction The Friedel–Crafts reaction (FCR) is a very powerful tool in organic chemistry for the synthesis of aromatic ketones. It is of great industrial importance and widely used
Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions
Beilstein J. Org. Chem. 2019, 15, 1226–1235, doi:10.3762/bjoc.15.120
- local defects accumulate preferentially at or near the crystal surface. Since the total area increases exponentially when the crystal size is reduced by the crystal-breaking process, this can further explain the exponential dependence of the onset time on the milling frequency. Keywords: ball-mill
- chemical phenomena [37], which are not captured in traditional fluid-phase kinetics treatments. Furthermore, many physical parameters are intimately coupled (e.g., milling-ball size and mass), and carefully designed studies are required to understand their independent effects on the reaction rate [29][38
- [17][18][44]. It is generally accepted that when the milling reaction reaches completion in a sealed system, a steady state is eventually achieved. The final phase composition does not change as long as the milling conditions are maintained [1][17][18][45][46]. Such equilibria depend on numerous
Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination
Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119
- mechanochemical amorphization of chitin. We measured the crystallinity index of chitin after milling it in a vibration mill in an apparatus made of copper, aluminum, brass, tungsten carbide, zirconia, stainless steel, polytetrafluoroethylene (PTFE), or poly(methyl methacrylate) (PMMA). These materials offer a
- range of Vickers hardness values and the impact of these parameters is discussed. The role of the size and mass of the balls is also studied in the case of stainless steel. This study also highlights one of the major challenges during milling, which is contamination of the studied samples. Keywords
- reactions are induced by the delivery of energy, by collision. The impact force is thus of importance and depends on the weight of the balls and [26] the surface of impact [28]. Also, in the context of the milling of crystalline and/or fairly hard materials, the nature of the milling media composing the
Mechanochemical synthesis of hyper-crosslinked polymers: influences on their pore structure and adsorption behaviour for organic vapors
Beilstein J. Org. Chem. 2019, 15, 1154–1161, doi:10.3762/bjoc.15.112
- chemical and milling parameters on the yield and surface area of the resulting polymer. Results and Discussion Polymer synthesis and characterization In our standard procedure HCP was synthesised via a mechanochemical reaction. This was accomplished by transferring BCMCP (4,4’-bis(chloromethyl)-1,1
- ’-biphenyl) and six equiv of anhydrous iron(III) chloride as mediator into a 45 mL zirconium oxide milling vessel filled with 22 balls (10 mm, 3.19 ± 0.05 g) of the same material (Figure 1). Consequently, the vessel was transferred into a (Pulverisette 7) premium line (Fritsch GmbH) and milled at 500 rpm for
- surface area) achieved with the classical solvent-based approach (Sol-HCP, SSABET = 1450 m2g−1, Vp = 1.55 cm−3g−1) [11] could not be reached. In order to improve this property, we varied the mechanochemical reaction parameters such as milling time and amount of oxidant in a systematic (DOE) design of
Extending mechanochemical porphyrin synthesis to bulkier aromatics: tetramesitylporphyrin
Beilstein J. Org. Chem. 2019, 15, 1149–1153, doi:10.3762/bjoc.15.111
- , simple, room-temperature method for producing tetra-meso-substituted porphyrins with bulky substituents. Keywords: condensation; grinding; mechanochemistry; milling; porphyrin; sterically-hindered; Introduction Porphyrins and related macrocycles such as chlorins, corroles, and bacteriochlorins carry
- Information File 1). Although we are not certain of the identity of intermediates or side products from the mechanochemical reaction, it may be possible that via milling they are activated enough so that mechanical stirring during the oxidation with DDQ in solution continues to promote the formation of
- porphyrinogen. Throughout the oxidation process, the porphyrinogen immediately gets irreversibly oxidized to porphyrin. It is clear that further work is needed to elucidate differences between the mechanochemical and the solvent-based porphyrin syntheses. Conclusion Mechanochemical milling has successfully led
Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation
Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110
