Electron-transfer-induced reductive dealkoxylation of alkyl aryl ethers. III. Reductive cleavage of methoxy-substituted <i>N</i>,<i>N</i>-dimethylanilines (<i>N</i>,<i>N</i>-dimethylanisidines)

The reactivity of the three isomeric methoxy-substituted N,N-dimethylanilines (N,N-dimethylanisidines) and of N,N-dimethyl-2,6-dimethoxyaniline in the reduction with alkali metals in aprotic solvents was investigated. N,N-Dimethyl-p-methoxyaniline was found to be unreactive, while the other substrates underwent exclusive cleavage of carbon-oxygen bond(s), with the following order of reactivity: 2,6-dimethoxy > o-methoxy > m-methoxy > p-methoxy. Both the relative reactivity and the regioselectivity of cleavage (demethoxylation vs. demethylation) was found to parallel closely that of the corresponding di- and trimethoxysubstituted substrates. These results suggest that intermediates with different electron distribution or even different intermediates are involved in the reductive cleavage of aryl-oxygen and arylnitrogen bonds

Structural elaboration of the surprising ortho-zincation of benzyl methyl ether

Breaking with convention, the reaction of the sodium zincate, [(TMEDA)Na(μ-TMP)(μ-tBu)Zn(tBu)] with benzyl methyl ether (PhCH2OMe) produces exclusively an ortho-zincated intermediate [(TMEDA)Na(μ-TMP)(μ-C6H4CH2OMe)Zn(tBu)] instead of the expected 'thermodynamic' α-metallated product

Active-alkali metal promoted reductive desulfurization of dibenzothiophene and its hindered analogues

Reductive desulfurisation of organic compounds is of importance both in organic synthesis and in industry. Benzo- and dibenzothiophenes are between the most abundant sulphur containing impurities in crude oils, and their desulfurization is a mandatory issue in the production of non polluting fuels. Following our interest in the development of efficient alkali metal-mediated synthetic procedures and alternative protocols for the chemical transformation of widespread environmental contaminants we wish to report here on the effectiveness of sodium and lithium metals, in the presence of catalytic amounts of tetraphenylethylene (TPE), in promoting the reductive desulfurization of dibenzothiophene, as well as of the corresponding sulfone and sulfoxide

Active-alkali metal promoted reductive desulfurization of dibenzothiophene and its hindered analogues

Reductive desulfurisation of organic compounds is of importance both in organic synthesis and in industry. Benzo- and dibenzothiophenes are between the most abundant sulphur containing impurities in crude oils, and their desulfurization is a mandatory issue in the production of non polluting fuels. Following our interest in the development of efficient alkali metal-mediated synthetic procedures and alternative protocols for the chemical transformation of widespread environmental contaminants we wish to report here on the effectiveness of sodium and lithium metals, in the presence of catalytic amounts of tetraphenylethylene (TPE), in promoting the reductive desulfurization of dibenzothiophene, as well as of the corresponding sulfone and sulfoxide

Principi di identificazione del paesaggio "storico": l'esempio degli oliveti periurbani della Sardegna nord-occidentale

The author highlights the importance of stating a few new tracks to identify “historical” landscapes; these new principles, though not yet a methodical approach, begin to show how the characters of land differing throughout the ages could be investigated analytically. So, the aim is not, or not only, scientific reconstruction of one or more historical phases of a context - which is actually a land and urban archaeology task - but analytical enquiring into anything we all perceive and enjoy today, or suffer when precluded, altered, wiped out: the historical peculiarities of a territory. It fits exactly to the subject the example of the “urban olive tree forest” of north-west Sardinia, though dealt with from an unusual point of view; it’s about typically historical places - a definition full of evocative force - which actually form a context heavy with aesthetic, economic, cultural and, as for peoples, quite affective values. A context which shows emblematic even in a negative sense: due to a destiny marked by the sneaky corrosion of “visual mess” (the landscape eclipse) caused by sudden overwhelming of sprawl and the obviously following thoughtless infrastructural network

Green and convenient arene-catalized reductive lithiation of heterocyclic compounds

