A. Ramesha Baba

Nickel-Catalyzed Formic Acid Reductions. A Selective Method for the Reduction of Nitro Compounds

Abstract Aliphatic and aromatic nitro compounds were selectively reduced to their corresponding amino derivatives in good yields using formic acid and raney nickel. This system is found to be compatible with several sensitive functionalities such as halogens, -OH, -OCH3, -CHO, -COCH3, -COC6H5, -COOH, -COOC2H5, -CONH2, -CN, -CH=CH-COOH, -NHCOCH3. The reduction can be carrid out not only with HCOOH but also with HCOONH4.

Utilization of 3-ethyl-1(N,N-dimethyl)aminopropylcarbodiimide (EDCI)/1-hydroxybenzotriazole (HOBt) as a polymerizing agent

The commonly used coupling reagents in peptide synthesessuch as dicyclohexylcabodiimide, diisopropylcarbodiimide and3-ethyl-1(N,N-dimethyl)aminopropylcarbodiimide with or without1-hydroxybenzotriazole or N-hydroxysuccinimide have been used as polymerizing agents in the synthesis of elastic/plastic protein-based polymers. It was found that 3-ethyl-1(N,N-dimethyl)aminopropylcarbodiimide with 1-hydroxybenzotriazole gave equally good polymers comparable toconventional p-nitrophenol approach. Further, we present here the polymerization and characterization of structural andfunctional properties of poly(Val-Pro-Gly-Val-Gly), which is themost striking repeating sequence in the bovine and porcine elastins. The polymers obtained by both p-nitrophenol and 3-ethyl-1(N,N-dimethyl)aminopropylcarbodiimide approach werecharacterized by carbon-13 and proton nuclear magnetic resonancespectroscopy, differential scanning calorimetry, circular dichroism and fourier transform infrared spectroscopy. These results conclude that poly(Val-Pro-Gly-Val-Gly) obtained by bothmethods were identical in all respects of physical and chemicalproperties indicates that 3-ethyl-1(N,N-dimethyl)aminopropylcarbodiimide with 1-hydroxybenzotriazole method can be conveniently employed to synthesize these polymers.

Synthesis of indolones and quinolones by reductive cyclisation of o-nitroaryl acids using zinc dust and ammonium formate

A novel protocol for the synthesis of indolone and quinolone derivatives from o-nitroaryl acids was developed using Zn and HCO2NH4 under supercritical fluid carbon dioxide (scCO2) medium. The process involves the reduction of the nitro group to an amino group followed by in situ cyclisation.

Simple and efficient reduction of azides to amines using recyclable polymer-supported formate and zinc

Polymer supported formate in conjunction with commercial zinc dust provides a mild and efficient procedure for the reduction of organic azides to corresponding amines. A variety of alkyl and aryl azides were selectively reduced in high yield and purity at room temperature.

Elastic Protein-Based Polymers a Step Towards Plasticity: Thermal Stability of Glu-Containing Co-Polypeptides as Analyzed by Differential Scanning Calorimetry

Plastic protein-based polymers with the same conformational potential, but with different degree of thermal stability have been synthesized and thermally characterized by differential scanning calorimetry to provide the conception of behavior of thermoplasticity. Dramatic increase in the temperature between melting and decomposition transitions has been observed, upon inclusion of glutamic acid residue into the hydrophobic sequence of FVGVP. Glu-containing co-polymers of IVGVP showed a markedly different behavior by exhibiting exothermic crystallization transition before melting shows the typical thermoplasticity. Secondary structure in trifluoroethanol for all the polymers show, a well behaved α-helix as evident from the circular dichroism studies, in association with a significant amount of random structure contributes to extended stability.