Coil-to-globule transitions of interfacial copolymers in better than theta-solvents

Experimental studies of the coil-to-globule transitions exhibited in better than -solvents by interfacial copolymers ofN-isopropylacrylamide and acrylamide imply that a lower bound for the value of n in then-clusters of poly(N-isopropylacrylamide) (PNIPAM) is 3. The corresponding upper bound is therefore likely to be 5 or 6. Statistical copolymers of PNIPAM containing upwards of 0.75 mole fraction of acrylamide (whose homopolymer does not itself displayn-clustering) exhibited this transition, which disappeared at higher mole fractions of acrylamide. Interfacial homopolymers ofN-ethylacrylamide and its statistical copolymers withN-isopropylacrylamide exhibitedn-clustering at all compositions.     

Photoinduced Decarboxylative Amino-Fluoroalkylation of Maleic Anhydride

A photoinduced decarboxylative three-component coupling reaction involving amine, maleic anhydride, and fluorinated alkyl iodides has been developed, leading to synthetically valuable fluoroalkyl-containing acrylamides with a high E selectivity. A broad array of substrates including monoprotected amino acid are capable coupling partners. Preliminary mechanistic studies suggest a stepwise process. This reaction represents the first example of photoinduced decarboxylative difunctionalization of maleic anhydride.     

A cascade formation of N-pyridylacrylamides from pyrido[1,2-a]pyrimidine diones and chromene aldehydes

Various N-(pyridin-2-yl)acrylamides bearing 4H-chromene fragment were synthesized via the condensation of 4H-chromene-3-carbaldehydes and their fused analogues with 2H-pyrido[1,2-a]pyrimidine-2,4(3H)-diones employing NH₄OAc/AcOH system. Possible mechanism of this hetero- domino reaction involves the consecutive Knoevenagel condensation, oxa-6v-electrocyclization, aza-6v-electrocyclic ring-opening, nucleophilic addition, retro-Alder-ene reaction and oxa-6v-electrocyclic ring-disclosure.     

Bio-rational design of photosystem II inhibitors (VIII)

Molecular modeling of acrylates (acrylamides) with Dl protein ofPisum sativum is presented. Studies show that the binding force mainly includes H-bond interaction, Van der Waals and π-ring stacking interaction. It was found that SER 268 in Dl protein might be an important binding site. It is important for high inhibitory activity of compounds whether an electronegative atom in alkyl of ester linkage could make H-bond interaction with SER 268 in Dl protein. Thus some new acrylates (acrylamides) were designed and synthesized. Bioassay indicated that these new compounds showed expected Hill reaction inhibitory activity. Project supported by the National Natural Science Foundation of China (Grant No. 29702006) and the special fund of Nature Science of Tianjin.     

Iron‐catalyzed radical polymerization of acrylamides in the presence of Lewis acid for simultaneous control of molecular weight and tacticity

This work is directed to the stereospecific living radical polymerization of acrylamides such as N,N‐dimethylacrylamide and N‐isopropylacrylamide with an iron complex and a Lewis acid. DMAM was polymerized with [FeCp(CO)₂]₂ in conjunction with an alkyl iodide [(CH₃)₂C(CO₂Et)I] as an initiator in the presence of Y(OTf)₃ in toluene/methanol (1/1) at 60 °C to be converted almost quantitatively to the polymers with controlled molecular weights and high isotacticity (m > 80%), wherein the Fe‐complex generates radical species from a covalent C? I bond of the dormant species and the Lewis acid controls the stereochemistry of the polymerization via coordination with the amide groups of the polymer terminal and the monomer. A series of Lewis acids were also used for the iron(I)‐catalyzed DMAM polymerization, and Yb(OTf)₃ and Yb(NTf₂)₃ proved effective in giving isotactic polymers without deteriorating the molecular weight control similar to Y(OTf)₃. Furthermore, a slight enhancement of isospecificity was observed for the iron‐catalyzed system in comparison with the α,α‐Azobisisobutyronitrile‐initiated, when coupled with Y(OTf)₃. Stereoblock polymerization of DMAM via a one‐pot reaction was also achieved by just adding the Y(OTf)₃ methanol solution in the course of the polymerization to give atactic‐b‐isotactic poly(DMAM). A similar but slightly lower control in the molecular weight and tacticity was achieved in the polymerization of NIPAM with [FeCp(CO)₂]₂/Y(OTf)₃. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2086–2098, 2006     

Visible-Light-Mediated Synthesis of Bicalutamide by Regioselective Hydroxysulfonylation of Acrylamides

Synthesis of anticancer drug bicalutamide promoted by visible light in one step from the corresponding N-arylacrylamide is described. This approach involves a one-pot hydroxysulfonylation reaction through a photocatalytic redox process. The use of Na₂Eosin Y as photocatalyst and blue light allows the access to a broad range of α-hydroxysulfonylamides bearing a quaternary center in moderate to good yields with complete regioselectivity via radical process.     

Ni-Catalyzed desilylative annulation of benzamides and acrylamides with alkynylsilanes: Access to 3-Methyleneisoindolin-1-one and 5-Methylene-1H-pyrrol-2(5H)-one derivatives

Abstract

The nickel-catalyzed desilylative annulation of C(sp²)–H bonds of benzamides and acrylamides with alkynylsilanes assisted by 8-aminoquinolyl directing group has been reported. A variety of benzamides and acrylamides were compatible in this protocol to construct various 3-methyleneisoindolin-1-one and 5-methylene-1H-pyrrol-2(5H)-one derivatives with Z-configuration selectivity in moderate to high yields.     

CNDO calculations of N-methyl substituted acrylamides

CNDO calculation is made for N-methyl acrylamide (both incis andtrans configurations) and N,N-dimethyl acrylamide. The charges, bond orders and dipole moments are discussed and compared with those of acrylamide. Thetrans form of N-methyl acrylamide is found to be more stable thancis isomer by 4.5 kcal/mole.