Synthetic investigations

Fallis A. G. Harvesting Diels and Alder s Garden Synthetic Investigations of Intramolecular [4 + 2] Cycloadditions Acc. Chem. Res. 1999 32 464-474 Keywords intramolecular Diels-Alder reaction... 

Synthetic investigations have, however, dominated this aspect of alkyliron chemistry. Acyl complexes of formula CpFe(CO)L(COMe) have been... 

TFA. Electrophilic aromatic thallation with TTFA therefore constitutes a simple and general procedure for the preparation of monoarylthallium(III) derivatives and has been the subject of detailed kinetic, mechanistic, and synthetic investigations. These aspects of the thallation reaction are discussed at length below. 

From the synthetic investigations that have been described in the previous schemes, an appreciation of the mechanism for these reactions (methods A-H) has emerged in our group. However, the characteristics and exact nature of the o-quinone methide intermediate are still debated. Our past observations clearly indicate the cascade leading to the reactive species that behaves as an o-quinone methide should behave is... 

Over thirty publications resulted from Tipson s work in Levene s laboratory. Along with the work on nucleic acid components, he also studied the structures of gum arabic and other plant gums, and conducted a range of synthetic investigations on sugars, with particular emphasis on uronic acids and 5-carbon ketoses. His 1939 observation that acetylated glycosyl halides... 

Shibata, T., Suzuki, S., Kawagoe, H., Komura, K., Kubota, Y., Sugi, Y., Kim, J.-H., and Seo, G. (2008) Synthetic investigation on MCM-68 zeolite with MSE topology and its application for shape-selective alkylation ofbiphenyl. Micropor. Mesopor. Mater., 116,... 

The synthesis of chiral metal-containing polyaryleneethynylenes was achieved after extensive synthetic investigations, stereochemical investigations, hetero-... 

The structure of the carbonyl ylide reveals that it is a 1,3-dipolar species and is poised to undergo a variety of different reactions. The ability of carbonyl ylides to engage in bond-forming processes has promoted their use in organic synthesis. Although there are several pathways open to these zwitterionic intermediates, there are a few that have been the focus of detailed mechanistic and synthetic investigations (Fig. 4.2). 

The reason for this may be attributed to the lower abundance of the parent compounds in fullerene soot, which has prevented their ample use in synthetic investigations. To complicate matters, C76,... 

Note that 1,5-diketones 29 (Scheme 2) are cyclodehydrated as soon as they are formed, and this process evidently occurs via protonation of the carbonyl group. The proton affinity in this case is probably determined by the substituent at each carbonyl group in 29. So far, there are no synthetic investigations of the problem, whereas quantum chemical calculations reveal the equal possibility for proton addition to both oxygen atoms in homophthalic dialdehyde (86KGS460). 

The alkaloids of the crinine group have been the objects of intensive synthetic investigations, and a number of general and useful strategies have been developed. The biogenetic approach to crinine (359) and maritidine (387) has been explored (176,191-196), and an attempt to access pretazettine (395) via an... 

The alkaloids related to crinine (359), which possess the 5,10b-ethanophen-anthridine nucleus, have been the subject of extensive synthetic investigations (190). Alkaloids of this family bearing oxygen functionality at C-ll occupy a special position since they are possible biosynthetic and chemical precursors of the subgroups that incorporate a 2-benzopyrano[3,4-c]indole ring such as those alkaloids related to pretazettine (395), tazettine (397), and macronine (401) and the methanomorphanthridines such as montanine (584). 

The spectroscopic and synthetic investigations suggested that these two compounds A and B were novel unsaturated methylketones determined as 5Z, Z,11Z)- and (5 E,8jZ,llZ)-5,8, ll-tetradecatrien-2-one, respectively (10). They are stereoisomers to each other, compound A having the same partial structure and configuration as that of a u-3 fatty acid. 

