Manganese(III) acetate: A versatile reagent in organic chemistry

Free radical reactions have become increasingly important, as well as a very attractive tool, in organic synthesis within the last two decades, due to their powerful, selective, specific, and mild reaction abilities. Mn(OAc)(3) mediated oxidative free radical reactions have been extensively developed in the last twenty years. Numerous regio-, chemo-, and stereoselective synthetic methods have been developed in both inter- and intramolecular reactions, and have detailed the progress of Mn(OAc)., mediated oxidative free radical reactions since the end of the 19(th) century. The new literature about the new synthetic methods on Mn(OAC)(3) mediated carbon-carbon bond formation and carbon-oxygen bond formation reactions has not been extensively reviewed. The present paper summarizes the recent developments in oxidative free radical reactions mediated by Mn(OAc)(3.) Mn(OAc)(3) mediated reactions of conjugated systems (e.g., alkenes, alkynes, 1,3-alkadienes, 1,3-alkadiynes, 1-alken-3-ynes) with beta-dicarbonyl compounds, Mn(OAc)(3) mediated alkylation, such as the oxidative addition of an aldehyde or ketone to alkenes, Mn(OAc)3 mediated free-radical cyclization of alkenes with active methylene compounds in the presence of oxygen to afford the cyclic peroxides; lactone synthesis by the Mn(OAc)3 mediated oxidative addition of carboxylic acids to alkenes, Mn(OAc)(3) mediated cyclization of alpha-(methythio)acetamides, enamides, and beta-keto carboxamides to afford cyclic products

Cyanide Ion Promoted Addition of Acylphosphonates to Diethyl Cyanophosphonate: Synthesis of Phosphonocyanohydrin O-Phosphates

Cyanide ion catalyzed addition of acylphosphonates to diethyl cyanophosphonate furnished phosphonocyanohydrin O-phosphates in high yield. The reaction works via the phosphonate-phosphate rearrangement, followed by the addition of diethyl cyanophosphonate to the cyanohydrin phosphate anion

New approaches to polysubstituted pyrroles and pyrrolinones from alpha-cyanomethyl-beta-ketoesters

In this present paper, we report the efficient, regioselective one-pot synthesis of 5-alkoxy and 5-alkylsulfanylpyrrole-3-carboxylates in high yields via the zinc perchlorate-catalyzed addition of alcohols and thiols to the nitrile carbon of alpha-cyanornethyl-beta-ketoesters followed by annulation. The addition-annulation process is undertaken in aqueous solution to give 4,5-dihydro-5-oxo-1H-pyrrole-beta-carboxylates (pyrrolinones) in good yields. These 4,5-dihydro-5-oxo-1H-pyrrole-3-carboxylates are also obtained by the hydrolysis of 5-alkoxypyrrole-3-carboxylates

Darzens Reaction of Acyl Phosphonates with alpha-Bromo Ketones: Selective Synthesis of cis- and trans-Epoxyphosphonates

Acyl phosphonates with alpha-halo ketones in the presence of bases at room temperature afford cis- and trans-epoxyphosphonates in good chemical yields and high selectivities using different bases. The diastereoselectivity of this reaction is easily controlled by changing the base. Changing the base from CS(2)CO(3) to DBU changed the diastereomeric ratio (trans/cis) from 3/2 to 9/1. Moreover, the treatment of the trans isomer with DBU showed a complete conversion to the corresponding cis isomer

A new proton sponge polymer synthesized by RAFT polymerization for intracellular delivery of biotherapeutics

A spermine-like polymer was synthesized via reversible addition–fragmentation chain transfer polymerization as a potential endosomal escaping agent. A new methacrylate monomer, 2-((tert-butoxycarbonyl)(2-((tert-butoxycarbonyl)amino)ethyl)amino)ethylmethacrylate (BocAEAEMA), was prepared and then polymerized via RAFT polymerization at constant monomer or initiator concentration at varying [M]/[R]/[I] ratios. In all polymerizations, ln[M]0/[M] increased linearly with time. The linear increase in Mn with monomer conversion was also observed. P(BocAEAEMA)s with controlled molecular weights and narrow molecular weight distributions were obtained. The in vitro cytotoxicity and proton sponge capacity of deprotected polymers P(AEAEMA) were investigated in comparison with a widely used endosomal-disruptive polymer, PEI. P(AEAEMA)s were found to possess proton sponge capacity comparable with PEI. More importantly, P(AEAEMA)s were not toxic on NIH 3T3 cells at concentrations where PEI (25 kDa) was highly toxic (0.4 μM and above). P(AEAEMA) was able to fully condense a DNA fragment at nitrogen/phosphate (N/P) ratios of 10 and above, as evidenced by gel electrophoresis. P(BocAEAEMA) was then chain-extended with a model sugar monomer, mannose-acrylate (ManAc), to yield P(AEAEMA)-b-P(ManAc) block copolymers, to potentially provide cell-recognition ability to the polyplex particles. Although the presence of the P(ManAc) block partially inhibited the interaction of P(AEAEMA) with DNA, P(AEAEMA)13-b-P(ManAc)7 was able to form polyplexes with DNA at N/P ratios ranging between 20/1 and 2/1. Dynamic light scattering measurements showed that while P(AEAEMA) (Mn = 5.5 kDa) and DNA formed polyplex particles having a hydrodynamic diameter (Dh) of 125 ± 51 nm, P(AEAEMA)13-b-P(ManAc)7 and DNA formed particles with a smaller Dh of 38 ± 10 nm

A Rare Gamma-Pyranopyrazole Skeleton: Design, One-Pot Synthesis and Computational Study

Drawing upon a consecutive amide coupling and intramolecular cyclisation pathway, a one-pot, straight-forward synthetic route has been developed for a range of pyrazole fused gamma-pyrone derivatives. The reaction mechanism proposed for the chemoselective formation of gamma-pyranopyrazole is furthermore fully supported by experimental and computational studies.WoSScopu

Sol-gel Approaches for Elaboration of Polyol Dehydrogenase-Based Bioelectrodes

This review describes the input of sol-gel chemistry to the immobilization of polyol dehydrogenases on electrodes, for applications in bioelectrocatalysis. The polyol dehydrogenases are described and their application for biosensing, biofuel cell and electrosynthesis are briefly discussed. The immobilization of proteins via sol-gel approaches is described, including a discussion on the difficulty to maintain the activity of proteins in a silica matrix and the strategies developed to offer a proper environment to the proteins by developing optimal organic-inorganic hybrid materials. Finally, the co-immobilization of the NAD(+) co-factor and of mediators for the elaboration of reagentless devices is presented, based on published and original data. All-in-all, sol-gel approaches appear to be a very promising for development of original electrochemical applications involving dehydrogenases in near future