In the last decades reductive lithiation established itself as a particularly powerful procedure for the generation of functionalized organometals. In addition, the enormous role of this reaction in the reductive ring opening and functionalization of heterocycles has been reported. Accordingly, critical experiments were performed for the generation of lithium radical anions of several PAHs and a diene in both solvents, under both CA and SA protocols. Almost all of the above mentioned hydrocarbons rapidly generate radical anions with different fascinating visible colors at 0 °C. Based on this, influence of different electron shuttles and their efficiency in the reductive lithiation of N-phenylaziridine, phthalan will be disclosed. Moreover, we will report an interesting example of chemoselectivity concerning to the reductive lithiation of 4-chlorobenzyl methyl ether in a green solvent

The future (?) of effective protection

This paper aims at a comparative reading of some archaeological remains in the island of Sardinia, starting from a reflection on the UNESCO discipline, which introduces a hierarchy of cultural heritage based on the level of worthiness of protection and provides enhanced protection for the goods that are on its list. The main goal of the study is to investigate in parallel the application of this ‘selective appreciation’ on the actual context of the protection of the so-called ‘real cultural heritage’ (article 9 of the Italian Constitution). The study proceeds by comparing some important sites on the island having similar contextualization, but different strategies for protection: the Archaeological Park of Porto Torres, Su Nuraxi in Barumini, registered since 1997 in the World Heritage List of UNESCO, and the archaeological area of Neapolis (Oristano). From comparisons and analysis carried out in selected areas it was possible to focus attention on some critical aspects of the UNESCO rules and on contradictions between the operational guidelines and the objectives that the organization provides for the protection of property. In the wake of new reforms for the reorganization of the Ministry of Heritage, Culture and Tourism, the critical issues discussed in this paper appear even more evident in Sardinia. The idea of a ‘protection of the exceptional’ appears to reduce the opportunities of intervention, by isolating the evidence from its context and making the action of protection inadequate for the territory and for the same items contained therein

The future (?) of effective protection

This paper aims at a comparative reading of some archaeological remains in the island of Sardinia, starting from a reflection on the UNESCO discipline, which introduces a hierarchy of cultural heritage based on the level of worthiness of protection and provides enhanced protection for the goods that are on its list. The main goal of the study is to investigate in parallel the application of this ‘selective appreciation’ on the actual context of the protection of the so-called ‘real cultural heritage’ (article 9 of the Italian Constitution). The study proceeds by comparing some important sites on the island having similar contextualization, but different strategies for protection: the Archaeological Park of Porto Torres, Su Nuraxi in Barumini, registered since 1997 in the World Heritage List of UNESCO, and the archaeological area of Neapolis (Oristano). From comparisons and analysis carried out in selected areas it was possible to focus attention on some critical aspects of the UNESCO rules and on contradictions between the operational guidelines and the objectives that the organization provides for the protection of property. In the wake of new reforms for the reorganization of the Ministry of Heritage, Culture and Tourism, the critical issues discussed in this paper appear even more evident in Sardinia. The idea of a ‘protection of the exceptional’ appears to reduce the opportunities of intervention, by isolating the evidence from its context and making the action of protection inadequate for the territory and for the same items contained therein

Coltura <i>in vitro</i> di apici vegetativi di <i>Quercus suber</i> L

The agamic propagation of Quercus suber L. could be useful for the genetic improvement of the species and could have noticeable advantages in forest nursery practices. For this purpose we have tried some experiments of in vitro cultures of tips obtained from vigorous new shoots collected from a cork-oak grove which had been affected by fire. The developmental stage ended with the sprouting of 25% of the tips. The two following subcultures showed an average rate of multiplication of 3.6:1. The 82.5% of the shoots that had been cultured gave off roots, but produced very small plants due to the poor growth of the shoots during the previous elongation stage

Stato di crisi e ricorsi alla delegazione legislativa: l’esperienza delle legislature XVI e XVII

The paper focuses on some of the constitutional issues raised by the action of the Government during the sixteenth and seventeenth legislature, in Italy, in the context of the international economic crisis. The economic crisis has become one of the legal order. In fact, to react to the crisis, the Government uses delegated legislation as a own instrument, reducing parliamentary powers. Therefore the delegated legislation has become an instrument for implementing the Government program, and to achieve important institutional reforms. The role of the Parliament in the legislative procedure has been reduced, and, ultimately, the constitutional system of checks and balances has been altered