Mechanochemical halogenation of unsymmetrically substituted azobenzenes

• Dajana Barišić,
• Mario Pajić,
• Ivan Halasz,
• Darko Babić and
• Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

• solvent-free synthesis of phenanthridinones via a cascaded oxidative C–N coupling followed by a halogenation reaction [50]. Only recently, our group carried out a detailed synthetic and mechanistic study of the mechanochemical PdII-catalyzed bromination of unsubstituted azobenzene (L1) by N

Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

• Akhil K. Dubey and
• Raghunath Chowdhury

Beilstein J. Org. Chem. 2021, 17, 2642–2649, doi:10.3762/bjoc.17.177

• experiments reveal that the presence of a β-silyl group in the enones is crucial for high reactivity under the optimized reaction conditions. Keywords: β-silyl α,β-unsaturated carbonyl compounds; β-silyl nitroalkanes; chiral organosilanes; organocatalysis; solvent-free synthesis; Introduction

• and good to excellent enantioselectivities at room temperature. The notable features of this reaction are access to both the (R) and (S) enantiomers of the products, solvent-free synthesis, mild reaction conditions, low catalyst loading, and use of only a small excess of nitromethane (2.5 equivalents

Electron-rich triarylphosphines as nucleophilic catalysts for oxa-Michael reactions

• Susanne M. Fischer,
• Simon Renner,
• A. Daniel Boese and
• Christian Slugovc

Beilstein J. Org. Chem. 2021, 17, 1689–1697, doi:10.3762/bjoc.17.117

• chemistry; organocatalysis; phosphine; solvent-free synthesis; Introduction Phosphines are potent nucleophiles that are used as catalysts in many reactions, like Rauhut–Currier, Morita–Baylis–Hillman or Michael reactions [1][2][3]. The first step of these reactions is a conjugate addition of the phosphine

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151

• carried out a large-scale one-pot solvent-free synthesis of amides 6a,b starting from propargyl alcohols 7a,b at room temperature (Scheme 4). At the first step, alcohols 7a,b in the reaction with PCl3 were transformed into the corresponding allenes 1a,h. Then, the addition of Brønsted acid (TfOH or H2SO4

• cations A, B, and F–H. Large-scale one-pot solvent-free synthesis of amides 6a,b from the corresponding propargylic alcohols. AlCl3-promoted hydroarylation of allene 1b by benzene leading to alkene Z-11n. Reaction of allene 1a with benzene under the action of AlCl3 followed by quenching of the reaction

The mechanochemical synthesis of quinazolin-4(3H)-ones by controlling the reactivity of IBX

• Md Toufique Alam,
• Saikat Maiti and
• Prasenjit Mal

Beilstein J. Org. Chem. 2018, 14, 2396–2403, doi:10.3762/bjoc.14.216

• constructions [4][6]. Mechanochemical conditions such as ball milling are considered to be one of the premium techniques in solvent-free synthesis [7]. Under these conditions, maximum concentration is expected to put those systems under high stress and therefore violent exothermic reactions or even explosions

High-speed vibration-milling-promoted synthesis of symmetrical frameworks containing two or three pyrrole units

• Marco Leonardi,
• Mercedes Villacampa and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2017, 13, 1957–1962, doi:10.3762/bjoc.13.190

• achieved by a different approach involving the homodimerization of 1-allyl- or 1-homoallylpyrroles by application of cross-metathesis chemistry. Keywords: diversity-oriented synthesis; mechanochemistry; multicomponent reactions; pyrroles; solvent-free synthesis; Introduction Symmetrical molecules formed

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• (C–X), etc. is documented. Mechanochemical syntheses of heterocyclic rings, multicomponent reactions and organometallic molecules including their catalytic applications are also highlighted. Keywords: ball-milling; green chemistry; mechanochemistry; solid-phase synthesis; solvent-free synthesis

• techniques like ball-milling or hand grinding are considered to be promising candidates in solvent-free synthesis [10][11]. Mechanochemical methods deal with chemical transformations induced by mechanical energy, such as compression, shear, or friction [12]. Wilhelm Ostwald, a Russian-German chemist who

• reaction medium, solvent-free synthesis, microwave synthesis, use of different Lewis acids FeCl3, NiCl2, BiCl3, InBr3, use of Brønsted acids PTSA, etc. are also reported [129][130]. Recently, Mal and co-workers reported a mechanochemical Biginelli reaction by a subcomponent synthesis approach [131][132

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• and 1,2-phenylenediamine, benzimidazolidine-2-thiones 14a–c were isolated in 100% yields via cyclization of an unstable intermediate 13 (Scheme 3b,c). Compared to the solvent-free synthesis, the corresponding solution reactions resulted in lower yields (81–95%). Li and co-workers conducted a mortar

• ). Mechanochemical solvent-free synthesis yields 27a–f as bench-stable solids, that are readily converted to thioureas 28a–g. Mechanosynthesis of a) bis-thiocarbamoyl benzotriazole 29 and b) benzimidazole thione 31. c) Synthesis of bis-thiourea 22a from mono- (27a) and bis- (29) N-thiocarbamoyl benzotriazoles. a

