Sulla trasformazione degli integrali doppi

Sunto. Applicando nozioni già utilizzate in precedenti lavori dello stesso A. sul problema della quadratura delle superficie, si danno formule generali di trasformazione degli integrali doppi.     

A new iridoid diglycoside from Sambucus ebulus L

Abstract

The phytochemical examination of the polar constituents of Sambucus ebulus L. leaves led to the identification of patrinoside (1) and of a new diglycoside iridoid, patrinoside-aglycone-11-O-[β-D-glucopyranosyl-(1→6)-2′-deoxy-β-D-glucopyranoside] (trivially named as sambuloside) (2). Both of these structures have been assigned by spectroscopic means (NMR and MS).     

Microwave-assisted synthesis of symmetric and asymmetric viologens

Viologens are generally synthesized by N-alkylating 4,4′-bipyridine with alkyl halides. Under conventional heating conditions, however, their synthesis suffers from long reaction times and, often, low yields. In this work, symmetric and asymmetric viologens were synthesized under the assistance of microwave irradiation in good to excellent yields and in short reaction times.     

Existence theorems for abstract multidimensional control problems

In the present paper, the author discusses an abstract formulation of control problems involving general operators :S V, :S Y from a Banach spaceS into spaceV andY of vector functions in a fixed domain with components inL _p ,p1. For this general formulation, the author states closure theorems, lower closure theorems, and existence theorems for an optimal solution. It is then shown that the problems of control involving Dieudonné-Rashevski partial differential equations previously considered by the author are particular cases of the present formulation. Finally, it is shown by examples that problems of control involving usual partial differential equations, linear or not, as well as other functional relations, can be framed in the present formulation. The present work concerns problems withdistributed controls. Work concerning problems withdistributed as well as boundary controls is forthcoming.Parts of this paper were read at the International Conference of Optimal Control, Tbilisi, Georgia, USSR, 1969, and at the Conference on Optimal Control, Ann Arbor, Michigan, 1969 (Tenth Annual Meeting of the Society for Natural Philosophy). This research was partially supported by AFOSR Research Project No. 69-1662.     

On symplectic half-flat manifolds

We construct examples of symplectic half-flat manifolds on compact quotients of solvable Lie groups. We prove that the Calabi-Yau structures are not rigid in the class of symplectic half-flat structures. Moreover, we provide an example of a compact 6-dimensional symplectic half-flat manifold whose real part of the complex volume form is d-exact. Finally we discuss the 4-dimensional case. This work was supported by the Projects M.I.U.R. “Geometric Properties of Real and Complex Manifolds”, “Riemannian Metrics and Differentiable Manifolds” and by G.N.S.A.G.A. of I.N.d.A.M.     

Synthesis of natural flutimide and analogous fully substituted pyrazine-2,6-diones, endonuclease inhibitors of influenza virus

Flutimide, a fully substituted 1-hydroxy-3H-pyrazine-2,6-dione, is a fungal metabolite isolated from a new species of Delitschia cofertaspora. It has been shown to selectively inhibit cap-dependent endonuclease activity of influenza virus A. The inhibition of this activity is a target for the potential development of a therapeutic agent to treat influenza infections. A convergent total synthesis of flutimide starting from L-leucine has been described. The synthetic methodology has been extended to include the synthesis of specifically designed aromatic analogues of flutimide, some of which exhibited greater than 7-fold improvement in activity. The most potent compounds were those with p-fluorobenzylidene or p-methoxybenzylidene substitutions at C-5 of 3H-pyrazine-2,6-dione and showed IC(50) values of 0.9 and 0.8 microM, respectively. The details of the rationale for the synthetic design, syntheses, and biological activities of these analogues are described.     

Synthesis of indolizidines from dialkylated isocyanides: a novel radical cyclisation/N-alkylation/ring closing metathesis approach

Two dialkylated isocyanides were first synthesised from simple starting materials and then used as building blocks for the synthesis of indolizidines via a novel radical cyclisation/N-alkylation/ring closing metathesis strategy. Several functionalised indolizidines were accessed in good to excellent yields.