Reactions aminoalkylation

The reaction of thioethers with ethyleneimine in the presence of acid yields sulfonium compounds. The reaction is reversible under alkaline conditions (125). Compounds in which double-bonded sulfur can exist in tautomerism with a form having a free SH group, such as thiourea (126,127), thiocarboxyhc acids (128), and thiophosphates (129), react to give aminoaLkylated products. The P-aminoethyl thiocarboxylate rearranges to give the amide. 

Reaction with Selenium Nucleophiles. The reactions of selenium nucleophiles are similar to those of the sulfur nucleophiles selenophosphates can be aminoaLkylated (135). A dihydroselenazine has been obtained by reaction of diethyl ketone, elementary selenium, and ethyleneimine (136). 

Cationic Starches. The two general categories of commercial cationic starches are tertiary and quaternary aminoalkyl ethers. Tertiary aminoalkyl ethers are prepared by treating an alkaline starch dispersion with a tertiary amine containing a P-halogenated alkyl, 3-chloto-2-hydtoxyptopyl radical, or a 2,3-epoxypropyl group. Under these reaction conditions, starch ethers are formed that contain tertiary amine free bases. Treatment with acid easily produces the cationic form. Amines used in this reaction include 2-dimethylaminoethyl chloride, 2-diethylaminoethyl chloride, and A/-(2,3-epoxypropyl) diethylamine. Commercial preparation of low DS derivatives employ reaction times of 6—12 h at 40—45°C for complete reaction. The final product is filtered, washed, and dried. 

Quaternary ammonium alkyl ethers are prepared similarly an alkaline starch is reacted with a quaternary ammonium salt containing a 3-chloto-2-hydtoxyptopyl or 2,3-epoxyptopyl radical. Alternatively, such derivatives can be prepared by simple quaternization of tertiary aminoalkyl ethers by reaction with methyl iodide. Sulfonium (107) and phosphonium (108) starch salts have also been prepared and investigated. Further work has explained the synthesis of diethyl aminoethyl starch (109) as well as the production of cationic starches from the reaction of alkaline starch with... 

The reaction between the photoexcited carbonyl compound and an amine occurs with substantially greater facility than that with most other hydrogen donors. The rate constants for triplet quenching by amines show little dependence on the amine a-C-H bond strength. However, the ability of the amine to release an electron is important.- - This is in keeping with a mechanism of radical generation which involves initial electron (or charge) transfer from the amine to the photoexcited carbonyl compound. Loss of a proton from the resultant complex (exciplex) results in an a-aminoalkyl radical which initiates polymerization. The... 

In this section alkylation, Michael additions, hydroxyalkylation (reaction with carbonyl compounds), aminoalkylation, acylation and some other reactions of a-sulphinyl carbanions will be discussed. 

Phenols, secondary and tertiary aromatic amines, pyrroles, and indoles can be aminomethylated by treatment with formaldehyde and a secondary amine. Other aldehydes have sometimes been employed. Aminoalkylation is a special case of the Mannich reaction (16-15). When phenols and other activated aromatic compounds are treated withA-hydroxymethylchloroacetamide, amidomethylation takes place " ... 

Bis(aminoalkyl)bithiazoles are useful as DNA cleavage agents. Bleomycin contains a 2,4 -bithiazole moiety which plays an important role in the interaction with double stranded DNA during the cleavage reaction. The 2,2 -bis(aminomethyl)-4,4 -bithiazole (70) has been synthesised by the condensation of l,4-dibromobutane-2,3-dione with Boc-glycinethioamide... 

Phosphaalkenes -P=C<, and phosphaimines -P=N- react with 1 to give secondary zirconated aminoalkyl or diamino phosphines, respectively, with P-coordination to the metal fragment (Scheme 8-24) [207]. An unexpected methylene-transfer reaction was observed upon reaction of 1 with Ph3P=CH2 (Scheme 8-24) [208],... 

Scheme 1.76 Test reaction with P-aminoalkyl ferrocenyl sulfide ligands.

Scheme 21 summarizes further reactions leading to phosphonic acid analogues of amino acids. Treatment of the nitrone (138 R =Me or Pr ) with a dialkyl hydrogen phosphonate (best as the Li derivative which shows greater diastereoselectivity than the Na or K salts), and subsequent steps involving acidolysis of the oximino compound (139) lead to the free (ot-aminoalkyl)-phosphonic acids (140)(phosphonoalanine, phosphonova1ine). 

Corrosion inhibition is primarily associated with acidizing. Buffered hydrofluoric acid compositions have been shown to be less corrosive (147). Corrosion inhibitors are designed to reduce the rate of reaction of fluid with metal surfaces, generally by forming films on the surfaces. Acetylenic alcohols and amines are frequently components of corrosion inhibitor blends. Other compounds that have been used include nitrogen heterocyclics, substituted thioureas, thiophenols, and alpha-aminoalkyl thioethers (148). 

The pretreated nylon then undergoes covalent fixation of dyes containing aminoalkyl groups. Interestingly, nylon treated with XLC showed markedly lower substantivity and reactivity with conventional dyes. If the pretreated nylon was reacted with ammonia, however, creating amino functionality at the reactive sites, normal reaction with a conventional reactive dye was restored [405]. 

Add a quantity of Aminoethyl-8 in methanol to equal a 25-fold molar excess over the amount of sulfhydryl present (including the amount of DTT added). The solution in methanol should be made concentrated enough so only a small amount of methanol has to be added to the reaction solution (i.e., no more than 10 percent of the final volume). A second addition of modifying agent may be made after 1 hour to drive the reaction more completely toward total —SH aminoalkylation. 

In solution, l-(ot-aminoalkyl)benzotriazoles 562 are in equilibrium with iminium cation 563 and hence with their benzotriazole-2-yl isomers 564 (Scheme 89). Protonation or complexation of the benzotriazolyl moiety (e.g., Mg, Zn, B, A1 reagents) facilitates the transformation. Intermediate iminium cations 563 can be trapped by nucleophiles providing synthetic pathways to various amines. Many such reactions are described in CHEC-II(1996) <1996CHEC-11(4)1 >, and some newer results are compiled in reviews <2005T2555>. 

The ylide obtained from (methyl)triphenylphosphonium bromide reacts with morpholine derivatives 597 to give phosphonium salts 598 which upon treatment with -butyllithium are converted to new ylides 599. In a reaction with aldehydes, ylides 599 form iV-(l,3-disubstituted allyl)-morpholines 602 (Scheme 94) <1996AQ138>. Another less common nucleophile that can be used for substitution of the benzotriazolyl moiety in Af-(a-aminoalkyl)benzotriazoles is an adduct of iV-benzylthiazolium salt to an aldehyde which reacts with compounds 597 to produce adducts 600. Under the reaction conditions, refluxing in acetonitrile, salts 600 decompose to liberate aminoketones 601 <1996H(42)273>. 

Reactions of iV-(a-aminoalkyl)benzotriazoles 898 with isonitriles catalyzed by boron trifluoride etherate give iV-(a-aminoalkylimidoyl)benzotriazoles 899 in high yield. Upon treatment with hydrochloric acid, derivatives 899 are conveniently converted to a-aminoamides 900 (Scheme 148) <2005JSC319>. 

The Mannich reaction has also been applied to the aminoalkylation of 4-phenyl-l,2,4-triazolidine-3,5-dione 54 <2000CHE1058, 2000KGS1214>. 

---