Mallory reaction

Hexa-peri-Hexabenzocoronenes (HBCs) and Related Systems 377 Expanded PAHs Nanographenes and Graphene Nanoribbons 386 Base-Induced Cydodehydrogenation 400 Oxidative Photocydization (Mallory Reaction) 406... 

Classical methods rely on electrocyclization reactions promoted by heat or, especially, by photochemical means, usually followed by an oxidation to deliver the aromatic compound. One of the most prominent routes is also known as the Mallory reaction, first reported in 1964 [84, 85]. Since then it has been further optimized [86] and applied, especially in the synthesis of helicenes [87], but also in a number of syntheses of graphene-type structures. Zhang et al. recently combined the Mallory reaction with a Scholl cyclization to access tetrabenzocoronene 135 (Scheme 33) [88]. A similar approach has been reported for the preparation of hexabenzocoronene [62]. 

J0rgensen KB (2010) Photochemical oxidative cyclisation of stilbenes and stilbenoids— the Mallory-reaction. Molecules 15 4334 358. doi 10.3390/moleculesl5064334... 

Photo-induced synthesis of thiahelicenes based on the Mallory reaction (2005MI1) is still one of the most widely used routes for the access to this class of hehcenes. As for carbohelicenes, this methodology utilizes, as starting material, modified stilbene-type precursors of type 2 generally including thiophene rings (Scheme 1). 

Mallory (Ref 19), Urtiew Kusubov (Ref 26b), Watson (Ref 26d), Persson (Ref 26c), Seely et al (Ref 26) Cook and co-workers (Ref 32) have shown similar effects in the detonation wave fronts of LE. However, inhomogeneities in the wave front were observed only for rather insensitive expls, particularly in expls diluted with inert additives. This is understandable if, as suggested by Shchelkin (Ref 8), the size of the inhomogeneities is determined by the reaction time of the expl under classical (C-J) conditions. For sensitive LE (eg, NG), these reaction times are short and inhomogenei-lties are too small to be resolved by instrumentation now available. The problem of wave front instability in all LE is still unresolved. There may be certain LE that behave classically, ie, their detonation fronts are stable, uniform and one dimensional (Ref 18)... 

F. B. Mallory and C. W. Mallory, Organic Reactions, vol. 30. Wiley (1984). This is an extensive compilation and discussion of the photocyclization reactions of stilbene and related systems. 

The compound of formula (4) is coupled with isoprene chloroacetate (1-acetoxy-4-chloro-3-methylbut-2-ene) (4a) to form the basic C2o skeleton of dehydrophytol. The chloroacetate is known and prepared by the chlorhydrination of isoprene in glacial acetic acid as described in an article by W. Oroshnik and R. A. Mallory, J. Amer. Chem. Soc. 72, 4608 (1950). The coupling reaction results in the preparation of 3,7,11,15-tetramethyl-l-acetoxyhexadec-2-en-5-yne (5), a C2o enyne. The coupling reaction may be carried out employing several methods. The following methods are preferred. 

Reagents.—Platinum hexafluoride and rhodium hexafluoride were prepared from 0.03-in. diameter pure metal wire supplied by Johnson, Matthey, and Mallory Ltd., Toronto. The reaction with fluorine was initiated by electrical heating of the wire, the metal reactor used being similar to that described by Weinstock, Malm, and Weaver [2]. Airco Reagent Grade xenon was used. 

Shippey and Donahue [11] were the first to show how to derive an empirical expression for the overall rate law for electroless deposition reactions. They studied an electroless copper system with tartrate as a complexing agent. Later, Molenaar et al. [12] performed similar kinetic studies concerning an electroless copper deposition reaction with EDTA as a complexing agent. The kinetics of electroless nickel deposition was investigated by Mallory and Lloyd [13]. 

Liver cell hydrops Liver cell hydrops is characterized by swollen hepatocytes, which contain a lot of liquid, but are generally free of fat. Hydropic liver cells may be 2 to 4 and even 10 times the size of normal hepatocytes. Cell hydrops is completely reversible when abstention is maintained. These cells usually die when alcohol intake is continued and are subsequently removed by macrophages and leucocytes. This leads to an alteration in the cytoskele-ton. Hydropically degenerated liver cells and hyaline liberated from Mallory bodies produce a leucocytic inflammatory reaction. Unless it is compensated by regenerative processes, this cellular deficit results in defective healing by fine-fibred, cell-poor fibrils. 

Fig. 28.1 Mallory bodies immunohistochemical reaction with an antibody against ubiquitin (arrow)...

This is an important reaction which competes with cis - trans photoisomerization of stilbenes even at low concentrations in solution or in the gas phase [470]. First observed for cis-stilbenc by Smakula [94] and identified by Moore et al. [471], it has been intensively studied by Mallory [472], Laarhoven [473], and several other groups [82, 125, 474-483]. In general, photocyclization of stilbenes provides a valuable synthetic route for generation of phenanthrenes. 

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