Synthesis of Symmetrical Bis-(2-chloro-1,3,2-benzodiazaphosphorinones) Hydrolysis and Fluorination of Selected Compounds

The series of symmetrical bis-amides 3 was formed by the reaction of N-methylisatoic anhydride ( 1 ), with the diamines 2 . Reaction of 3 with phosphorus trichloride led to the formation of the symmetrical bis-(1,3,2-benzodiazaphosphorinones) ( 4 ). 4 c , 4 d and 4 e were easily hydrolyzed in moist air, leading to the formation of 5 c , 5 d and 5 e . In the presence of triethylamine, 4 c , 4 d and 4 e were allowed to react with Et₃N · 3 HF to give the symmetrical bis-P–F derivatives 6 c , 6 d and 6 e , which could be readily oxidized by (NH₂)₂C(:O) · H₂O₂, leading to the formation of a series of P(:O)F compounds 7 c , 7 d and 7 e . All compounds were characterized unambiguously by ¹H, ¹³C, ¹⁹F, and ³¹P-NMR-spectroscopy, mass spectrometry, and elemental analysis. All the bis-amides and bis-(1,3,2-benzodiazaphosphorinones), except 4 b and 4 f , exist as single conformers in common solvents such as toluene, diethyl ether, dichloromethane or chloroform. For compound 6 c , a single crystal X-ray structure analysis was conducted. The molecule displays crystallographic inversion symmetry.