Phenols aminoalkylation

Diaikanol aminoalkyl phenols as admixtures enhance the strength [675]. The additives are useful in very small amounts and do not affect the initial properties of the fluid. The strength additive does not cause set acceleration or early set strength enhancement but provides enhanced compressive strength of the cement in later stages. Addition of small amounts of potassium ferricyanide and nitrile-trimethyl phosphonic acid promotes the formation of complex compounds and thus increases the strength of cement rock [1771]. 

Reduction of 4/7-chromene-4-ylidene imines with borohydrides has been shown to lead to aminoalkyl phenols <2001T6809>. 

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 " ... 

The aminoalkylation reactions applied to the synthesis of alkaloids arc mostly cycliyui-tions of the type described in Chap, I, C.4, usually involving CH substrates such as alkyl ketones. The analogous reactions on alkcncs arc frequently accompanied by more or less relevant modiheations of the substrate molecule (Chap. I, C.5). Activated aromatic substrates, particularly phenols and their alkylether derivatives, arc also subjected to Mannich reaction. 

Catecholamines degrade rapidly via oxidative reactions and are catalyzed by oxygen, pH s >6, heavy metal ions, heat, and UV-VIS radiation. UV-VIS radiation is more deleterious than temperature, and UV is 15 times more deleterious than VIS radiation. The degradation rates, of individual catecholamines, vary and are dependent on the position of their phenolic groups and the type of N-substituents in the aminoalkyl side chain. For instance, norepinephrine is more stable than epinephrine, and epinephrine is more stable than isoprenaline. 

This copolymer can be obtained from a polydimethylsiloxane that has aminoalkyl end groups in a reaction with the polyetherimide formed from the reaction of a bis(ether anhydride) with diaminobenzene. The material is fire resistant and is used in cable insulations. Among other more complex copolymers with practical applications are poly[2,2-propanebis(4-phenyl)-carbonate]-b/ock-poly(dimethylsiloxane)] and a silicone phenol formaldehyde copolymer obtained in two steps, the first being the heating of a polydimethylsiloxane that has reactive end groups with glycerol, and the second step being the reaction with a phenol formaldehyde resin. 

General experimental details are as follows.697b It is usual first to mix the carbonyl component with the amine, which is presented as, e.g., hydrochloride or acetate. An appropriate hydrogen ion concentration must be maintained. For the preparation of aminoalkyl compounds that are liable to hydrolysis it is recommended that the water produced be removed by a drying agent or by azeotropic distillation. Dioxan is a suitable solvent, but it is often recommended that acetic acid be added to it. Ketones react better in alcohol with paraformaldehyde. Copper chloride or iron chloride is said to be a useful addition in reactions of acetylenes. Reactions of amines, phenols, and furans, even under mild conditions, may be accompanied by multiple condensation or resinification. 4-Hydroxybenzylamine is reported706 to be obtained in 92% yield when ammonia is led into a mixture of phenol and formaldehyde. 

Friedel-Crafts alkylations of arenes with mesylates, benzyl or allyl alcohols, aldehyde/diol combinations (reductive alkylation), 1,3-dienes, or alkenes in an ionic liquid are also effectively catalyzed by Sc(OTf)3. Sc(OTf)3 works as an efficient catalyst for the condensation reaction of trimethylhydroquinone with isophytol to afford a-tocopherol. 2-Aminoalkylation of phenols with a-iminoacetates (or glyoxylate/amine) is catalyzed by Sc(OTf)3 to produce amino acid derivatives. The Sc(OTf)3-catalyzed alkylations of indoles with a-hydroxy esters, aziri-dines, acetals, and aldehydes have been utilized as key steps of total syntheses as exemplified in eq 15. ... 

Related with the previous synthesis, an FC aminoalkylation through a tosyliminium ion allowed the total synthesis of ( )-schefferine (Scheme 2.6) [7], which is a phenolic alkaloid isolated from Schefferomitra subaequalis, a liana climber found on rain forest trees. The known amidal 41 was treated at -78°C with 4-allyl-l,2-dimethoxybenzene (42) and BF Et O to regioselectively give 43 in 88% yield. The allylic chain of the aromatic ring was then modified to furnish alcohol 44, which after deprotection of the tosylamide was cyclized via a Mitsunobu reaction to give ( )-schefferine (46). 

Chloroacetamides of aminoalkyl derivatives of electron-rich aromatics 17, such as phenols, anisoles, or electron-rich heterocycles, easily dechlorinate and offer a useful entry to new medium-sized heterocycles (e.g., apogeissoschizine 18), according to Scheme 8.6a [6]. This is another example of the photochemical access to complex structures, that has been conveniently extended to macrocycle 19 (Scheme 8.6b), as well as to the reaction of W-alkylphthalimides [6]. 

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