Inter- and intramolecular Mitsunobu reaction and metal complexation study: synthesis of S-amino acids derived chiral 1,2,3,4-tetrahydroquinoxaline, benzo-annulated [9]-N3 peraza, [12]-N4 peraza-macrocycles.
Substituted 1,2,3,4-tetrahydroquinoxaline, benzo-annulated unsymmetrical chiral [9]-N(3) peraza, and [12]-N(4) peraza-macrocycles have been synthesized employing an inter- and intramolecular Mitsunobu reaction from an amino acid derived common synthetic intermediate 3. The metal complexation study of these macrocycles has been investigated by UV-visible spectroscopic technique with binding constant (K(b)) value 1.84 × 10(3) dm(3) mol(-1) using the Benesi-Hildebrand equation and a Gibbs free energy (ΔG) -19.4 kJ mol(-1) at 35 °C for 14d with Co(2+). The binding properties of the metal were dependent on the structure of polyaza-macrocycles that were confirmed by the DFT optimized structure of two macrocycles. A detailed investigaton of UV-visible spectra of macrocycles and their complete interpretation with the help of TD-DFT along with the frontier molecular orbital calculations are presented.
Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, 226001 UP, India.
Krishnananda
K
Samanta
Nitin
N
Srivastava
Satyen
S
Saha
Gautam
G
Panda
D000596:Amino Acids / Q000737:chemistry*; D001372:Aza Compounds / Q000138:chemical synthesis*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011810:Quinoxalines / Q000138:chemical synthesis*; D013237:Stereoisomerism
D000596:Amino Acids; D001372:Aza Compounds; D047028:Macrocyclic Compounds; D008670:Metals; D011810:Quinoxalines