Charles R. Harrison

Phase transfer catalysed polymer-supported Wittig reactions

Abstract Arylsubstituted olefins can be prepared in high yield using phase transfer catalysed polymer-supported Wittig reactions.

Polymer-supported periodate and iodate as oxidizing agents

The periodate forms of some commercial macroporous anion-exchange resins can be used in either protic or aprotic solvents to oxidize various quinols, catechols, and glycols and also triphenylphosphine, hydrazobenzene, and benzohydroxamic acid. The reagents in methanol oxidize thioethers. Polymer-supported iodate also oxidizes quinols and catechols.

Oxidation of some penicillins and other sulphides by use of a polymer-supported peroxy-acid

Ein durch Chlormethylierung von Polystyrolperlen und Oxidation der Chlormethylgruppen hergestelltes Peroxysaure-Harz oxidiert Tetrahydrothiophen (in THF) und L-Methionin (in Wasser) zu einem Sulfoxid-Sulfon-Gemisch, bzw. bei einem ca. 3fachen Uberschus an Peroxysaure-Aquivalenten zu reinem Sulfon (Ausbeuten 94 bzw. 100%).

Preparation of polymer-supported peroxy-acids and their use to oxidise olefins to epoxides

Treatment of carboxy-substituted polystyrene resins with hydrogen peroxide in methanesulphonic acid gave resins containing aromatic peroxy-acid residues (3.5–4.0 mmol g–1). The resins generally reacted with di- and tri-substituted olefins in tetrahydrofuran at 40 °C to give epoxides (or products derived from epoxides) in yields greater than 50%. Monosubstituted olefins reacted poorly. In cases where mixtures of stereoisomeric epoxides were formed the proportions of the isomers were essentially the same as those obtained by using monomeric aromatic peroxy-acid reagents.

Chemistry of quinones. Part 6. The selective hydrolysis of α-acetoxyanthraquinones and related compounds by trifluoroacetic acid containing small amounts of water

Acetoxy- or benzoyloxy-substituents adjacent to the carbonyl groups of anthraquinone, 1,4-naphthoquinone, naphthacene-5,12-quinone, benzophenone, and methyl benzoate are selectively converted into hydroxy-groups by treatment with trifluoroacetic acid containing small amounts of water. In the absence of water a reversible acidolysis occurs. Water reacts with the acylating agent, thus preventing the reverse reaction. Evidence is presented that the hydrolyses are of the AAC1 type.

Determination of the configuration of some penicillin S-oxides by 13C nuclear magnetic resonance spectroscopy

The 13C n.m.r. spectra of a range of penicillins and some sulphoxides and sulphones derived from them are presented. Along the series sulphide, β-sulphoxide, α-sulphone there is a clear pattern in the changes of the shifts of C-2, -3, -5, and -6 and the C-2 methyl groups. This means that 13C n.m.r. spectroscopy can be used to determine the configuration of sulphoxides, and using this technique we have shown that oxidation of 6,6-dibromopenicillanic acid by peroxy-acid gives mainly the α-sulphoxide, whereas methyl penicillanate and its 6α-chloro- and 6α-bromo-derivatives give mainly the β-sulphoxides.

Increase in reaction rate consequent on the use of a polymer-supported reagent. Evidence for interaction between a high proportion of the groups of a polymer-supported reagent

The conversion of alcohols into alkyl chlorides and of acids into acid chlorides by aryl phosphines and carbon tetrachloride proceeds more rapidly when the phosphine is polymer-supported; in these reactions, the main pathway appears to involve two phosphorus-containing residues on the polymer reacting together.

Preparation of a polymer-supported per-acid and its use to oxidize olefins to epoxides

A polymeric per-acid has been prepared and used to oxidize several olefins to their epoxides in good yield.