Fries mechanism

The mechanism of the Fries reaction is not known with certainty. One mechanism regards it as a true intramolecular rearrangement in which the acyl group migrates directly from the oxygen atom to the carbon atoms of the ring. Another scheme postulates that the ester is cleaved by the reagent... 

II IS imporlanl lo remember lhal each slage consisls of more lhan one elemenlary step Therefore a complete mechanism can have many steps and look complicated if we fry lo absorb all of il al once If we keep Ihe Iwo slages separate m our minds and build on whal we already know our job becomes easier Two poinls are helpful... 

N. Fried, Degradation of Composite Materials The Effect of Water on Glass-Reinforced Plastic, in Mechanics of Composite Materials, Proceedings of the 5th Symposium on Naval Structural Mechanics, Philadelphia, Pennsylvania, 8-10 May 1967, F. W. Wendt, H. Liebowitz, and N. Perrone (Editors), Pergamon, Now York, 1970, pp. 813-837. 

At total reflux (L/V) = 1) Capps found several points in the FRI data that corresponded with this [241] definition of ultimate capacity, i.e., the liquid and vapor load at which any increase in either liquid or vapor would induce flooding by at least one of the following mechanisms ... 

On the basis of all these experiments various mechanisms have at some stage been advanced for the Fries rearrangement involving the free acylium ion or as a tightly bound ion pair, Ji-complexes and cyclic intermediates. It is clearly impossible to reconcile all the experimental data by one reaction mechanism. It is probable that many such mechanisms are possible, each one operative under a certain set of conditions. 

Malbran A, Hammer C, Frank M. Fries L Acquired angioedema observations on the mechanism of action of autoanfibodies directed against C1 esterase inhibitor. J Allergy Clin Immunol 1988 81 1199-1204. 

Mechanism of NPYR Formation The consistent occurrence of NPYR in fried bacon and cooked-out fat has led to an intensive search for both the precursors and mechanism that could account for its formation. Although model system studies have implicated a number of compounds including proline, collagen, putreseine, spermidine, pyrrolidine and glycyl-L-glycine as possible... 

The mechanism of NPYR formation has been studied by Coleman (37) and Bharucha et al. ( ). Coleman (37) reported that the requirement for a high temperature, the inhibitory effects of water and antioxidants, and the catalytic effect of a lipid hydroperoxide are consistent with the involvement of a free radical in the formation of NPYR. Similarly, Bharucha et al. (29) suggested that, since both NPYR and NDMA increase substantially towards the end of the frying process, N-nitros-amine formation during frying of bacon occurs essentially, if not entirely, in the fat phase after the bulk of the water is removed and therefore by a radical rather than an ionic mechanism. These authors speculated that, during the frying of... 

Data from Kowalska, T., Kaczmarski, K., and Prus, W., Theory and mechanism of thin-layer chromatography, in Handbook of Thin-Layer Chromatography, 3rd ed., revised and expanded, Chromatographic Science Series, 89, Sherma, J. and Fried, B., Eds., Marcel Dekker, New York, 2003, chap. 2. 

Fry You need both to produce the wave, but you have a mechanism there for producing a wave. If only you could show that in the smooth muscle cell you had this loose coupling. 

Fry Are you saying that the gastric cells have no internal release mechanisms ... 

The results in this paper support an N-C bond cleavage mechanism (Schemes I and II) for the photolysis of both TDI and MDI based polyurethanes. The substituted anilinyl radicals observed no doubt are formed by diffusion from a solvent cage after the primary N-C bond cleavage. Although not specifically shown in this paper, the reported photo-Fries products (6) are probably formed by attack of the carboxyl radical on the phenyl ring before radical diffusion occurs. The solvent separated anilinyl radicals rapidly abstract hydrogens from the solvent to give the reported aromatic amine product (6). 

In addition, recent studies of amides include the 1,3-acyl migration of enamides to obtain the enamines through a photo-Fries like mechanism (equations 103160 and 104161). 

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