Scheller reaction

Scheller reaction Schercamox DML Schercamox DMM Schercomid Schercomid CME Schercotaine Schereowet Scher-Montroll model Schetty-Pfeiffer ligands Schiff base Schiff bases... 

Scheller 17 modified the Bart reaction to such an extent that his method is often referred to as the Scheller reaction. Primary aromatic amines, dissolved in methanol or glacial acetic acid, are diazotized in the presence of arsenic trichloride and a trace of cuprous chloride. Removal of the solvent followed by treatment with water and sodium hydrosulfite gives the expected arsonic acids. 

Sulfo and Sulfamido Groups. It has been shown that sulfanilic acid can be converted into p-sulfophenylarsonic acid (25-45%).49 60 By the ordinary Bart reaction p-sulfamidophenylatsonic acid (25%) may be prepared,60 although a better yield (57%) is obtained by a modified Scheller reaction.18 Apparently, metanilic acid and naphthionic acid will not yield the corresponding arsonic adds.18 61 Although m-sulfamido-phenylarsonic add is not available by the usual procedure it can be prepared in a 58% yield by the method of Scheller.18... 

The Bart reaction is successful with a wide variety of aromatic and heterocyclic amines. A variation in which an aromatic amine, in the presence of arsenic trichloride, is diazotized in an organic solvent (the Scheller reaction) has also found wide application. Both arsonic and arsinic acids can be prepared by the Scheller reaction which often gives better yields than the Bart reaction with electron-attracting substituents on the aromatic ring. For the commercial preparation of 4-aminophenylarsonic acid [98-50-0] (arsanilic acid), C HgAsNO, and 4-hydroxyphenylarsonic acid [98-14-6], C FTAsO the Bnchamp... 

An important modification of the original Bart procedure was made by Scheller who diazotized primary amines, dissolved in alcohol or glacial acetic acid, in the presence of arsenic trichloride and found that better yields of arsonic acids could sometimes be obtained, particularly if the amine carried negative substituents in the meta position. The method has been slightly modified 140). The Scheller reaction has recently been used to prepare arsonic acids of 3-nitro-4-fluorobenzene and 2,5-dimethylpyridine 141, 142), and to prepare a number of arsinic acids such as (CeHs)[4,3-CH3(N02)C6H3]As02H by the reaction 143)... 

The success of the Bart reaction when applied to nuclear- substituted anilines is often much affected by the pH of the reaction-mixture. Furthermore, the yields obtained from some m-substituted anilines, which under the normal conditions are usually low, arc considerably increased by the modifications introduced by Scheller, and by Doak, in which the diazotisation is carried out in ethanolic solution followed by reaction with arsenic trichloride in the presence of a cuprous chloride or bromide catalyst. 

Meffert, M. K., Calakos, N. C., Scheller, R. H. and Schulman, H. Nitric oxide modulates synaptic vesicle docking/fusion reactions. Neuron 16 1229-1236,1996. 

Martin TF (2001) PI(4,5)P(2) regulation of surface membrane traffic. Curr Opin Cell Biol 13 493-9 Meffert MK, Calakos NC, Scheller RH, Schulman H (1996) Nitric oxide modulates synaptic vesicle docking fusion reactions. Neuron 16 1229-36 Menniti FS, Faraci WS, Schmidt CJ (2006) Phosphodiesterases in the CNS targets for drug development. Nat Rev Drug Discov 5 660-70... 

P. E. Jensen, M. Gilpin, J. Knoetzel, and H.V. Scheller. 2000. The PSI-K subunit of photosystem I is involved in the interaction between light-harvesting complex I and the photosystem I reaction center core J. Biol. Chem. 275 24701-24708. (PubMed)... 

The last type of redox recycling is substrate recycling rather than true redox recycling. Two enzymes are used, with the product of the first enzyme reaction serving as substrate for the second enzyme. In turn, the product of the second reaction acts as the substrate for the first enzyme. Both the degradation of a co-substrate and the production of a product like hydrogen peroxide can be quantified electrochemically. This concept can be applied to other electrochemical transducers, such as ion selective electrodes, because label conversion is not accomplished with the electrode. Amplification factors of 3-48,000 were reported by Scheller and colleagues [55-58] for ampero-metric multienzyme electrodes with the appropriate substrates. 

