Alkylating agent alcohols

Alcohol Alkylating agent Reaction conditions % yield... 

Disconnection on either side of the alkyne leads us back to a bromo-alcohol alkylating agent. In the synthesis of the pheromone, it turned out to be best if the hydroxyl group was protected as its THP ether. You should be able to think of other alkylation-type reactions that you have met that proceed reliably and therefore provide a good basis for a disconnection—the alkylation of enolates of esters or ketones, for example (Chapter 26). 

The above is a general procedure for preparing trialkyl orthophosphates. Similar yields are obtained for trimethyl phosphate, b.p. 62°/5 mm. triethyl phosphate, b.p. 75-5°/5 mm. tri-n-propyl phosphate, b.p. 107-5°/5 mm. tri-Mo-propyl phosphate, b.p. 83-5°/5 mm. tri-wo-butyl phosphate, b.p. 117°/5-5 mm. and tri- -amyl phosphate, b.p. 167-5°/5 mm. The alkyl phosphates are excellent alkylating agents for primary aromatic amines (see Section IV,41) they can also be ua for alkylating phenols (compare Sections IV,104-105). Trimethyl phosphate also finds application as a methylating agent for aliphatie alcohols (compare Section 111,58). 

Other catalysts which may be used in the Friedel - Crafts alkylation reaction include ferric chloride, antimony pentachloride, zirconium tetrachloride, boron trifluoride, zinc chloride and hydrogen fluoride but these are generally not so effective in academic laboratories. The alkylating agents include alkyl halides, alcohols and olefines. 

With the more acidic 2-acetamido-4-R-thiazoles. using the weaker base NaOH as condensation agent, a mixture of ring (45) and exocyclic N-alkylation (46) may be observed (Scheme 33) (121). Reaction of 2-acetamido-4-methylthiazole in alcoholic sodium ethoxide solution with a variety of alkylating agents has been reported (40-44). 

The hydroxyl groups can be alkylated with the usual alkylating agents. To obtain aryl ethers a reverse treatment is used, such as treatment of butynediol toluenesulfonate or dibromobutyne with a phenol (44). Alkylene oxides give ether alcohols (46). 

The cychc haUdes can be converted to discrete substitution products by reaction with amines, alcohol, or alkylating agents. For example, (NPCl ) reacts with ammonia to form (NP(NH2)2)3 [13597-92-7] withy -NaOCgH CH to form (NP(OCgH4CH2)2)3 [27122-73-2] and with CH MgCl to form (NP(CH3)2)3 [6607-30-3]. Among the cychc members, the trimeric haUdes are the most inert toward substitution and tetrameric haUdes are the most active. 

Ketones and alcohols are frequently used as alkylating agents Ketones often condense with two molecules of an aromatic compound through an alcohol intermediate [79, 20, 21] T,r,I -Trifluoroacetophenone and aniline afford 1,1 bis(4-ammophenyl) 1 phenyl 2,2,2-trifluoroethane [27] (equation 14)... 

The required xanthates 1 can be prepared from alcohols 5 by reaction with carbon disulfide in the presence of sodium hydroxide and subsequent alkylation of the intermediate sodium xanthate 6. Often methyl iodide is used as the alkylating agent ... 

Meerwein s reagent, triethvloxonium tetrafluoroborate, is a powerful ethylating agent that converts alcohols into ethyl ethers at neutral pH. Show the reaction of Meerwein s Teagent with cyclohexanol, and account for the fact that trialkyloxonium salts are much more reactive alkylating agents than alkyl iodides. 

N -Ethyl-jK-toluidine has been obtained by passing m-toluidine and ethyl alcohol over a catalyst at high temperatures,1 and by the use of ethyl />-toluenesulfonate 2 as an alkylating agent. The present method of purification is a modification of a general procedure for secondary amines developed by Diepolder.3... 

Ether carboxylates are used not only in powdered detergents but in liquid laundry detergents for their hard water stability, lime soap dispersibility, and electrolyte stability they improve the suspension stability and rheology of the electrolyte builder [130,131]. Formulations based particularly on lauryl ether carboxylate + 4.5 EO combined with fatty acid salt and other anionic surfactants are described [132], sometimes in combination with quaternary compounds as softeners [133,163]. Ether carboxylates show improved cleaning properties as suds-controlling agents in formulations with ethoxylated alkylphenol or fatty alcohol, alkyl phosphate esters or alkoxylate phosphate esters, and water-soluble builders [134]. 

Oxonium ions are excellent alkylating agents, and ethers can be conveniently prepared by treating them with alcohols or phenols. Quaternary ammonium salts can sometimes also be used. ... 

This chapter compares the reaction of gas-phase methylation of phenol with methanol in basic and in acid catalysis, with the aim of investigating how the transformations occurring on methanol affect the catalytic performance and the reaction mechanism. It is proposed that with the basic catalyst, Mg/Fe/0, the tme alkylating agent is formaldehyde, obtained by dehydrogenation of methanol. Formaldehyde reacts with phenol to yield salicyl alcohol, which rapidly dehydrogenates to salicyladehyde. The latter was isolated in tests made by feeding directly a formalin/phenol aqueous solution. Salicylaldehyde then transforms to o-cresol, the main product of the basic-catalyzed methylation of phenol, likely by means of an intramolecular H-transfer with formaldehyde. With an acid catalyst, H-mordenite, the main products were anisole and cresols moreover, methanol was transformed to alkylaromatics. 

Apart from the alkyl halide-Lewis acid combination, two other sources of carbo-cations are often used in Friedel-Crafts reactions. Alcohols can serve as carbocation precursors in strong acids such as sulfuric or phosphoric acid. Alkylation can also be effected by alcohols in combination with BF3 or A1C13.37 Alkenes can serve as alkylating agents when a protic acid, especially H2S04, H3P04, and HF, or a Lewis acid, such as BF3 and A1C13, is used as a catalyst.38... 

However, pMBCl 42 has a thermal stability issue and is expensive (Aldrich price 25 g for 69.90 the largest bottle). On the other hand, pMBOH 43 is stable and economically viable (Aldrich price 500 g for 84.90 the largest bottle). It was found that mono-N-alkylation of 36 proceeded well by slow addition (over 3 h) of 43 to a solution of 36 in acetonitrile in the presence of a catalytic amount of acid (p-TsOH) at 70 °C, as shown in Scheme 1.16. Slow addition of alcohol 43 minimized the self-condensation of 43 to form symmetrical ether 44, which was an equally effective alkylating agent. The product 41 was then directly crystallized from the reaction mixture by addition of water and was isolated in 90% yield and in >99% purity. A toluene solution of 41 can be used for the next reaction without isolation but the yield and optical purity of the asymmetric addition product were more robust if isolated 41 was used. In general, the more complex the reaction, the purer the starting materials the better. 

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