457071-60-2Relevant academic research and scientific papers
Experiment and Computational Study on the Regioselectivity of Nucleophilic Addition to Unsymmetrical p-Benzynes Derived from Bergman Cyclization of Enediynes
Das, Eshani,Basak, Shyam,Anoop, Anakuthil,Basak, Amit
, p. 7730 - 7740 (2018/06/01)
The regioselectivity in addition of nucleophiles to the p-benzyne intermediates derived from unsymmetrical aza-substituted enediynes via Bergman cyclization was studied. Computational studies [using UB3LYP/6-31G(d,p) level of theory] suggest that the p-benzyne intermediate retains its similar electrophilic character at the two radical centers even under unsymmetrical electronic perturbation, thus supporting the predicted model of nucleophilic addition to p-benzyne proposed by Perrin and co-workers (Perrin et al. J. Am. Chem. Soc. 2007, 129, 4795-4799) and later by Alabugin and co-workers (Peterson et al. Eur. J. Org. Chem. 2013, 2013, 2505-2527). However, observed experimental results suggest that there was small but definite regioselectivity (～5-25%), the extent varying with the electronic nature of the substituents. Differential solvated halide ion concentrations around the vicinity of two radical centers arising due to surrounding surface electrostatic potential (computationally calculated) may be one of the possible factors for such selectivity in some of the examined p-benzynes. However, other complicated dynamical issues like the trajectory of the attacking nucleophile to the radical center which can be influenced by electronic and/or steric perturbation of starting enediyne conformation cannot be ruled out. The overall yield of the anionic addition was in the range of 80-99%.
Design, synthesis and inhibition activity of a novel cyclic enediyne amino acid conjugates against MPtpA
Chandra, Koushik,Dutta, Debajyoti,Mitra, Analava,Das, Amit K.,Basak, Amit
experimental part, p. 3274 - 3279 (2011/06/25)
In course of studies towards the discovery of selective inhibitors of MPtpA, a novel cyclic endiyne malonamic acid has been designed and synthesized. The synthesis involves a crucial intramolecular Knoevenagel reaction. The compound displayed a reversible non-competitive inhibition against MPtpA with inhibition constant Ki of 22.5 μM. The enediyne acts as a recognition framework in inducing the inhibition and not as a reactive functional moiety. This was confirmed by comparing the inhibiting activity with that of the corresponding saturated cyclic non-enediyne analogue.
Design and synthesis of enediyne-peptide conjugates and their inhibiting activity against chymotrypsin
Dutta, Sansa,Basak, Amit,Dasgupta, Swagata
experimental part, p. 3900 - 3908 (2009/10/02)
Novel enediyne-amino acid conjugates 1-4 have been synthesized. All of these effectively target the enzyme chymotrypsin inhibiting its proteolytic activity. The conjugate with a directly linked phenyl alanine is the most effective inhibitor with a Ki
Benzene fused monocyclic enediynyl amides: Synthesis, reactivity and DNA-cleavage activity in comparison to the corresponding sulfonamides
Basak, Amit,Mandal, Subrata,Das, Amit Kumar,Bertolasi, Valerio
, p. 873 - 877 (2007/10/03)
Monocyclic enediynyl amides 2a-2c have been synthesized via the corresponding free amine 5. Kinetic studies in chloroform revealed the reactivity of these amides towards Bergman cyclization to be less than that of the corresponding sulfonamides. However, differential scanning calorimetry (DSC) measurements in the solid state and DNA-cleavage studies in aqueous buffer showed higher reactivity for the amides than the sulphonamides.
