Aromatic Nucleophilic Substitution Reactions.

The review summarizes current trends and developments in the polymerization of alkylene oxides in the last two decades since 1995, with a particular focus on the most important epoxide monomers ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO). Classical synthetic pathways, i.e., anionic polymerization, coordination polymerization, and cationic polymerization of epoxides (oxiranes), are briefly reviewed. The main focus of the review lies on more recent and in some cases metal-free methods for epoxide polymerization, i.e., the activated monomer strategy, the use of organocatalysts, such as N-heterocyclic carbenes (NHCs) and N-heterocyclic olefins (NHOs) as well as phosphazene bases. In addition, the commercially relevant double-metal cyanide (DMC) catalyst systems are discussed. Besides the synthetic progress, new types of multifunctional linear PEG (mf-PEG) and PPO structures accessible by copolymerization of EO or PO with functional epoxide comonomers are presented as well as complex bra...

Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation.

Publisher Summary This chapter discusses the studies relating to the chemical nature of alkylation, from the products of nucleoside alkylation to in vivo effects of alkylating agents that are oncogenic. The reactions of simple methylating agents with nucleosides, nucleotides, and polynucleotides have also been discussed in the chapter. More recent studies of the mechanism of alkylation by nitroso compounds and ethylating agents have shown that both qualitatively and quantitatively the site of alkylation is a function of both the type of reagent used and the conformation and milieu of the nucleic acid. However, translation of this body of knowledge to an understanding of the biological mechanism of alkylation-induced mutagenesis and carcinogenesis is difficult. Further studies of mutation in picornaviruses or their RNAs would be fruitful since these viral RNAs are also messenger RNAs and are directly translated, whereas in vivo studies, definitive information is still lacking as to whether alkylation of DNA, RNA, or perhaps protein, is the biologically important event.

The chemical effects of nucleic acid alkylation and their relation to mutagenesis and carcinogenesis.

It is generally acknowledged that geometrical and conformational properties of biopolymers have an important effect on their biochemical behaviour. It is less easily recognized that these properties depend also on their macromolecular electronic characteristics.The aim of this review is to demonstrate the significance of such macromolecular electronic effects. Particularly useful for this sake is the recently much developed concept of ‘molecular electrostatic potential’ (MEP) (Scrocco & Tomasi, 1973, 1978) by which is defined the electrostatic (Coulomb) potential created in the neighbouring space by the nuclear charges and the eletronic distribution of a molecule.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033583500002341

Molecular electrostatic potential of the nucleic acids.

It was discovered that olefinic double bonds are readily oxidized in an aqueous solution of periodate which contains only catalytic amounts of permanganate. The data suggest that in the effective p...

Periodate–permanganate oxidations: i. oxidation of olefins

The synthesis of 4-hydroxyquinolines; through ethoxymethylene malonic ester.

Relative reactivities for monofunctional nitrogen mustard alkylation of nucleic acid components.

p-Nitrophenyl Disulfide, p-Nitrophenyl Sulfide and p-Nitrothiophenol1

For the purposes of our discussion, alkylation may be defined as the conversion H-X + R-X. The source of the alkyl group, R, may be a simple alkylating agent, R-Y, from certain cyclic compounds, CC, or from \\ / Y an unsaturated compound, C=C. The alkylations of biological interest apparently all involve attachment of the alkyl group to X through an oxygen, nitrogen, or sulfur atom. Starting with an alkylating agent, R-Y, where Y is a group stable as an anion (Ye), there are two generally recognized mechanisms for alkylation.' In one, so-called first-order nucleophilic substitution, s N 1 , the reaction proceeds in two steps. The first step is a rate-controlling ionization of the R-Y bond, aided by a polar solvent that solvates and stabilizes the resulting ions. The second step is a rapid (and rather indiscriminate) reaction of the resulting alkyl carbonium ion (R+) with a solvent molecule or some new anion (X-):

Charles C. Price

Papers

The synthesis of 4-hydroxyquinolines; through ethoxymethylene malonic ester.

Relative reactivities for monofunctional nitrogen mustard alkylation of nucleic acid components.

p-Nitrophenyl Disulfide, p-Nitrophenyl Sulfide and p-Nitrothiophenol1

Fundamental mechanisms of alkylation.

The Kinetics of the Periodate Oxidation of 1,2-Glycols. II. Ethylene Glycol, Pinacol and cis- and trans-Cyclohexene Glycols