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The development of green protocols for amide bond formation is a major socioeconomic goal for chemical and pharmaceutical industries and an important challenge for academic research. We herein report a protocol for the quantitative conversion of carboxylic acids and amines to form amides at 100 °C in the presence of a TiO2powder catalyst, under monomodal microwave irradiation. The sustainability of the process appears to be augmented by the ease with which the catalyst is recycled.

Besides the well-known role of ultrasound in initiation and acceleration of radical reactions, this low-energy acoustic field has recently become a valuable tool for physico-chemical investigations of solvation phenomena in homogeneous ionic reactions in aqueous and aqueous-organic solutions. In this mini-review we summarize these experimental data, showing that the application of classical quantitative methods, such as reaction kinetics and correlation analysis, if combined with sonication of the reaction medium, can reveal subtle hydrophobic interactions that remain hidden in the conventional experiments. Correlation of kinetic sonication effects with substrate hydrophobicity has revealed that independent of the reaction mechanism the decrease in reaction rate with the increasing content of different hydrophobic co-solvents can be explained by the reaction ground-state stabilization, which is largely of hydrophobic origin. When ultrasound suppresses this hydrophobic stabilization of reagents, it accelerates the reaction. On the contrary, if sonication perturbs the stabilization of encounter complexes between reagents, it hinders the reaction. Many of the conclusions reviewed in this article make a contribution to the chemistry of solutions and physical organic chemistry.

The estrogenic activity of a series of analogues of the daucane ester ferutinin (1a) modified at the acyl moiety was investigated in a yeast screen containing the human estrogen receptor α. Rather strict structure−activity relationships were observed. Thus, while the parent polyol (jaeschkeanadiol, 2a) was inactive, the presence of a p-hydroxybenzoyl moiety was necessary for activity in the yeast screen. Homologation and vinylation were both detrimental for activity, as were methylation of the p-hydroxyl substituent and the introduction of oxygen functions on the adjacent carbons.

A regioselective synthesis of 5-methyl- and 5-ethyl-4-hydroxycoumarin (1b and 1c, respectively) is described. Starting from these compounds, several prenylated polyketide coumarins of limited availability from natural sources and important taxonomic relevance were prepared.

A short and practical process for the isolation of ingenol (1a) from an agricultural commodity (the seeds of Euphorbia lathyris) is described. Macrocyclic diterpene esters are obtained as byproducts, and the esterification pattern of the Euphorbia factors L2 (3), L3 (4a), and L8 (4b) was established by 2D NMR measurements. Full spectroscopic data for these compounds are reported.

The dianion of ethyl 3-(2-hydroxyphenyl)-3-oxopropanoate can be regioselectively alkylated with isoprenyl bromides to give, after hydrolytic work-up, the corresponding 3-substituted-4-hydroxycoumarins.

A number of phorboid 20-homovanillates were prepared by condensation of phorbol 12,13-diesters and 12-dehydrophorbol 13-esters with Mem-homovanillic acid followed by removal of the protecting group with SnCl4 in THF. These compounds were evaluated for their ability to inhibit [³H]resiniferatoxin (RTX) binding to rat spinal cord membranes. Compounds bearing a lipophilic ester group on ring C were considerably active, but a surprising tolerance of the vanilloid receptor toward the location and the orientation of this ester group was disclosed. Unexpectedly, these ligands could also diminish, to a variable degree, the positive cooperativity which characterizes RTX binding to the vanilloid receptor. Phorbol 12-phenylacetate 13-acetate 20-homovanillate (PPAHV, 6a), a compound which abolished binding cooperativity, was further tested in a variety of in vivo assays used to characterize vanilloid-like activity. PPAHV showed only a marginal pungency and failed to induce a measurable hypothermia response at doses (up to 200 mg/kg) at which it effectively desensitized against neurogenic inflammation. These data suggest that the peculiar binding behavior of these ligands might be associated with a distinct spectrum of biological activity.

The roots of the nonpoisonous chemotype of giant fennel (Ferula communis) from Sardinia afforded a novel cadinanetriol (1), whose structure was established by spectroscopic data and confirmed by synthesis from the E,E-Δ ^1(10),5 germacradiene allohedycariol. A number of known compounds were also identified. Despite the lack of morphological differences, a broad chemical diversity exists within giant fennel, underlying the contrasting data on its poisonous properties.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

In order to avoid bis‐alkylation of (I), a 4:1 molar excess of enolate vs.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.