Crystal Structure of N‐(2‐Hydroxynapthylidene)‐L‐isoleucinyl‐4,6‐O‐ethylidene‐β‐D‐glucopyranosylamine and an Insight from Experimental and Theoretical Calculations

Abstract

Dimethyl sulfoxide solution of N‐(2‐hydroxynapthylidene)‐L‐isoleucinyl‐4,6‐O‐ethylidene‐β‐D‐glucopyranosylamine (L1) affords single crystals of its ketoenamine configuration. The noncovalent intermolecular interactions present in the molecules have been explored by Hirshfeld surface analysis and 2D fingerprint plots generated using crystallographic data. The structural parameters of L1 in both the tautomeric forms (ketoenamine and phenolimine) at ground states have been optimized using Hartree–Fock and density functional theory calculations in gaseous and solution phases. The Fourier transform infrared, nuclear magnetic resonance, and UV–visible spectra of this molecule have been compared with the theoretically calculated data of both the tautomeric forms. Additionally, Mulliken population analysis, molecular electrostatic potential, and natural bond order analysis provide a better understanding of charge distribution, presence of electrophilic/nucleophilic sites, and intramolecular charge transfer, respectively, in the molecule.

Synthesis of Catalyst Using Bio‐benign Precursors and Its Application in One‐Pot Catalytic Synthesis of Imidazo[1,2‐a]pyridines

“…The protons (bold front) −HN−C H −Ar appears as a doublet (δ 9.10 ppm, J =8.3 Hz), while − H N−CH−Ar as a triplet (δ 14.25 ppm, J =7.7 Hz). The dynamic equilibrium between enolimine and ketoenamine tautomeric forms of naphthaldimine derivatives in solution has already been established [21–23] …”

“…The dynamic equilibrium between enolimine and ketoenamine tautomeric forms of naphthaldimine derivatives in solution has already been established. [21][22][23] Metal ion interaction studies using UV-visible and fluorescence spectroscopy LH 2 has been treated with acetates of Na(I), Sn(II), Mg(II), Ca(II), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ag(I), Hg(II), Pb(II) and Al(III) in methanol and the interaction has been monitored using UV-visible absorption and fluorescence spectroscopy. Free ligand exhibited three major absorption peaks in near UV to the visible region (305, 403, and 421 nm), while excitation of the molecule at 290 nm yielded emission peaks at 317, 355, and 445 nm, analogous to the previous report on naphthalene derivatives.…”

“…It is also noteworthy to mention that with the decrease in temperature longer time is required for the completion of the reaction (Table 1, entry [15][16][17][18][19][20]. Replacement of the catalytic system with 5 mol% of cupric acetate only resulted in 10.7 and 17.9 % yield after 24 and 48 hours, respectively (Table 1, entry [22][23]. No product formation was noted in the absence of a catalytic system or the presence of LH 2 (5 mol%; no copper source) (Table 1, entries 21 and 24).…”