Hisamatsu, Yosuke Shirai, Naohiro Ikeda, Shin-ichi Odashima, Kazunori A New Quadruple Hydrogen-Bonding Module Based on Five-Membered Heterocyclic Urea Structure <i>N</i>,<i>N</i>′-Di-4-triazolylurea (DTU) has developed as a new ADDA module and DTU forms a stable ADDA•DAAD heterocomplex with 2,7-diamido-1,8-naphthyridine (DAN) (<i>K</i><sub>s</sub> = 2.6 × 10<sup>5</sup> M<sup>−1</sup> in CHCl<sub>3</sub>). The <i>K</i><sub>s</sub> value of the complex between DTU and DAN is 100-fold greater than that of the complex between <i>N</i>,<i>N</i>′-di-2-pyridylurea and DAN due to replacement of a pyridine ring with a 1,2,3-triazole ring. DAN;Ks value;ADDA module;pyridine ring;DTU forms 2010-04-16
    https://acs.figshare.com/articles/journal_contribution/A_New_Quadruple_Hydrogen_Bonding_Module_Based_on_Five_Membered_Heterocyclic_Urea_Structure/2776387
10.1021/ol100385b.s002