Acrylamide derivatives

An aqueous ethanol solution of acrylamide, 2,2 -methylenebisacrylamide as cross-linked agent and third acrylamide derivative, is dispersed in an n-alkane. Then three monomers are polymerized to spherical porous gels. The effect of the composition of the third monomer on the exclusion limits of the gel in size-exclusion chromatography has been investigated (82). 

Aromatic thioureas were more active than alkyl (octyl, cyclohexyl) derivatives. Thioureas with trilluoromethyl substituents were even more effective. The same group also showed that these organocatalysts can act as weak Lewis acids and are thus able to alter the stereochemistry of the Diels-Alder reaction between cyclopentadiene and chiral acrylamide derivatives (Scheme 49) [167]. 

The relative proportions of triads is determined by the synthetic conditions chosen as described above for acrylic acid copolymers of acrylamide derived by either direct copolymerization or by hydrolysis. Also, the polymerization pH has a considerable effect on the reactivity in acrylamide/acrylic acid copolymerization. 

Enantiomerically pure tetrahydro-l//-pyrrolo[2, l -natural products or drugs. Compound 86a was submitted to debromination with Bu3SnH followed by ring opening in KOH and further reduction with BHj to give diol 89 that was then easily transformed into (A)-4-(2,2,4-trimethyl-l,3-dioxolan-4-yl)-lT>utanol 90, a key intermediate for )-frontalin, <2002TA155>,... 

A series of enantiomerically pure tetrahydro-l//-pyrrolo[2,l-c][l,4]oxazine-l,4(3//)-diones 86a-d have been prepared by bromolactonization of acrylamides derived from proline mediated by NBS (Equation 5). These compounds... 

An interesting family of polymeric ligands show inverse temperature dependence of solubihty in water, i.e. they can be precipitated from aqueous solutions by increasing the temperature above the so-called cloud point. Typically these ligands contain poly(oxyalkylene) chains, but the phenomenon can be similarly observed with poly(N-isopropyl acrylamide) derivatives (e.g. 132) and methylated cyclodextrins, too. At or above their cloud points these compounds fall off the solution, due to the break-up and loss of the hydration shell which prevents aggregation and precipitation of their molecules. Conversely, upon cooling below this temperature (also called the lower critical solution temperature, LCST) these substances dissolve again. 

Honomer Selection. In practice the amide/blocked aldehyde precursor 1 (ADDA) proved more readily accessible than 2. The two forms were completely Interconvertible and equally useful as self-and substrate reactive crosslinkers (6). In our addition polymer systems, the acrylamide derivative 1 (R=CH3) provided a good blend of accessibility, physical properties, and ready copolymerizablllty with most commercially Important monomers. Structure/property relationships for other related monomers will be reported elsewhere. 

Some derivatives of poly(acrylamide), such as the (2-aminoethyl) derivative, may be dried by lyophilization, but other derivatives should not be dried. Some derivatives may be stored in the wet state in buffer solution at low temperature, but others may not be so stored. In general, poly(acrylamide) derivatives should be used immediately after preparation. It is especially important that poly(acrylamide) derivatives should not be subjected to alternate freezing and thawing, as such treatment will cause fragmentation of the poly(acrylamide) beads. 

Many different types of responsive gels have been synthesized by various techniques. Copolymerization/crosslinking of monofunctional and polyfunctional monomers has been extensively used to produce responsive gels of vinyl monomers, especially of a wide variety of acrylamide derivatives such as N-isopropylacrylamide, acrylic acid, and diethylacrylamide [4-11, 21-36]. Crosslinking of linear polymers by either chemical means or y-radiation has also been used to produce a wide range of responsive gels. The precursor polymers... 

Very recently, Inomata et al. have reported that the Tc of thermosensitive gels consisting of the following /V-substituted acrylamide derivatives varies depending on the species of the substituent groups [69] ... 

Copolymerization of St with Acrylamide Derivatives. The dependence of the M2 fraction in instantaneously-formed polymer on the total conversion is compared among four kinds of acrylamides-St copolymerizations at f = 0.4 (Figure 4) (14). HMA and DMA resemble AA concerning the copolymerization mode, that is, their reaction course is divided into three stages. On the other hand MA copolymerizes in a different mode. 

The photochemical electrocyclic reaction of acrylamides represents a versatile strategy for alkaloid synthesis. Thus, (S)-pipecoline has been synthesized using the photochemical cyclization of enantiomerically pure acrylamide derivatives in the presence of NaBH4, which causes reduction of the imonium intermediate. The lactam may then easily be transformed into the desired heterocyclic compound (Scheme 9.26) [38]. 

The polymers manufactured are high molecular weight acrylamide derivatives used in water purification, enhanced oil recovery and solid flocculation. 

In previous and subsequent investigations by co-authors Wu (2,3), acrylamide, (I), and hydroxyethyl acrylamide derivatives, (n), respectively, were prepared that were... 

Although the triaminocyclopropenium ion is stable to water, even hot water, unlike the trichloro and triphenyl derivatives, this ion readily reacts with the hydroxide ion at room temperature to afford diamino-cyclopropenone (77) as the major product and an acrylamide derivative (75) as the minor product i ) (Eq. 10). On the other hand, the reaction with sodium sulfide yields diaminocyclopropenethione (79) and di-... 

Cycloaddition Reactions. Chiral acrylamides derived from pyrrolidines (2) or (3) undergo stereoselective [4 + 2] cycloaddition reactions with a variety of cyclic dienes. Similarly, nitroso compounds derivatized with pyrrolidine (2) and generated in situ give cycloadducts with a high degree of stereoselectivity (eq 6). Intramolecular [2 + 2] cycloadditions involving pyrrolidine-derived keteniminium salts have been shown to produce chiral cyclobutanones. ... 

In contrast to agarose, polyacrylamide is a synthetic polymer, and gel formation depends on chemical cross-linking. The bifunctional acrylamide derivative, N,N -methylene-6is-acrylamide is included in the polymerisation mixture to insert cross-links between chains of... 

The highly reactive vinamidinium salt (7s) has been prepared starting from N.N-dimethylcanoacetamide by reaction with dimethylformamide diethylacetal, followed by treatment of the acrylamide derivative obtained with phosphoryl chloride and conversion to the stable perchlorate34 ... 

Reaction of 2,3-diphenylcyclopropenone with 2-aminothiazole and related compounds in tet-rahydrofuran produced acrylamide derivatives 2 and/or c -dihydropyrimidine derivatives 3. ... 

TMS-acrylamide derived from homochiral camphor sultam as the key step [390]. 

A different strategy for preparing enzymes for immobilization is to introduce vinyl groups by alkylating or acylating enzymes with activated vinyl monomers [40]. The modified enzymes are then polymerized with mono- and bifunctional acrylamide derivatives to yield elastic particles of irregular shape after crushing of the formed polymer blocks. Such copolymerization processes have yielded stable industrial biocatalysts for pharmaceutical application which are especially suited for stirred tank applications [41]. 

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