Harry J. Wadsworth

Allylic acetoxylation of Δ5-steroids at C-4

The allylic acetoxylation of Δ5-steroids at C-4 by reaction with bromine and silver acetate has been shown to depend upon the nature of the C-3 substituent. 2H Labelling studies have shown that the reaction, which proceeds via the 5α,6β-dibromide, involves the trans diaxial elimination of a 4β-proton to form a Δ4-6β-bromide which then undergoes an SN2′ displacement by the incoming acetate assisted by the silver ion.

The biosynthesis of the steroid, viridiol, by Gliocladium deliquescens

Abstract The incorporation of squalene, lanosterol, dehydroxydemethoxyviridin and demethoxyviridin into viridiol by the fungus, Gliocladium deliquescens , is described.

Studies in terpenoid biosynthesis. Part 28. The acetate and mevalonate labelling patterns of the steroid, demethoxyviridin

The enrichment and labelling patterns of demethoxyviridin, biosynthesized by Nodulisporium hinnuleum from [1-13C]-, [1,2-13C2]-acetate, [2-13C]- and [5-13C]-mevalonate have been used to define the isoprene units in this metabolite and are consistent with a triterpenoid origin. The number and location of the hydrogen atoms originating from acetate and the 2-, 4-, and 5-positions of mevalonate, have been determined by a combination of 3H : 14C ratio and 2H n.m.r. studies.

The solvolysis of 4β-hydroxy-3β-p-tolylsulphonyloxyandrost-5-enes

The solvolysis of 3β-p-tolylsulphonyloxyandrost-5-enes in acetic acid containing sodium acetate, is retarded by the presence of a 4β-acetoxy- or hydroxy-group. The products of solvolysis include the A-nor-3-formyl-steroids except in the presence of a 7-ketone.

Biosynthesis of demethoxyviridin

Demethoxyviridin has 2H and 13C enrichment and coupling patterns when derived from [2-2H3]-, [1-13C]-, and [1,2-13C2]-acetate and [2-2H2]-, [5-2H2]-, [2-13C]-, and [5-13C]-mevalonate, consistent with a triterpenoid origin.

Ring-contraction of 5β,6β-epoxyandrostane-4,17-dione

Stereospecific methods for the preparation of 5α,6α- and 5β,6β-epoxyandrostane-4,17-dione are described. A Favorskii-type ring contraction of the 5β,6β-epoxide affords a rapid route to A-nor-steroids.

Studies of terpenoid biosynthesis. Part 29. The cleavage of the sterol side chain in the biosynthesis of demethoxyviridin

The structures of a group of C6 and C7 alcohols obtained from Nodulisporium hinnuleum have been elucidated. When biosynthesized from [2-14C] mevalonic acid they have been shown to have a specific activity consistent with a common origin with their co-metabolite, demethoxyviridin. The number of [2-2H2] mevalonoid hydrogen atoms which were incorporated suggests that they were formed initially at the aldehyde oxidation level.

Fungal cleavage of the sterol side chain

A group of alcohols with the structure of the sterol side chain have been isolated from Nodulisporium hinnuleum and shown to have a specific activity when biosynthesized from [2-14C]mevalonic acid, consistent with a common origin with their co-metabolite, the 17-keto-steroid demethoxyviridin.

Preparation of androsta-2,5-dien-4-ones

Simple sequences are described for the preparation of the title compounds from dehydroisoandrosterone(3β-hydroxyandrost-5-en-17-one) and testosterone (17β-hydroxyandrost-4-en-3-one).

Enantioselective syntheses of (S)- and (R)-3-hydroxypyrrolidin-2-ones via lactate dehydrogenase catalysed reductions of 4-benzyloxycarbonylamino-2-oxobutanoic acid

The first examples of the BS- and SE-lactate dehydrogenase catalysed reductions of an α-keto acid incorporating a nitrogen containing function in the side chain are described: (S)- and (R)-benzyloxycarbonylamino-2-hydroxybutanoic acids were prepared in good yield and excellent enantioselectivities and were converted to the (S)- and (R)-3-hydroxypyrrolidin-2-ones respectively.