A highly efficient and mild protocol for the aminocarbonylation of a nucleoside is developed by employing palladium/(1,3,5-triaza-7-phosphaadamantan-1-ium-1-yl)butane-1-sulfonate (Pd/PTABS) as the catalytic system. The developed aminocarbonylation methodology employs CO gas at a relatively low temperature of 60 °C and is suitable for a wide range of amines, including (heteroaryl)benzylic, aliphatic acyclic, alicyclic and secondary amines. This protocol is also utilized for the synthesis of a sangivamycin precursor by carrying out the Pd-catalyzed amination and aminocarbonylation simultaneously. The utility of this protocol is further demonstrated by the synthesis of the drugs moclobemide and nikethamide.

The osmotic coefficient measurements for binary aqueous solutions of 2,2,2-cryptand (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8] hexacosane) in the concentration range of ~0.009 to ~0.24 mol·kg(-1) and in ternary aqueous solutions containing a fixed concentration of 2,2,2-cryptand of ~0.1 mol·kg(-1) with varying concentration of KBr (~0.06 to ~0.16 mol·kg(-1)) have been reported at 298.15 K. The diamine gets hydrolyzed in aqueous solutions and needs proper approach to obtain meaningful thermodynamic properties. The measured osmotic coefficient values are corrected for hydrolysis and are used to determine the solvent activity and mean ionic activity coefficients of solute as a function of concentration. Strong ion-pair formation is observed, and the ion-pair dissociation constant for the species [CrptH](+)[OH(-)] is reported. The excess and mixing thermodynamic properties (Gibbs free energy, enthalpy, and entropy changes) have been obtained using the activity data from this study and the heat data reported in the literature. Further, the data are utilized to compute the partial molal entropies of solvent and solute at finite as well as infinite dilution of 2,2,2-cryptand in water. The concentration dependent non-linear enthalpy-entropy compensation effect has been observed for the studied system, and the compensation temperature along with entropic parameter are reported. Using solute activity coefficient data in ternary solutions, the transfer Gibbs free energies for transfer of the cryptand from water to aqueous KBr as well as transfer of KBr from water to aqueous cryptand were obtained and utilized to obtain the salting constant (ks) and thermodynamic equilibrium constant (log K) values for the complex (2,2,2-cryptand:K(+)) at 298.15 K. The value of log K = 5.8 ± 0.1 obtained in this work is found to be in good agreement with that reported by Lehn and Sauvage. The standard molar entropy for complexation is also estimated for the 2,2,2-cryptand-KBr complex in aqueous medium.

Review covering the synthesis of 5- and 6-membered as well as condensed heteroarenes, focussing on the combinations in cooperative catalytic systems in strategies used to achieve selectivity and also highlights the mode of action for the cooperative catalysis leading to the synthesis of commercially and biologically relevant heteroarenes.

Herein, we reported our studies related to structural elucidation and gas-phase fragmentation patterns of the imidazolium and pyridinium based ionic liquids, using a positive ion electrospray ionization triple quadrupole mass spectrometry. Ionic liquids mainly imidazolium/ pyridinium/alkylammonium salts, possess properties due to which there are many applications from the point of view of green chemistry. The recorded mass spectral patterns are presented and possible pathways for fragmentations are suggested. The mass spectrum of tetrabutylammonium bromide and its fragmentation pattern is discussed since we used this compound as a template in the synthesis of ionic liquids. Our analysis also suggests possibilities of associations of ions in the form of C2A + species in vapour phase for the studied ionic liquids.

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