Chloride, benzyl reaction with amines

The benzylation of a wide variety of aHphatic, aromatic, and heterocycHc amines has been reported. Benzyl chloride is converted into mono-, di-, and tribenzyl amines by reaction with ammonia. Benzylaniline [103-32-2] results from the reaction of benzyl chloride with aniline. Reaction with tertiary amines yields quaternary ammonium salts with trialkylpbospbines, quaternary phosphonium salts and with sulfides, sulfonium salts are formed. 

Reaction of dibenzylamine with ethylene oxide affords the amino alcohol, 82. Treatment of that product with thionyl chloride gives the a-sympathetic blocking agent, dibenamine (83). (Condensation of phenol with propylene chlorohydrin (84) gives the alcohol, 85. Reaction with thionyl chloride affords the chloride (86). Use of the halide to alkylate ethanolamine affords the secondary amine (87). Alkylation of this last with benzyl chloride... 

Poly (ethylene oxide) macromonomers72 761 are made in a similar way, as the alkoxide end group is reactive enough towards benzylic halides. With methacryloyl chloride, side reactions are involved. It is better to first protonate the PEO, and then to have it react with methacryloyl chloride in the presence of some triethyl amine. One can also react co-hydroxy polyethylene oxide) with methacryloyl imidazole, or with methacrylic acid in the presence of dicyclohexyl carbodiimide (DCCf)77). 

It is worth mentioning at this point that according to Normant et al. (1975) simple polyamines such as tetramethylethylenediamine (TMEDA) are even more active than [2.2.2]-cryptand in the benzylation of acetates in acetonitrile under liquid-solid conditions. These authors suggested that the activity was due to salt solubilization by cation complexation and not to formation of a quaternary ammonium ion since the latter showed no activity. This statement, however, is not in line with the results of Cote and Bauer (1977), who were unable to detect any interaction between K+ and TMEDA in acetonitrile. Furthermore, Vander Zwan and Hartner (1978) found Aliquat 336 (tricaprylylmethylammonium chloride) to be almost as effective as TMEDA in this reaction (Table 30). It might well be, however, that in amine-catalysed benzylation reactions the quaternary salt formed in situ acts both as a reactant and as a phase-transfer catalyst, since Dou et al. (1977) have shown that the benzyltriethylammonium ion is a powerful benzylation agent. 

Acid-treated clays Alcylation reactions (e.g. of benzene with benzyl chloride) Dimerization reactions (e.g. of a-methylstyrene) Etherification reactions (e.g. of ferf-butanol with methanol) Condensation reactions (e.g. of cyclohexanone) Separation of close boiling aromatic amines Separation of isomers of xylene... 

Thenyl chloride is more reactive than benzyl chloride. The rates of formolyses (ki x 104s-1) in 20% dioxane at 20 °C are as follows (75H(3)l) benzyl chloride, 0.85 2-thenyl chloride, 1.51 and furfuryl chloride, 695.0. The rates of reaction with various amines also increase in the same order. Normal replacement of the chlorine in 2-thenyl chloride by CN takes place in 30% aqueous MeCN with NaCN or KCN (conditions under which an abnormal product is exclusively formed with furfuryl chloride). 

With phenols either the phenolic nr nuclear hydrogens can react lo give benzylaryl ether or benzylated phenols. Reaction with NaCN gives benzyl cyanide (phenylacelonitrile) with aliphatic primary amines the product is (he N-alkylbenzylamine. and with aromatic primary amines N-benzylaniline is formed. Benzyl chloride is converted 10 butyl benzyl phlhalatc plasticizer and other chemicals. 

Alkyl halides with (3-hydrogens generally undergo only elimination reactions under the conditions of the vinyl substitution (100 C in the presence of an amine or other base). Exceptions are known only in cases where intramolecular reactions are favorable. Even alkyl halides without (3-hydrogens appear not to participate in the intermolecular alkene substitution since no examples have been reported, with the exception of reactions with benzyl chloride and perfluoroalkyl iodides. 

It is difficult to anticipate the optimum activation time for the oxidation of a certain alcohol. Hindered alcohols are expected to require more than 15 min. On the other hand, a prolonged activation time, although not deleterious for the oxidation of many alcohols, whose corresponding alkox-ydisulfonium chlorides are stable, may promote side reactions, particularly in allylic, benzylic and propargylic alcohols. In such alcohols, it may be advisable to use a very short activation time at a very low temperature, followed by a prolonged reaction with an amine at low temperature. 

Catalytic amounts of tin(II) chloride have been found to give good yields (72-86%) of the trans-amino alcohols when oxiranes have been treated with aromatic amines in acetonitrile at room temperature.27 Only the reaction with styrene oxide was regiospe-ciflc with the amine adding to the benzylic carbon of the epoxide ring. 

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