Naming alkyl halides

Only symmetric intermolecular thionocarbonates (X—0—CS—-0— X) have been synthesized. They have been produced by treatment of 0-(so-dium thiolthiocarbonyl) derivatives with certain alkyl halides, namely,... 

Foster and Wolfrom, in 1956, encountered an anomalous reaction of methyl 3,4-0-isopropylidene-2-0-(sodium thiolthiocarbonyl)- S-D-arabino-pyranoside (LIX) with certain alkyl halides, namely ethyl iodide, propyl bromide, isopropyl bromide, and ter<-butyl chloride. The expected 2-0-[(alkylthio)thiocarbonyl] esters LX were not formed, but, in each case, bis(methyl 3,4-0-isopropylidene-j8-D-arabinopyranoside) 2-thionocarbonate (VI) was isolated. A probable explanation of this behavior was suggested... 

ALKYL HALIDES Name functional group first, such as chlorine, which would become chloro, fluorine would become fluoro, and so on. Then name the hydrocarbon backbone one carbon would be methane, two carbons ethane, and so on. For exanple, chloro methane. Or name the hydrocarbon backbone first one carbon would become methyl, two carbons ethyl, and so on. Then name the functional group and add ide for an ending. For example, chlorine would become chloride, fluorine would become fluoride, and so on. An example is methyl chloride. 

Most recently the core cross-linking approach was adopted for the preparation of novel nanoassemblies derived from pH-responsive AB diblock copolymers prepared via RAFT (222). Here the A block was the permanently hydrophilic DMA species with the timably hydrophilic/hydrophobic DMBVA forming the B block. In aqueous media, at high pH, these block copolymers form core-shell structures with the DMA residues forming the corona and the DMVBA chains in the core. Addition of a hydrophobic, difimctional, alkyl halide namely 1,4-bisbromomethylbenzene results in this species being sequestered into the hydrophobic core of the micelles where it reactions with the tertiary amine residues via the Menshutkin reaction to yield the core-cross-linked species. Successful core cross-linking was... 

TABLE 6.1 Some Alkyl Halides, Names, and Known Properties... 

The lUPAC rules permit alkyl halides to be named m two different ways called func twnal class nomenclature and substitutive nomenclature In functional class nomencla ture the alkyl group and the halide (fluoride chloride bromide or iodide) are desig nated as separate words The alkyl group is named on the basis of its longest continuous chain beginning at the carbon to which the halogen is attached... 

Nitriles contain the —C=N functional group We have already discussed the two mam procedures by which they are prepared namely the nucleophilic substitution of alkyl halides by cyanide and the conversion of aldehydes and ketones to cyanohydrins Table 20 6 reviews aspects of these reactions Neither of the reactions m Table 20 6 is suitable for aryl nitriles (ArC=N) these compounds are readily prepared by a reaction to be dis cussed m Chapter 22... 

The amines are a group of compounds with the general formula R-NHj, and all the common amines are hazardous. As a class the amines pose more than one hazard, being flammable, toxic, and, in some cases, corrosive. The amines are an analogous series of compounds and follow the naming pattern of the alkyl halides and the alcohols that is, the simplest amine is methyl amine, with the molecular formula of CH NHj. Methyl amine is a colorless gas with an ammonia-like odor and an ignition temperature of 806°F. It is a tissue irritant and toxic, and it is used as an intermediate in the manufacture of many chemicals. Ethyl amine is next in the series, followed by propyl amine, isopropyl amine, butyl amine and its isomers, and so on. 

Reaction of alkyl halides 1 with hexamethylenetetramine 2 (trivial name urotropine) followed by a hydrolysis step, leads to formation of primary amines 3 free of higher substituted amines. This method is called the Delepine reaction, a comparable method is the Gabriel synthesis. 

Enamines 1 are useful intermediates in organic synthesis. Their use for the synthesis of a-substituted aldehydes or ketones 3 by reaction with an electrophilic reactant—e.g. an alkyl halide 2, an acyl halide or an acceptor-substituted alkene—is named after Gilbert Stork. 

