Unsaturated Amines

Primary amines, RNH2, add to aldehydes and ketones to yield imines, R2C=NR. Secondary amines, R2NH, add similarly to yield enamines, R2N—CR=CR2 (ene + amine = unsaturated amine). 

The lower members Polybasic acids and Acids. Phenols. Primary amines. Unsaturated Saturated aliphatic Nitro compounds... 

Syntheses of this type are from urea, thiourea, and amidine and guanidine derivatives. Ureas give tetrahydro-l,3,5-triazin-2-ones on reaction with a primary amine (1 equiv.) and aqueous formaldehyde (2-30 equiv.). In general, alkyl and aryl amines, unsaturated amines, amino alcohols, and a-amino esters form triazinone derivatives (Equation (43)). Methyl and benzyl have proven to be the most useful urea substituents with respect to high yields and product solubility. N,N -Dicyclohexyl- and A,A -diphenyl-urea gave poor yields of triazinone <90TL2109>. 

Crotonic acid esters of cellulose undergo addition reaction with cycloaliphatic amines, like morpholine or piperidine and with aliphatic primary amines. Unsaturated polymers can also undergo Diels-Alder reactions. One example is a reaction of hexachlorocyclopentadiene with polycyclopentadiene ... 

It has been tentatively suggested that one mechanism underlies the Willgerodt reaction and the Kindler modification of it. A labile intermediate is first formed which has a carbon—carbon bond in the side chain. The scheme is indicated below it postulates a series of steps involving the addition of ammonia or amine (R = H or alkyl), elimination of water, re addition and eUmination of ammonia or amine until the unsaturation appears at the end of the chain then an irreversible oxidation between sulphur and the nitrogen compound may occur to produce a thioamide. 

There also exists an acidregioselective condensation of the aldol type, namely the Mannich reaction (B. Reichert, 1959 H. Hellmann, 1960 see also p. 291f.). The condensation of secondary amines with aldehydes yields Immonium salts, which react with ketones to give 3-amino ketones (=Mannich bases). Ketones with two enolizable CHj-groupings may form 1,5-diamino-3-pentanones, but monosubstitution products can always be obtained in high yield. Unsymmetrical ketones react preferentially at the most highly substituted carbon atom. Sterical hindrance can reverse this regioselectivity. Thermal elimination of amines leads to the a,)3-unsaturated ketone. Another efficient pathway to vinyl ketones starts with the addition of terminal alkynes to immonium salts. On mercury(ll) catalyzed hydration the product is converted to the Mannich base (H. Smith, 1964). 

The Birch reductions of C C double bonds with alkali metals in liquid ammonia or amines obey other rules than do the catalytic hydrogenations (D. Caine, 1976). In these reactions regio- and stereoselectivities are mainly determined by the stabilities of the intermediate carbanions. If one reduces, for example, the a, -unsaturated decalone below with lithium, a dianion is formed, whereof three different conformations (A), (B), and (C) are conceivable. Conformation (A) is the most stable, because repulsion disfavors the cis-decalin system (B) and in (C) the conjugation of the dianion is interrupted. Thus, protonation yields the trans-decalone system (G. Stork, 1964B). 

The reaction of the vinylcyclopropanedicarboxylate 301 with amines affords an allylic amine via the 7r-allylpalladium complex 302[50]. Similarly, three-membered ring A -tosyl-2-(l,3-butadienyl)aziridine (303) and the four-mem-bered ring azetidine 304 can be rearranged to the five- and six-membered ring unsaturated cyclic amines[183]. 

Allylamines are not easily cleaved with Pd catalysts, but the carbonylation of the allylic amine 395 proceeds at 110 C to give the /3,7-unsaturated amide 396 by using dppp as a ligand[252], Dccarboxylation-carbonylation of allyl diethyl-carbamate under severe conditions (100 C, 80 atm) affords /3,7-unsaturated amides[2531. The 3-vinylaziridine 397 is converted into the a-vinyl-J-lactam 398 under mild conditions[254]. 

