83 research outputs found
Regio- and Stereodivergent Allylic Reductions of Bicyclic Piperidine Enecarbamate Derivatives
The
particular nature of tetrahydropyrido[4,3-e]-1,4,2-dioxazines of type 1 allows the regio-
and stereoselective obtainment of substituted N-carbamoyl
tetrahydropyridines by common reducing agents. A completely
novel, biologically active, bicyclic 1,3-diaza-4-oxa-[3.3.1]-nonene
scaffold can be generated by the use of lithium triethylborohydride
through unprecedented cascade syn-SN2′
reduction/carbamate reduction/cyclization reactions. The remarkable
regioselectivity switches in the allylic reduction process have been
rationalized with the aid of computational studies
Catalytic Enantioselective Annulations via 1,4-Addition−Aldol Cyclization of Functionalized Organozinc Reagents
Copper Phosphoramidite Catalyzed Enantioselective Ring-Opening of Oxabicyclic Alkenes: Remarkable Reversal of Stereocontrol
Copper-Catalyzed Ring-Opening Reactions of Alkyl Aziridines with B2pin2: Experimental and Computational Studies
The possibility to form new C–B bonds with aziridines using diboron derivatives continues to be a particularly challenging field in view of the direct preparation of functionalized β-aminoboronates, which are important compounds in drug discovery, being a bioisostere of β-aminoacids. We now report experimental and computational data that allows the individuation of the structural requisites and of reaction conditions necessary to open alkyl aziridines using bis(pinacolate)diboron (B2pin2) in a regioselective nucleophilic addition reaction under copper catalysis
New Coumarin Dipicolinate Europium Complexes with a Rich Chemical Speciation and Tunable Luminescence
Europium (III) luminescent chelates possess intrinsic photophysical properties that are
extremely useful in a wide range of applications. The lack of examples of coumarin‐based lantha‐
nide complexes is mainly due to poor photo‐sensitization attempts. However, with the appeal of
using such a versatile scaffold as antenna, especially in the development of responsive molecular
probes, it is worth the effort to research new structural motifs. In this work, we present a series of
two new tris coumarin‐dipicolinate europium (III) complexes, specifically tailored to be either a
mono or a dual emitter, tuning their properties with a simple chemical modification. We also en‐
countered a rich chemical speciation in solution, studied in detail by means of paramagnetic NMR
and emission spectroscopy
New 1,3-Disubstituted Benzo[h]Isoquinoline Cyclen-Based Ligand Platform: Synthesis, Eu3+ Multiphoton Sensitization and Imaging Applications
The development of lanthanide-based luminescent probes with a long emission lifetime has the potential to revolutionize imaging-based diagnostic techniques. By a rational design strategy taking advantage of computational predictions, a novel, water-soluble Eu3+ complex from a cyclen-based ligand bearing 1,3-disubstituted benzo[h]isoquinoline arms was realized. The ligand has been obtained overcoming the lack of reactivity of position 3 of the isoquinoline moiety. Notably, steric hindrance of the heteroaromatic chromophore allowed selective and stoichiometry-controlled insertion of two or three antennas on the cyclen platform without any protection strategy. The complex bears a fourth heptanoic arm for easy conjugation to biomolecules. This new chromophore allowed the sensitization of the metal center either with one or two photons excitation. The suitability as a luminescent bioprobe was validated by imaging BMI1 oncomarker in lung carcinoma cells following an established immunofluorescence approach. The use of a conventional epifluorescence microscope equipped with a linear structured illumination module disclosed a simple and inexpensive way to image confocally Ln-bioprobes by single photon excitation in the 350–400 nm window, where ordinary confocal systems have no excitation sources
1,3-DIAZO-4-OXA-[3.3.1]-BICYCLIC DERIVATIVES,PROCESS FOR THEIR MANUFACTURE AND THEIR USE AS A MEDICAMENT, IN PARTICULAR FOR TREATING DIABETES
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