This reaction, which is named after W. Williamson, is the most important method for the synthesis of unsymmetrical ethers 3. For this purpose an alkoxide or phenoxide 1 is reacted with an alkyl halide 2 (with R = alkyl, allyl or benzyl). Symmetrical ethers can of course also be prepared by this route, but are accessible by other routes as well. 

The sex attractant given off by the common housefly is an alkene named muscahtre. Propose a synthesis of muscalure starting from acetylene and any alkyl halides needed. What is the IUPAC name for muscalure ... 

Alkyl halides are encountered less frequently than their oxygen-containing relatives alcohols and ethers, but some of the kinds of reactions they undergo—nucleophilic substitutions and eliminations—are encountered frequently. Thus, alkyl halide chemistry acts as a relatively simple model for many mechanistically similar but structurally more complex reactions found in biornolecules. We ll begin in this chapter with a look at how to name and prepare alkyl halides, and we ll see several of their reactions. Then in the following chapter, we ll make a detailed study of the substitution and elimination reactions of alkyl halides—two of the most important and well-studied reaction types in organic chemistry. 

Although members of the class are commonly called alkyl halides, they are named systematically as haloalkanes (Section 3.4), treating the halogen as a substituent on a parent alkane chain. There are three steps ... 

In addition to their systematic names, many simple alkyl halides are also named by identifying first the alkyl group and then the halogen, for example, CH3T can be called either iodomethane or methyl iodide. Such names are well entrenched in the chemical literature and in daily usage, but they won t be used in this book. 

Problem 10,1 j Give IUPAC names for the following alkyl halides ... 

Thomson11 jW Click Organic Interactive to use a web-based palette to draw structures for alkyl halides, based on their IUPAC names. 

Note that the product acid has one more carbon than the starling alkyl halide. An example occurs in the commercial synthesis of fenoprofen, a nonsteroidal antiinflammatory drug, or NSAID, marketed under the trade name Nalton. (See Chapter 15 Focus On.)... 

Thiol (s), 652, 667-668 disulfides from, 668 electrostatic potential map of, 75 from alkyl halides, 667 hybridization of, 20 naming, 667 odor of, 667 oxidation of, 668 pKa of, 604... 

This is not a new reaction. This is just an Sn2 reaction. We are simply using the alkoxide ion (ethoxide in this case) to function as the attacking nucleophile. But notice the net result of this reaction we have combined an alcohol and an alkyl halide to form an ether. This process has a special name. It is called the Williamson Ether Synthesis. This process relies on an Sn2 reaction as the main step, and therefore, we must be careful to obey the restrictions of Sn2 reactions. It is best to use a primary alkyl halide. Secondary alkyl halides cannot be used because elimination will predominate over substitution (as seen in Sections 10.9), and tertiary alkyl halides certainly cannot be used. 

As noted in the preceding section, one of the most general methods of synthesis of esters is by reaction of alcohols with an acyl chloride or other activated carboxylic acid derivative. Section 3.2.5 dealt with two other important methods, namely, reactions with diazoalkanes and reactions of carboxylate salts with alkyl halides or sulfonate esters. There is also the acid-catalyzed reaction of carboxylic acids with alcohols, which is called the Fischer esterification. 

Common names for simple haloalkanes are accepted by the IUPAC => alkyl halides (radicofunctional nomenclature). 

The validity of equation (12) has been checked for several families of alkyl halides for which D and E /x- are known (Ref. 32, see particularly figure 6 therein). It was thus found that for v = 0.1 V s the constant is equal to 0.3 eV at 20°C (expressing D in eV and the potentials in V). Equation (12) was then applied to the approximate determination of unknown BDEs in several series of compounds undergoing dissociative electron transfer, namely, TV-halosultams,32 sulfonium cations,33 vicinal dihalides,34 1,3-dihaloadamantes, 1,4-dihalo-bicyclo[2.2.2]octanes, and l,3-dihalobicyclo[l.l.l]pentanes.35 In the latter case, the mutual influence of the two halogens could be rationalized thanks to the conversion of the peak potential data to bond dissociation energies. 

Alkyl Halides and Triflates to Alkanes. The normal requirements for conversion of alkyl halides (and triflates) to alkanes using organosilicon hydrides are essentially the same as those needed for the reduction of the corresponding alcohols, namely, the substrates must generally be able to serve as precursors to... 

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