- transformation of a base-catalyzed, mechano-assisted Knoevenagel condensation of mono-fluorinated benzaldehyde derivatives (p-, m-, o-benzaldehyde) with malonodinitrile was investigated in situ and in real time. Upon milling, the para-substituted product was found to crystallize initially into two different
- monitoring multi-phase reactions during ball milling. Keywords: ball milling; C–C coupling; in situ; mechanochemistry; multivariate data analysis; Introduction Mechanochemistry offers a wide array of applications. It is used widely for synthesis of inorganic, metal-organic, and organic molecules and
- real time, using in situ techniques [12][13]. The first in situ and real time study was performed by X-ray powder diffraction (XRPD) to monitor transformations during a milling process [12]. In situ studies allow novel insight into the mechanism of a mechanochemical process, without changing the
Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration
Beilstein J. Org. Chem. 2019, 15, 963–970, doi:10.3762/bjoc.15.93
- can now be obtained through green mechanochemical synthesis. In addition to the general merits of mechanochemistry, such as being solvent-free and resulting in high conversions, we herein explore rate acceleration under ball-milling conditions while the conventional solution-state synthesis suffer
- from low reactivity. The solvent-free mechanochemical polymerization of trimethylene carbonate using the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) are examined herein. The polymerizations under ball-milling conditions exhibited significant
- rate enhancements compared to polymerizations in solution. A number of milling parameters were evaluated for the ball-milling polymerization. Temperature increases due to ball collisions and exothermic energy output did not affect the polymerization rate significantly and the initial mixing speed was
Mechanochemistry of supramolecules
Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86
- . Contrastingly, achieving syntheses through mechanochemical methods are generally time-saving, environmentally friendly and more economical. This review is written to shed some light on supramolecular chemistry and the synthesis of various supramolecules through mechanochemistry. Keywords: ball milling
- liberation of undesired byproducts [34][35]. In literature, classical small organic molecules’ synthesis has been well explored which includes multistep synthesis [36][37][38][39]. However, the concept of supramolecular chemistry under mechano-milling conditions only has limited number of examples [40][41
- milling frequency of 22.5 Hz (Figure 6b) [59]. The stoppers were constructed in situ with 1,8-diaminonaphthalene through the formation of an imine via dehydration of the amine and aldehyde. Interestingly, a synthesis of the smallest [2]rotaxane also has been demonstrated by the same group [60]. They
Synthesis of acylglycerol derivatives by mechanochemistry
Beilstein J. Org. Chem. 2019, 15, 811–817, doi:10.3762/bjoc.15.78
- , mechanosynthesis of lipids by ball milling techniques has remained essentially unexplored. In this work, a multistep synthetic route to access mono- and diacylglycerol derivatives by mechanochemistry has been realized, including the synthesis of diacylglycerol-coumarin conjugates. Keywords: ball mill; coumarin
- loads has led to mechanoenzymatic transformations [5][6][7], and to synthesize amino acid derivatives [8][9][10] and peptides [11][12][13] by ball milling and extrusion techniques. Similarly, mechanochemical derivatizations of sugars and sugar derivatives such as cyclodextrins (CDs) have proven
- compatible with the use of ball mills. These reports showed advantages such as higher selectivity by ball milling compared to classic solution methods and the possibility to effectively react CDs and reactants of different solubility profiles [14][15][16][17]. The compatibility of synthesizing biologically
Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives
Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36
- transformations without purification. The authors do not report ratios of α- and β-anomers or the yields, except for the pivaloyl derivative (77%) that was purified via silica gel chromatography. Mechanochemical methods (ball milling) of glycosylation of silylated nicotinamide 10a with 1 equivalent of 1,2,3,5
- presence of methanol under ball milling conditions (30 min at 25 Hz) resulted in the corresponding 1,4-dihydronicotinamide riboside NRH 21 isolated in quantitative yields. Alternatively, this deprotection procedure was conducted with 1 M sodium methoxide in MeOH over a longer period of time [58]. 1,4
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