The study demonstrates the feasibility of using an in situ bacterial treatment to enhance gas release and resource recovery from landfill soil containing lignocellulosic waste. This article is protected by copyright. All rights reserved.
Covering: 1973 to 2013. The biological activities of tigliane, lathyrane, ingenane, casbane, jatropholane and premyrsinane diterpenoids which contain the gem-dimethylcyclopropyl unit are described. Particular attention is given to their anti-viral, anti-microbial and cytotoxic activities. In the main text there are 132 references. The electronic supplementary information contains tables listing 424 of these diterpenoids, their occurrence and biological activity together with the references.
The structure 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide (1) was assigned to a metabolite of Botrytis cinerea, but the spectra of several synthetic analogues had significant differences from that of 1. Examination of the constituents of a B. cinerea mutant that overproduces polyketides gave sufficient quantities of 1, now named cinbotolide, for chemical transformations. These led to a revised γ-butyrolactone structure for the metabolite. This structure has been confirmed by an asymmetric total synthesis, which also established its absolute configuration.
A novel diterpenoid, gaditanone (2), which possesses an unprecedented 5/6/4/6-fused gaditanane tetracyclic ring skeleton, and a new jatrophane (1) were isolated from the aerial parts of Euphorbia gaditana. The chemical structures and absolute configurations were determined by extensive spectroscopic NMR studies and ECD data analysis. A proposed biosynthetic pathway is presented for compound 2.
A new method for the chemo- and stereoselective conversion of allylic alcohols into the corresponding cyclopropane derivatives has been developed. The cyclopropanation reaction was carried out with an unprecedented titanium carbenoid generated in situ from Nugent's reagent, manganese and methylene diiodide. The reaction involving the participation of an allylic hydroxyl group, proceeded with conservation of the alkene geometry and in a high diastereomeric excess. The scope, limitations and mechanism of this metal-catalysed reaction are discussed.
A method for the conversion of primary, secondary and tertiary alcohols into the corresponding THF ethers at room temperature and primary and secondary alcohols into the corresponding THP ethers, has been developed using titanium(III) species generated from a catalytic amount of titanocene dichloride or (4R,5R)‐(–)‐2,2‐dimethyl‐α,α,α′,α′‐tetra(1‐naphthyl)‐1,3‐dioxolane‐4,5‐dimethanolatotitanium(IV) dichloride:acetonitrile adduct together with manganese(0) as a reductant and bromoform in THF or THP as the solvent. A radical mechanism is proposed for this transformation revealing an intriguing role of the solvent in the single‐electron transfer reactions catalysed by the low valent TiIII system.
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