Solvent-free organic synthese

Metzger, J.O. (1998) Solvent-Free Organic Syntheses. Angewandte Chemie International Edition, 37, 2975-2978. 

Varma, R.S., Solvent-free organic syntheses, Green Chem., 1999, 1, 43. 

Solvent-Free Organic Syntheses Homogeneous Catalysis... 

Varma RS (1999) Solvent-free organic syntheses Using supported reagents and microwave irradiation. Green Chem 1 43-55... 

Solvent-free organic syntheses among them syntheses with participation of heterocycles 00CRV1025. 

J. O. Metzger, Solvent-free organic syntheses, Angew. Chem. Int. Ed., 37 2975 (1998). 

Expeditious Solvent-Free Organic Syntheses Using Microwave Irradiation... 

Waste prevention and environmental protection are major requirements in an overcrowded world of increasing demands. Synthetic chemistry continues to develop various techniques for obtaining better products with less environmental impact. One of the more promising approaches is solvent-free organic synthesis this book of Koichi Tanaka collects recent examples in this field in a concise way so that their performance and merits can be easily judged. This endeavor is very welcome, as most recent syntheses and educational textbooks largely neglect solvent-free techniques. 

The elimination of volatile organic solvents in organic syntheses is a most important goal in green chemistry. Solvent-free organic reactions make syntheses simpler, save energy, and prevent solvent wastes, hazards, and toxicity. 

Richer T, Hauptmann S (2003) The ehemistiy of heterocycles structure, reaetions, syntheses, and applications, 2nd edn. Wiley-VC H, Weinheim Varma RS (1999) Solvent-free organic synthesis. Green Chem 1 43-55 Gharib A, Jahangir M (2013) Hindawi Publishing Corporation, Organic Chemistry International, Article ID 693763, 7 p... 

The sustainability of chemical reactions has gained relevance lately. In this context, the use of ball mills in solvent-free organic synthesis started to attract a considerable attention [5, 11]. In fact, until recently, all the methods employed in organic synthesis were restricted to reactions in solution because of the restricted conformational and translational degrees of freedom of molecules in solids [12]. However, in mechanochemical synthesis, ball milling modifies the conditions under which a chemical reaction commonly takes place, and various applications including C-C bond formations [11c], amine condensations, and syntheses of heterocycles [Ic] were found. 

Kragl and coworkers investigated using organic-solvent-free systems to overcome the thermodynamic limitations in the synthesis of optically active ketone cyanohydrins. With organic-solvent-free systems under optimized reaction conditions, conversions up to 78% with > 99.0 enantiomeric excess (ee) (S) were obtained. Finally, 5 mL of (S)-acetophenone cyanohydrin with an ee of 98.5% was synthesized using MeHNL [52]. 

The protection-deprotection reaction sequences constitute an integral part of organic syntheses such as the preparation of monomers, fine chemicals, and reaction intermediates or precursors for pharmaceuticals. These reactions often involve the use of acidic, basic or hazardous reagents and toxic metal salts [30], The solvent-free MW-accelerated protection/deprotection of functional groups, developed during the last decade, provides an attractive alternative to the conventional cleavage reactions. 

Recent advances in the use of Lawesson s reagent include its application in microwave assisted solvent-free syntheses, solid-phase synthesis and combinatorial chemistry.165 Despite the ubiquity of Lawesson s reagent for organic thionation reactions, there are still some classes of compounds that it does not... 

Chiral cyanohydrins are versatile intermediates in the synthesis of a-hydroxy acids, /3-amino alcohols, amino nitriles, a-hydroxy ketones and aziridines. For the synthesis of enantiopure cyanohydrins, the use of hydroxynitrile lyases is currently the most effective approach.Application of an organic-solvent-free system allows thermodynamically hindered substrates to be converted with moderate to excellent yields. With the use of the highly selective hydroxynitrile lyase from Manihot esculenta, the syntheses of several acetophenone cyanohydrins with excellent enantioselectivities were developed (Figure 8.2). (5)-Acetophenone cyanohydrin was synthesized on a preparative scale. ... 

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