Methyl iodide alkylation with

All lation. Alkylating agents such as diaLkyl sulfates and alkyl hahdes react with ahphatic amine oxides to form trialkylalkoxyammonium quaternaries. For example (33), methyl iodide reacts with trimethyl amine oxide to form trimethylmethoxyammonium iodide... 

Deghenghi et al studied the reductive alkylation of 16-dehydropregneno-lone acetate in ammonia-tetrahydrofuran using excess lithium and alkyl iodides. Alkylation with methyl iodide followed by reacetylation of the 3-hydroxyl group affords 17a-methylpregnenolone acetate in 20% yield after purification by column chromatography. Ethyl iodide affords the 17a-ethyl analog in 40% yield, but n-propyl iodide affords the 17a-propyl compound in only a 12 % yield. 

Inclusion of basic nitrogen in the p-position is also compatible with antiinflammatory activity in this series. Nitration of phenylacetic acid (27) affords 28. Methyl iodide alkylation of the enolate prepared from 28 using two equivalents of sodium hydride gives 29. This appears to involve an Ivanov intermediate (28a). Catalytic reduction of the... 

Methyl iodide, reactions with dialkyl-amino-thiazoles, 32. See also Alkylation 4-Methylthiazole, preparation of, from Na/NH3 reduction of 4-methyl-A-4-thiazoline-2-thione, 397 2-Methylthio-3-methylthiazolium salts, as catalyst for methylthiothiazole rearrangement, 406 Methylvinylketone, reaction of, with... 

The results are summarized in Table 2. With the exception of methyl iodide, alkyl halides did not react, but alkyl trifluoromethanesulfonates could be employed instead. After hydrolysis and work-up, the corresponding diastereomeric adducts 7 and 8 were isolated by column chromatography. In several cases, the diastereomers were separated. The diastereomeric excesses were determined using H NMR, or by H.P.L.C., or by weighing the isomers after separation. 

In the robust, very easily accessible cationic complexes [FeCp(arene)][PF6]10 (Cp = h5-cyclopen-tadienyl), the benzyhc protons are more acidic than in the free arene because of the electron-withdrawing character of the 12-electron CpFe+ moiety. For instance, FeCp(C6Me6) Pl6 is more acidic by 15 pKa units (pKa = 28 in DMSO) (DMSO = dimethyl sulfoxide) than in the corresponding free arene (pKa = 43 in DMSO). Asa result, these complexes are much more easily deprotonated than the free arene.11 This key proton-reservoir property led us to synthesize stars and dendrimers in an easy way.12 Indeed, reaction of [FeCp(C6Me6)][PF6], with excess KOH (or i-BuOK) in THF (THF = tetrahydrofuran) or DME (DME = 1,2-dimethoxyethane) and excess methyl iodide, alkyl iodide, allyl bromide, or benzylbromide results in the one-pot hexasubstitution (Scheme 11. la).5,13,14 With allyl bromide (or iodide) in DME, the hexaallylated... 

The reactivity of the normal alkyl halides varies with the halogen and with the alkyl group the more reactive are those with the smaller number of carbon atoms. The iodides are the most reactive, the chlorides the most inert. Methyl iodide is much used in organic syntheses, as it reacts readily with many substances and serves as a means of introducing the methyl group into such compounds. An alcoholic solution of methyl iodide reacts with a similar solution of silver nitrate in the cold, and silver iodide is formed. With ethyl iodide the reaction proceeds much more slowly, and with the higher alkyl iodides the application of heat is necessary to bring about reaction. 

Methyl -tolyl sulfone has been prepared by oxidation of methyl -tolyl sulfide with hydrogen peroxide or ruthenium tetroxide, by alkylation of sodium -toluenesulfinate with methyl iodide or with methyl potassium sulfate, by decarboxylation of -tolylsulfonylacetic acid, by thermal decomposition of tetramethylammonium -toluenesulfinate, " by reaction of cw-bis-(j >-tolylsulfonyl)-ethene with sodium hydroxide (low yield), by the reaction of methanesulfonyl chloride with toluene in the presence of aluminum chloride (mixture of isomers)by... 

Unbranched and substituted alkyl carbamates, such as 146 or 147 [62,88] do not cause any problems in the deprotonation step. Deuteration (with CH3OD or dissolved CH3CO2D), methoxycarbonylation (gaseous CO2, followed by diazomethane after work-up or methyl chloroformate), alkylation with methyl iodide, substitution with trialkylsilyl chlorides, trialkyltin chlorides and even tri-methyllead bromide, addition onto aldehydes and ketones, and acylation with acid chlorides or esters, all proceed without difficulties. Although a ketone is formed in the latter reactions, which is at least 15 orders of magnitude thermodynamically more acidic than the alkyl carbamate we never observed enolate formation, racemization or epimerization - with one exception it occurred to some extent after formylation with formate esters [79]. 

Methyl iodide alkylates this delocalized anion on position a, generating a ketone with p,y-unsaturation. 

The chemistry of protoberberine-acetone adducts has been reconsidered within the context of ease of alkylation and oxidation. Naruto and his students have reported that reactive alkyl halides such as methyl iodide react with berberine-acetone to yield, in addition to the expected berberine and 13-methylberberine, the bridged derivatives 38 and 39. ... 

For example, in a typical process, methyl iodide reacts with ethyl dimethyl phosphite to produce iodomethane and ethyl methyl methylphosphonate. Presumably, the alkylation occurs on phosphorus and the liberated iodide anion then subsequently attacks the methyl group and displace the phosphonate (Scheme 10.50) in a Michaelis-Arbuzov reaction. 

The hemiacetal hydroxyl is more readily alkylated than the true alcoholic hydroxyls and can be methylated selectively by treatment of the sugar with one equivalent of the Haworth reagent (see Chapter IV). When the hemiacetal hydroxyl of an aldohexose is blocked, some selective methylation of the hydroxyls at carbons 2 and/or 6 may be achieved with alkali and methyl iodide 22), With starch and cellulose, it has been reported 23) that alkali and methyl iodide lead preponderantly to the 2-0-methyl derivative, the hydroxyl group at carbon 6 presumably being rendered less... 

---