Solvatochromic absorption and fluorescence studies of adenine, thymine and uracil thio-derived acyclonucleosides

Adenine, thymine and uracil thio-derived acyclonucleosides were synthesized and characterized by UV-Vis, FT-IR, 1H and 13C NMR spectroscopic techniques. The photophysical properties of the derivatives were evaluated in solvents with diverse polarities and at various pH values. The solvent dependent absorbance and emission spectral shifts were analysed using physical parameters of the selected solvents. The regression and correlation coefficients were calculated using multiple regression techniques. The fitting coefficients gave an estimate of the contribution of each interaction to the total spectral shift in various solutions. Multiple linear regression studies, Kamlet-Taft equation and stokes shift correlation with orientation polarizability provide valuable information concerning spectroscopic characteristics of the studied molecules

Sustained and controlled release of daunomycin from cross-linked poly(aldehyde guluronate) hydrogels

We have incorporated daunomycin, an antineoplastic agent, into a biodegradable hydrogel through a labile covalent bond. In brief, sodium alginate was chemically broken down to low molecular weight and followed by oxidation to prepare poly(aldehyde guluronate). Adipic dihydrazide was used to incorporate the drug into the polymer backbone and cross-link the polymer to form hydrogels. Daunomycin can be released from the hydrogel after the hydrolysis of the covalent linkage between the drug and the polymer. A wide range of release profiles of daunomycin (e.g., from 2 days to 6 weeks) has been achieved using these materials, and the biological activity of the released daunomycin was maintained. © 2000 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 89: 910–919, 2000Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34502/1/8_ftp.pd

Facile Preparation of the Tosylhydrazone Derivatives of a Series of Racemic trans-3,4-Substituted Cyclopentanones

We report the synthesis and characterization of a variety of trans-3,4-substituted cyclopentanones and the corresponding tosylhydrazone derivatives starting with diethyl fumarate. Protection of the keto group followed by selective monohydrolysis of esters was achieved, resulting in cyclopentanones with different substituents at positions 3 and 4. The tosylhydrazone derivative of each cyclopentanone intermediate was prepared in moderate to good yields. These compounds are potential precursors for functionalized methanofullerenes

Synthesis of Novel Fluorinated Benzofurans and Dihydrobenzofurans

International audienceStarting from easily accessible propargylic fluorides an intramolecular oxa-Michael addition affords, in good yields, new gem-difluorodihydrobenzofurans bearing an electrophilic double bond in position 2. On these intermediates nucleophilic additions and Diels-Alder reactions have been performed affording functionalized fluorinated dihydrobenzofurans. On the other hand, Pd-catalyzed defluorinations give the corresponding fluorine containing benzofurans

Preparation and biological evaluation of novel acylhydrazide derivatives of 2,3-dichloronaphthoquinone

International audienc

Active scaffolds for on-demand drug and cell delivery

Porous biomaterials have been widely used as scaffolds in tissue engineering and cell-based therapies. The release of biological agents from conventional porous scaffolds is typically governed by molecular diffusion, material degradation, and cell migration, which do not allow for dynamic external regulation. We present a new active porous scaffold that can be remotely controlled by a magnetic field to deliver various biological agents on demand. The active porous scaffold, in the form of a macroporous ferrogel, gives a large deformation and volume change of over 70% under a moderate magnetic field. The deformation and volume variation allows a new mechanism to trigger and enhance the release of various drugs including mitoxantrone, plasmid DNA, and a chemokine from the scaffold. The porous scaffold can also act as a depot of various cells, whose release can be controlled by external magnetic fields.Harvard University. Materials Research Science and Engineering CenterNational Institutes of Health (U.S.)National Institute of Dental and Craniofacial Research (U.S.) (Research Grant R01 DE019917)Harvard University. BASF Advanced Research InitiativeUnited States. Defense Advanced Research Projects Agency (W911NF-10-0113)Pratt School of Engineering (Duke University