Synthesis of mimosamycin

Mimosamycin (1) was synthesized in eight steps with an overall yield of 13% from 2-methoxy-3-methyl-1,4-benzoquinone by regioselective introduction of a chloromethyl group at C-6 and a methoxycarbonylmethyl group at C-5 and subsequent reaction of the intermediate methyl (o-(chloromethyl)phenyl)acetate derivative 16 with methylamine. Oxidation of the 5,7,8-trimethoxy-2,6-dimethyl-1, 4-dihydroisoquinoline-3(2H)-one 17 thus obtained, using cerium(IV) ammonium nitrate as a selective oxidizing agent, gave mimosamycin (1) in good overall yield.     

Synthesis of two naphthoquinone antibiotics, dehydroherbarin and 6-deoxybostrycoidin

The synthesis of two naphthoquinone antibiotics, dehydroherbarin (7) and 6-deoxybostrycoidin (5), was accomplished by reaction of 3-acetonyl-2-bromomethyl-6,8-dimethoxy-1,4-naphthoquinone (23) with either triethylamine or ammonia, respectively. This is the first report on their synthesis.     

Enhanced aromaticity of the transition structures for the diels-alder reactions of quinodimethanes: evidence from ab initio and DFT computations

The Diels-Alder reactions of various quinodimethanes with ethylene are studied by means of ab initio molecular orbital and density functional theory (DFT) to show the effect of aromaticity on the reaction path. The calculations reveal that these reactions are both kinetically and thermodynamically much more favored than the prototype butadiene-ethylene Diels-Alder reaction due to the aromatization process in the transition state (TS) and product. A progressive aromaticity gain is noticed during the reaction, and hence the partial pi-delocalized peripheral diene ring function is coupled with the six-electron sigma,pi-delocalized cyclic unit resulting in an enhanced aromaticity of the TS. The magnetic criteria such as magnetic susceptibility exaltation and nucleus independent chemical shift provide definitive evidence for and fully support the aromatization process and the aromaticity of the TS. The extent of sigma-pi delocalization and the bond make-break at the TS are consistent with each other, and this is strongly influenced by the adjacent pi-aromatization process. Moreover, the aromaticity trends in the resulting TSs and products parallel the activation and reaction energies; the extent of aromatization increases with increasing reaction rate and exothermicity. This confirms that aromaticity is the driving factor governing cycloadditions involving quinodimethanes.     

Synthesis of biaryls via intermolecular radical addition of heteroaryl and aryl bromides onto arenes

Tris(trimethylsilyl)silane (TTMSS) and azobisisobutironitrile (AIBN) promoted the easy intermolecular arylation of aryl and heteroaryl bromides under thermal conditions via a radical pathway.     

Synthesis of an orange anthrathiophene pigment isolated from a Japanese bryozoan

A short, regiospecific synthesis of the naturally occurring anthrathiophene 1 from naphthazarin (7) is described.     

Continuous variable quantum teleportation with sculptured and noisy non-Gaussian resources

We investigate continuous variable (CV) quantum teleportation using relevant classes of non-Gaussian states of the radiation field as entangled resources. First, we introduce the class two-mode squeezed symmetric superposition of Fock states, including finite truncations of twin-beam Gaussian states as special realizations. These states depend on a set of free independent parameters that can be adjusted for the optimization of teleportation protocols, with an enhancement of the success probability of teleportation both for coherent and Fock input states. We show that the optimization procedure reduces the entangled resources to truncated twin beam states, which thus represents an optimal class of non-Gaussian resources for quantum teleportation. We then introduce a further class of two-mode non-Gaussian entangled resources, in the form of squeezed cat-like states. We analyze the performance and the properties of such states when optimized for (CV) teleportation, and compare them to the optimized squeezed Bell-like states introduced in a previous work [12]. We discuss how optimal resources for teleportation are characterized by a suitable balance of entanglement content and squeezed vacuum affinity. We finally investigate the effects of thermal noise on the efficiency of quantum teleportation. To this aim, a convenient framework is to describe noisy entangled resources as linear superpositions of non-Gaussian state and thermal states. Although the presence of the thermal component strongly reduces the teleportation fidelity, noisy non-Gaussian states remain preferred resources when compared to noisy twin-beam Gaussian states.     

The Tausk Controversy on the Foundations of Quantum Mechanics: Physics, Philosophy, and Politics

In 1966 the Brazilian physicist Klaus Tausk (b. 1927) circulated a preprint from the International Centre for Theoretical Physics in Trieste, Italy, criticizing Adriana Daneri,Angelo Loinger,and Giovanni Maria Prosperi’s theory of 1962 on the measurement problem in quantum mechanics. A heated controversy ensued between two opposing camps within the orthodox interpretation of quantum theory, represented by Léon Rosenfeld and Eugene P.Wigner. The controversy went well beyond the strictly scientific issues, however, reflecting philosophical and political commitments within the context of the Cold War, the relationship between science in developed and Third World countries, the importance of social skills, and personal idiosyncrasies.