Fries arrangement

Mass spectral studies have shown that the largest fraction other than III has a molecular weight of 312. This compound (XI) appears to be formed by a photochemical rearrangement most likely, a Photo-Fries arrangement of III (1 ), as shown in Scheme 3. It is difficult to predict at this stage whether the rearrangement occurs at only one of the aromatic centers or both, i.e. to form a monophenol (XI) or bisphenol (XII). 

The styrylpyridine based polyarylates and their model compounds were synthesized. The order of the relative char yield and oxygen indices were polyarylates > p,p -bis(B-2-vinylpyridyl)diphenyl terephthalate (p,p -BVPDPT) = p,p -2,6-(3-2-vinylpyridyl)diphenyl dibenzoate >(p,p -2,6 -2,6-(B-2-vinylpyridyl)phenyl benzoate (p-VPPB). This is also probably due to the Diels-Alder reaction of the C=C double bonds present in the main chain with the pryidine group. The result is a highly crosslinked C-C bond char. The styrylpyridine based model compounds of the ester and carbonate underwent the Photo-Fries arrangement when irradiated with UV light to give o-hydroxybenzophenone related structures. 

Fries rule. The most stable form of a polynuclear hydrocarbon is that in which the maximum number of rings has the benzenoid arrangement of three double bonds. A benzenoid electronic configuration is energetically favored and, therefore, particularly stable. 

FIGURE 9.6 The prediction of Koch and Brady (for random arrangement of spheres) [28] for longitudinal and transverse total effective thermal diffusivity, compared with the experimental results of many investigators as presented in Fried and Combamous [29]. 

Salicylate-type additives are largely imsuitable for use in aromatic polyesters, but some UV-stabilising ability has been shown by polyesters which contain moieties capable of transformation in the same way as the salicylates the so-called Photo-Fries rearrangement [20-22]. More recently, re-arrangeable polymers such as poly(phenyl acrylate) and poly(p-methylphenyl acrylate) have been proposed... 

As indicated above, supply, both offensive and defensive, came mainly from the British and French. At first, Fries attempted to handle supply personally through liaison offices established in London and Paris and through the supply services of the AEF. Maj. Robert W. Crawford, as Chief of Gas Service supply, soon relieved Fries of supply operating functions. Crawford found that the Gas Service was automatically assigned lowest priority by the established supply services who had their own problems. He accordingly secured direct purchase authority for the Gas Service and arranged for the Gas Service to handle its own supply system all the way from requisition or purchase to actual supply to troops in the field. ... 

Perhaps the most cogent manifestation of the characteristic approach of the American chemists was Harry Fry s contribution in the symposium on Atomic Structure and Valence. He attempted to articulate what he called the pragmatic outlook. He started by posing a single question that should be dealt with by the (organic) chemists. What would be the kind of modifications to the structural formulas so as to conform to the current concepts of electronic valence This, he insisted, should by no means lead to a confusion of the fundamental purpose of a structural formula, which was to present the number, the kind, and the arrangement of atoms in a molecule as well as to correlate the manifold chemical reactions displayed by the molecule. 

Stenberg, V. I., Photo-Fries reaction and related arrangements, Org. Photochem., 1, 127, 1967. 

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