Riedel synthesis

An old and satisfactory method is the Riedel synthesis in which o-nitrobenzaldehyde is converted to its bisformaraido derivative followed by reductive cyclization with zinc and acetic acid, or with iron and hydrochloric acid. This synthesis has been used to make... 

Raman spectra of pyrid-4-one, 353 2-thiophenealdehyde, 13 Raman spectroscopy, in study of tautomerism, 338 Reductones, structure of, 363 Refractive index, as method to study tautomerism, 337 Riedel synthesis, 300 Rutaecarpine, 301, 304... 

Synthesis (Hoffmann-La Roche, 1931 Volk (Riedel-de Haen), 1954 Kleemann et al., 1999) ... 

Riedel and coworkers have also uncovered some extremely novel chemistry based on the use of carbodiimide chemistry, including a case where precursor architecture influences phase and compositional development49. The process begins with the very simple synthesis of silylcarbodiimides (equations 15 and 16). In the case where R = Me, the compound is a 16-atom heterocycle (x = 4). For R = H, a polymer is obtained that gives a 65 wt% ceramic yield at 1500 °C and a SiCi.gNi.3 (1000 °C) composition. 

S. Riedel, A. Donnerstag, L. Hennig, P. W. Richter, K. Hobert, and D. M. van Heijenoort, Synthesis and transglycosylase-inhibiting properties of a disaccharide analogue of moenomycin A lacking substitution at C-4 of unit F, Tetrahedron, 55 (1999) 1921-1936. 

Claus RA, Wtistholz A, Muller S, Bockmeyer CL, Riedel NH, Kinscherf R, Deigner HP. Synthesis and antiapoptotic activity of a novel analogue of the neutral sphingomyelinase inhibitor scyphostatin. ChemBioChem 2005 6 726-737. 

The reductive cyclization of 2-nitrobenzyl-A, A -bis(formamide) with zinc in acetic acid to quinazoline was first described by RiedelT ° The reaction is used successfully for the synthesis of larger quantities of quinazoline and its benzene-ring-substituted derivatives 12 from 2-ni-trobenzyl-A, A -bis(formamides) 11. The method is suitable only for the preparation of 4-un-substituted quinazolines, because 2-nitro-substituted phenones do not condense with aliphatic amides to yield bis(amide) derivatives. Zinc in acetic acid is the reducing agent of choice, but iron in hydrochloric acid or Raney nickel can also be used. " Applications of compounds other than bis(formamides) [e.g., bis(acetamides) ] and preparation of 2-substituted quinazolines by Riedel s synthesis are scarce. 

Riedel et al. and Kienzle published the synthesis of a polyborosilazane by ammonolysis of tris(dichloromethylsilyl-ethylene)borane, B(C2H4Si(CH3)Cl2)3... 

The examination of structure/property relations of molecular educts and resulting ceramics required the synthesis of stoichiometrically and stmcturally different precursors. A variety of synthesis routes for Si-B-N-C precursors fiom organosilanes, silazanes, and boron compounds have been reported in recent years [3 - 5]. As an example, Riedel obtained a polymeric precursor via hydroboration of methylvinyldichlorosilane and subsequent condensation of the hydroboration product with ammonia (Eq. 1). Pyrolysis led to silicoboron carbonitride ceramics exhibiting thermal stability up to 2000 °C [6]. 

P.H. Choi, K.W. Jun, S.J. Lee, M.J. Choi, K.W. Lee, Catalysis Letters 40 (1996) 115 H. Schulz, K. Beck, E. Erich, Stud. Surf. Sci. Catal. 36 (1988) 457 H. Schulz, S. Nehren, Erdol und Kohle - Erdgas - Petrochemie 39 (1986) 93 H. Schulz, G. Schaub, M. Claeys, T. Riedel, S. Walter, "Initial transient rates and selectivities of Fischer-Tropsch synthesis with CO2 as carbon source",... 

Hydroquinones — quinones [1, 533-534, at end]. The most convenient synthesis of 4,5-dimethoxy-o-benzoquinone (8) involves oxidation of catchol (7) with lead dioxide (Riedel-deHaen) in the presence of sodium methoxide.7a... 

In a typical synthesis, 4.2 g. pseudoboehmite (Catapal B, 73% AI2O3) was dispersed in 15.0 g. water. 6.93 g. orthophosphoric acid (85%, S. D. Fine Chemicals) was diluted in 9.7 g. water and then added to a dispersed pseudoboehmite in water. The aluminophosphate gel thus obtained was aged for 24 hours and 3.91 g n-DBA (99%, Riedel-de Haen) was added to the aged gel. The mixture was stirred for 10 minutes and then crystallized in a stainless steel autoclave between 415-418K for 24 hours. After crystallization the autoclave was quenched... 

R. Riedel, G. Passing, H. Schonfelder, and R. J. Brook, Synthesis of Dense Silicon-Based Ceramics at Low Temperatures, Nature, 355, 714-7 (1992). 

Liss PS and Merlivat L (1986) Air-sea gas exchange rates introduction and synthesis. In Baut-Menard P (ed.) The Role of Air-Sea Exchange in Geochemical Cycling, pp. 113-127. Dordrecht Riedel. 

Bill J, Kienzle A, Sasaki M, Riedel R, Aldinger F (1995) Novel routes for the synthesis of... 

Manuf./Distrib. AccuStandard Acres Org. Aldrich Fluka ICN Biomed. Research Prods. Lancaster Synthesis Mallinckrodt Baker Pfaltz Bauer RIedel-deFlaen TCI Am. 

Manuf./Distrib. A E Connock ABCR Acros Org. Advanced Synthesis Tech. Aldrich Chemol Cognis/Chems. Group Fleurchem Fluka Indofine Jarchem Ind. NOF Am. Penta Mfg. Pfaltz Bauer Procter Gamble Riedel-deHaen Sigma Stepan UniqemaAm. 

CaO powders from Riedel-de Haen " (CaOR) and Fluka" (CaOp) and two materials of biogenic origin, widesptread in the nature - egg shells and land snail Arianta arbustorum) shells, were chosen. These materials were selected as raw materials for obtaining CaO and further usage in the synthesis process of CaP. 

A. Zerr, G. Miehe, G. Serghiou, M. Schwarz, E. Kroke, R. Riedel, H. Fuess P. Kroll R. Boehler, Synthesis of cubic silicon nitride, Nature 400 340-12 (1999)... 

Uses Antifog in photography Manuf./Distrib. Acros Org. http //www.acros.be] Aldrich http //www.sigma-aidrich.com] EMS-Dottikon AG http //www.ems-dottikon.ch] Fluka http //www.sigma-aidrich.com] ICN Biomed. Research Prods, http //www.icnbiomed.com Lancaster Synthesis Pfaltz Bauer http //WWW.pfaitzandbauer. com] Riedel-deHa n... 

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