Unusual cyclocarbonylation of allylic acetates proceeds in the presence of acetic anhydride and an amine to afford acetates of phenol derivatives. The cinnamyl acetate derivative 408 undergoes carbonylation and Friedel-Crafts-type cyclization to form the a-naphthyl acetate 410 under severe condi-tions[263,264]. The reaction proceeds at 140-170 under 50-70 atm of CO in the presence of acetic anhydride and Et N. Addition of acetic anhydride is essential for the cyclization. The key step seems to be the Friedel-Crafts-type cyclization of an acylpalladium complex as shown by 409. When MeOH is added instead of acetic anhydride, /3,7-unsaturated esters such as 388 are... 

Ammonia and amines undergo conjugate addition to a 3 unsaturated carbonyl compounds (Section 18 12) On the basis of this information predict the pnncipal organic product of each of the following reactions... 

The Perkin reaction, uti1i2ing an aromatic aldehyde, an acid anhydride, and a base such as an acid salt or amine, produces the corresponding a,P-unsaturated acid. 

Aqueous mineral acids react with BF to yield the hydrates of BF or the hydroxyfluoroboric acids, fluoroboric acid, or boric acid. Solution in aqueous alkali gives the soluble salts of the hydroxyfluoroboric acids, fluoroboric acids, or boric acid. Boron trifluoride, slightly soluble in many organic solvents including saturated hydrocarbons (qv), halogenated hydrocarbons, and aromatic compounds, easily polymerizes unsaturated compounds such as butylenes (qv), styrene (qv), or vinyl esters, as well as easily cleaved cycHc molecules such as tetrahydrofuran (see Furan derivatives). Other molecules containing electron-donating atoms such as O, S, N, P, etc, eg, alcohols, acids, amines, phosphines, and ethers, may dissolve BF to produce soluble adducts. 

Glycerol, the simplest trihydric alcohol, forms esters, ethers, haUdes, amines, aldehydes, and such unsaturated compounds as acrolein (qv). As an alcohol, glycerol also has the abiUty to form salts such as sodium glyceroxide (see also Alcohols, polyhydric). 

Among other examples are unsaturated amines (190,191), carbohydrates (192,193), heterocycHc olefins (194), phosphoms and sulfur compounds (195,196), organometaUic compounds (148,197,198), functionalized iatermediates ia natural product syntheses (98—105,199,200), and many other compounds described ia reviews (5,6,8,9,13). 

Aromatic diacyl peroxides such as dibenzoyl peroxide (BPO) [94-36-0] may be used with promoters to lower the usehil decomposition temperatures of the peroxides, although usually with some sacrifice to radical generation efficiency. The most widely used promoter is dimethylaniline (DMA). The BPO—DMA combination is used for hardening (curing) of unsaturated polyester resin compositions, eg, body putty in auto repair kits. Here, the aromatic amine promoter attacks the BPO to initially form W-benzoyloxydimethylanilinium benzoate (ion pair) which subsequentiy decomposes at room temperature to form a benzoate ion, a dimethylaniline radical cation, and a benzoyloxy radical that, in turn, initiates the curing reaction (33) ... 

Wheieas the BPO—DMA ledox system works well for curing of unsaturated polyester blends, it is not a very effective system for initiating vinyl monomer polymerizations, and therefore it generally is not used in such appHcations (34). However, combinations of amines (eg, DMA) and acyl sulfonyl peroxides (eg, ACSP) are very effective initiator systems at 0°C for high conversion suspension polymerizations of vinyl chloride (35). BPO has also been used in combination with ferrous ammonium sulfate to initiate emulsion polymerizations of vinyl monomers via a redox reaction (36). 

Other Reactants. Other reactants are used in smaller amounts to provide phenoHc resins that have specific properties, especially coatings appHcations. Aniline had been incorporated into both resoles and novolaks but this practice has been generally discontinued because of the toxicity of aromatic amines. Other materials include rosin (abietic acid), dicyclopentadiene, unsaturated oils such as tung oil and linseed oil, and polyvalent cations for cross-linking. 

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