One‐Step Synthesis of Lumazine and Xanthine: First Co‐Crystal of Lumazine and Perchloric Acid with a Unique Monohydrated Hydronium Ion (H₅O₂⁺) Mediated Supramolecular Assembly of the Lumazine Dimer

Abstract

A perchloric acid mediated one-step synthesis of lumazine derivatives from pterins and xanthine from guanine is reported. However, 2-pivaloylamino derivatives of pterins underwent simple hydrolysis of the pivaloylamino group generating free pterin compounds, but the 2-oxo derivatives, that is, the lumazine compounds, were not obtained. A novel supramolecular assembly is constructed by the unique hydrogen bonding of H 5 O 2 + bridging two hydrogen-bonded di-

Adeninium perchlorate

“…As a nucleobase, adenine exhibits a tendency to selfassociate with the help of Watson-Crick and Hoogsteen hydrogen bonds. We have recently reported the unique hydrogen bonding participation of H 5 O 2 + bridging two hydrogen-bonded dimers of lumazine in its co-crystal with aqueous perchloric acid and the supramolecular assembly of protonated xanthine alkaloids in their perchlorate salts (Goswami et al, 2007). In the present work, we report the crystal structure of adenine perchlorate.…”

“…For general background to and applications of the title adeninium salt, see: Biradha et al (2010); Goswami et al (2007). For a closely related adeninium structure, see: Zeleň á k et al (2004).…”

Supramolecular Assembly of Protonated Xanthine Alkaloids in Their Perchlorate Salts

“…Some of us recently reported the bridging of hydrogen bonded dimers of lumazine by H 5 O 2 þ in its perchlorate salt. 22 The sp 2 nitrogen of imidazole ring has a higher affinity to react with acids due to its more basic nature in all four structures. The treatment of xanthine derivatives with 70% of HClO 4 resulted in their salts Hxt 3 ClO 4 3 2(H 2 O), 1; Htp 3 ClO 4 , 2; Htb 3 ClO 4 , 3; and Hcf 3 ClO 4 3 H 2 O, 4 (xanthine (xt), caffeine (cf), theophylline (tp), and theobromine (tb)).…”

Redox mechanism of lumazine at a glassy carbon electrode

“…The coordination chemistry of pteridine derivatives has been a subject of interest for many years, and has been studied from different perspectives [8,10,11,[13][14][15][16][17]. A large number of LMZ-metal complexes [14,17,18] has been studied to mimic the environment and reactivity of the metal site of the enzymes.…”

“…A large number of LMZ-metal complexes [14,17,18] has been studied to mimic the environment and reactivity of the metal site of the enzymes. Some of these complexes have been characterized by X-ray crystallography [18] and their biological activity evaluated [7].…”