Encaging palladium(0) in layered double hydroxide: A sustainable catalyst for solvent-free and ligand-free Heck reaction in a ball mill

• Wei Shi,
• Jingbo Yu,
• Zhijiang Jiang,
• Qiaoling Shao and
• Weike Su

Beilstein J. Org. Chem. 2017, 13, 1661–1668, doi:10.3762/bjoc.13.160

• such as Heck, Suzuki, Sonogashira and Glaser reactions are still unusual methods for the formation of C–C bonds [1][2][3][4][5][6][7], but the method arouse considerable attention because of an environmentally benign and solvent-free synthesis approach as well as high efficiency and good atom economy

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• Engineering, Saarland University, Saarbrücken, Germany Fraunhofer Institute for Material and Beam Technology IWS, Dresden, Germany 10.3762/bjoc.13.130 Abstract A solvent-free synthesis of hierarchical porous carbons is conducted by a facile and fast mechanochemical reaction in a ball mill. By means of a

• . The solvent-free synthesis results in a higher specific surface area and pore volume as compared to the liquid-assisted approach. We suggest that this is also attributed to more homogenously distributed particles while conducting the polymerization solvent-free. In the presence of solvents, a phase

• purchased from Sigma-Aldrich. Ethylene glycol (EG, purity 99.5%) was purchased from Fluka Analytics. For the solvent-free synthesis of hierarchical porous carbons, 5.25 g CA were ground with 7.10 g TIPP in a molar ratio of 1:1 in a 45 mL ZrO2 milling cup for 1 min with 700 rpm. Seven grinding balls out of

Solvent-free synthesis of novel para-menthane-3,8-diol ester derivatives from citronellal using a polymer-supported scandium triflate catalyst

• Lubabalo Mafu,
• Ben Zeelie and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 2046–2054, doi:10.3762/bjoc.12.193

A facile, rapid, one-pot regio/stereoselective synthesis of 2-iminothiazolidin-4-ones under solvent/scavenger-free conditions

• Murugan Sathishkumar,
• Sangaraiah Nagarajan,
• Poovan Shanmugavelan,
• Murugan Dinesh and
• Alagusundaram Ponnuswamy

Beilstein J. Org. Chem. 2013, 9, 689–697, doi:10.3762/bjoc.9.78

• environmentally friendly methodologies for the synthesis of 2-iminothiazolidin-4-ones is worth attempting. In this regard, and in continuation of our recent reports on the solvent-free synthesis of amides [19][20], thioamides [21], cyclic imides [22], thiazolidin-4-ones [23], spirothiazolidin-4-ones [24], 1,2,3

• . Optimization of solution-phase and solvent-free synthesis of 2-iminothiazolidin-4-one 4f. Screening of base and equivalents of chloroacetic acid in the solvent-free synthesis of 2-iminothiazolidin-4-one 4f. Solvent/scavenger-free synthesis of 2-iminothiazolidin-4-ones 4a–n. Solvent/scavenger-free synthesis of

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• hydroxide or barium hydroxide. More recently, another one-pot two-steps procedure using the environmentally benign solvent ethanol was described [24]. The reaction is based on the same mechanism as the solvent-free synthesis described above, but provides better yields. This protocol was recently used to

Solvent-free and time-efficient Suzuki–Miyaura reaction in a ball mill: the solid reagent system KF–Al₂O₃ under inspection

• Franziska Bernhardt,
• Ronald Trotzki,
• Tony Szuppa,
• Achim Stolle and
• Bernd Ondruschka

Beilstein J. Org. Chem. 2010, 6, No. 7, doi:10.3762/bjoc.6.7

• vogue [1][2]. This trend has led to an explosive growth in the fields of solvent-free synthesis [3][4][5][6][7][8][9][10][11][12][13] and solid-supported reagents [14][15][16][17][18] such as potassium fluoride on alumina (KF–Al2O3) [19][20]. This versatile reagent was originally introduced in 1979 by

Zeolite catalyzed solvent- free one-pot synthesis of dihydropyrimidin- 2(1H)-ones – A practical synthesis of monastrol

• Mukund G. Kulkarni,
• Sanjay W. Chavhan,
• Mahadev P. Shinde,
• Dnyaneshwar D. Gaikwad,
• Ajit S. Borhade,
• Attrimuni P. Dhondge,
• Yunnus B. Shaikh,
• Vijay B. Ningdale,
• Mayur P. Desai and
• Deekshaputra R. Birhade

Beilstein J. Org. Chem. 2009, 5, No. 4, doi:10.3762/bjoc.5.4

• demonstrated by preparing 11.2 g of monastrol starting with 5.0 g of 3-hydroxybenzaldehyde. Thus an efficient one-step, solvent-free synthesis of DHPMs was achieved in very good yields. Conclusion In conclusion, we have developed a practical methodology for the synthesis of dihydropyrimidones, which has been