Salts as intermediates

The imidazolium effect is also used on the following route, where N-arylsulfonyl-N -methy limidazolium salts as intermediates are aminolyzed easily in aqueous solution because hydrolysis is much slower [19]... 

Selective chlorination or bromination of the 5 -hydroxyl group in unprotected D-ribonucleosides has been achieved75 by treatment with thionyl chloride or thionyl bromide, respectively, in hexamethyl-phosphoric triamide at room temperature for 10-15 hours the 5 -deoxy-5 -halogeno derivatives of cytidine and adenosine have been prepared in this way. The reactions presumably occur by way of alkoxyphosphonium salts as intermediates.78... 

A. Formation through Crystalline Acid Salts as Intermediates. 55... 

Thieno[3,4-c]pyridines have also been prepared in an acylation-cyclization reaction from 2,5-disubstituted 3-acetonylthiophenes on treatment with acetic anhydride and perchloric acid via the thieno[3,4-c]pyrylium salts as intermediates (c/. Scheme 66) (72MIP31700, 75CHE551). 

Expanding on established chemistry using iV-acylpyridinium salts as intermediates for the preparation of iV-acyldihydropyridines and dihydropyridones, Wanner and co-workers examined a method using a bicyclolactone... 

Porphobilinogen and Studies of Its Biosynthesis, ft. Neier. Synthesis and Cycloaddition Reactions of Iso-Condensed Heteroaromatic Pyrroles, C. K. Sha. Azacyclopentadienyl Metal Compounds Historical Background and Recent Advances, C. Janiak and N. Kuhn. Recent Developments in the Synthesis of Marine Pyridoacridine Alkaloids, A. M. Echavar-ren. Alkaloid Synthesis Using 1-Acylpyridinium Salts as Intermediates, D. L. Comins and S. P. Joseph. Index. S S... 

Ferrini and Marxer65 have recently shown that vinylene carbonate reacts with primary amides, in the presence of polyphosphoric acid, to yield 2-substituted oxazole derivatives. Yields are low (2-34%), and phenoxy- and phenyl-acetamide, p-methylbenzamide, and salicylamide do not give oxazole derivatives. Although the reaction has been interpreted according to Scheme 3, the nucleophilic attack of a nitrile molecule (from the amide dehydration), with a nitrilium salt as intermediate (Scheme 4), cannot be excluded.06... 

The final conclusion is drawn as follows cryptands can be prepared in very good yield by the high-pressure double-quaternization method using highly polar solvents like dimethylformamide. The corresponding bisquatemary salts as intermediates need not to be isolated before demethylation to give the cryptands. 

The reaction of a 2,4-dialkoxypyrimidine with a halogenose (or an alkyl halide) has been assumed by Hilbert30 to proceed via a quaternary salt as intermediate. Thus, the stable l-methyl-2-methoxy-4-... 

Three different crystallographic modifications of the anhydrous salt can be prepared. The decompositions of these reactants (430 to 506 K) exhibit sigmoid a-time curves which have been attributed [11] to a chain-type process through the formation of the volatile and unstable copper(I) salt as intermediate. This was indicated by the formation of a copper mirror on the containing vessel. Schuffenecker et al. [11] identified the rate limiting step as electron transfer. Erofeev et al. [10,12] showed that the kinetic behaviours of two forms of the salt were different. This was ascribed to variations in the dispositions of copper ions in the crystal structures of the reactants. 

How would you prepare the following compounds from phenylamine (aniline) using arenediazonium salts as intermediates ... 

Think about benzenediazonium salts as intermediates likely to be useful in these. 

Preparation of mixed metal oxide precursors for SOFCs represents a very complex chemical process in which a metal may form oxides, hydroxides, and various complex basic salts as intermediates. Understanding of the relationship between the calcination process, the final composition, particle sizes, sinterability, and SOFC performance for nickel, copper and cobalt-based anode materials is a necessity [26]. 

N-subst. 21, 515 a-ketocarboxylic acid thio-amides 19, 378 suppl. 21 N-Acylcyclimmonium salts as intermediates 21, 821... 

Starting with benzene or toluene, outline a synthesis of each of the following compounds using diazonium salts as intermediates. (You need not repeat syntheses carried out in earlier parts of this problem.)... 

Molecular Orbital (M.O.) studies of reaction intermediates have been reported for the rearrangement of l-propenethiol, for the addition of sulphenyl halides to ethylene (sulphurane rather than thiiranium salt as intermediate), and for similar additions to alkynes (thiirenium ions or /ff-alkylthiovinyl cations, depending upon the substituents). Electronic effects of substituents on energy levels of orbitals of... 

Conversions of thiols into disulphides and thiolsulphonates through their reactions with DMSO and TFAA involve the alkylthio-sulphonium salts as intermediates, the thiolsulphonate arising when water is present/ Bis-(arylthio)sulphonium salts are effective reagents for the conversion of alkenes into thiirans/ ... 

Husson H-P 1980 Iminium salts as intermediates in the biomimetic syntheses of indole alkaloids. In Phillipson J D, Zenk M H (eds) Indole and biogenetically related alkaloids. Academic Press New York, 185-200... 

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