Synthesis of Atropisomeric\nQuinazolin-4-one Derivatives\nBased on Remote H/D and <sup>12</sup>C/<sup>13</sup>C Discrimination

Both enantiomers of 2-ethylquinazolin-4-ones bearing <i>ortho</i>-CH<sub>3</sub>O/CD<sub>3</sub>O and CH<sub>3</sub>O/<sup>13</sup>CH<sub>3</sub>O phenyl groups at the N3 position were\nprepared. These\nare isotopic atropisomeric compounds based on a remote and conformationally\nflexible H/D and <sup>12</sup>C/<sup>13</sup>C discrimination, and\nit was found that a CHCl<sub>3</sub> solution of <i>ortho</i>-CH<sub>3</sub>O/CD<sub>3</sub>O derivative shows a slight specific\noptical rotation. Furthermore, diastereomeric quinazolinone derivatives\nbearing a chiral carbon were prepared, and their stereochemical purities\nand rotational stability as well as the isotopic atropisomerism were\nverified by <sup>1</sup>H NMR and chiral high-performance liquid chromatography\n(HPLC) analyses.