William P. Jackson

Cyclisation reactions of alkenyl β-ketoesters involving a novel phenylseleno group migration

Abstract A number of alkenyl-substituted α-phenylseleno β-ketoesters can be cyclised in the presence of acidic catalysts in which a novel migration of phenylseleno moiety occurs.

Selenium-mediated cyclization reactions of alkenyl-substituted β-ketoesters

Phenylselenating agents, in which the counter ion is non-nucleophilic, react with certain alkenyl-substituted β-ketoesters to afford cyclized products, some of which can be further rearranged using SnCl4.

New cyclization procedure for alkenyl-substituted β-dicarbonyl compounds using N-phenylselenophthalimide

N-Phenylselenophthalimide can be used as an effective cyclizing reagent for certain alkenyl-substituted β-dicarbonyl compounds to give a number of polyfunctionalised products.

Synthesis and platelet aggregation inhibiting activity of 1'-carboxyl modified hydantoin prostaglandin analogues

A series of hydantoin prostaglandin analogues, in which the 1′-carboxy group was replaced by tetrazole, amine, alcohol, amide, cyanamide, or sulphonamide functionalities, was prepared and evaluated for platelet aggregation inhibiting activity. The 2′-decarboxy-2′-(tetrazol-5-yl) analogue (30) proved to have interesting activity, being approximately equipotent (ca. 17 × PGE1) to BW245C (1). Activity was often lost when the carboxy group was replaced by neutral or basic moieties. Substitution of the carboxy terminus by other groups of similar acidity gave rise to reduced activity. These results suggest that the platelet receptor which mediates these effects possesses a cationic site requiring binding of an anionic group at the agonist 1′-position. However, additional factors are clearly involved in determining agonist potency.

Larger scale preparation of optically-active allylic alcohols

An efficient and practical synthesis of optically-active allylic alcohols from 2,3-epoxytoluene-p-sulfonates by the in situ formation of the epoxy iodides and their subsequent reduction with zinc–copper couple has been established. Application of this procedure to the larger-scale synthesis of (S)-(+)-but-3-en-2-ol from (2S,3S)-3-methylglycidyl toluene-p-sulfonate has also been investigated.

Synthesis of substituted cis-decalins as potential insect antifeedants

2β-Acetoxy-1α-acetoxymethyl-5,5-dimethyl-1α,6α,10Oα-bicyclo[4.4.0]decane-10-spiro-2′-oxiran (4) has been prepared from 4,4-dimethylcyclohex-2-enone in eight steps, one of which involves a useful Lewis acid-catalysed cyclisation of an acetylenic β-oxo-ester (7). The structure of (4) was determined by X-ray crystallography. At a concentration of 1 000 p.p.m. compound (4) showed a 72% inhibition of feeding by Locusta migratoria.

Synthesis of a substituted cis-decalin as a potential insect antifeedant

A cis-decalin containing epoxydiacetate functions has been synthesised as a potential insect antifeedant.