Three new Diels-Alder adducts, macrourins E - G (1: -3: ), one new 2-arylbenzofuran, macrourin H (4: ), and eight known Diels-Alder adducts (5: -12: ) were isolated from Morus macroura. Their structures were elucidated through extensive analysis of spectroscopic data. The 1H NMR and ECD trends in the determination of the configurations of these Diels-Alder adducts were summarized. The tyrosinas...

There is currently a tremendous interest in developing bioorthogonal "click chemistry" methods for the modification of biopolymers. Very recently, inverse-electron-demand Diels-Alder reactions have received attention, but to date they have not been applied to nucleic acids. Here we describe the first example of DNA modification by inverse-electron-demand Diels-Alder reaction. We synthesized fou...

Invasive tree pathogens threaten forests worldwide, but their effects on streams are poorly understood. Nevertheless, infections that lead to changes in the characteristics of litter inputs may affect stream communities and ecosystem processes. We studied cross-ecosystem derived from Phytophthora cinnamomi, ×alni, Ophiostoma novo-ulmi infection Castanea sativa (chestnut), Alnus lusitanica (alde...

The Carboni-Lindsey reaction between tetrazines and strained unsaturated hydrocarbons has in recent years become a useful tool bioorthogonal chemistry for labelling biomolecules vitro vivo. Here, we report computational studies on the mechanism of Diels-Alder/Retro-Diels-Alder commercially available tetrazine norbornene. Isomerism with norbornene-amide relevant applications bioconjugation chemi...

In this study, the focus was on evaluating effects of initial treatment wood ash and sewage sludge hybrid alder clones’ aboveground biomass elemental content. To measure element concentrations in tree rings, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) utilized, which is a valuable tool for dendrochemistry research, albeit with some challenges accurate quantification....

We explore the potential of the Diels-Alder cycloaddition for the functional tagging of DNA strands. A deoxyuridine triphosphate derivative carrying a diene at position 5 of the pyrimidine base was synthesized using a two-step procedure. The derivative was efficiently accepted as substrate in enzymatic polymerization assays. Diene carrying strands underwent successful cycloaddition with maleimi...

The quality of grey alder logs (Alnus incana) was studied by sawing sample logs from two different forests in November 1995–February 1996. For grading of grey alder logs and sawn timber the proposed system of Keinänen and Tahvanainen (1995) plus the reject -grade was used. In general, grey alder logs have knots from the base to the top. All types of knots appear, and the length of the knot-free...

2.1.8. Michael Reaction 2245 2.1.9. Others 2247 2.2. Cyclization Reactions 2248 2.2.1. Carbon Diels−Alder Reactions 2248 2.2.2. Aza-Diels−Alder Reactions 2252 2.2.3. Other Hetero-Diels−Alder Reactions 2255 2.2.4. Ionic Diels−Alder Reaction 2256 2.2.5. 1,3-Dipolar Cycloadditions 2256 2.2.6. Other Cycloaddition Reactions 2258 2.2.7. Prins-type Cyclization 2259 2.3. Friedel−Crafts Acylation and Al...

2,4,6-triisopropylstryrene was synthesized in a single step via the witting reaction from the corresponding aldehyde. the reaction of three styrene's derivatives, 2,6-dimethylstyrene, 2,4,6-trimethylstyrene, and 2,4,6- triisopropylstyrene with 4-methyl-l,2,4-triazoline-3,5-dion(m etd) was investigated. these reactions are instantaneous at room temperature and lead to the formation of 2: 1 ...

as they were being used (see, for example, Bowie, 1955; Howie and Timbury, 1956; Scott, 1957; Magee and Oakes, 1958; Nuffield Trust Report, 1958; Medical Research Council Report, 1959; and Wells and Whitwell, 1960). From the same work and that of others (see Bowie, 1958a and b; Alder and Gillespie, 1957; Knox and Penikett, 1958; Penikett, Rowe, and Robson, 1958; Rice, 1958; 1960; Medical Resear...