ABSTRACT
With N-Boc-protected 4-(allylaminomethyl)-2(5H)furanones as starting materials, a photochemical approach is presented to give 3,9-diazatricyclo[5.3.0.0(1,5)]decanes as conformationally restricted bis-pyrrolidines. The products are orthogonally protected at the two nitrogen atoms and exhibit, depending on the substitution pattern at positions C5, C6, and C7, latent C2 symmetry. When the furanones had a phenyl group at the 3-position (X(3)), alternative photochemical pathways were observed.
Subject(s)
4-Butyrolactone/chemistry , Polycyclic Compounds/chemistry , Polycyclic Compounds/chemical synthesis , Cycloaddition Reaction , Molecular Structure , Photochemistry , Pyrrolidines/chemistry , StereoisomerismABSTRACT
Intramolecular [2+2] photocycloaddition reactions of diversely substituted N-Boc protected 4-(allylaminomethyl)-2(5H)-furanones resulted in rigid products (53-75%) with three spatially defined positions for further functionalisation.
Subject(s)
Pyrrolidines/chemistry , Amines/chemistry , Azabicyclo Compounds/chemistry , Cycloaddition Reaction , Furans/chemistry , Heptanes/chemistry , Photochemical Processes , StereoisomerismABSTRACT
The behavior of water confined near nonpolar surfaces has important implications for a number of biological phenomena. In this type of confined environment the properties of "hydrophobicity" and "hydrophilicity" are closely related to the structure of the interfacial water, which in turn can depend on temperature in a very subtle way. Although the physical-chemical consequences of this fact have been theoretically addressed to a great extent, the underlying thermodynamic question is still widely discussed. Accordingly we performed thermogravimetric analysis and variable-temperature powder X-ray diffraction studies on representative hydrogen bonding organic pores occupied by water. The results indicate that a hydrophilic-to-hydrophobic transition of the inner surface of the pores occurs upon increasing temperature, which may be attributed to a strong influence of the dynamics and thermodynamics of local water molecules on the surface affinity of the pores. The relevance of our findings to the understanding of the phenomenon of water transport in natural pores is discussed.
Subject(s)
Organic Chemicals/chemistry , Water/chemistry , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Models, Chemical , Porosity , Temperature , Thermodynamics , X-Ray DiffractionABSTRACT
Banana pulps at any ripening stage can be completely dissolved in solvent systems based on the ionic liquid (IL) 1-n-butyl-3-methylimidazolium chloride ([C4mim]Cl), and variations in the carbohydrate composition of the fruit analyzed directly on the resulting solutions using high-resolution 13C NMR spectroscopy.
