Chloromethyl with amines

Weak Base Anion Exchangers. Both styreoic and acryHc copolymers can be converted to weak base anion-exchange resias, but differeat syathetic routes are aecessary. Styreae—DVB copolymers are chloromethylated and aminated ia a two-step process. Chloromethyl groups are attached to the aromatic rings (5) by reactioa of chloromethyl methyl ether [107-30-2] CH2OCH2CI, with the copolymer ia the preseace of a Friedel-Crafts catalyst such as aluminum chloride [7446-70-0], AlCl, iroa(III) chloride [7705-08-0], FeCl, or ziac chloride [7646-85-7], ZaCl. ... 

It has been proposed that the ring-expansion reaction is initiated by attack of the base at position 2 of the quinazoline oxide, which is rendered electron deficient by the inductive effect of the (V-oxide group. In fact, 2-(Chloromethyl)quinazolines, compounds that lack this feature, react with amines to give only simple substitution products.1133... 

The scope of the chemistry outlined in Figure 16.21 can be further expanded by including other acids susceptible to irreversible reaction with a primary amine. These can be other halocarboxylic acids, such as (chloromethyl)benzoic acids, or acrylic acid, which reacts with amines to yield N-substituted (1-alanines. N-Substituted oligo((5-ala-nines) have been successfully prepared by sequentially acylating support-bound amines with acrylic acid and then performing a Michael addition with primary amines [239]. 

Based on these reactivities various derivatives of carbenes, such as the aminocarbene 238, are prepared by displacement of the OR group in 237 with amine via addition elimination, analogous to transesterification [74,75], As an example the carbanion 240, generated by deprotonation of 239, attacks ethylene oxide to give the lactone equivalent 241, which is further alkylated by chloromethyl methyl ether, again at the -position. Finally the oc-methylene-y-lactone 242 is obtained by oxidative demetallation with a Ce(TV) salt [76],... 

The limitations of this approach can be seen in the reaction of a saturated solution of ammonia in 90% ethanol with ethyl bromide in a 16 1 molar ratio, under which conditions the yield of primary amine was 34.2% (at a 1 1 ratio the yield was 11.3%). Alkyl amines can be one type of substrate that does give reasonable yields of primary amine (provided a large excess of NH3 is used) are a-halo acids, which are converted to amino acids. A-Chloromethyl lactams also react with amines to give good yields to the A-aminomethyl lactam. Primary amines can be prepared from alkyl halides by 10-43, followed by reduction of the azide (19-32), or by the Gabriel synthesis (10-41). 

The preparation and properties of SDVB copolymers have been described in the preceding section. SDVB copolymers can be converted to anion-exchange resins through chloromethylation with monochlorodimethyl ether using a Friedel-Crafts catalyst followed by treatment with different amines 133 147>. Anderson133) studied in detail the influence of various Friedel-Crafts catalysts for the chloromethylation of SDVB copolymers. A chlorosulfonic acid — methylal mixture has also been used for the chloromethylation of SDVB copolymers 148-152). 

The anion-exchange group is introduced into the polymer by chloromethylation and amination with trimethylamine according to the following reaction scheme ... 

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