Iodides secondary

Tellurolates can be easily alkylated and, under suitable conditions, arylated to produce symmetrical and unsymmetrical diorgano tellurium (p. 387) and alkyl aryl tellurium (p.409) compounds. Examples of alkylating agents are primary ra-alkyl bromides and iodides, secondary alkyl bromides, dimethyl sulfate, allyl bromides6-9, chlorodifluoro-methane10, dichloroiodomethane11, methyl co-bromoalkanoates12, n, 3-halopropanoic... 

Most Williamson reactions proceed by the 8 2 mechanism, but there is evidence (see p. 446) that in some cases the SET mechanism can take place, especially with alkyl iodides. Secondary alcohols have been converted to the corresponding methyl ether by reaction with methanol in the presence of ferric nitrate nonahy-drate. Vinyl ethers have been formed by coupling tetravinyl tin with phenols, in the presence of cupric acetate and oxygen. " The palladium-catalyzed coupling of vinyl triflates and phenols has also been reported. ... 

Tertiary and cyclic alkyl halides (cyclohexyl iodide), secondary alkyl chlorides and primary and secondary tosylates cannot be used in these intermolecular alkylations. This is also the case with dibro-moethane and 2-bromo-2-nitropropane, which both lead instead to a,3-dithianylalkanes resulting from the oxidative coupling of the carbanion. 

OCtyl iodide. (caprylic iodide secondary capryl iodide). Cl I3(CI I2)3CI IICII3. 

R -j-CHj—OR, Equation 4.13). The reaction is also competitive for many nitroalkanes, alkyl iodides, secondary and tertiary alkyl bromides, and tertiary alkyl chlorides, but not for RCH2—Y compounds of higher C—Y bond strengths, such as unbranched alkanols and alkyl chlorides for these [(M — HY)" ] > [(M — Y) ] as in Equation 4.23 (see Section 4.9). As is expected for an inductive effect, the influence of the charge site can affect a bond that is farther away if it has more polarizable electrons the loss of CH2CI is much larger in Equation 4.24 than in 4.23. 

After the primary step in a photochemical reaction, the secondary processes may be quite complicated, e.g. when atoms and free radicals are fcrnied. Consequently the quantum yield, i.e. the number of molecules which are caused to react for a single quantum of light absorbed, is only exceptionally equal to exactly unity. E.g. the quantum yield of the decomposition of methyl iodide by u.v. light is only about 10" because some of the free radicals formed re-combine. The quantum yield of the reaction of H2 -f- CI2 is 10 to 10 (and the mixture may explode) because this is a chain reaction. 

Place a mixture of 0-5 g. of finely powdered thiourea, 0-5 g. of the alkyl halide and 5 ml. of alcohol in a test-tube or small flask equipped with a reflux condenser. Reflux the mixture for a j)eriod depending upon the nature of the halide primary alkyl bromides and iodides, 10-20 minutes (according to the molecular weight) secondary alkyl bromides or iodides, 2-3 hours alkyl chlorides, 3-5 hours polymethy lene dibromides or di-iodides, 20-50 minutes. Then add 0 5 g. of picric acid, boil until a clear solution is obtained, and cool. If no precipitate is obtained, add a few drops of water. RecrystaUise the resulting S-alkyl-iso-thiuronium picrate from alcohol. 

It consists in treating a solution of sodium iodide in pure acetone with the organic compound. The reaction is probably of the S 2 type involving a bimolecular attack of the iodide ion upon the carbon atom carrying the chlorine or bromine the order of reactivities of halides is primary > secondary > tertiary and Br > Cl. 

Iodoallenes can also be prepared in reasonable yields by treatment of secondary acetylenic alcohols with triphenylphosphite-methyl iodide, using DMF as a solvent. One of the -OPh groups is probably first replaced by the propargyloxy group. This intermediate subsequently undergoes attack by iodide on the terminal acetylenic carbon atom, affording the iodoallene in a 1,3-substitution ... 

When It IS necessary to prepare secondary alkyl halides with assurance that no trace of rearrangement accompanies their formation the corresponding alcohol is first converted to its p toluenesulfonate ester and this ester is then allowed to react with sodium chloride bromide or iodide as described m Section 8 14... 

The alkyl halide can be primary secondary or tertiary Alkyl iodides are the most reac tive followed by bromides then chlorides Fluorides are relatively unreactive... 

Methyl and primary alkyl halides especially iodides work best Elimination becomes a problem with secondary and tertiary alkyl halides... 

The reactions of trialkylboranes with bromine and iodine are gready accelerated by bases. The use of sodium methoxide in methanol gives good yields of the corresponding alkyl bromides or iodides. AH three primary alkyl groups are utilized in the bromination reaction and only two in the iodination reaction. Secondary groups are less reactive and the yields are lower. Both Br and I reactions proceed with predominant inversion of configuration thus, for example, tri( X(9-2-norbomyl)borane yields >75% endo product (237,238). In contrast, the dark reaction of bromine with tri( X(9-2-norbomyl)borane yields cleanly X(9-2-norbomyl bromide (239). Consequentiy, the dark bromination complements the base-induced bromination. 

Finally, secondary arsines can be obtained by the reductive cleavage of diarsines with mercury and hydrogen iodide (49) or with hthium aluminum hydride... 

Cyanopyridazines add ammonia, primary and secondary amines and hydroxylamine to give amidines or amidoximes. Substituted amides, thioamides and carboximidates can be also prepared. With hydrazine, 3-pyridazinylcarbohydrazide imide is formed and addition of methylmagnesium iodide with subsequent hydrolysis of the imine affords the corresponding pyridazinyl methyl ketone. 

F. Analysis for ozone. The analysis is made by passing a definite amount of oxygen through the ozonizer at a selected secondary voltage and then through a neutral 5% solution of potassium iodide. Iodine is liberated,... 

Ammodendrine, C jH oONj, HjO (No. 1, table, p. 116). The base has m.p. 73 °, becomes anhydrous at 70-80°, and then melts at 50-60°, Wd i 0°. The salts are amorphous and deliquescent except the hydriodide B. HI, which forms a crystalline precipitate, m.p. 218-20°, from alcohol, and the perchlorate, m.p. 199-200°. An amorphous A-benzoyl derivative was obtained. With methyl iodide ammodendrine behaves as a secondary base, yielding first A-methylammodendrine hydriodide (a crystalline precipitate, m.p. 183-5°, from a mixture of alcohol and acetone), and at the second stage iV-methylammodendrine methiodide, m.p. 163-5°. On hydrogenation ammodendrine furnishes a dihydro-base, which is hydrolysed into acetic acid and 2 3 -dipiperidyl, C oHjoNj, and must be dZ-A-acetyl-3-a-piperidylpiperidine. Ammodendrine should therefore be acetyltetrahydroanabasine and is of biological interest as the first recorded occurrence of this type of alkaloid in the Leguminoss. ... 

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