Conjugated allylamine

The conjugation of catechin on poly(allylamine) using ML as catalyst was examined under air. During the conjugation, the reaction mixture turned brown and a new peak at 430 nm was observed in the UV-vis spectrum. At pH 7, the reaction rate was the highest. The conjugation hardly occurred in the absence of laccase, indicating that the reaction proceeded via enzyme catalysis. 

Beak and co-workers have also produced the key alcohol intermediate 74 by the sparteine-mediated lithiation and conjugate addition of allylamines to nitroalkenes to give Z-enecarbamates in good yields with high enantio- and diastereoselectivty (Scheme 16). Thus treatment of the allylamine 87 with n-BuLi in the presence of (-)-sparteine followed by conjugate addition to nitroalkene 88 gave the desired enecarbamate 89 in... 

A novel ring-expansion protocol has been developed, based on the conjugate additions of cyclic allylamines (215) to (jo-toluenesulfonyl)ethyne (216), followed by aza-Cope rearrangement of the resulting zwitterions (217), to afford medium- and large-ring cyclic amines (218) under remarkably mild conditions.261... 

Similarly, Chien et al. used a poly(acrylic acid)/poly(acrylamide) (PAA/PAM) multilayer system in which PAA was replaced by PAA conjugated with photoreactive 4-azidoaniline (AZ) after several bilayers [110]. As a result, the polyelectrolyte multilayer could be covalently crosslinked by UV irradiation through a mask. For an enhanced cell repellence, poly(allylamine) was conjugated with polyethylene glycol methyl ether) and incorporated into the top layers of the film. 

Alkenyl aziridines are useful synthetic building blocks and can be converted to allylamines by conjugate addition of organocuprates [29], to pyrroline derivatives by rearrangement [30] and to P-lactams by Pd-catalyzed carbonylation [31]. 

Beak reported that sparteine (111) mediated the conjugate addition of lithi-ated allylamine 114 to give nitroalkene adduct 115 with high diastereoselectivi-ty and enantioselectivity [62]. The product 115 was converted to paroxetine (88) by conventional synthetic manipulations. 

The equilibration of allylamines like 176, which have an isolated C=C double bond, to conjugated enamines under basic conditions has been studied extensively139,292 297. With only one exception298, that of l-(indol-3-ylethyl)-3-pyrroline (181), which is only partially transformed into its enamine 182 (equation 15), the equilibrium generally lies far on the side of the enamine l-JV,JV-dimethylamino-2-propene (183) is isomerized292 with potassium terf-butoxide in DMSO, first to the Z-enamine (184) and then to the thermodynamically more stable is-enamine293,294 (185, see equation 16) as was shown by XH-NMR spectroscopy. 

The gold nanoparticle/polyelectrolyte coated latex particles are then conjugated with biotin molecules through a layer of biotinylated poly(allylamine hydrochloride) that is deposited on the particle surface before biotin binding. Fluorescein isothiocyanate labled anti-biotin immunoglobulin (FITC-anti-biotin IgG)... 

Olefin isomerization catalyzed by ruthenium alkylidene complexes can be applied to the deprotection of allyl ethers, allyl amines, and synthesis of cyclic enol ethers by the sequential reaction of RCM and olefin isomerization. Treatment of 70 with allyl ether affords corresponding vinyl ether, which is subsequently converted into alcohol with an aqueous HCl solution (Eq. 12.37) [44]. In contrast, the allylic chain was substituted at the Cl position, and allyl ether 94 was converted to the corresponding homoallylic 95 (Eq. 12.38). The corresponding enamines were formed by the reaction of 70 with allylamines [44, 45]. Selective deprotection of the allylamines in the presence of allyl ethers by 69 has been observed (Eq. 12.39), which is comparable with the Jt-allyl palladium deallylation methodology. This selectivity was attributed to the ability of the lone pair of the nitrogen atom to conjugate with a new double bond of the enamine intermediate. 

Addition to imines. A diastereo- and enantioselective synthesis of protected P-amino silanes is hinged on the addition of organoceriums to a-silyl SAMP/RAMP hydrazones. Conjugated imines show regioselectivity that favors the generation of allylamines. ... 

The equilibration of allylamines like 176, which have an isolated C=C double bond, to conjugated enamines under basic conditions has been studied extensively ... 

Hine and coworkers showed that the dimethylamino group is by far one of the best known double-bond stabilizing substituents. This may be evaluated quantitatively from experimental enthalpies of formation and of hydrogenation presented in Table 17 and may be seen from the value of Hammett s ffp(NMe2)-constant which, at —0.83, has one of the largest negative values observed. Both enthalpy values mentioned show a stabilization of the enamine due to conjugation by — 5 to — 6 kcal mol with respect to allylamines which may be corrected in relation to olefinic systems to about —2.5 kc mol ... 

Stereocontrol in allylamine to enamine isomerisation in hydrogenation and 1,5-hydrogen shift in conjugated dienes, catalyzed by metal derivatives. 

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