Selenoesters are effective radical precursors which can afford aldehydes by direct reduction with reagents such as Bu3SnH, or decarbonylated (nor-aldehyde) products. For example, Stojanovic and Renaud described the decarbonylative reduction of phenylse-lenoester (73) during their synthetic investigations (equation 44)280. Similarly, Alcaide and his associates utilised decarbonylative reduction of a phenylselenoester during their... 

We are well aware that this discussion of the electrode material and its role in electro-organic chemistry is severely limited, both with respect to the number of examples quoted and to the number of possible factors involved. However, we think that the mere fact that hardly any synthetic investigations dealing with the problem have adequately characterized the surfaces of the electrode materials used gives us a good excuse for refraining from such a discussion. Let us first get the experimental facts on this point ... 

Reaction 5. Another aspect of the reaction chemistry of Mn(III) is demonstrated by the classic kinetic studies of the decomposition chemistry of manganese (III) oxalate complexes (35, 36). These studies derive from an earlier discussion of the synthesis of manganese (III)-oxalate compounds (37). A similar set of kinetic and synthetic investigations, have been summarized for the manganese (III )-malonate complexes (38, 39). Both sets of studies confirm that Mn(III) has a particularly strong... 

The photochemical behavior of enamines and their derivatives has been the subject of extensive mechanistic and synthetic investigations. The goal of this chapter is to summarize the photochemistry of enamines as well as enamides, enaminones, en-amidones and enaminonitriles, with particular emphasis on the application of the photochemistry of these chromophores in the synthesis of natural products. 

The potential for salicylihalamide A to become a tool for the study of V-ATPases has led to a number of synthetic investigations including total syntheses by live groups, formal total syntheses by... 

In contrast, synthetic investigations using PLD have been quite promising. h32 Recent studies of Mn cZni cFe204 have shown that crystalline films can be prepared on (100) oriented MgO substrates. Because the physical properties (e.g. resistivity and saturation magnetization) of this ferrite depend... 

It was our Initial aim to develop a basic oligomer or family of oligomers that. In suitably formulated systems, were relatively unaffected by the usual Inhibiting action of molecular oxygen. It was fortunate that In the early stages of the synthetic investigations such materials were obtained. Consequently, these newly synthesized oligomer structures became the basis for the Uvimer resins. Variants on the basic structures were later developed to obtain specific end-use properties. 

Although the completion of the natural product synthesis has not been published by the authors, their work comprises a very detailed synthetic investigation concerning the assembly of the ABC framework. It also served to familiarize the chemical community as to the challenges associated with the synthesis of these natural products. 

This synthetic investigation confirmed the structure of the metabolite by comparison of fast atom bombardment-mass spectrometry (FAB-MS) spectra for the natural and synthetic cyclostellettamine C and for the monomeric synthetic compound 80 obtained by cyclization as indicated in Fig. (27). Additional confirmation came by comparing the bioactivities shown by synthetic dimer 55, mono-pyridinium 80 and natural cyclostellettamine C as antagonist agents for muscarinic receptors [43]. 

Wender, P. A., Smith, T. E. Transition metai-cataiyzed intramoiecuiar [4 + 2] cycioadditions mechanistic and synthetic investigations. Tetrahedron 1998, 54,1255-1275. 

The emphasis is placed on the analytic and synthetic investigations which have helped to elucidate some of the classical problems of the chemistry of polycyclic substances which occur in the vegetable kingdom. Such special topics have been selected as are of the greatest intrinsic interest, an interest perhaps most reliably indicated by the number and length of memoirs concerned with their study. The availability of am author who has worked intensively on some aspect of the subject and the association of the present writer with some one of its facets have also been factors in the choice. As far as possible the original literature has been consulted, and it is hoped that these books will be of interest to students and afford both stimulus and help to those engaged in further research. 

As mentioned above, the twin drug 72 (Fig. 19) was also prepared from naltrexone (1) and showed s receptor antagonist activity [88], In the course of the synthetic investigation of 72, we unexpectedly obtained a triplet drug 73 with a 1,3,5-trioxazatriquinane skeleton (red color in Fig. 19). 

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