Halides as reagent

Catalyst consisting of a solid olefin polymer, BF3, and an organomagnesium halide as reagent Acid-treated clay catalysts... 

Halide-based ionic liquids are simple to prepare. Conventionally, they are synthesized by reacting heterocyclic starting materials, for example N-methylimidazole, pyridine, or thiazole, with an appropriate alkyl halide in a nonpolar solvent, for example toluene (Scheme 7.1). The reactions can be also performed using a large excess of the alkyl halide as reagent and solvent. The reactions usually take between 3 and 72 h to reach completion. Symmetrical N,N -disubstituted imidazolium halide... 

Fontana, A., and E. Scoffone Sulfenyl Halides as Reagents in Peptide and Protein Chemistry. Mechanisms of Reactions of Sulfur Compounds (N. Kharasch, Ed.), Intra-Science Res. Foundation, Santa Monica, Calif. 4, 15-24 (1969). 

Alkyl mercuric halides. Grignard reagents, prepared from alkyl halides, react with a mercuric halide that contains the same halogen as the reagent to form alkyl mercuric halides ... 

Ruonnated carboxylic anhydrides and acyl halides as common acylating reagents to convert amines to amides and to acy late suitable heterocyclic nitiogen atoms have already been described in the first edition [10] Like in the acylation at oxygen, much synthetic activity was concentrated m the past few years on the denvatization of biomolecules by fluoroacylation reactions, that is, tnfluoroacetylation of amino sugars,... 

In previous papers1,2 we described reactivity studies of cationic isobutylene polymerization using r-butyl halide initiators, alkylaluminum coinitiators and methyl halide solvents. The effects of these reagents as well as temperature on the overall rate of polymerization and polyisobutylene (PIB) yield were studied and reactivity orders were established. These results were explained by a modified initiation mechanism based on an earlier model proposed by Kennedy and co-workers3,4. This paper concerns the effects of f-butyl halide, alkylaluminums and methyl halide, as well as temperature and isobutylene concentration on PIB molecular weights. 

When iodine is the reagent, the ratio between the reactants is very important and determines the products. A 1 1 ratio of salt to iodine gives the alkyl halide, as above. A 2 1 ratio, however, gives the ester RCOOR. This is called the Simonini reaction and is sometimes used to prepare carboxylic esters. The Simonini reaction can also be carried out with lead salts of acids." A more convenient way to perform the Hunsdiecker reaction is by use of a mixture of the acid and mercuric oxide instead of the salt, since the silver salt must be very pure and dry and such pure silver salts are often not easy to prepare. 

Where a reagent is starred, the star indicates the atom that accepts electrons from, or donates electrons to, the substrate as the case may be. No clear distinction can necessarily be made between what constitutes a reagent and what a substrate, for though N02, OH, etc., are normally thought of as reagents, the carbanion (41) could, at will, be either reagent or substrate, when reacted with, for example, an alkyl halide. The reaction of the former on the latter is a nucleophilic attack, while that of the latter on the former would be looked upon as an electrophilic attack but no matter from which reactant s standpoint a reaction is viewed, its essential nature is not for a moment in doubt. 

Heterocyclic phosphines 32 were prepared from base-induced condensation of a secondary 1,8-diamino-naphthalene with phosphorus trichloride (the corresponding As- and Sb-analogues were obtained analogously) and converted into cyclic phosphenium cations 33 by Lewis acid promoted halide abstraction using GaCl3 or trimethylsilyl triflate as reagents (Scheme 18) [15, 92],... 

Haloperoxidases act as halide-transfer reagents in the presence of halide ions and hydrogen peroxide. In the first step, the halide ion is oxidized to a halonium-ion carrier, from which the positive halogen species is then transferred to the double bond. In an aqueous medium, the intermediary carbocation is trapped and racemic halohydrins are formed (Eq. 7). Selective examples of CPO-cata-lyzed formation of halohydrins are given in Table 9. In CPO-catalyzed reaction. 

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