Bart reaction. (Scheller modification Star-key modification). Formation of aromatic arsonic acids by treating aromatic diazonium compounds with alkali arsenites in the presence of cupric salts or powdered silver or copper in the Scheller modification, primary aromatic amines are diazotized in the presence of arsenious chloride and a trace of cuprous chloride. 

JS Okkels, B Kj r, O Flansson, I Svendsen, BL Mtller and FIV Scheller (1992) A membrane-bound monoheme cytochromecss of a novel type is the immediate electron donorto P840 ofthe Chlorobium vibriforme photosynthetic reaction center complex. J Biol Chem 267 21139-21145... 

In the meantime, Scheller, Svendsen and Mpller carried out a careful analysis ofthe stoichiometry of polypeptide subunits relative to the primary donor P700 in the P700-chlorophyll a-protein isolated from barley. They found one mole of each ofthe two homologous subunits per mole ofP700, each with molecular masses of 82 kDa, as well as some lower-molecular-mass polypeptides. These results plus the accumulated information on the total number of iron and sulfur atoms relative to P700, and results of the renewed X-ray absorption and Mossbauer spectroscopic studies, have now conclusively confirmed the presence of a single [4Fe 4S] cluster in FeS-X in the PS-I reaction-center core. 

R Malkin (1996) Photosystem I electron transfer reactions components and kinetics. In DR Ort and OF Yocum (eds) Oxygenic Photosynthesis The Light Reactions, pp. 313-332.. Kluwer Acad PubI B Andersson, HV Scheller and BL Miller (1992) The PSi-E subunit of photosystem i bindsferredoxin-NADF -oxidoreductase. FEBS Lett 311 169-173... 

If the given classification is used, the simplest model of an amperometric sensor is that of a stationary single-layer monoenzyme electrode with linear reaction kinetics and electrode-active product, P (Schulmeister and Scheller, 1985a). 

Provided the respective concentrations are in a range that permits linearization of the reaction term, a linear approach becomes applicable for nonlinear reaction kinetics (Schulmeister and Scheller, 1985a). The model then becomes ... 

A selectivity enhancement by inhibition of interfering reactions has been achieved by Riedel and Scheller (1987), who added chloromer-curibenzoate and NaF to the measuring solution of a B. subtilis sensor for glutamate to block glucose permeation and assimilation. In this manner the interference of glucose in the glutamate measurement was completely eliminated. 

Fig. 140. Internal signal processing in biosensors using coupled enzyme reactions. (Redrawn from Scheller et al., 1985b).

On the other hand, Scheller 110 goes to great length to obtain acetylene in a pure condition for reaction with steam at a temperature of 600° C. over a catalyst composed of molybdenum oxide deposited on asbestos. Despite the high temperature used a yield of 17 per cent of acetaldehyde is claimed. This may in part be attributed to the high proportion of steam used, i.e., 400 volumes steairi to IS volumes acetylene. With a 35 cm. length of catalyst a rate of one liter of this mixture per minute per sq. cm. of cross section is used. 

BAMBERGER Benzotnazine synthesis 17 BAMFORD - STEVENS CAGLIOTI - SHAPIRO Reaction 18 BARBIER Reaction 19 BARBIER - WIELAND Degradation 20 BART SCHELLER Arsonyfation 21 BARTON Name photolysis 22 BARTON Deamination 23 BARTON Decarboxylation 24... 

Scheller, F. W., Renneberg, R., Schubert, F., Coupled Enzyme Reactions in Enzyme Electrodes Using Sequence, Amplification, Competition, and Antiinterference Principles , in Methods in Enzymology Vol. 137, Colowick, S. P., Kaplan, N. O., Mosbach, K. (eds) San Diego Academic Press, 1988, pp. 29-44. 

It is pertinent to mention here that the success of the Bart Reaction when applied to nuclear-substituted anilines e.g., m-substitued anilines) is invariably effected by the prevailing pH of the reaction medium. Scheller (1992) and Doak et al. (1946) suggested certain modifications whereby the yields obtained from certain m-substituted anilines, which under the usual conditions of reactions are very low, could be enhanced considerably by carrying out... 

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